For years I have always had a "Tapey" (sp) brake test done on mine so that the centre diff is not wound up on the rollers. Was at a new garage today and the chap running said that they are no longer allowed to take a car out and do a tapey brake test on cars that have viscous awd systems. He mentioned something about the MOT testing kit actually saying that they had to use the rollers in order to test the car.

I've not heard this one before, but the guy did actually seem genuine so I don't really know what to make of it. He was clearly into his performance cars, although he was a member of the "dark side".

 

Ask him to sign a waiver saying any damage caused to the centre diff by the roller test is his responsibility. He'll soon back off and do a road test.

 

In theory, if the MOT station has a roller setup that can do 4wd drive cars, then alls well and good.

If not, then its the Tapley test box afaik

phone your local MOT HQ for a proppa update


Mart

 

so will he fix the car if it go's **** up when tested that way ???????????????????

 

VOSA's contact details

Id get it from the horses mouth. I suspect that he is incorrect, albeit well-meaning.

Simon

 

Here...something else I've learned cheers..

 

KT green always did a two wheel brake test on my car, only for a short period though

 

from my experience,which was just 1 MOT some years ago on my RB5

The wheels don't actually rotate during the test at anytime

The tester puts the car on said rollers.

Then he applies the brakes and only then starts the machine.He can read the forces from the dial,turns the machine off and then releases the brakes.

So unless you've got one totally ineffective brake the wheels will never rotate

..or shall I just shut up?

 

He was talking me through the procedure he would do if I took the car to him. He did say the wheels would rotate up to a certain speed, at which point the braking force would be applied. He was saying that so long as care is taken then there are no issues. Gently speed the wheels up and then do the test, don't faff about, and no hard revving.

However, I still don't feel that good about taking onto rollers. He was trying to assure me that as it was a differential its whole point in life was to allow slip. However, in my opinion, there is a lot of difference between speed, and one end of the diff being forcibly held stationary.

 

That'll be the wrong way round as your testing the stopping strength not holding strength(handbrake);the machine is started then the brakes are applied..