In the UK we have an annual road worthiness test that includes a brake test....This test is usually done with the transmission in neutral and either the front wheels or rear wheels in rollers and being rotated.....you then apply the brakes and the efficiency of the brakes is displayed on a couple of meters....so what I am wondering is whether there is any risk to the Turbo4's transmission, VC or anything else of testing the brakes in this way.

When the front wheels are in rollers, the rears are stationary on the ground and vice versa. But am i right in thinking if the transmission is in neutral, then front and rear are not connected together anyway....

I don't really understand how front axles, rear axles, LSD and transmission are all interlinked.....so any explanations would be fabulous...thanks

cheers Taj.

 

Check with the authorities that run the tests to see if AWD cars are required to run the test at all on rollers/dynos on one axle.

In the NYC, USA, annual emissions require a test on dynos, however AWD cars are waived.

If only one axle is run, you will encounter damage to the transmission and VC. I don't even think its possible to run one axle without uncoupling the VC.

 

Hello

My MOT centre does the brake test on road with a brake instrument that they put on the floor in the passenger side. I don't think that you can run the car on the single axle rollers.

Have fun

Steve

 

Ditto as Steve says

 

A knowledgeable MOT station won't put a 993tt on the brake test rollers because the LSD will affect the rear brake balance test.

 

But would the fact that the car is out of gear make a difference? i.e. could the car be put on 2 wheel rollers if it is in neutral?

 

I belive the fourwheel drive may take damage. They do an alternitive testing of the brakes on open road instead here in Sweden because of that risk.

 

Neutral disconnects the engine from the drivetrain, but everything else is still connected. You cannot do this safely.

 

Hi All,

Finally got round to doing some sort of testing on the 4wd system...here's what happened... Put the car on axle stands all round and started her up....put her in 4th gear ...released the clutch and all 4 wheels start rotating forwards at the same time......the rear wheels did not start rotating first...they just all started at the same time...and spun up to speed..So then I stopped the engine, applied the rear handbrake, got my brother to hold one of the front wheels firm and rotated the other wheel by hand.....the wheel I was rotating was not easy to turn...definately some resistance there.....probably because the Viscous Coupler is applying drag....I could not really turn it that easily and probably managed 2-3 turns....also it seemed to be getting stiffer to turn the more I turned it.

Conclusion....I think its working......I will now move on to a test on a slippery surface to test it all in action.....but am struggling to find somewhere suitable.

Any comments appreciated.

cheers

Taj.

 

A wet sealed asphalt parking lot is a good spot. Turn the steering to full lock and gas it from a stop to get things spinning, you'll feel the AWD working in the steering wheel.