drum brakes not releasing

RS

Hi, I would be inclined to check that the front pistons are not sticking in the cylinders, which could well happen if the brakes have not been used for a long time.

Keith

~As a few of you will remember, i am putting a 1981 X reg mini pickup back on the road, that has been stood for 8 years. I have just blead the brakes, and the rears work perfectly. The fronts lock as the wheel is spun and the brake pedal is pressed, but then do not release. After a few seconds the wheel can be just turned. I have fitted the springs correctly, and the shoes are adjusted to "fully off" the drum. I am suspecting a blockage in the pipes or the presure reducing valve underneath the master cylinder. am i right, or does anyone else have an idea? as i say, rears are great. cheers

RS

Hi, I would be inclined to check that the front pistons are not sticking in the cylinders, which could well happen if the brakes have not been used for a long time.

Keith

sorry, forgot to say that i have replaced all 6 wheel cylinders and bleed nipple, and never-siezed all threads. with the shoes off i can push the cylinders back with my fingers. one strange thing, when i push one back, the other pops out see-saw like. to reset them both to rest i have to crack the bleed nipple and push both back.

any more ideas?

A blockage in the pipes could cause the problem as there would be too much restriction stopping the fluid from going back up the pipe under vacuum.

And as it is both wheels then it has to be from the tee on the subframe back up to the pressure valve and master cylinder, is the pipe squashed there?

Try disconnected the pipe and bleeding through to wash out any dirt.

Another simple thing.... Try the brakes with the master cylinder cap off, the vent might be blocked.

If that doesn't cure it then It may be worth changing the master cylinder, as I don't think that the biasing valve would have such an effect although you never know!

Happy Xmas!

miniman

Hi, Another problem I have met in the past is where the lining of the brake hose comes away and blocks the brake hose.

Keith

Try opening the brake pipe at the calliper, then at the flexi hose then at the "T" junction, then the regulator, and so on, this would indicate where the problem is , but I would go for the regulator,,, Fitzy Merry Chrimbo

Not trying to be difficult, but your line lengths are set so long that your material is unreadable without considerable effort. Also your sig attachment shouldn't really be there in a text-only newsgroup. Some ISPs will not propogate your posts as a result. Both problems should be easy to deal with.

Regards, David Betts snipped-for-privacy@minilist.org The Mini Gallery: