Brakes wont bleed.

[Spyda]

Trying to get the mk1 back on the road, i recently replaced the brake boost and master cylinder with units off a Cordoba following Peter Jones tutorial.
The reason for the replacement was that the previous master cylinder failed, brakes barely worked, it was sucking in air, the rear drums would not bleed and I ended up finding break fluid in side the brake booster.

While I was at it I also threw on a set of 280mm disks and VR6 calipers.

I found time today to move the cars about and get the mk1 out on to flat ground to bleed the brakes. Starting with the rear right, after a while the air in the line had come out and brake fluid finally started to flow but very very slowly and still had bubbles. I wasn't making any progress so i thought I see how i went with the other brakes.

This is what ****s me.........the front right doesn't do anything, no bleeding, no air, nothing. The front left bleeds perfectly but no change in pedal feel. The rear left barely does anything either, some fluid comes through with a lot of air when i use the hand pump and the rear right is a bit better but still consistent bubbles that don't seem to want to go away.
The brake pedal is very soft, goes down quick with ease and comes up very very slowly.

Any ideas?

[gldgti]

Its hard to diagnose because you've changed nealry all the parts and only with second hand bits.

Heres a list of reasons that I have expereinced which made bleeding nearly impossible or impossible:

> failed seals in MC
> cracked hardlines
> leaking threaded joints
> rusted through hard lines
> cracked/persihed rubber lines
> failed seals in rear drum pistons
> failed seals in caliper pistons

From you description about the rear drums not bleeding, I might suspect that you have a problem with the lines running to the back.

Hope that helps.

[Spyda]

Its hard to diagnose because you've changed nealry all the parts and only with second hand bits.

Heres a list of reasons that I have expereinced which made bleeding nearly impossible or impossible:

> failed seals in MC
> cracked hardlines
> leaking threaded joints
> rusted through hard lines
> cracked/persihed rubber lines
> failed seals in rear drum pistons
> failed seals in caliper pistons

From you description about the rear drums not bleeding, I might suspect that you have a problem with the lines running to the back.

Hope that helps.

Cheers man.
What is the best way to test the lines apart from looking for leaks and kinks?

[jords]

did you bench bleed the master cylinder? I fell for this after replacing the master cylinder. Same symptoms as you, very little fluid coming from the bleed nipples. Plenty of tutorials on the net, just google bench bleeding master cylinder.

Until all the air is out of the master cylinder, then you won't be able to bleed the brakes. Are you doing the bleeding the manual of power bleed method?

[gldgti]

if you get a bit creative with a bike pump, you should be able to pressure test each line pretty easily. Pump em up to whatever you can manage (50-60psi is probably reasonably doable) and should find any leaks big enough that might cause you problems bleeding.

[Spyda]

Thanks guys, ill give it a shot qnd see how it goes. The bench bleeding thing looks promising.