Would a cracked reservoir cap lead to braking issues?

[baller908790]

If I press the brake peddle repeatedly when the car is off the peddle doesn't become hard. I replaced the wheel cylinders, calipers, and brake lines. Do you think this is a master cylinder problem? The brakes work but only when you reach close to the floor.

[roadhog0]

Shouldnt be a problem at all. Have you bled your brakes to get ALL the air out? It took me a good half hour to get air out after removing lines...

[baller908790]

I've bled all 4 corner about 4 times each and the master.

[andrey]

Yeah, it sounds like the master cylinder is the problem. Try "bench bleeding" it first (on the car is fine) and then re-bleed the whole system. If that doesn't solve it, I'd buy a new one, bench bleed it, replace it, bleed the system again, etc.

[Guest Anonymous]

Might not be the case but it could have moisture in the system... Brake fluid is hydraulic and needs to be a sealed system a crack could possibly let moisture in causing the moisture to compress and cause a soft pedal

[mossyboy6]

No, shouldnt be a problem for testing, you just dont want to run it long term with a cracked cap, because brake fluid will suck water vapor out of the atmosphere, and eventually lead to fade

[baller908790]

If the master is bad does that mean no braking at all? My brakes work but only when the peddle is about 80% down the travel area. On top of the master is a little bolt that if you open you fluid comes out and I used thaat the "bleed" the master cylinder. Should I do it by removing all the lines off the master?

[Napes]

I would also recommend following this brake adjustment procedure carefully and completely. The braking system, to function correctly, needs to have the rear brakes and the e-brake properly adjusted. I would suggest, re: Item #4 on the list, that you get eight 7/8" nuts to use in place of the copper tubing suggested in the tutorial. They are countersunk on each side allowing the lug nuts to tightly seat when adjusting the rear drums.

http://www.zeebuck.com/bimmers/tech/rearbrakes.html

Bob Napier

[baller908790]

When I adjusted the drums I didn't adjust them with the wheels on but did with the wheels off and adjusted them until a slight dragging was felt/ the shoes barely scraping against the drum.

[Napes]

That sounds good, but you need to have the wheels on to adjust the e-brake. This is assuming the drums were on tight, as per the above link.

If you use the 7/8" nuts under the lug nuts, and tighten them completely, the drums are on the same as when you have the wheels on, but you have sufficient room to work.

Bob Napier

[c.d.iesel]

you stated : If I press the brake peddle repeatedly

when the car is off the peddle doesn't become hard. =

if the motor is off and you pump the pedal - you deplete

the vacuum booster of all stored vacuum so the

pedal goes from spongy to rock hard as the

vacuum is bled out by repeated pumping

of the pedal

you stated: I replaced the wheel cylinders,

calipers, and brake lines. Do you think this is a

master cylinder problem? = if the pedal is going to

the floor and it only gets firm 1-2 inchs from the bottom - floor?

you have a few things that will cause that. Air still in the system.

Rear shoes way out of adjustment. A bad master cylinder.

you need a pressure bleeder .

you stated: The brakes work but only when

you reach close to the floor. = engine running and driving ?

or on jack stands and motor off?

you need a pressure bleeder, only adjust the rear shoes with wheels

mounted to secure and hold the drums properly - and so you have the

wheel to turn while listening and feeling for shoe-to-drum drag.

[baller908790]

I ordered a master from Ireland and hopefully it

will resolve the problem as I have bled the lines

and clutch numerous times and I'm not sure how

old this master is so it will just be best to replace it.

Also C.D

you stated: The brakes work but only when

you reach close to the floor. = engine running and driving ?

or on jack stands and motor off?

It works with the engine on and the car running and if I floor the brakes while driving 15-25 mph the rear wheels lock up if that makes a difference. I'll see if the new master will resolve it.

[AsbestosIcan]

Does your car have a proportioning valve?

A 76 i had had a similar issue.The valve which was below and right of the master cylinder on the right firewall was leaky

you could see and feel brake fluid leaking out of it

I removed it and routed 2 lines back to the master cylinder and bled and the brakes had firmmness back and even braking again

[photog02]

Everyone else has given you good suggestions, but you do need to replace that cracked fluid reservoir cap. Brake fluid's performance, as well as its ability to help prevent corrosion and brake system problems, depends on not having moisture in it. Your cracked cap will allow more moisture into the system.

[baller908790]

I'm not sure if the car has that but there are no leaks anywhere.