lightweight braking problem

howdy folks!
for the past 2 years i have been rebuilding a series 2a lightweight, its my first landy so things have been going slowley, but by far, the most annoying job is the braking system. its had new everything, wheel cylinders, master cylinder, pipes/lines inc flexi hoses, shoes etc

first problem i had was the wheels froze solid going backwards - later worked out bottom spring was in the wrong place - sorted (i think)

second the back left wheel is siezed solid forwards and backwards, snail cam is wound off, i had all the wheels of and on axel stands, stick it in first gear and 'set off' jus to get the wheels turning, the back right is fine, back left solid as a rock, but after aplying the brakes whilst on hte axels stands and things still in gear etc, open the bleed nipple on the wheel cylinder and fluid comes out and the drum will rotate as normal, but apply the brakes and its sticks on undo the bleed nipple and itll go again (and so on)

the front wheels are fine rotate forwards and backwards as normal


im thinking that its the master cylinder 'return valve' (for lack of better words (the little rod inside that hooks in the little metal cup))

so thats the story so far and im fresh out of ideas
any offers?!

No ideas.....

But my series 3 brakes are stiff in reverse, this is after replacing new cylinders and shoes, checked and double checked springs, bleed em till I bled, and still the brakes are worse than before I started.....

First you must establish what is holding the brake ON.
Is it something mechanical, or is it hydraulics?

If it is residual pressure in the hydraulics due to a master cylinder malfunction, then ALL the brakes would be affected.

Assuming only ONE wheel is affected, I would check VERY carefully along the pipe from that brake working towards the front. You are looking for a kinked flexible hose or a crushed pipe - these can let pressure through, but stop it coming back, thus jamming the brake on. Your problem seems to be fluid getting IN to that wheel slave cylinder, but not back out again.

Let me know what you find.

CharlesY

cheers dude ill have a gander

there are a few reasonably sharp bends in the copper pipe, but im not sure how sharp is too sharp! im tempted to change the flexi hose to the rear axel incase its a bit dodgy, ill probably have to wait till tuesday now, because i think everyware is shut.

ill keep investigating any other causes

ypcmarshal said:

there are a few reasonably sharp bends in the copper pipe, but im not sure how sharp is too sharp! im tempted to change the flexi hose to the rear axel incase its a bit dodgy, ill probably have to wait till tuesday now, because i think everyware is shut.

ill keep investigating any other causes

Click to expand...

Excellent plan.
I was assuming all new pipes and hoses.
A month or so back, we had a similar problem with a front brake on a Ford car. The guy had fitted THREE exchange calipers before he asked me to look.

You're going to like this bit ...

The flexible hose passes through a steel guide on the front strut, which forms a close fit right round the hose. This had rusted inside so much that as the rust formed it crushed the rubber pipe! The pressure from the master cylinder could force past and apply the brake, but the fluid would not come back to release the brake.

In your case, THERE IS A REASON. All you have to do is find it.
A dodgy hose is a prime candidate. It may have swelled up INSIDE because of some contaminant in the fluid, or just because it felt like it, or with any luck you may find it passing through a rusty guide ring! A simple kink or twist in a flexible hose is easily capable of causing your problem.

Let me know!

CharlesY

all the hoses on it are new already but im running out of ideas and id heard (like you said) that they have a habbit of doing what they please, and for the sake of a fiver i may aswell check it.

OK,

So the next stage is some way to check the free movement of fluid both ways in the system, from the pipe out of the master cylinder right to where it joins the wheel cylinder.

You can do this by taking both ends off, and use an air line or foot pump to blow into the ends of the pipe to see if air comes out the other end easily, from both ends, but first try the stunt below. This just needs yopu to take the wheel and brake drum off, but not to open the hydraulics.

We first need to be very sure you have the brake shoes fitted properly and good strong return springs too.

With the drum OFF, get an "an assistant" (her usually) to shove the footbrake pedal down ONCE while you watch the brake shoes. You will see the shoes being separated at the wheel cylinder, and if the brake is to release, you MUST see the shoes return to their start position when the "assistant" (her) lets the pedal up.

If the shoes do not return, do not let the assistant pump the brake pedal up and down or the wheel cylinder pistons and seals will be shoved right out the wheel cylinder, and that's a bummer.

If "she" can push the pedal up and down, while you watch the shoes opening and closing, the brakes SHOULD release.

Is there any chance you have the wrong shoes fitted? They could be too wide or over-diameter ...

CharlesY

i had thought that the pads were just bad pattern parts and jus sh1t dimensions i intend to stick some decent ones on though once theyre sorted. and the 'her' wouldnt touch the thing with a barge pole, (if she was about still that is lol)
ill atempt that tonight with dad or whoever is kicking about

cheers

check the shoes are central, although they should be by now wiff the amount of pumping theve had so far. then check the drums are round.; even noo ones can be oval as we found out in the past couple of weeks

Had the same problem with my series 1, i adjusted the rod incorectly on the master cylinder to try and reduce peddle travel, it turned out the system wudnt let fluid flow back or replenish it. re adjusted the rod and it went strate through an mot.
Hope this helps

in not completely sure on how to adjust the rod on the master cylinder, any pointers or guidelines??

BEFORE you do this, remember that if that is the problem, ALL the brakes will stick.

It is extremely unusual for this to go wrong in use.

If it is only ONE brake doing it, and if that brake releases when you let fluid out, then there MUST be a fluid blocker somewhere in the line to THAT brake.

Fluid is getting through, but not back .... keep thinking!
Logic will show you the way.

CharlesY

im thinking a collapsed flexi pipe to the rear axel, i intend to have it off some time soon to have a look.

cheers

alrighty then, new rear flexi pipe on seems to have sorted one side out, on the rear right you take the drum off and the trailing shoe (the one toward the back of the vehicle) expands the second you take the drum off!?
any offers on that one?
sorry for asking so many questions ive jus lost the will to live having been workin on the brakes for a long time

cheers

ypcmarshal said:

on the rear right you take the drum off and the trailing shoe (the one toward the back of the vehicle) expands the second you take the drum off!?

Click to expand...

Isint that what it should do?
On my 2a it will pop out if you dont wire it up quick.

It is pushed out by the springs on the other wheels, so i would just check them to make sure that all the other springs are fitted correctly and are of similar strength.

il have a look, all the springs are new, but because the cylinder expands it locks the drum going backwards (and it doesnt do it on the other wheels)
it might be that jus one side of the cylinder is a bit stiff, but as its a new girling part im hoping its not!

ben

Just to throw something else into the mix. Have you tried swapping your drums round ? I'd stuck the whole new cylinder / brakes / pipes on my series 3 and still had a brake sticking. until it turned out it was a drum which was slightly out.

£15 for a new one and it's done the trick for me.

The shoes should NOT expand OUT when the drum is taken off.
The brake shoe springs should be (MUST be) strong enough to pull the shoes IN and clear of the drums.

There MUST be a problem still in there.

Get another pair of hands and eyes to check all the springs and bits are fitted the right way round in the right places!

CharlesY

i managed to get it to move backwards, its only binds/catches when there is pressure on the drum, ie when the road wheel is on and tightened up, im gonna ask a mate to skim the drums to see if it makes a difference
ben