Adam, Would it be possible to add another catagory under C3 VETTES to include a brakes discussion page ? C3's are notorious for having brake problems. I have been battleing my brakes, and had numerous mechanics try to diagnose and fix them since I purchased it two years ago to no avail. I have replace almost the entire system at a conciderable expense and still expeierence soggy pedal. A majority of C3 Owners are in the same boat. I would like to see how many others share my frustration and read how they have overcome this problem. I am still working on mine.
Thanks,
Joe V.

|UPDATED|4/9/02 6:37:16 PM|/UPDATED|

A brakes catagory is a good idea!
My brake pedal went almost all the way to the floor at a gas station one day...got out and took a look for fluid on the ground but there was none.
I got her home on just the front brakes. The rear half of the master cylinder was empty! Where did the fluid go?
Before I go dumping $$ into the brake system I hope someone can share with us"the fix" to our common brake problem.

Joe give me a brief rundown of whats been done as well as what you are experiencing now with your brakes system !!

G
PS if you feel it could get lengthly send an e/mail

4webbers beat me to it. I was going to ask the same question. I have had considerable luck in restoring a couple of Corvette problems. There are a couple of basic rules that I have found to pick up the pedal. When bleeding always put some of the lugs on the rotor and just make them a bit snug with a wrench (that is if the rivits have already been drilled out) What I have found happens if the rotors have been drilled out, as you are pumping the brake the pistons are actually putting side to side movement in the rotor, very slight, but enough to cause a small cavitation in the caliper causing small air bubbles. Also, if there is any play at all either in the front bearings or rear bearings, that can cause a slight wobble in the rotor, causing the pistons in the calipers to move in and out at a high rate which causes cavitation again making lots of air. That was the cure for my brakes. I know that was a known problem on the early 68's which was corrected by GM late in the model year.
I also changed to the Dot 5 synthetic fluid. That made all the difference right there.
All the above worked for me,
JoeB

75Corvette -- check rotor run out front and rear. Excessive run out will pump air into the system as WoodWorkr explained.

Dyza77 -- If there was no fluid in the rear of the master cylinder, you've got a leak. Check each of the rear calipers, inner and outer halves. Check the backsides of the rear wheels for evidence of brake fluid; check the rear brake hoses for evidence of leaks; check the proportioning valve down on the frame, although these seldom leak or go bad; check the rear bowl of the master cylinder.

|UPDATED|3/15/02 2:39:19 PM|/UPDATED|

Pay attention to bleeding sequence as well. I goofed up the first time I flushed the brake fluid and had a very interesting ride home one evening (especially since my emergency brake doesn't work very well)...!!!

The service manual I have says to start at the right rear, then left rear next, right front, and finish with the left front. It was a slow process without any help so recruit a peddle-pumper if you can.

I owe you both a huge THANK YOU !!!!!!!!
It was exactly what the problem was. I have had at least 8 mechanics working on my problem in the last 2 years. I've had every thing, and I mean everything replaced in the braking system EXCEPT the rotors. and that is because they all said the rotors were O.K. and nobody ever checked the run out. I put my trust and my money in these guys and I feel like I was taken advantage of. I printed your response to my post and took it with me to a new mechanic and he checked the whole system and low and behold he said the rotors were bad.
I have been so frustrated with this problem that I was about to sell my vette, I mean 2 years and at least 2 grand and it turned out to be the rotors. I've had 6 master cyladers, 2 complete sets of calipers, 3 proportioning valves, 2 sets of brake lines. the brakes have been bleed at least 20 -25 times using various methods.
Thats all I have to say right now Except THANKS FOR ALL YOUR HELP. I HAVE BRAKES !!!!!!!!!!

Also thanks to ALL WHO RESPONDED TO THIS POST.
AND THANKS TO THE C3VR FOR THIS SITE.

|UPDATED|4/9/02 6:30:39 PM|/UPDATED|