uneven rear brakes zx - volcane
I am having a problem with SWMBO's zx volcane. The MOT test in n Ireland is now very thorough and is computer controlled. Breaking on all wheels must be even. The volcane has failed the mot twice because one rear wheel brakes more than the other it now has a 60% imbalance. New discs and pads fitted all round. I am also going to replace the rear offending caliper and also replace one of the pressure regulating valves.
has anyone any tips on how to get the rear brakes right and also how to test the success of any work done without taking it for yet another mot.
uneven rear brakes zx - greaser pv
Sorry for stating the obvious- but, check the tyre pressures, they can make quite a difference when testing the balance of the brakes. I suppose after you've changed the caliper the next item would be the flexi brake hose, it is possible ( unlikely though )that it has developed a thrombosis internally, thus restricting the fluid
uneven rear brakes zx - M.M
If both the calipers seemed OK when you changed the pads, ie pistons moving back OK and no fluid leakage I'm not sure I'd change one on a whim before looking at the pressure regulating valve. They can be expensive depending on source.

The normal brake effort on the rear of a disc equipped ZX is quite low and a fairly small fault in the way the regulator valve works will take the effort right off.

As a very long shot I've had a similar problem on a Ford where the car had been lifted incorrectly flattening a metal brake pipe.

Is there any obvious difference in the way the brake fluid bleeds from each side?

uneven rear brakes zx - volcane
Did the work on the zx last night, firstly replaced the regulator valve then bled the system. Thought that there was too much resistance to the bleed so put on a replacement caliper (from 01 xsara) it bled much easier. On testing the brakes using a crowbar with the car jacked up there still seems to be some imbalance. I will do a complete bleed of the system before the next mot. I'm not sure what else can be done. Thinking anotther way there may be too much brake force going to the other rear wheel??

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