Ok, I'm completely stumped. I'm working on my neighbors '69 SS as a hobbie. I've been tackling the brakeing system for some time now and I still can't get the car to stop at all. I've replaced the master cylinder, power booster, all bads and shoes, rear wheel cylinders and have bled the system numerous times but the pedal still goes to the floor and the car won't stop. What can I do?! It's driving be crazy!! Any help will be gratly appreciated. Thanks

The first step is to make ABSOLUTELY sure that the master cyclinder is bench bled and that all air is gone from it!! Otherwise, you will be bleeding forever with no pedal when you're done. After you're done bench bleeding, remount the master cylinder and starting with the right rear, begin your bleeding procedure. Now, if you've had everything open to replace wheel cyclinders, etc, open the bleeder valve and go in the house and have a beer. When you come out, see if any fluid appears at the valve just from gravity. If so, install your bleeder hose, immerse the other end in a jar of brake fluid and, with help, start bleeding. Now, with the engine OFF, have your helper SLOWLY, push the pedal down to the floor. Close the valve. Let him/her SLOWLY let the pedal up. Keep this up until you no longer see ANY air bubbles, just a clean stream of fluid. It would help to have a third person checking the fluid level in the master. Check it often. Move to the left rear. Perform the same procedure until NO MORE AIR BUBBLES ARE PRESENT!! NONE! Move to the front. If you have disc brakes, be sure the bleeder valves are facing UP. If not, you have the calipers reversed, right to left. Again, front right first. Open the valve, have your helper push the pedal SLOWLY down. Close the valve. Let the pedal up. Do the same for the left front. If you've had brake fluid flow at ALL four wheels with NO air bubbles, you should now have brakes. If not, your master cyclinder is more than likely the problem, especially if it's a rebuilt unit. This procedure has worked for me for the last 38 years or so of working on cars, and has always worked for the last 32 years on the Chevelle. If it doesn't, look for a bad brake line, hose, or, a defective rebuilt master cylinder.

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
580,000+ miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

Thankd for the advice. Further inspection and testing revealed a faulty rear brake hose that was letting a small amount of air into the rear lines. After replacing, the brakes work GREAT!! However, when going relatively fats and when the brakes are applied hard, they woprk well for a few seconds and then they suddenly go away and the pedal is lost. I'm thinking their might be a poicket of air still trapped in the master cylinder since the problem goes away after a few quick pumps. Still, it's an unpredictable and dangerous problem. Overall though, the main problem is deffinately fixed.

How much cam does he have. I have to use a vacuum canister with my setup, without it, my brakes worked about like you're describing. The cam sucked all the vacuum out of the motor. Just another thought.

How much vacuum has NO effect on the actual braking action...just the braking EFFORT! If you have no brakes, it's a problem in the hydraulic system. Logical troubleshooting is the key here. In my line of work, electronics, many times, going through the alignment proceedure will highlight the problem. Same thing here. If normal braking operation can not be had by the typical bleeding operation, then, further troubleshooting is in order. The rear lines are especially difficult when it comes to eliminating all the air. If there is ALOT of air, or the front to rear line was replaced, either a pressure bleed is called for OR leave both rear bleeder valves open for a bit, letting gravity get most of the air out. Then, normal bleeding should take care of the rest. If ALL the air is gone and you still have a pedal that goes to the floor, then you have a bad master cylinder that is leaking down under pressure.

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
580,000+ miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

Well thanks for the advice. The cam is stock and there is no vacume loss. Besides, a vacume loss would ontly make it harder to press the pedal, not easier. I'm sure there's just a bubble trapped somewhere. I'll just keep bleeding till i find it. Thanks for all of the help.