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Can MOT testing damage transfer Box?

3K views 46 replies 0 participants last post by  NT 
G
#1 ·
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?
 
G
#2 ·
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

"Dunga" <test@test.com> wrote in message
news:42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net...
> 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?
>
 
G
#3 ·
> "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
 
G
#4 ·
On Fri, 10 Jun 2005 12:39:00 +0100
"Jeff" <jeff@local.host> wrote:

> > "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
 
G
#5 ·
On or around Fri, 10 Jun 2005 12:39:00 +0100, "Jeff" <jeff@local.host>
enlightened us thusly:

>> "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.


--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Beyond the horizon of the place we lived when we were young / In a world
of magnets and miracles / Our thoughts strayed constantly and without
boundary / The ringing of the Division bell had begun. Pink Floyd (1994)
 
G
#6 ·
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

"Fred Labrosse" <ffl@aber.ac.uk> wrote in message
news:20050610134058.78b121dd@localhost...
> On Fri, 10 Jun 2005 12:39:00 +0100
> "Jeff" <jeff@local.host> wrote:
>
>> > "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
 
G
#8 ·
In message <d8bu4k$j4r$1@news6.svr.pol.co.uk>
"Jeff" <jeff@local.host> wrote:

> > "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
--
www.beamends-lrspares.co.uk sales@beamends-lrspares.co.uk
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
 
G
#7 ·
In message <42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net>
"Dunga" <test@test.com> wrote:

> 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
--
www.beamends-lrspares.co.uk sales@beamends-lrspares.co.uk
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
 
G
#9 ·
"beamendsltd" <beamendsltd@btconnect.com> wrote in message
news:23d1d8784d%beamendsltd@btconnect.com...
> In message <42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net>
> "Dunga" <test@test.com> wrote:
>
>> 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
> --
> www.beamends-lrspares.co.uk sales@beamends-lrspares.co.uk
> 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
 
G
#10 ·
In message <42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net>, Dunga
<test@test.com> writes
>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.

--
Marc Draper
 
G
#11 ·
On Fri, 10 Jun 2005 10:37:48 +0100, "Dunga" <test@test.com> wrote:

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

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G
#12 ·
In message <42a9971c$0$2044$ed2e19e4@ptn-nntp-reader04.plus.net>
"Dunga" <test@test.com> wrote:

> "beamendsltd" <beamendsltd@btconnect.com> wrote in message
> news:23d1d8784d%beamendsltd@btconnect.com...
> > In message <42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net>
> > "Dunga" <test@test.com> wrote:
> >
> >> 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
> > --
> > www.beamends-lrspares.co.uk sales@beamends-lrspares.co.uk
> > 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
--
www.beamends-lrspares.co.uk sales@beamends-lrspares.co.uk
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
 
G
#13 ·
On 2005-06-10, Austin Shackles <austinNOSPAM@ddol-las.net> wrote:

> 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.

--
For every expert, there is an equal but opposite expert
 
G
#14 ·
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


"Dunga" <test@test.com> wrote in message
news:42a95f89$0$1735$ed2e19e4@ptn-nntp-reader04.plus.net...
> 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?
>
>
 
G
#15 ·
>
> 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.
 
G
#16 ·
On or around Fri, 10 Jun 2005 22:35:22 +0000 (UTC), "SimonJ" <me@mine.net>
enlightened us thusly:

>>
>> 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.

>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.


--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Appearances: You don't really need make-up. Celebrate your authentic
face by frightening people in the street.
from the Little Book of Complete B***ocks by Alistair Beaton.
 
G
#17 ·
In message <7p3la1pa7iql0rh08vecnu0klhcasoetgl@4ax.com>, Austin Shackles
<austinNOSPAM@ddol-las.net> writes
> 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.

--
Marc Draper
 
G
#18 ·
Why not just disengage 4WD oh forgot you can't do that in modern land rovers
can you :)



--
Larry
Series 3 rust and holes


"Marc Draper" <marc@mdeng.demon.co.uk> wrote in message
news:+kImO2fPzsqCFwHu@mdeng.demon.co.uk...
> In message <7p3la1pa7iql0rh08vecnu0klhcasoetgl@4ax.com>, Austin Shackles
> <austinNOSPAM@ddol-las.net> writes
>
> Yes Austin I would pull the prop because the speeds involved are much
> greater than a rolling road.
>
> --
> Marc Draper
 
G
#19 ·
In message <d8ejjv$kr5$1@newsg4.svr.pol.co.uk>, Larry
<NDA@larry-arnold.com> writes
>Why not just disengage 4WD oh forgot you can't do that in modern land rovers
>can you :)



No thankfully they have progressed !
--
Marc
 
G
#21 ·
Dave Liquorice wrote:
> On Sat, 11 Jun 2005 12:58:15 +0100, Larry wrote:
>
>>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.
 
G
#20 ·
On Sat, 11 Jun 2005 12:58:15 +0100, Larry wrote:

> 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-)

--
Cheers new5pam@howhill.com
Dave. pam is missing e-mail
 
G
#22 ·
In message <nyyfbegfubjuvyypbz.ihxta40.pminews@news.howhill.com>, Dave
Liquorice <new5pam@howhill.com> writes


>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.
--
Marc Draper
 
G
#23 ·
Well that is a matter of opinion, do the doors fit any better ?


--
Larry
Series 3 rust and holes



"Marc Draper" <marc@mdeng.demon.co.uk> wrote in message
news:FX6YiSgFxwqCFwCM@mdeng.demon.co.uk...
> In message <d8ejjv$kr5$1@newsg4.svr.pol.co.uk>, Larry
> <NDA@larry-arnold.com> writes
> >Why not just disengage 4WD oh forgot you can't do that in modern land

rovers
> >can you :)

>
>
> No thankfully they have progressed !
> --
> Marc
 
G
#24 ·
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
 
G
#25 ·
On 2005-06-11, Larry <NDA@larry-arnold.com> wrote:

> 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
 
G
#26 ·
On or around Sat, 11 Jun 2005 18:00:02 +0100, Marc Draper
<marc@mdeng.demon.co.uk> enlightened us thusly:

>In message <nyyfbegfubjuvyypbz.ihxta40.pminews@news.howhill.com>, Dave
>Liquorice <new5pam@howhill.com> writes
>
>
>>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.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Confidence: Before important work meetings, boost your confidence by
reading a few pages from "The Tibetan Book of the Dead"
from the Little Book of Complete B***ocks by Alistair Beaton.
 
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