[TubeTek]

I've got a 69 that I've owned since 72. Same brakes. The factory service manual on these cars says you can't get the air out of the system without a pressure bleeder and I've fooled with mine enough over the years to know that's true.

I just rigged up an aluminum plate with a piece of rubber glued to it and an air fitting threaded into it to make a shadetree pressure bleeder. Take the cap off and clamp it in place. Few pounds of air pressure and make sure you don't let the reservoirs go dry in the process, and you can bleed them right out in no time.

Due to the way the brake lines are routed to the rear in particular, there are areas where there's an inverted trap in the line. In normal bleeding by pumping the pedal and holding, air sits at the top of the loop, moves some when you open the bleed screw, and goes right back to the top of the loop as soon as the flow stops. The pressure bleeder just creates enough flow to carry the air on to the calipers so it can get out.

Getting all the air out is even more critical if using DOT 5 (silicone) brake fluid. Air will entrain in silicone, and if you happen to drive up in the mountains the air will expand due to the decreased atmospheric pressure and your pedal will go completely away. Drove 30 miles like that one day on the Blue Ridge Parkway and it weren't no fun at all.

[bocephus86]

[QUOTE=jncgitrdun]my dad has a 1974 corvette with power assist brakes. the master went bad and leaked the fluid out. we put a new maste and new front hoses on it. the problem we r havein is gettin the pedal back. is there a special procedure or method to bleedin them? we bench bleed the master than bleed at the lines on the master than bleed every caliper but still nothing. the pedal hold the car but its very soft and at higher speeds it woukd never stop the car. if anyone has any answers we woukld be very greatful. thanks[/QUOTE

don,t no if it is posiable to do on vett but i have seen calipers get mixed up
left to right /right to left putting the bleeders on the bottom therefor not
letting all air bleed out

[Gene Neal]

Well just thought I would through this in the works !I have read all the post and they are all good advice , but I Was just wondering if this 1974 Car came with a dull brake system, you know front brakes and rear brakes. They have two lines coming from the master cylinder and going to a shut off valve . must of the time this system has a indicator light that will come on ( Break fail ) if it had been activated. The reason I'm asking is that the shot off valve some times gets sent to one side or the other while bleeding the brakes. There are a few different kind so they all don't work the same but some you must remove the electric sensor so the shot off valve will reposition its self the replace the sensor. Another one has spring pine that while bleeding the brakes the piston inside moves to one side or the other and the pine falls into a detente and keeps the piston from returning. this one is a bit difficult to reposition as you just pull back on the pine while some one pushes the brake peddle down ,and slightly open the wheel cylinder bleeder and moving the piston back the other way till it again falls into the center detente. this some times makes the brakes fell like they have air in the lines.

Do this for your vacuum boost to see if it is working OK or not : with the engine shut off pump up the brakes and hold the peddle down tight , while doing that then start the engine up and the brake peddle should be sucked down. if it does that then the boost is working!
-------------------------------just my thoughts! Your Friend, Gene Neal

[Mini Cobra]

The system is drum brakes, no power assist. I have replaced all the replaceable parts on the system, Master, Wheel, Hoses, Shoes. Bleeding rr, rl, fr, fl. Bleeding process: open bleeder, push down on brake pedal, hold, close bleeder, release pedal, repeat until no air comes out. This has been the process I have used for years. It has been a long time since I have bled a GM system of this age. Is there something I have missed?

[HotRodMan]

I have used that same brake bleeding method for years and it always worked until I worked on a corvette. For some reason it would not work at all on that car. Try this.

1. Go to the parts store a buy a one man brake bleed kit. Its just a plastic bottle with a clear hose and its cheap.

2. Start bleeding with the rear passenger side of the car.

3. Open the bleeder screw, connect your hose and raise the bottle higher than the brake drum, while you are pumping the brake pedal. No need to open and close the bleeder screw like you normally do. Leave it open until you are finished bleeding. The key is to have that bottle up high and do not let your master cylinder run out of brake fluid. Pump the brake pedal slow up and down until you no longer see air bubbles going thru that clear hose.

4. Use the same procedure on the other wheels. Rear driver's side would be next followed by front passenger side then front driver's side.

I have used this procedure on all my cars for years and it has never failed me.