I've noticed that SHY seems to have a problem on the rear brakes. In that they 'hang on' for a few seconds after the car is stopped. I noticed today on a hill. I stopped and released the brakes...... counted to 3 and the car began to roll !
The current setup is (wrong I know ) servo on the fronts, rears fed from the normal place at the back of the master cylinder, oh and the brake pedal spring is still missing
I assume it's the lack of servo to rear causing the problem, but why ? And how should it be piped ?
Having the servo hooked up to the front brakes only wouldn't be the cause of the problem.
Are you sure it's only the rear brakes holding on?
If it is only the rear brakes, then it could be sticking wheel cylinder pistons. It's also possible that the rear flexible brake hose has collapsed internally & restricting the return of fluid to the master cylinder.
Does the problem happen with the handbrake too?
The missing brake pedal return spring shouldn't be a problem, but if the master cylinder is at all slow in returning to its rest position, then having the pedal pushrod against it isn't going to help.
Scott
[url=http://img133.imageshack.us/img133/523/bo16vy.jpg]1948 Series MM[/url]
[url=http://img133.imageshack.us/img133/2484/dcp001046qp.jpg]1962 1000[/url]
[url=http://img207.imageshack.us/img207/9625/19705bp.jpg]1970 1000[/url]
[url=http://img137.imageshack.us/img137/7259/nullabor25ns.jpg]1959 Van[/url]
The rear is a sliding cylinder so i wouldn't expect it to come off instantly, however if the car holds on a hill for 3 seconds before rolling off it might not even be the rears
(the rear brakes would barely hold the car on a hill anyway )
Hi Jim Piping of servo ......... I did this for my A35 ....2 pipes from master cyl-one to rear brks /one to front . block off one pipe @m/cyl with a bleed nipple ,other pipe goes to servo . from servo t-off to fr/rear pipes . I assume the minor master cyl is same configuration as mine ? ANYBODY?
I don't think that having the fronts servoed only has anything
to do with dragging rears. I have the same set-up with no
problems. The pertinent question has been asked above...
does this dragging happen when the handbrake is released?
If yes then either the handbrake cables are semi seized or the
outer wheel cylinder pistons are semi seized. OR the rear brake
shoes are not free to centralise themselves because the sliding pivot
needs freeing. You could also have weak stretched brake shoe
springs.
Are you sure it's the rear brakes sticking on then? The handbrake operates via the rear wheel cylinders outer piston. If the handbrake isn't sticking, then I doubt only the inner wheel cylinder piston is sticking.
Try clamping off the rear brake flexible hose (with the correct tool if possible) & see if the brake are still sticking.
If they are, then I'd say it might be servo related holding on the front brakes.
Scott
[url=http://img133.imageshack.us/img133/523/bo16vy.jpg]1948 Series MM[/url]
[url=http://img133.imageshack.us/img133/2484/dcp001046qp.jpg]1962 1000[/url]
[url=http://img207.imageshack.us/img207/9625/19705bp.jpg]1970 1000[/url]
[url=http://img137.imageshack.us/img137/7259/nullabor25ns.jpg]1959 Van[/url]
If the hand brake releases the road wheels ok then it suggests
that the INNER pistons on the rear wheel cylinders are not
returning to the proper rest position. I have had this problem with the
front wheel cylinders and it was apparently caused by the cylinders
being too 'gummed up' in their bores(by old special red brake grease).
I cleaned out the bores and the pistons and re- tried, a slight
improvement but still dragging. I then renewed the wheel cylinder
rubbers, still not right. The only cure was to replace the wheel cylinders with new ones! So, if SCOTTS' servo check doesn't isolate that as
the culprit, An easy way to check for sticky inner pistons is to
operate the foot brake hard at least ten times with the engine off
(to release the vacuum in the servo so that it is now non operative)
and then,with the rear brakes exposed get someone to GENTLY
apply the foot brake so that you see the shoes expand(shout STOP
before too much expansion), they should retract immediately when
the foot pedal is released, if not then it suggest you have 'sticky'
inner pistons. You should not be able to physically push them
any further back into their bores.
) servo on the fronts, rears fed from the normal place at the back of the master cylinder, oh and the brake pedal spring is still missing 
)