brake bleeding from scratch

[mister bridger]

I wish the answer was that simple! Definitely on the right way round.

[Richard Fridd]

How is the bore condition?

[mister bridger]

As far as I could tell it was good. No pitting or scratches.

[roddy]

Just a couple of small points :-  you are aware that the piston in the m/c bore has a ring of small holes, which has a smooth steel washer held against the holes by the rubber seal.  This is in effect a one-way valve for the flow of brake fluid.  The washer is there?

Also, it is possible to transpose the rear calipers.  You definitely have the bleed nipples to the inside and to the top side of the caliper?  If the bleed nipples are to the bottom, the circuit won't bleed.

Regards - Roddy

[mister bridger]

Just a couple of small points :-  you are aware that the piston in the m/c bore has a ring of small holes, which has a smooth steel washer held against the holes by the rubber seal.  This is in effect a one-way valve for the flow of brake fluid.  The washer is there?



Regards - Roddy

I'll take it apart again tomorrow and examine what's there - I don't remember a smooth washer, so we could be on to something. Rear calipers are fitted correctly (I just went out to the garage and checked!)

[Richard Fridd]

I take it the  nipples facing south was a joke! Imagine pumping away in that situation

[chugga boom]

I don’t understand how fluid can come back up into the reservoir. The first millimetre of movement of the pistons in the master-cylinder should close off the hole that feeds fluid between the reservoir and the cylinder.

If your problem is just excessive pedal travel, one possibility might be that the push-rod between pedal and servo is too short. I had trouble with this and had to successively adjust it to increase the length of the rod. Beware, if you set it too long, the pistons in their relaxed position will cover the feed hole and as the brakes get warm they will seize on!

What fun!

Colin  

 I've litterally just had this problem with my fulvia, basically the futher you went the more the brakes siezed on, when i rebuilt the car the mastercylender was shot, i sourced a better one out of the shed and rebuilt it, stupidly not thinking to check the push rod length i just bolted it on and away to go, today we measured the length of the rod and found it was 3mm to long therfore doing exactly as you said, the other noticable difference now is the pedal travel is correct where as before the brakes were right at the top of the pedal with nearly no travel, anyway alls sorted now MOT this week and ready for use, crazy little fault thats easily missed

[mister bridger]

OK, these are the parts of the front piston/plunger, in the order in which they were fitted. Can anyone confirm whether they are right or wrong?

[Neil]

I tried to attach a page from the spares book, but after reducing the file size it was still to large (3MB PDF), hopefully this small screen shot will help, I can mail a larger full page copy if required.

[ColinMarr]

That looks right to me and they line up with the parts shown on the diagram that I have (the same as Neil has just posted). There should also be a coil spring (number 18 on my diagram) that presses this assembly back down the master-cylinder and there should be another similar spring between this plunger assembly and the rear plunger/ piston. Is it possible that one of these is missing?

Colin

[mister bridger]

Damn! All is as it should be then, including the bigger springs, so I'm no nearer solving the problem.

[lancialulu]

And from the concise repair manual....

Seems strange as you look like to have the right sequence. The front plunger operates the larger of the front caliper pistons. Is it possible you have got the plumbing round the wrong way?

Tim

[mister bridger]

And from the concise repair manual....

Seems strange as you look like to have the right sequence. The front plunger operates the larger of the front caliper pistons. Is it possible you have got the plumbing round the wrong way?

Tim

That's the pic I've been working from. Don't think the plumbing is wrong but hard to tell exactly as the pipes do cross over and are hard to see. It will be tomorrow's job to check.

[lancialulu]

Could the front stop screw be leaking?

[mister bridger]

Taken everything apart and all is as it should be, and pipes to brake calipers are correct. All I have succeeded in doing is getting air back into the system and my mate who helped me with the bleeding is on holiday! Will just have to wait I guess and try again.