14 replies to this topic

[blacktulip]

I took my master cylinder off my 69 cooper (no servo) to spruce the bay up and now I have refitted it I have tried to bleed the system through. The passenger rear lets fluid through but the front calipers and drivers rear let nothing through. The nipples open but the pedal is not pushing through. The pedal feels like it does when everything is normal and running. I initially wondered if the master was seized so I tried the passenger rear again as that one let the fluid through and it did push through so it's not a seized master. Has anyone ever seen this happen? Can the lines block up?

Edited by blacktulip, 29 June 2020 - 09:36 AM.

[cal844]

Are the calipers on the correct side? (Nipple to the top)

For brake bleeding I use the two man method, one pumps the pedal and checks fluid level, the other does the unions and nipples.



You need to chase the air from the master cylinder to the slave cylinders and calipers.

Crack the MC union that is giving problems (you may need to wind out a couple of turns, if the pedal is stiff)

pump the pedal until fluid comes out between the union and pipe.

Nip up that union so the fluid stops between the pipe union.

Repeat this along the line, especially past the FAMwtf valve on the bulkhead (if fitted, I think your car may be too early for that system.)
Personally I wouldnt disturb the flexible lines, just proceed straight to the cylinder or caliper nipple.

You want to leave the nipple open (whilst doing the above) ideally use a piece of hose from the nipple end into a jar of clean fluid so you can see the air escaping.(once you have fluid along the full system.)

What I then do at this stage is stop, make sure there are no leaks further back the system then get your assistant to give 5 full stroke pumps of the pedal and hold it fully down. You then close the nipple and release the pedal.

Bleed order that I use is
Nsr passenger rear
Osr drivers rear
NSF passenger front
Osf drivers front

If you are struggling to get a pedal you can clamp all flex lines, checking the pedal once you have each clamp fitted to see where the air is.
If you clamp one and the pedal is still soft or long you need to bleed that corner more.

A long winded post but I've tried to include all I can think of.

Any issues dont hesitate to report back!

Regards

Cal

[mkw]

Gunsons Eazibleed may help, force the fluding down the line and out under a constant pressure

[sonscar]

Are both rear brakes teed on the same circuit,if one bleeds so should the other?Steve.

[blacktulip]

Hi guys, sorry if I haven't explained myself properly. The nipples are free and not siezed but the pedal won't push down. The pedal feels like the brakes are as normal I.e bled and ready to drive even when the nipples are open. I will jack all 4 corners up and see if the calipers and rears lock up when pressed.

[Edington]

A bit of a late reply to this but I've been having a similar problem and after a lot of investigation and having purchased a new master brake cylinder (the large volume type for 7.5" front discs) and having also purchased a pair of new callipers (thread stripped on the existing one     ) I found that despite my wife pressing hard on the brake pedal no fluid came out even when I took the bleed nipple right out!  So I took the calliper off and put it on my bench. Even with my air compressor attached to the inlet I couldn't shift the inboard piston it appeared to be stuck solid. So I used a brass drift and a big hammer and carefully proceeded to knock the piston out. Eventually it started to move and after a bit of playing with it was able to push it back in by hand. My worry was that the outboard piston had the same problem and there would be no way to get behind that and push it out. Anyway I bit the bullet and refitted the calliper and low and behold it bled freely. I can only assume that on assembly no rubber grease was used on the piston seal. So another issue resolved to add to the many I've had during the total rebuild of my 1969 Morris Cooper, the moral here is don't take too long over a restoration project, mine is coming up to 8 years!!!

[Maccmike8]

Goodridge speed bleeders will have this sorted in a jiff.

[burchy35]

I have never seen those before, what a cracking idea.
I have minispares alloy 4 ports on the front and standard drums on the rear. Have you any idea what thread sizes they are? I know the calipers are slightly bigger.
Sorry for butting into the thread.
Thanks

[Maccmike8]

3/8 unf.

I fit them to every car I change brake fluid on. 

Ive done every single type of bleeding method and equipment and nothing is easier than these.

[beardylondon]

Excuse my ignorance, but how exactly do the speed bleeders work?

3/8 unf.
I fit them to every car I change brake fluid on.
Ive done every single type of bleeding method and equipment and nothing is easier than these.

[Maccmike8]

They have a spring loaded ball bearing.

Fit them as normal then slacken them off a turn, keep the fluid topped up and slowly pump the pedal.

The ball bearing stops air coming in when the pedal is returning.

[beardylondon]

Ah right, genius!

[MiniMadRacer]

Never seen or heard of them before either. but certainly would encourage regular brake fluid changes as it makes it a one man job and much easier. Certainly seem to be worth fitting to a car you are keeping

[Maccmike8]

I first took a punt on them years ago as the missus was getting fed up pumping the pedal.

Never looked back. 

[gazza82]

Back in the 70s I had some that were spring loaded so half a turn and you could bleed them on you own. Nip them back up and voila.

6 months later I found the missing 7/16" ring spanner still attached to the bleed nipple ... and still have it today!