Brake Drama's

[dohc]

Hi All,

This is a weird one, well for me anyway. I'll give you the background first:

I've just replaced the rear brake shoes, struts and springs, along with the front springs. On hooking all of the break lines back up and bleeding the rubbish out of the lines I can't get a firm brake pedal.

Before starting out the brakes were OK, if a little spungy, now (without the engine running) I can get it back to OK, but not hard.

Now the weird bit is when I start the engine the pedal goes limp. I don't mean soft I mean LIMP. I can actually push it to the floor with one finger?

I'm thinking dollars and the master cylinder but is there anything else i can check? Any kind of valves that might be jammed?

Thanks,

Ross

[ZmeFly]

my money would be on the booster or the check valve. if you have a vacumn tester you can eliminate rather quickly

[dohc]

Where's the Check Valve?

Is that between the engine and the Master Cylinder?

R.

[Bambikiller240]

Originally posted by dohc

Where's the Check Valve?

Is that between the engine and the Master Cylinder?

R.

The Vac Hose from the manifold is a two piece hose.The check Valve is mounted in a bracket on the firewall IN BETWEEN the two hose pieces that connect the Brake Booster to the Intake manifold.

It's a small round valve supported in a bracket at the firewall.

[dohc]

Cheers, I'll have to check that when I get home.... I recon I've got a spare on the parts car that was working....

Is it strange for it to fail so quickly like that? and is there anything else that should be inspected before I fork out for a new master cylinder?

Thanks guys,

Ross.

[Bambikiller240]

Originally posted by dohc

is there anything else that should be inspected before I fork out for a new master cylinder?

The loss of vac. can explain the pedal going to the floor using just your finger, but if the brake system is bleeding properly, you should be able to get a reasonably firm pedal without the engine operating. Bleed the Master Cylinder first, then you bleed Right Rear, then Left Rear, then Right Front, then Left Front? (for a LHD car)

OH, if you have a RHD car you probably need to do LR, then RR, the LF, then RF since the Master Vac and Cyl are on the "wrong" side of the car.

[dohc]

Thanks for that BambiKiller, I've bled them in the right direction already (as it's a RHD car with the master cylinder on the "right" side of the engine bay :classic: )

I got a reasonable pedal but not great so I'm hoping that that valve is all that is playing up..... Make it a very cheap operation if it is.

Cheers,

R.

[Daniel]

Did you adjust the new shoes to the max that would allow you to put the drum back on?If not you can either backup alot while tapping your brake or hold the button in on your emergency brake and pump it .You should hear the adjuster's in the drum's clicking.A trick is to put a board (2x4 or such) under the brake pedal before you start the bleeding.Remember the pedal hasn't been that far down in years.Rust and crapola will kill the master cylinder piston seals as it travels into this unsmooth area.

[dohc]

Thanks guys for the suggestions but after swapping the check valve out there was no change at all.... Still limp with the engine running and while watching the fluid reservoir I can see bubbles coming up in there when I'm pretty sure there shouldn't be any....

Master cylinder is definately dead....

Thanks again all.

Ross.

BTW: Daniel, yeah I adjusted the shoes right out before fitting the drum and even then I should be able to get some feel into the pedal with the engine on..... I think I may have destroyed it with the rust etc you mentioned as judging from the black crap in the brake lines I don't think the system has been bleed in years.

Bugga.

[Z Kid]

Ross, The cheapest master cylinder I found was from restorers hotline.

[dohc]

Thanks Chris, Do you remember how much? I'm on a hell ova tight budget at the moment?

Cheers,

R.

[Z Kid]

I paid 88 bucks for the 240 one from memory, I have the one of my parts car which did work(looks rough though, could have something to do with my removal method), you can have it, and I can send it to town with mum if you want to pick it up??

PS Andrew it the guy at restorers hotline to speak to.