mrp

Does anyone know if the standard MOT brake test will (or can) damage the diff (or am I just being paranoid?).

thanks

Martin

Markus

thought that the standard test put the front wheels on a roller, if so then the scooby will go right through the wall in front of it, unless they lift the rears of the ground.

best bet is to mention to the MOT people that the car is four wheel drive and they'll use, I think a hand tester thingy (technical term ) which should do the same job.

of course I could be wrong about this

Jolly Green Monster

iTrader: (4)

I was concerned about this...

Had MOT last Saturday.. told them it was 4WD and they reconned it would be fine...
I watched with bated breath as the rear wheels went onto the roller and they rears wheels span round as the rollers turned and he tested the rear brakes, then he backed the car up and the fronts on the rollers and round they went.. tested them..
The middle diff must stop the other two wheels rotating so as I understand it is you did it for prolonged period then it could overheat and damage it. It took all of 5to10seconds on each axle..
I suspect if it broke they'd be liable as I warned them.. but it was fine.
Wonder what Subaru's line on this would be though.
Done about 800miles since last Saturday and all is fine...

The Green Monster past first time too

rotdot

All constant 4wd should be tested with the tappley meter (road tested) as u get a incorrect reading from the rollers as it shows bind,Due to drag from the transmission. as well as possible damage to the diff.The down side to this is u cannot see how each brake is working ie do the rear brakes have the same braking effort.Its good to know your brakes are working ok when ur driving a high performance car!!!!!!!

[Edited by rotdot - 1/27/2002 9:24:25 AM]

mrp

Thanks to all for the info.


Martin

alistair

NO

They shouldn't put a 4wd car on the rollers - it can damage the centre diff.

They should always road test a scoob - they normally don't need to be told this twice - at the place I go the guys eyes lit up and he couldn't get his road test measuring box out quick enough !

nostradamus

Any car with 4 or AWD or with a limited slip diff should be brake tested on a road test. putting any of these on rollers or on a stand can/will do damage to the diffs/transmission. Any half decent MOT station should know this cos it is in the testing manual on ways to do things, if they don't then imho run for the hills (whats else are they going to do to your pride and joy?) So come MOT time remember to point this out i'm sure the tester wont mind too much mmmmmmmmm roadtest [in homer simpson stylee ]

mrp

Well I'm hoping testers know what to do as all our MOT test centres here are run by the Department of the Environment. At least I now know what they shouldn't be doing!

rotdot

the exact wording as per my testing manual,
Manual section 3.7 page18
Vehicles NOT to be tested on a roller brake tester are,
1/ More than 1 driving axle permantly engaged
2/ limited slip diff
3/ belt driven transmission
these vehicles should be tested using the decelerometer

so now u know the facts and can qoute them if need be !!!

TURBO7379

Every time I've got my 4wd scoob tested in Enniskillen test centre they have never tested the brakes , not even on the road . I was told that they are not allowed to in case they damage the centre diff . If you have selectable 4wd they put it in 2wd and test it that way . The last time the tester asked me were the brakes working OK . They were but would I have said no if they weren't ? Mind you a week after I passed the MOT I thought the brakes felt funny . Tried a couple of emergency stops on a quiet road to test them and on the second one the pedal went straight to the floor . The steel brake pipework to the rear brakes was completely rotten and could easily be spotted from underneath the car , especially if you're standing in a pit with a bright work lamp like the MOT tester . Is was probably leaking slightly and then burst when I was testing the brakes . Luckily it didn't happen during a real emergency stop .

Derek

rotdot

how do they get away with it ? if i'd done that i'd loose my licence to test!!! (not that i'd want to anyway cos by not doing some form of brake test your playing with peoples lives).

Jolly Green Monster 2

Sounds like I was luck not to have mine damaged then..