MOT tester & LSD

[g8ape]

I was checking out a new to me local MOT tester to see if he would mind me hovering about and generally being a nuisance when he asked if my Griff had an *LSD because if so he would have to road test it rather than use the rollers.

I was initially much impressed by his comment but then got to wondering why this hadn't come up with any other testers as I've had a few cars with LSD's in the past...

Is he just super diligent or has he got old fashioned rollers I wonder, I'm there tomorrow collecting some tyres so will ask.

I just wondered if anyone has an opinion or experience of this

• LSD= Limited slip diff.

[NNH]

I think that only applies to 4WD, not 2WD with LSD.

[Oldred_V8S]

The place I go to always road test the brakes because of the LSD, I have heard of it it in other places too.

[Russell Mc]

Think the sad fact is most MOT testers simply don't realise they shouldn't do roller brake test on a car with an LSD

[carsy]

This has come up a few times. It seems some testers use the rollers others will do a road test. I think most use the rollers though, It has been suggested putting the lsd through the roller brake test can upset it. Not sure how true it is. Mine the last couple of times has gone on the rollers and the diff is still working as it should. think i will call in on John Reid and ask his opinion tho before my next test.

[e600]

When taking the E Types in I always asked for the tapey meter rather than rollers, and without exception they obliged. Just ask.

[g8ape]

Thanks for all the replies, road test for me from now on

[rigga]

Yes lsd equipped cars should be tested with a tapley meter rather than using the rollers,it does the diff no good.
http://www.tapley.org.uk/braketestmeter.html

My tester uses a smaller hand held device rather than the older larger ones that used to sit in the footwell when used.

[PeteGriff]

My regular MOT guy who does the Griff never uses the rollers to test the rear brakes, he uses a meter in the car and does a short road test. Another thing I noticed last time was that when the guy called up the VOSA details for the MOT cert it stated a warning regarding LSD for the vehicle. Always go to good clued in MOT stations/garages. Regards, Pete

[Jhonno]

As has been said.. LSD means road test. Not many seem to be aware of this!

[rigga]

anonymous said:

[redacted]

Think about it .....this scenario would never happen, I can understand the reason for not trying to hold one wheel whilst the input shaft is being rotated by the engine/gearbox, but on the roller test the gearbox does not drive the rollers, they are done mechanically by the machine itself, even if the car was in gear the clutch would be depressed and no drive would be going to the rear axle.

[rigga]

This is my understanding.of the issue ...When the brakes are tested individually (not the balance test) the wheels are rotated separately and the one not under evaluation is static which would risk damaging the internals of some, if not all, lsds,also it might cause the car to jump out of the rollers when the wheel locks up.

[Jhonno]

anonymous said:

[redacted]

An LSD effectively 'locks' the rear wheels into rotating together.. (Well with some slip). In simple terms, imagined it is locked in the middle, rotate the wheels then apply a force to one wheel only whilst stopping the other rotating any faster.. It can wear the LSD plates or even break it. It could also cause the car to leave the rollers I believe.

[cureton]

Please excuse my question: Does the Griff normally have a LSD?

[carsy]

cureton said:

Please excuse my question: Does the Griff normally have a LSD?

Yes. A gkn in the early cars and a btr in the rest.