Went to collect my car from the mot and it wasnt there! The garage said theyd taken it out on the road to test the Limited Slip Differential. Is this true or were they just using an excuse to rag my car? Anybody else had an MOT where they drive the car on the road?

they dont check the LSD as part of the test, but mabey decided to carry out a tapley brake test. rather than risk damaging the diff on the rolling road.

any car fitted with a LSD *HAS* to be tested with a tapley meter instead of in the rollers. unless you've got a nice posh plate brake tester like iv got ;)

 

there are loads of places that just chuck them in the rollers however :rolleyes:

Can anyone explain what a Tapley meter is and how it works. How can something not attached to the rear wheels check the diff or brakes?

A tapley meter is a device that sits in the footwell of the car and measures brake effort. It is essentially an analogue gauge on a frame (although electronic ones are now available). As brake effort is applied, the g-force causes the gauge to swing in the frame and the needle on the gauge moves leaving a marker needle at the point of maximum g-force. They can then take the brake effort reading.

 

Not very well explained I'm afraid, but using these units is common practice. I used to work in the garage equipment industry and we used to get thousands of these tapley meters calibrated every year. They are pretty much as accurate as your normal brake tester

 

Gareth

 

Cheers for the explanation. Anybody know the test regulations, that is whats done in the mot with a Tapley meter. What speed braking takes place, and as it measures G-Force, is that stopping in a straight line or breaking whilst going round a round-about

I don't know for sure but I would imagine that they have to perform the brake test in the same manner that they do on the roller braketesters. If thats the case then it would be braking in a straight line and from a relatively low speed

Here you go!...

 

1. If the vehicle is of a type which cannot be tested on a roller brake tester,

. set up the decelerometer in the vehicle in accordance with the equipment manufacturer's instructions

. drive the vehicle on a level road at a steady speed of approximately 20mph (32kph) and note the brake efficiency recorded...

any car fitted with a LSD *HAS* to be tested with a tapley meter instead of in the rollers.

Is this a matter of regulations, or does it damage the LSD if the rollers are used? :eek:

it can break the LSD

 

I would commend them that they knew they had to do it, some MOT stations don't understand,

absolutely right . make a note of them and go back next year .. a proper test which is safer for you and every other road user is hard to find its too much like making easy money for some garages and they dont even bother to check the basics thats why there are so many killer cars and ringers still on the road

any car fitted with a LSD *HAS* to be tested with a tapley meter instead of in the rollers. unless you've got a nice posh plate brake tester like iv got ;)

 

there are loads of places that just chuck them in the rollers however :rolleyes:

I've had two Zed's m.o.t tested and one Trans-am all with LSD and all tested on the rolling Brake tester!! :confused:

Should have seen my face when the new MOT bloke in my local garage put my Integrale on the rollers. I was walking back from the local shop to see my car jumping out of the garage backwards. Luckly he didn't manage to break anything. :smash:

I've had two Zed's m.o.t tested and one Trans-am all with LSD and all tested on the rolling Brake tester!! :confused:

 

tell them to read the MOT inspection manual then!! :slap: