So, I was in getting an MOT yesterday, at a place I hadn't been to before, when the tester informs me that because the Z has an LSD they can't test the rear brakes on the rollers like they usually can. He needs to take it out on the road and do a 'Tapley test', with some device that seems like it measures braking g force, or something?

 

Is this actually proper procedure for cars with LSDs or, given that the youngish tester and his mate looked like a couple of cruiser types, have I been taken for a ride? (Literally, as there was no way they were going out with me coming along!) :confused:

Errrr, I have never heard of that. Plus there is no way he would be insured to do so unless on the companies insurance and I really doubt they can.

 

If they say they cant do it ask for a refund and take it to a normal MOT who "can" do MOTs on LSD cars.

 

Personally I think he is pulling your leg. I cant see how an LSD can effect any brake tests.

 

Stuart

I have! My last MOT was done that way! (but i wonder if he just wanted to drive it, as when he got back he said that it had way too much power and the back end slides when you boot it)

Personally I think he is pulling your leg. I cant see how an LSD can effect any brake tests.

 

Yeah I suspected the same :mad: If I remember correctly he said that if the rear wheels were forced to turn at different speeds during the test it would damage the LSD - seemed strange to me because, firstly, that's what the thing is there for isn't it?? Secondly, I assume both rear brakes are tested at the same time... :nono:

 

Still, I got my pass, so I suppose I shouldn't complain :)

 

(but i wonder if he just wanted to drive it, as when he got back he said that it had way too much power and the back end slides when you boot it)

 

:eek: That's why I crammed myself into the back seat and went along :D

No the brake test does damage the LSD, my examiner just passed mine, haven't heard of the other test!

Whats an LSD?

Where's Paul C when u need him!!!

Mine was done on the rollers with no problems and I have known my MOT Tester for donkies years.

He does take the old fellas Range Rover out on the road and tests it witha device though, but laways thought that was cos it was a 4x4.

 

Paul will tell us..................................

 

Nick

:cool:

Dixon - limited slip diff,

Ive never heard of the roller damaging it either.

where u gone paulc......

mine was tested last week, on the rollers and passed, never heard of M.OT testers having to take a car for a spin?

the're quite correct vehicles with LSD's should not be tested on brake rollers as there is a possibility of damage.

 

we have a plate brake tester, which is far more flash & is fine to use.

 

all garages with rollers must have a Tapley Meter (decellerometer) for measuring braking force in cases like this!!

strange, ive never heard of this before. Anyone care to expand on how it can damage the diff?

strange, ive never heard of this before. Anyone care to expand on how it can damage the diff?

 

the rollers can cause "wind up" in the diff.

 

TBH its unlikely at the speeds the rollers turn at, & iv put LSD cars in the rollers myself, but it is a possibility & i guess the VI dont want to be held liable for any damage

So, should all Zeds be tested this way?

I understood that you couldn't/shouldn't test 4WD brakes on rollers, is this essentialy because of the same reason, the diffs?

I understood that you couldn't/shouldn't test 4WD brakes on rollers, is this essentialy because of the same reason, the diffs?

 

PERMENANT 4wd systems should not be tested on the rollers for the same reason - wind up in the transmission.

 

Graham - no car with a LSD should be tested on rollers, so all zeds should be tested on a plate type tester (which is what we have - plates sunk into the garage floor, you drive up & hammer the brakes on, theres 4 separate "plates" hooked up to a computer that measures braking force on each individual wheel), which not many garages have, or tested with the Tapley Meter.

 

any Zed tested in rollers is being tested INCORRECTLY!

 

HTH

Cheers Paul :bow: :D :bow:

 

Nick

:cool: