Transfer box in neutral for brake rollers?

When i was having brake issues with my Disco 1, i'd take it to my MOT man with the front prop shaft removed so he could put it on the brake rollers for a proper test.
If i slipped the transfer box into neutral could my Disco 2 be put onto the brake rollers without causing damage?

I wouldn't do it at all.

But, don't just take my word for it ...there's a vid on the tube of a certain Mr Ashcroft saying it can take just seconds to trash the centre diff if it is spinning independently .....

Take Mr Tapley out for a little drive

A 4x4 shouldn't be tested on rollers according to Mot testers handbook, a manual floor mounted tester should be used by driving the car on the road and measuring generated braking force.
My Mot tester refuses to test my D2 on the rollers.

swatts70 said:

A 4x4 shouldn't be tested on rollers according to Mot testers handbook, a manual floor mounted tester should be used by driving the car on the road and measuring generated braking force.
My Mot tester refuses to test my D2 on the rollers.

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Indeed. And I refuse to let the rollers anywhere near our D1's - tis what the Tapley meter is for

Thanks guys. The brakes on this Disco work well so i don't need to get it on the rollers for a 'proper' test. Just wondered if flicking it into neutral was an option?
I'm guessing that's a big NOT!

yfo866 said:

I'm guessing that's a big NOT!

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That's correct. And remind them that the handbrake is mounted on the transmission and it's meant to be used only for parking and not as an emergency brake.

With brake testing rollers it only one wheel at a time that’s tested, my disco has be tested that way ever since it required an MOT so something like 19 years, if there is an issue there’s none so far.

Disco1BFG said:

Indeed. And I refuse to let the rollers anywhere near our D1's - tis what the Tapley meter is for

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No, its for a garage that carries out MOTs but can’t afford the cost of a brake testing roller

A mate tests my D90 (he also runs his own garage and his own 4x4) and does one on the rollers with the xfr box in neutral, it’s not for long and has never done any damage. Gives a better test as well in terms of knowing what is doing what on each corner

discool said:

With brake testing rollers it only one wheel at a time that’s tested, my disco has be tested that way ever since it required an MOT so something like 19 years, if there is an issue there’s none so far.

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Really?
"b. Brake imbalances across an axle such that:
i. the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle. Or in the case of testing on the road, the vehicle deviates excessively from a straight line Major
ii. the braking effort from any wheel is less than 50% of the maximum effort recorded from the other wheel on a steered axle"

from https://www.motester.co.uk/mot-test-of-brakes/

Stanleysteamer said:

Really?
"b. Brake imbalances across an axle such that:
i. the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle. Or in the case of testing on the road, the vehicle deviates excessively from a straight line Major
ii. the braking effort from any wheel is less than 50% of the maximum effort recorded from the other wheel on a steered axle"

from https://www.motester.co.uk/mot-test-of-brakes/

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So.. your point is

discool said:

No, its for a garage that carries out MOTs but can’t afford the cost of a brake testing roller

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I think you will find it was how all test were done before new rules came in, but 4x4 were still allowed to be tested this way, I remember the wood box with this meter in it that used to sit in the footwell on the drive up the back drive to test brakes.(would love to find out what dad did with theirs)

accurate adequate at the time

flat said:

with the xfr box in neutral

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does nothing to assist center diff only taking off a prop will do that.

is it right only on 2 rollers? Not really. Will it hurt for 3seconds not had any problem yet.

J

discool said:

So.. your point is

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Whenever I have sat in a car and had it tested on the rollers, they always do the wheels independently then they do them together, to get the comparison, can't rmember how much it is exactly but they have to be within is it 20% of each other for braking force, to pass the test. they can't do this accurately without doing the whole axle together.
You said they only test them individually. If so they aren't carrying out the test properly.
My Discos are all tested with a Tapley meter. I mentioned the idea of dropping a prop and testing it that way, they just laughed and said they wouldn't do it and wouldn't be responsible for it. I know them very well and have been going there for 30+ years. They value my business.

See also this https://www.gov.uk/guidance/mot-ins...senger-and-light-commercial-vehicles/1-brakes which says the same.
Just saying

This is from Discovery 2 RAVE :



IMO, there are too many ifs and buts for brake roller testing and all it takes is an oversight by one of the testers and your central diff is gone.

So if you get a little stuck and spin a wheel what will happen

J

marjon said:

So if you get a little stuck and spin a wheel what will happen

J

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Find and watch the video I referred to by Ashcroft

marjon said:

I think you will find it was how all test were done before new rules came in, but 4x4 were still allowed to be tested this way, I remember the wood box with this meter in it that used to sit in the footwell on the drive up the back drive to test brakes.(would love to find out what dad did with theirs)

accurate adequate at the time



does nothing to assist center diff only taking off a prop will do that.

is it right only on 2 rollers? Not really. Will it hurt for 3seconds not had any problem yet.

J

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I glad u understand the two roller system used in brake testing, the Tapley was used to test the brakes on my RR back then, when it was in at a main dealer for its service. I found that out when I saw the RR being delivered late back to the dealer with trade plates attached, the test had been farmed out to a small garage around the corner.

So yes that how vehicles brakes were tested then, now a with technology used in 4x4s and the magic differentials I suspect that the Talley is still use, but that’s not all 4x4s and not the D1 or the RR with identical transmission

To digress...
I suspect even my Jag ES that is all-wheel drive the MOT done at the dealer use a Tapley, I haven’t seen it done but maybe the two roller kit is so advance now it can handle the electronics that are used with two wheel or all wheel drive Jaguar transmission.

Mine passed every MOT since the beginning without any involvment of the transfer box. If the stand has the regulated right/left rotation function dedicated for 4x4 vehicles on that setting the wheels are spinning in opposite directions with the same speed and the propshaft rests. I've seen that every time and nothing bad can happen. I agree with @discool, maybe some MOT testers dont have the proper equipment

here's an example of such equipment https://www.maha.de/cps/rde/xbcr/SID-8C73D582-0301A6E0/maha_de/AMZ_Allrad_EN.pdf

marjon said:

So if you get a little stuck and spin a wheel what will happen

J

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Hopefully not instantaneous, only once has that happened to me, forced up on the grass in a tractor wide lane, when I came to move off only one wheel driving/spinning, but thanks to diff lock I had grip to move off, that was in my RR first & last time it was engaged.

NPG said:

This is from Discovery 2 RAVE :

View attachment 201553

IMO, there are too many ifs and buts for brake roller testing and all it takes is an oversight by one of the testers and your central diff is gone.

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Is it two wheel rolling road or a two wheel brake roller u don’t understand, there is a difference.