Can MOT testing damage transfer Box?

[Dunga]

Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.

My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

[Wolverine]

Looking at my fuse box cover... it reads...
"A single axle roller rig may be used for speeds up to 5km/h. The centre
differential lock must be disengaged. For roller tests over 5km/h, either
all four wheels must be rotated at the same speed or if only a single axle
roller rig is available, the centre differential must be locked and the
propeller shaft to the stationary axle must be removed."
Was it a 4x4 specialist garage?
Hope this helps.

Wolverine
Big Red 110CSW

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying
the handbrake while on the rolling road?

[Jeff]

Post by Wolverine
"A single axle roller rig may be used for speeds up to 5km/h. The centre
differential lock must be disengaged. For roller tests over 5km/h, either
all four wheels must be rotated at the same speed or if only a single axle
roller rig is available, the centre differential must be locked and the
propeller shaft to the stationary axle must be removed."
Was it a 4x4 specialist garage?
Hope this helps.

There are similar warnings about suspended towing;

I wonder if someone could explain the damage mechanism? As I see it a
single roller, or suspended tow is not a lot different to the situation
where one pair of wheels on the same axle are spinning in mud and the others
are stationary. (without the centre diff locked). Surely this is not going
to damage things?

Regards
Jeff

[Fred Labrosse]

On Fri, 10 Jun 2005 12:39:00 +0100

Post by Jeff

Post by Wolverine
"A single axle roller rig may be used for speeds up to 5km/h. The
centre differential lock must be disengaged. For roller tests over
5km/h, either all four wheels must be rotated at the same speed or
if only a single axle roller rig is available, the centre
differential must be locked and the propeller shaft to the
stationary axle must be removed." Was it a 4x4 specialist garage?
Hope this helps.

There are similar warnings about suspended towing;
I wonder if someone could explain the damage mechanism? As I see it
a single roller, or suspended tow is not a lot different to the
situation where one pair of wheels on the same axle are spinning in
mud and the others are stationary. (without the centre diff locked).
Surely this is not going to damage things?

However, the initial question was about applying the handbrake while on
the roller. A very good question indeed when one reads the driver
manual of def's specifying that one should not apply the handbrake
before the car is stationary.

Fred

[Wolverine]

God! I forgot about that one. Did it by accident once whilst pulling into
the drive. The steering wheel still has the impression of my teeth in it!!
:)
Wolverine
Big Red 110CSW

Post by Fred Labrosse
On Fri, 10 Jun 2005 12:39:00 +0100

Post by Jeff

Post by Wolverine
"A single axle roller rig may be used for speeds up to 5km/h. The
centre differential lock must be disengaged. For roller tests over
5km/h, either all four wheels must be rotated at the same speed or
if only a single axle roller rig is available, the centre
differential must be locked and the propeller shaft to the
stationary axle must be removed." Was it a 4x4 specialist garage?
Hope this helps.

There are similar warnings about suspended towing;
I wonder if someone could explain the damage mechanism? As I see it
a single roller, or suspended tow is not a lot different to the
situation where one pair of wheels on the same axle are spinning in
mud and the others are stationary. (without the centre diff locked).
Surely this is not going to damage things?

However, the initial question was about applying the handbrake while on
the roller. A very good question indeed when one reads the driver
manual of def's specifying that one should not apply the handbrake
before the car is stationary.
Fred

[NT]

The vehicle handbrake is for holding the vehicle when parked, but it is
also an Emergency Brake.
As such, it needs to be tested to prove it is capable of bringing the
vehicle to a halt when required.

The transmission handbrake can be tested on rolling roads. There is a
procedure outlined in the MOT Inspection manual to perform this test.

Both rollers must be run together.
The handbrake must be pulled up very s-l-o-w-l-y while holding the
release trigger in.
The tester will know what readings to expect to see, and as soon as
these readings are attained, then the brake should be released.

The readings are 16% for dual circuit brakes, and 25% for single
circuit.
Using a vehicle of 2000kg as an example, this equates to:
16% = 320kgf (or 160kgf per rear wheel)
25% = 500kgf (or 250kgf per rear wheel)

[Austin Shackles]

Post by Jeff

Post by Wolverine
"A single axle roller rig may be used for speeds up to 5km/h. The centre
differential lock must be disengaged. For roller tests over 5km/h, either
all four wheels must be rotated at the same speed or if only a single axle
roller rig is available, the centre differential must be locked and the
propeller shaft to the stationary axle must be removed."
Was it a 4x4 specialist garage?
Hope this helps.

There are similar warnings about suspended towing;
I wonder if someone could explain the damage mechanism? As I see it a
single roller, or suspended tow is not a lot different to the situation
where one pair of wheels on the same axle are spinning in mud and the others
are stationary. (without the centre diff locked). Surely this is not going
to damage things?

depends. You don't spin the wheels at e.g. 40 mph for extended periods. In
other words, the speed difference across the diff is not very large and is
only maintained for a short period.

[Ian Rawlings]

Post by Austin Shackles
depends. You don't spin the wheels at e.g. 40 mph for extended periods. In
other words, the speed difference across the diff is not very large and is
only maintained for a short period.

I had to have my centre diff replaced because it had been damaged due
to excessive speed difference across it, I can't remember what the
damage is but they're certainly only designed to take a fairly limited
speed differential between the two outputs. Hence the warnings about
towing in most 4x4 vehicles, including my old Audi 90 Quattro.

[beamendsltd]

Post by Jeff

Post by Wolverine
"A single axle roller rig may be used for speeds up to 5km/h. The centre
differential lock must be disengaged. For roller tests over 5km/h, either
all four wheels must be rotated at the same speed or if only a single axle
roller rig is available, the centre differential must be locked and the
propeller shaft to the stationary axle must be removed."
Was it a 4x4 specialist garage?
Hope this helps.

There are similar warnings about suspended towing;
I wonder if someone could explain the damage mechanism? As I see it a
single roller, or suspended tow is not a lot different to the situation
where one pair of wheels on the same axle are spinning in mud and the others
are stationary. (without the centre diff locked). Surely this is not going
to damage things?
Regards
Jeff

Someone who knows how diffs *really* work once expplained to me why
the two wheels driving the diff is not the same the diff driving the
two wheels. But it was a while ago, when our 7.5 tonner needed a tow
after it broke down and the recovery block took the rear prop off,
which was apparently the correct thing to do.

Richard

[SimonJ]

Post by beamendsltd
Someone who knows how diffs *really* work once expplained to me why
the two wheels driving the diff is not the same the diff driving the
two wheels. But it was a while ago, when our 7.5 tonner needed a tow
after it broke down and the recovery block took the rear prop off,
which was apparently the correct thing to do.

That's nowt to do with the diff, removing the prop doesn't stop the wheels
driving the diff. The prop is removed to stop the gearbox being damaged (on
commercial vehicle gearboxes, there is very often an oil pump driven from
the input shaft. If you tow the vehicle with the prop connected, the gears
are spinning, but the oil pump isn't, hence oil starvation, and a buggered
gearbox.) The alternative method is to remove a halfshaft, slightly messier,
as oil escapes, but sometimes you cant get to the propshaft, for e.g. on a
tri-axle tractor unit.

[Austin Shackles]

Post by SimonJ

Post by beamendsltd
Someone who knows how diffs *really* work once expplained to me why
the two wheels driving the diff is not the same the diff driving the
two wheels. But it was a while ago, when our 7.5 tonner needed a tow
after it broke down and the recovery block took the rear prop off,
which was apparently the correct thing to do.

That's nowt to do with the diff, removing the prop doesn't stop the wheels
driving the diff. The prop is removed to stop the gearbox being damaged (on
commercial vehicle gearboxes, there is very often an oil pump driven from
the input shaft.

same's true of land rovers with LT77, R380 or auto boxes.

Post by SimonJ
If you tow the vehicle with the prop connected, the gears
are spinning, but the oil pump isn't, hence oil starvation, and a buggered
gearbox.) The alternative method is to remove a halfshaft, slightly messier,
as oil escapes, but sometimes you cant get to the propshaft, for e.g. on a
tri-axle tractor unit.

However, there is a point about the diff, too. having one set of wheels
turning and the other not for extended periods or at high speed is not what
it's intended for; the whole diff is on bloody great roller bearings,
whereas the planet gears, which while going straight ahead do nothing at all
and on normal cornering only turn slowly, are not; they are, typically, as
was said, just on a plain shaft. Spinning the diff (especially if under
power on a rolling road) with one axle stationary is working those much
harder than they should be.

As regards suspended towing, in the case of the LRs with a neutral in the
transfer box, you can put the main box in gear (P on an auto) and the
transfer box in neutral. That stops the main box from turning at all and
the only stuff that turns is the lower half of the transfer box, and since
that's old-fashioned splash-lube, it should be fine. Suspended tow on 2
wheels does run the diff as mentioned above, but it's only driving the T-box
internals and therefore not under load, and I doubt it'd be a problem for
shortish distances - for long distances, I'd pull the prop anyway, to be on
the safe side.

[Marc Draper]

Post by Austin Shackles
Suspended tow on 2
wheels does run the diff as mentioned above, but it's only driving the T-box
internals and therefore not under load, and I doubt it'd be a problem for
shortish distances - for long distances, I'd pull the prop anyway, to be on
the safe side.

Yes Austin I would pull the prop because the speeds involved are much
greater than a rolling road.

[Larry]

Why not just disengage 4WD oh forgot you can't do that in modern land rovers
can you :)
--
Larry
Series 3 rust and holes

Post by Marc Draper
Yes Austin I would pull the prop because the speeds involved are much
greater than a rolling road.
--
Marc Draper

[Marc Draper]

Post by Larry
Why not just disengage 4WD oh forgot you can't do that in modern land rovers
can you :)

No thankfully they have progressed !

[Larry]

Well that is a matter of opinion, do the doors fit any better ?
--
Larry
Series 3 rust and holes

Post by Marc Draper

Post by Larry
Why not just disengage 4WD oh forgot you can't do that in modern land rovers
can you :)

No thankfully they have progressed !
--
Marc

[Ian Rawlings]

Post by Larry
Well that is a matter of opinion, do the doors fit any better ?

Yes the series 3 doors fit just fine on a Defender! Thankfully, the
Defender doors are crap..

[Wolverine]

Really? Series doors fit Defenders? They're better than Defender doors too?
I need a few doors for my 110!
Wolverine
Big Red 110CSW

Post by Ian Rawlings

Post by Larry
Well that is a matter of opinion, do the doors fit any better ?

Yes the series 3 doors fit just fine on a Defender! Thankfully, the
Defender doors are crap..
--
For every expert, there is an equal but opposite expert

[Larry]

Second hand Series doors are hard to find because most of them are rotted to
buggery.
--
Larry
Series 3 rust and holes

Post by Wolverine
Really? Series doors fit Defenders? They're better than Defender doors too?
I need a few doors for my 110!
Wolverine
Big Red 110CSW

[Ian Rawlings]

Post by Larry
Second hand Series doors are hard to find because most of them are
rotted to buggery.

Sure but even brand new they're much cheaper than Defender doors.
Defender doors are pants, they restrict legroom and elbow room more
than series doors and they're badly designed.

[Ian Rawlings]

Post by Wolverine
Really? Series doors fit Defenders? They're better than Defender
doors too? I need a few doors for my 110!

Series doors are simpler than Defender doors and give more legroom and
elbow room, you can get them second-hand but they're hard to find and
are often in bad condition. A bad condition series door will work
though, which is more than can be said for a Defender door! The
window raise mechanism and the lock mechanism are weak on the Defender
doors.

[Dave Liquorice]

Post by Larry
Why not just disengage 4WD oh forgot you can't do that in modern
land rovers can you :)

No but you can put the transfer box into neutral so only the diff with
the wheels on the ground and half of the transfer box is turning...

I'm not up enough on how diffs work let alone throwing in a transfer
box to know if that helps at all... I must look in a toy shop as some
point to find some model diffs to play with. B-)

[Dougal]

Post by Dave Liquorice

Post by Larry
Why not just disengage 4WD oh forgot you can't do that in modern
land rovers can you :)

No but you can put the transfer box into neutral so only the diff with
the wheels on the ground and half of the transfer box is turning...

Not so! This is the difficulty alluded to in the previous message. It is
not possible with the full-time 4WD used beyond the Series models to
stop any part of the ground-driven part of the transfer box (which
includes the inter-axle differential) from rotating. You can't
disconnect the two wheels which are not on the ground.

Putting the transfer box in neutral only disconnects the transfer box
from the main gearbox.

Hence the previous suggestion that in these circumstances the propshaft
to the axle on the ground needs to be disconnected for a suspended tow
of any significant distance.

[Marc Draper]

Post by Dave Liquorice
No but you can put the transfer box into neutral so only the diff with
the wheels on the ground and half of the transfer box is turning...

Dave you are missing the point. That is exactly the problem, with
constant 4 wheel drive on a suspended tow you have all the drive going
through one half of the centre diff. This is what kills them. The rest
of the transfer box is only to happy to turn no matter what end the
power is coming from. By disconnecting the prop you can save it.

[Austin Shackles]

On or around Sat, 11 Jun 2005 18:00:02 +0100, Marc Draper

Post by Marc Draper

Post by Dave Liquorice
No but you can put the transfer box into neutral so only the diff with
the wheels on the ground and half of the transfer box is turning...

Dave you are missing the point. That is exactly the problem, with
constant 4 wheel drive on a suspended tow you have all the drive going
through one half of the centre diff. This is what kills them. The rest
of the transfer box is only to happy to turn no matter what end the
power is coming from. By disconnecting the prop you can save it.

still, with no load on it, I reckon it'd be OK for short distances. 's a
very different story to, for exmaple, running full power through one set of
wheels on a dyno.

[Dougal]

Post by Austin Shackles
On or around Sat, 11 Jun 2005 18:00:02 +0100, Marc Draper

Post by Marc Draper

Post by Dave Liquorice
No but you can put the transfer box into neutral so only the diff with
the wheels on the ground and half of the transfer box is turning...

Dave you are missing the point. That is exactly the problem, with
constant 4 wheel drive on a suspended tow you have all the drive going
through one half of the centre diff. This is what kills them. The rest
of the transfer box is only to happy to turn no matter what end the
power is coming from. By disconnecting the prop you can save it.

still, with no load on it, I reckon it'd be OK for short distances. 's a
very different story to, for example, running full power through one set of
wheels on a dyno.

Excepting your single axle dyno. (as opposed to MOT brake test) example
the two other cases that we're considering are effectively zero
torque systems where a wheel, axle or transfer box is rotating without
resistance. It's not totally free of torque as accelerating the gears
and friction will provide some torque. If there is little torque there
is little power in the system.

As someone mentioned earlier, possibly even you yourself Austin, the
killer is when the relative speed between the differential pinions and
the shafts on which they run goes beyond that for which they were
designed. Remember, too, that there is little lubrication at this
critical interface.

If we wish, we can discuss on another occasion how differential pinion
speeds can reach 'horrendous' values.

[Paul Tasker]

Hi All

My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the floorpan
and he test drives it on the road and measures inertia when braking.

Hope this helps

Paul

[Marc Draper]

Post by Paul Tasker
Hi All
My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the floorpan
and he test drives it on the road and measures inertia when braking.

28 years of MOT experience ! And no knowledge of how a Landrover gearbox
works.

That may sound a bit harsh but the internals of the disco/defender
transfer box are not magic or mystical. It is all just gears, bearings
and oil. And in the configuration used in the above vehicles it will not
be damaged by use of a brake tester.

I personally put well over 100 landrovers a year through their MOT and
all non viscous transfer boxes are pull on the brake tester. It is a
much more accurate way of assessing the safety of our brakes.

[PhilD]

Post by Marc Draper

Post by Paul Tasker
Hi All
My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the floorpan
and he test drives it on the road and measures inertia when braking.

28 years of MOT experience ! And no knowledge of how a Landrover gearbox
works.
That may sound a bit harsh but the internals of the disco/defender
transfer box are not magic or mystical. It is all just gears, bearings and
oil. And in the configuration used in the above vehicles it will not be
damaged by use of a brake tester.
I personally put well over 100 landrovers a year through their MOT and all
non viscous transfer boxes are pull on the brake tester. It is a much more
accurate way of assessing the safety of our brakes.
--

Here in NT Australia I've used the Govt test shed for all but one year of
the 26 years that I've had my 1975 RR. For about the first 10 years they had
these vehicles go through the truck bay that had 4 moveable plates that you
idled up to and slammed on the brakes. The gauge was 4 column's of fluid
that had to rise to a particular minimum level. Handbrake test was stall
engine by trying to drive off while it was engaged. They changed and
insisted that we use brake dyno, but I've never really been happy with it
but had no evidence to refute their statement that they had consulted
dealer/manufacturer. The only year I had it tested elsewhere, the idiot
"mechanic" couldn't tell the difference between a rear brake fluid leak that
he thought he saw and what turned out to be actually another leather axle
oil seal failing. Fixed it myself and then went to Govt shed, not back to
him. I have no problem telling the "diff" between the smell and feel of
each.

As to accuracy of testing safety of brakes, I disagree. Two years ago I got
mine passed while booster was faulty (actually did fail while driving
there). Brakes had pressure for just a few seconds so I braked heavily, and
as he looked at the right readings I lifted off quickly. Passed rego and
drove straight to repair shop. If they were really serious they would make
us brake a few times in quick succession to see if it remains good, but it's
not up to me to re-educate them on that.

They are a real pain on some other things though, like don't all LR products
leak oil and it's not necessarily a safety hazard. Comment not long ago was
"You did a good job cleaning up the oil" (he had tested me a few times).

The best/worst problem's I've had with the test shed were:
1. Your rear diff pinion shaft is loose (not the RR) and it might come loose
and disappear inside. Went away, thought for a short time and came back, saw
another tester who agreed that it was impossible and passed it.
2. After twelve years of passing my aircraft quality, stainless braided &
teflon lined front brake hoses they insisted that I put back standard ones,
only because they didn't have certification stamping on them. No
deterioration, visually or in performance, was evident, just following
rules.
3. Taking brother-in-law's car through. It failed but he then recognised
name as son of his past workshop foreman elsewhere. Changed to passed and
said fix it before next year.
4. Taking company 4x4 through that should have failed with list of items
they found, but said that he knew that we (the company) gets things fixed
anyway.

PhilD
(sorry for long rant)

[Marc Draper]

Post by PhilD
As to accuracy of testing safety of brakes, I disagree. Two years ago I got
mine passed while booster was faulty (actually did fail while driving
there).

In the UK the brakes are tested differently

And the owner is only allowed to watch for those very reasons.

The mot tester will check for correct operation of the servo as part of
the test.

The rolling road will pickup imbalance due to oil leaking onto the brake
discs etc. as well as calculating the efficiency based on the weight of
the vehicle.

[Alan Morris]

Post by Paul Tasker
Hi All
My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the floorpan
and he test drives it on the road and measures inertia when braking.
Hope this helps
Paul

That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.

My normal service man (LR expert) was ill so I had to use another MOT
tester.

He used a single axial rolling road.

VI would not accept responsibility for the damage and would take no action
against the MOT tester. Got my MP involved and he got VI to have an
'independent' investigation.

The result was that the tester needed to change his working methods, but was
not held responsible for the damage to my Disco.

The damage caused the Disco to verge to the right by half a lane while
towing a caravan at 55mph on the M11 at night.

If it had happened on a normal road with a vehicle coming the other way, it
would have caused a head-on collision.

The MOT test is to promote safety - but we could have been killed by the
error of that tester. I read sometime later in the local paper that the
tester's son had died in a vehicle accident. I wonder if this father caused
his son's death.

Alan

[Andy.Smalley]

Post by Paul Tasker

Post by Paul Tasker
Hi All
My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the

floorpan

Post by Paul Tasker
and he test drives it on the road and measures inertia when braking.
Hope this helps
Paul

That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.
My normal service man (LR expert) was ill so I had to use another MOT
tester.
He used a single axial rolling road.
VI would not accept responsibility for the damage and would take no action
against the MOT tester. Got my MP involved and he got VI to have an
'independent' investigation.
The result was that the tester needed to change his working methods, but was
not held responsible for the damage to my Disco.
The damage caused the Disco to verge to the right by half a lane while
towing a caravan at 55mph on the M11 at night.
If it had happened on a normal road with a vehicle coming the other way, it
would have caused a head-on collision.
The MOT test is to promote safety - but we could have been killed by the
error of that tester. I read sometime later in the local paper that the
tester's son had died in a vehicle accident. I wonder if this father caused
his son's death.
Alan

What was the damage caused as I find it difficult to believe that a damaged
centre diff would "cause the Disco to verge to the right by half a lane while
towing a caravan at 55mph on the M11 at night"
How long after the test did this occur
I suspect that this was caused by a brake imbalance which should have
been noted on a single axle roller tester or other mechanical fault but
the test only proves the vehicle was roadworthy on the day of the test
so any faults arising after the test are not the tester responsibility which
could be the reason no action was taken against him

I have tested hundreds of defenders,disco's and range rovers on a
single axle roller tester and have never had a problem arise
I have even done freelanders but don't anymore

[Marc Draper]

Post by Alan Morris
That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.

Please give details of how you feel you vehicle was damaged by the test?

AS we have discussed at length the only possible way to damage it would
be by applying the handbrake on the rolling road.

There is no way that damage to the centre diif you cause your vehicle to
swerve into on coming traffic.

[Austin Shackles]

On or around Mon, 13 Jun 2005 08:11:54 +0100, Marc Draper

Post by Marc Draper

Post by Alan Morris
That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.

Please give details of how you feel you vehicle was damaged by the test?
AS we have discussed at length the only possible way to damage it would
be by applying the handbrake on the rolling road.
There is no way that damage to the centre diif you cause your vehicle to
swerve into on coming traffic.

Inclined to agree, there. Mind, *rear* diff, I've had one of them cause
interesting effects.

[Marc Draper]

Post by Austin Shackles

Post by Marc Draper
There is no way that damage to the centre diif you cause your vehicle to
swerve into on coming traffic.

Inclined to agree, there. Mind, *rear* diff, I've had one of them cause
interesting effects.

Yes Austin.

Wheel bearings, CVJ, front or rear diffs, bushes and ball joints could
all cause it to swerve and none of them can be damaged by a brake
tester.

[Austin Shackles]

On or around Mon, 13 Jun 2005 16:10:23 +0100, Marc Draper

Post by Marc Draper

Post by Austin Shackles

Post by Marc Draper
There is no way that damage to the centre diif you cause your vehicle to
swerve into on coming traffic.

Inclined to agree, there. Mind, *rear* diff, I've had one of them cause
interesting effects.

Yes Austin.
Wheel bearings, CVJ, front or rear diffs, bushes and ball joints could
all cause it to swerve and none of them can be damaged by a brake
tester.

aye. Discounting the possibility that something was on the verge of failing
anyway, I spose, and the act of braking with the transmission brake
overloaded something already-weak in the transmission. But that's a very
long shot.

[Alan Morris]

Post by Marc Draper

Post by Alan Morris
That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.

Please give details of how you feel you vehicle was damaged by the test?
AS we have discussed at length the only possible way to damage it would
be by applying the handbrake on the rolling road.
There is no way that damage to the centre diif you cause your vehicle to
swerve into on coming traffic.
--
Marc Draper

A front CVJ locked solid and the tyre got a flat spot on it.

I was not in the workshop while the test was being conducted, but I saw the
large dials rotate to something like 80%. Then on the second axial, the
dials only went to about 10%, and the engine revs reduced much quicker. I
assumed that it had failed.

But it passed.

My service man and the VI person I spoke with at first, agreed that the
tester had put a massive force on the transmission.

The first journey after the test was when the wheel locked.

The VI man told me that the tester was at fault. But after a written
complaint, I their story changed.

It was suggested to me that the centre diff was on during the test.

The big question. Why did the dials on the second axial only go to such a
low level. The only answer that makes sense is that the tester remembered
that he was doing it wrong.

There was also a minor problem with the need to change bushes on the rear
shocks, which did not need changing. Clearly the tester had no idea how to
test Land Rovers.

Alan
Alan.

[SimonJ]

Post by Alan Morris
A front CVJ locked solid and the tyre got a flat spot on it.
I was not in the workshop while the test was being conducted, but I saw the
large dials rotate to something like 80%. Then on the second axial, the
dials only went to about 10%, and the engine revs reduced much quicker. I
assumed that it had failed.

What have engine revs got to do with it, the test is done with the vehicle
in neutral?

Post by Alan Morris
But it passed.
My service man and the VI person I spoke with at first, agreed that the
tester had put a massive force on the transmission.
The first journey after the test was when the wheel locked.
The VI man told me that the tester was at fault. But after a written
complaint, I their story changed.
It was suggested to me that the centre diff was on during the test.

Assuming that you mean diff lock, had that been on it would have shown
itself imediately the rollers had started turning.

Post by Alan Morris
The big question. Why did the dials on the second axial only go to such a
low level. The only answer that makes sense is that the tester remembered
that he was doing it wrong.

Or perhaps that the brakes on the rear axle aren't as effective as the rear
(front= discs, rear= drums)

Post by Alan Morris
There was also a minor problem with the need to change bushes on the rear
shocks, which did not need changing. Clearly the tester had no idea how to
test Land Rovers.

The rear shock bushes on a land rover are no different to any other vehicle.

[Andy.Smalley]

Post by SimonJ

Post by Alan Morris
A front CVJ locked solid and the tyre got a flat spot on it.
I was not in the workshop while the test was being conducted, but I saw

the

Post by Alan Morris
large dials rotate to something like 80%. Then on the second axial, the
dials only went to about 10%, and the engine revs reduced much quicker. I
assumed that it had failed.

What have engine revs got to do with it, the test is done with the vehicle
in neutral?

Post by Alan Morris
But it passed.
My service man and the VI person I spoke with at first, agreed that the
tester had put a massive force on the transmission.
The first journey after the test was when the wheel locked.
The VI man told me that the tester was at fault. But after a written
complaint, I their story changed.
It was suggested to me that the centre diff was on during the test.

Assuming that you mean diff lock, had that been on it would have
shown itself imediately the rollers had started turning.

Normally when the vehicle is placed in the rollers both rollers a run together to
straighten up the vehicle if the diff lock had been in and the hand brake applied
then yes the dials would have shot up or if the roller not being run locks (some
do to help you get out) again this would have had the same effect
But as SimonJ said it would have shown itself imediately the rollers had started
turning
The question is who put the diff lock in? A chap tried this on me because he
had a faulty rear brake that wouldn't show itself on a tapley (decelerometer)
test but did on the rollers

Post by SimonJ

Post by Alan Morris
The big question. Why did the dials on the second axial only go to such a
low level. The only answer that makes sense is that the tester remembered
that he was doing it wrong.

Or perhaps that the brakes on the rear axle aren't as effective as the rear
(front= discs, rear= drums)

Or there is a pressure limiting valve on the rear brakes

[Austin Shackles]

On or around Tue, 14 Jun 2005 00:12:45 -0000, "Alan Morris"

Post by Alan Morris

Post by Marc Draper
Please give details of how you feel you vehicle was damaged by the test?
AS we have discussed at length the only possible way to damage it would
be by applying the handbrake on the rolling road.

A front CVJ locked solid and the tyre got a flat spot on it.

was this the incident on the road?

If so, then the CV joint was worn/damaged beforehand, very probably. Front
brake test doesn't load the CV joints. If the diff lock had been engaged in
the centre diff, then the brake tester would have immediately showed this.
Could have damaged the diff or the difflock, but not likely the CV joint,
IMHO. The CV joints are pretty tough.

Post by Alan Morris
But it passed.
My service man and the VI person I spoke with at first, agreed that the
tester had put a massive force on the transmission.
The first journey after the test was when the wheel locked.

I'd not actually rule out the possibility that the CV joint was damaged, but
it is, IMHO, extremely unlikely. Nor would damage to the centre diff or
difflock affect the CV joint.

The only brake test that can damage things in the rear half of the
transmission is the handbrake, which is of course a drum on the gearbox.
Thus the REAR half of the transmission is put under (possibly excessive)
load by hauling on the handbrake. Front brakes, however, work on the wheels
and put no load on the transmission, UNLESS the centre diff was locked,
which there would be no need to do. Still, I doubt if such loads would
damage a CV joint unless it was already weak, more likely to damage the
centre diff or the difflock.

CV joints in "straight" position are pretty strong.

[Marc Draper]

Post by Alan Morris
A front CVJ locked solid and the tyre got a flat spot on it.
I was not in the workshop while the test was being conducted, but I saw the
large dials rotate to something like 80%. Then on the second axial, the
dials only went to about 10%, and the engine revs reduced much quicker. I
assumed that it had failed.
But it passed.
My service man and the VI person I spoke with at first, agreed that the
tester had put a massive force on the transmission.
The first journey after the test was when the wheel locked.
The VI man told me that the tester was at fault. But after a written
complaint, I their story changed.
It was suggested to me that the centre diff was on during the test.
The big question. Why did the dials on the second axial only go to such a
low level. The only answer that makes sense is that the tester remembered
that he was doing it wrong.
There was also a minor problem with the need to change bushes on the rear
shocks, which did not need changing. Clearly the tester had no idea how to
test Land Rovers.
Alan
Alan.

The wheels are not driven by the engine during the brake test !

The front axle should be a lot higher in reading than the rear !

If the centre diff was engaged then the front wheels would either not
turn because the hand brake was on or it would just pop out of the
rollers because the rears would turn as the fronts were driven by the
rollers.

I find it very hard to believe that the rolling road can but the
transmission under more load than the car can itself when under general
usage especially a Discovery. The CVJ are hugely strong.

The reason your tyre was flat spotted is because your CJV locked up
other wise the other one would have had a flat spot too !


If the bushes have play in them then they need changing

I do think your failure was more bad luck than MOT damage.

To make a comment as you did regarding the death of his son was
unnecessary on a public forum !

[Autolycus]

Post by Paul Tasker

Post by Paul Tasker
Hi All
My mot man of 28years (so he is experienced) wont put my disco on the
rolling road for exactly that reason. He has a meter he puts on the

floorpan

Post by Paul Tasker
and he test drives it on the road and measures inertia when braking.
Hope this helps
Paul

That is the correct method according to the Vehicle Inspectorate (they now
have a new name), which I discovered when a MOT test damaged my 1991 Disco.
My normal service man (LR expert) was ill so I had to use another MOT
tester.
He used a single axial rolling road.
VI would not accept responsibility for the damage and would take no action
against the MOT tester. Got my MP involved and he got VI to have an
'independent' investigation.
The result was that the tester needed to change his working methods, but was
not held responsible for the damage to my Disco.

<snip tale of odd problem after MoT>

My MoT tester now has a roller brake testing rig that has a "4wd"
setting, which rotates the wheel not being braked in the opposite
direction to the braked wheel - hence no turning of the prop shaft. I
presume the test sequence doesn't include the usual "brake gently and
watch the two readings rise" section. I wonder how the new
Swansea-linked MoT will cope with oddities like 4wd or mechanical brake
servos? As the test sequence will, AIUI, come up with vehicle-specific
instructions, I wonder if someone at Swansea will have decided which
vehicles can have just the Tapley meter test?

[beamendsltd]

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

I'm absolutely not casting any aspertions on the MOT tester's abilities,
but yanking the handbrake on when on the rolling road (as most do
fro the MOT) can buckle the brake back plate. I'm saying no more....

Richard

[Dunga]

Post by beamendsltd

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

I'm absolutely not casting any aspertions on the MOT tester's abilities,
but yanking the handbrake on when on the rolling road (as most do
fro the MOT) can buckle the brake back plate. I'm saying no more....
Richard
--
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Helping keep Land Rovers on and off the road to annoy the Lib Dems

Richard

Is this likely to cause the problems that I have 'transfer box oil seal
failure and therefore oil contaminated brake shoes"?

Regards

[beamendsltd]

Post by beamendsltd

Post by beamendsltd

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

I'm absolutely not casting any aspertions on the MOT tester's abilities,
but yanking the handbrake on when on the rolling road (as most do
fro the MOT) can buckle the brake back plate. I'm saying no more....
Richard
--
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Helping keep Land Rovers on and off the road to annoy the Lib Dems

Richard
Is this likely to cause the problems that I have 'transfer box oil seal
failure and therefore oil contaminated brake shoes"?
Regards

Its a possibility, but it would need careful examination to
reach that conclusion - I'm treading very carefully on this
as my wording could be misinterpreted.....

Richard

[Marc Draper]

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

It is the wrong procedure to test a Landrover handbrake on a rolling
road. Due to possible damage to brake backplate and prop UJs.

The act of having two wheels on the brake testrer. spinning with the
others are stationary will do NO damage at all to the transfer box.

If you were underpower on a Dyno then a two wheel rolling road would
damage the diff in the transfer box.

When under load on a two wheel rolling road the diff is having to pass
all the power via the planet gears. These have no real bearings so to
speak and soon die.

This is why if you get stuck and sit spinning your wheels you will
knacker your axle diffs over time.

[MVP]

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?

I imagine the diff and the UJ's in the propshaft would be subject to
quite a bit of torque, which wouls also apply to the front axle via
the transfer box and centre diff.
Though if it bust an oil seal I expect said seal was about to go
anyway.

had a double-system brake failure on a 110 once (sabotaged) and in
panic I used the handbrake rather earlier than I should have (should
have used the gears first), was on gravel at the time and managed an
impressive but brief 4-wheel skid. No damage done (beyond the obvious
sabotage).
(don't worry nige, it wasn't the 110 you are currently driving).


Regards.
Mark.
--
_________________________________________
3.9 V8i LPG auto Disco - coming soon
1990 SAAB 9000 fastasyoulike
www.4x4info.info
www.mvp-fine-art.co.uk
www.markvarleyphoto.co.uk
charity calendar project -
http://www.4x4info.info/calendar/
_________________________________________



................................................................
Posted via TITANnews - Uncensored Newsgroups Access

Post by Dunga

at http://www.TitanNews.com <<<<

-=Every Newsgroup - Anonymous, UNCENSORED, BROADBAND Downloads=-

[Larry]

I wouldn't think so having driven some distance with the handbrake
inadvertently on only to see the thing smoking away merrily which cannot
have done the brake much good but my transmission is in tact. Of course my
handbrake is not what it was and will need sorting before the MOT I suspect.
--
Larry
Series 3 rust and holes

Post by Dunga
Just fitted new brake shoes to my 1985, 110, it went for retest at MOT
station and they failed again on the handbrake, now the transfer box oil
seal is knackered and brake shoes are contaminated with oil from transfer
box.
My question is, what sort of damage could the MOT station do by applying the
handbrake while on the rolling road?