Have a question for a friend, and it's not a Vette, it's a 70's Nova. But I figure you guys could help since it's basically the same deal. He says he is bleeding it and gets plently of pedal pressure, but as soon as he starts the car, the pedal goes to the floor and stays there. He's gone through several bottles of fluid. He says there are no leaks. He did replace a caliiper if that might have something to do with it. It sounds like he is doing the bleeding properly, he's doing it by hand.

 

Sounds like he needs a new Master Cylinder!

seeya

 

Oh, that suks. Anyway to be sure?

 

Sucks? They're $19.95 at Kragen all day long.

If the pedal goes to the floor - it's the master cylinder or one of the other calipers/wheel cylinders.

The hydraulics at the wheels would leak if they were bad.

I'd give it a 75-90% chance that it's the master. I bought those rebuilt ones from kragen for an old truck - worked great. I guess you can rebuild them when the thing is made out of cast iron. Aluminum is a no-no.

 

Pedal to the floor, with no visible system leaks is generally the MC.

The fact that he gets a firm pedal till he starts it, would indicate to me that as soon as the power assist is added, the MC goes away.

Advise him to buy a new MC, not a rebuilt. Rebuilds cannot replace the metal in the cylinder bore

seeya

 

My thoughts were that the whole car was bad. Wanna hear how the whole ordeal started. He was on his way to work, he heard a pop like he hit a rock. He pulled over, didn't see anything. A little farther down the road he heard it again. Same thing, nothing to see on the car bad. Starts driving and gets to about 30mph and the front left wheel comes off. He ground the steel junker to a halt. He replaced the wheel, caliper, rotor, and studs/lugs. Upon trying to bleed it he has this problem so I figured that there was a problem with the bleed. Could a master cylinder just go bad liek that? I guess for $20 he'll probably be willing to replace it.....


Err, hold on. He's now telling me that one of the brakes isn't getting fluid out of it(not the replacement one, one of the rears). He says it sounds like its working when he touches the pedal but there is no fluid coming out when trying to bleed. I'm going to have to go over there and see this for myself.

 

Sounds like he should not be allowed to work on vehicles that will be used on public highways! No offense! To You!

But if the car is that bad, get him a bike!

 

LOL, you won't believe this, but he had a bike(motorcycle, Yamaha R1), but he wrecked it twice in the first 4 weeks he had it. So now he drives a truck. Guess he needs a pedal bike.

Sorry about this thread, I'm going to look at the car this weekend and see what's actually happening. He seemed to know what he was talking about, until now.

Later.

 

Don't let him drive it east of the Mississippi.

 

Sounds like a M/C. Its cheap, make sure you buy a new one and not a reman. one. Also quite simple to install.

 

...
I think this is the same guy who helped me in Pep Boys once..

 

Since this is a Nova with read drum brakes, I am guessing that the metering valve may be the culprit. I do believe changing the master cylinder would definetely help. Make sure that when he is bleeding the system, he placed the bleed tube into a jar with brake fluid in it and the tube or hose stays below the fluid. He could be introducing air into the system without realizing it.

Good luck.
Dino

 

BLEED the MC. I had the same problem on my '69 Vette. I had done a bench bleed on the MC, and thought that would do it, especially since many MC's don't have bleeder valves on them (tho I have seen some that do).

Here's what you do. Have an assistant slowly push down the brake pedal while you crack open one brake line fitting at the MC. I bet you see some bubbles as the air comes out. When you're just getting fluid, then tighten it up and do the other one.

If this doesn't work, then you need a new MC.

Good luck. Happy motoring, Doug