brakes staing on

[rubicon]

My brakes are staying on. The pressure in the lines won't drop. where should I look first and what could cause this. List everything you can think of. Its almost 70 degrees out and I won't to get it on the road. Thanks

 

[ellis8500]

Define your brake system. MC location, components in the lines, wheel cylinders/calipers. I have MC on firewall, no proportioning valve, no check valves and 4-wheel discs with fronts larger than rear. Have no problems of any sort.

 

[old round fart]

Be sure your linkage into the master cylinder has a little play.

 

[choppedtop]

Are all four wheels locked up? If so, probably the m/c. If not crack the bleeders on each brake to help locate the problem. Also X2 on orf's suggestion.

 

[rubicon]

I have disc all four corners. I have a proportioning valve. check valve from MS to Proportioning valve. I put some play in the linkage to the MS the brakes came loose. That may have been the problem but please give me any other ideas that could cause it. Just in case that wasn't it. Thanks I did go on my first ride. How sweet it was.

 

[choppedtop]

Sounds like you found the problem. Pretty common thing really. It don't take much, but you have to have a bit of free travel. Now you can have some fun.

 

[lincolnuT]

Why do you have a Check Valve in the system? With 4 wheel Disk you probably don't need a Prop Valve either even though I don't think you need any Prop valve at all even for Drum Brakes.........

 

[rubicon]

This is the way it came from CCR. I'm sure Jerry knows more about this than I do. I thought the check valve was to keep the brakes from bleeding back to the MC. Not sure.

 

[fletcherson]

This is the way it came from CCR. I'm sure Jerry knows more about this than I do. I thought the check valve was to keep the brakes from bleeding back to the MC. Not sure.

You are right, it prevents the calipers from collapsing so the pad remains in contact with the rotor. With the caliper piston being much larger than the master cylinder, if the caliper collapsed, it could take several pumps to refill it, in theory, and you wouldn't have good brakes.

 

[lincolnuT]

I will just leave that alone then but I respectfully disagree with Jim at CCR..........I have 4 wheel Disk on my bucket and I have neither a check valve or a Prop valve and the car will stop on a dime & give you change on the first pump........My master is below the floor in my bucket.........

 

[Spanky]

I had a similar problem on my disc/drum setup. Traced it to not enough pedal travel. Pedal was not returning all the way due to hitting the floor board. Cut the opening a little larger and, voila - no brake drag!

 

[fletcherson]

I will just leave that alone then but I respectfully disagree with Jim at CCR..........I have 4 wheel Disk on my bucket and I have neither a check valve or a Prop valve and the car will stop on a dime & give you change on the first pump........My master is below the floor in my bucket.........

Out of queriosity, what master are you using?

 

[Indycars]

That may have been the problem but please give me any other ideas that could cause it.

This should provide a few ideas!

 

[Spanky]

Wow . . . that's very comprehensive!

 

[rubicon]

Thanks for all the replies. Looks like I have my work cut out for me. Never gave it a thought that the pedal could be dragging or binding. Ill check that out today. Thanks for all the charts Indy. That must have taken awhile to down load. Ill let you guys know what I find.

 

[lincolnuT]

Fletcherson I am using a 1975 Chev Monza cylinder for non power brakes, I bought from Rock Auto.......

 

[rbsWELDER]

Indycars - Great Info! Thank you!

 

[choppinczech]

Indycars - Great Info! Thank you!

Yeah, I'm saving that!

 

[Indycars]

Glad you all found it useful!

 

[fletcherson]

I like flow chart troubleshooting charts. Over simplistic at times, but when you have your hands in stuff, it's hard to flip through pages, get online, etc... I still have paper manuals from the '60's through 2000 or so for that reason, even though I have full Petersen "on demand" software. The old motor manuals and the like gave good detailed troubleshooting data, in addition to tear down and reassembly. The software actually has decent flow charts too. The transmission series is less detailed than I like.