Brake balance valve

[bigtalljim]

I am seeking to replace my brake balance device located under the bonnet adjacent to the servo. It is the little cylinder that all the brake pipes go into to apportion pressure around the system.
During my MOT the tester noticed that my rear brakes were more powerfull that the fronts on the rollers. This is not so on the road due to fading and brake dynamics but needs sorting.

Does anybody know where I can get a new one from or a fix?

[Barkychoc]

The only thing I can think of is if you get some sort of racing brake valve that is adjustable to alter the front / rear bias. Pete Humphries is probably the man to talk to (GreenV8S).

Chris

[GreenV8S]

bigtalljim said:

I am seeking to replace my brake balance device located under the bonnet adjacent to the servo. It is the little cylinder that all the brake pipes go into to apportion pressure around the system.
During my MOT the tester noticed that my rear brakes were more powerfull that the fronts on the rollers. This is not so on the road due to fading and brake dynamics but needs sorting.

Does anybody know where I can get a new one from or a fix?

Most likely there's nothing wrong with your brakes, the MOT tester is mistaken.

The brake balance is determined by a bias valve in the rear circuit. The bias valve on this model is triggered by deceleration and restricts the flow to the rear brakes when the vehicle is decelerating, to compensate for the weight transfer that occurs under heavy braking. When you test the brakes on the rollers there is no weight transfer and the bias valve doesn't operate, leading to more braking on the rear than you would see in normal use on the road. The MOT tester should be aware of this but perhaps doesn't recognise the brakes on your TVR.

I suggest before you get any further you test the brakes to confirm they actually are working correctly. Find a quiet bit of road with no hazards around and brake firmly (not hard enough to lock all four wheels) while cornering very slightly. The car should pull up with no significant steering correction needed. If the rear brakes lock up and spin you off, your MOT tester is quite right and there's a problem with the front brakes.

Assuming the brakes do pass the test above, go back to the MOT tester and explain that your car has an inertia type bias valve (refer him to Sierra 2.0 non-ABS if he asks for details) which is causing the high results on the rollers. If he still isn't happy then invite him to do a rolling brake test to confirm it is operating properly.