Hi
i'm new here, and i know a lot of Forums encourage people to start new threads rather than tag onto ancient ones, but this mystifies me sometimes, when all the info is there in a thread, with possibly useful details to whoever finds it, albeit (in this case) 15 years later :-
I am struggling with this exact
problem, same as O.P., and i am retired Trade so quite humbling. If anyone picks this up, and has found the cause due to the same experience, then it would make my day.
So symptoms are much the same as O.P. but only on one wheel, and MOT Tester did me a favour one year ago by letting me go with an advisory, so stripped off wheel and brake drum to have another head-scratching session as MOT due soon.
Things that it isn't:
1/ Drum hardly worn and not distorted (41k miles)
2/ Brake shoes hardly worn, plenty of life left.
3/ Slave cylinder, as it's as good as new/replaced a year ago.
4/ Air in this wheel's hydralic system.
5/ Brake shoes are not wet/have never shown signs of being wet with brake fluid.
6/ Fluid leak anywhere.
The handbrake works fine and even favours the "bad" wheel slightly.
I'm trying to think outside the box, but it's such a subtle
problem, it's going to be a pretty wacky solution. even wondering if the proportioning valve can favour one circuit/starve the other. Another thought is that models were fitted with slightly different shoe dimensions, that the brake shoes are somehow distorted from new or during use. I've also tried to get the auto-adjust to advance one click without success, drum comes off fairly easily, but not overly so - it's the same for both rear wheels. I am going to heavily de-glaze drum and shoes in an effort to improve matters slightly, which does work, but not for long.
If I manage to just pass MOT this time then i wiil reluctantly fit new shoes as a last resort, but they don't need replacing.
It's a strange one..