Brake Problems

[jimmybb]

Hello everyone this is new to me so not sure if I'm doing this right.
I have been elected to work on my son-in law's mother's 75 vette and having problems with the brakes. The car has over 100.000 miles and looked like it has been a long time since any work has been done,I replaced the rear pads , had the rotors turned and ended up at above specs. Did not open any lines just replaced the pads. Had a very low pedal to start with now have no pedal at all and the light is on the dash???
What do I do next? It's hard to think i 'd have tp bled the brakes because never opened a line? Any ideas??

 

[Rex S]

We'll need a bit more information such as when the car last had any brake work and what kind. Here are a couple things.

1. Master cylinder bleeding by internally.
2. System leaks due to previous rotor run out (air can actually be drawn into the calipers).

Try bleeding the system first but I have a hunch it's just time for a major overhaul.

 

[Vettehead Mikey]

You might have created a problem by having the rotors turned. Can't do that on C2/C3 Corvettes as it usually induces a rotor runout problem where none existed before.

Get your self a dial indicator and measure the runout. Ideally should be less than .003" measured around mid span.

 

[jimmybb]

Brake problem

Well don't know what history of this vette is, the lady just bought it. ($6000).However it is a 1975 and the rotors was already drilled out so it has been apart before, the old pads where worn on a angel, there is no parking brake shoes, someone took them off, parking brake cables are cut off. the reason for looking at the brakes was a clunk noise under 5mph. I did notice a few drops of fuild on one of the pistons when I put the pads.
From what I've read sounds like a real problem. Also the rubber seal on the cap of the MC is swelled up and looks like it does not seal right.

 

[sstearns2]

I did a total brake rebuild on my 77 years ago. I'd bet the calipers already have stainless sleeves in them. I'd get rebuild kits for all the calipers. They are pretty cheap and the calipers are pretty simple to rebuild. I bought new calipers only to find I could have rebuilt the ones on the car a lot cheaper. If one of them is leaking then they are probably all in need of new seals, it's only $15 per caliper for a seal kit.

I would get new rotors at least for the fronts. I personally never have rotors turned, just get new ones and recycle the old ones. A new rotor in only $65 and they are probably going to charge you $20 to turn an old one.

A rebuild kit for the master cylinder is pretty cheap, even a new one is pretty cheap and change the fluid. Also if the rubber hose don't look pretty new I'd replace them, they're pretty cheap.

If you going to go to the trouble of tearing into it then it's really not that much more time and money just to rebuild the whole system. The whole parking brake system is only $160 on Ecklers.

Cheers,
Scott

 

[jimmybb]

Brakes

Thanks for the info. Do you feel that the e-brake is that inportant? It is a automatic. The reason why I'm asking is the lady that owns it is going to ask me..... Can I get all that I need at this Ecklers? Also the rear rotors is the ones that was turned, should I replace those also? Do you have to hone the bores on the calipers? One more Question, The rears have metal lines going to the calipers can you replace them with hoses?
I really appreciate the help!!!

 

[Vettehead Mikey]

Jimmy,

Please read up on the pitfalls of 'rotor runout' on this site or others as it applies to C2 and C3 Corvettes. A new rotor or one that has been turned must be measured after installation to ensure that runout is below .003".

 

[petes74ttop]

How to for parking brakes www.corvettemagazine.com/technical-articles/c3/107-corvette-parking-brake-rebuild.html

About turning rotors www.oeqf.com/techinfo/index.htm

 

[Vettehead Mikey]

Machining the rotors OFF the car as shown on the video might have been the start of the OPs problems.

 

[sstearns2]

Thanks for the info. Do you feel that the e-brake is that inportant? It is a automatic. The reason why I'm asking is the lady that owns it is going to ask me..... Can I get all that I need at this Ecklers? Also the rear rotors is the ones that was turned, should I replace those also? Do you have to hone the bores on the calipers? One more Question, The rears have metal lines going to the calipers can you replace them with hoses?
I really appreciate the help!!!

Ecklers and Mid America are two big corvette parts places.

I would restore the parking brake. If you park the car on a hill it will be difficult to get the transmission out of park since the weight of the car is resting on the gear. After watching that video from the post above, I'd just replace all the rotors.

There should be rubber lines somewhere to each caliper to let the caliper move with the suspension. If I remember right there is a hard line leaving the caliper that connects to a rubber line that then connects to a hard line on the frame.

Good luck. Keep us posted...
Scott