We just got our master cyl. and booster back from being redone and we are having problems getting the air out of the system. The m/c was sleeved with a stainless sleeve and the booster was rebuilt to spec. The m/c is the original mast. cyl. that has the bleeder screws on the side of it and with the reservoirs filled, we are not getting any fluid out of the bleeder holes with someone operating the brake pedal. The bleeder screws are bone dry. What would cause this? I tried to open the right rear wheel cylinder to get the air out that way. Still nothing. Any helpful hints? The car is a 70 Elky SS 396 with power brakes and disc fronts. We completely replaced the whole brake lines with stainless steel lines and replaced the rubber lines as well. Would renting a pressure bleeder be the answer to my problems? I need to get this done soon so I can get the car mobile to get some very minor repaint work done to it before my first show on May 2nd. Thanks for the suggestions in advance.

Brian

Thanks,

Brian Kapral
Boonton, NJ

Did you bench bleed your master cylinder first? Near impossible to get the new system correct without doing this.
Fill the reservoir and have a tube from the outlet back into the resorvoir. (mount the M/C in a vice) Slowly press the piston in using a dowel such as a bromm stick until all bubbles are gone. Try not to introduce bubbles when pouring brake fluid.
Good luck.

I suggest you bench bleed the master cylinder off the car and then reinstall it. My manuals tell me the master must be level when bench bleeding to ensure no air is trapped in a high spot. When the master is on the car, it is tilted high at the front. The air accumulates here and you can never bleed it out while in that tilted position. That may be your problem. When I bench bled my new master 3 weeks ago, I was surprised at how long it took to get all the air out of it. Finally, it pushed fluid and no air bubbles.

Do you still need to bench bleed the m/c even though there are the bleeder screws on the side of the m/c? I thought thats what they were there for?

Hi Brian...I agree. You will probably need to bench bleed the master (as stated above)even if it has the original bleeders. I have tubes I made up with some stainless steel lines I had sitting around. They take the fluid out of the lines and dump it back into the reservoir. Your welcome to borrow them if you feel like a 1/2 ride south on 287....You will need to remove the master and stick it in a vise (with a rag so you don't scratch it)

Well, what I have done in the past is stick the m/c in a vise to bench bleed the air out but I have always used either a piece of rubber or two blocks of wood to prevent the vise from scratching the finish. Looks like I will need to yank the m/c off tonight when I get home.

Thanks for the input.

Brian

Well all, I think I finally figured out what the problem was.... I ended up calling Van (owner of Vanco power brakes in CA) and he said to go through the whole bleeding procedure with him on the phone. After that didnt work, he told me to take the master cyl out and bench bleed it with my fingers covering the holes. When the piston was released, the front line (front calipers) was getting suction on it casing my finger to stick to the hole in turn casing the piston to not return all the way. This is why I could not bleed the brakes and was having problems with it. He told me to send it back and he would personally disassemble and inspect it and rebuild it himself and send it back to me. I currently have a friends 71 master cyl on there. When I bled out the brakes and started doing the fronts, still nothing but air. Then when all else failed, I read the directions (now theres a shock) and found out that you need to push in the button on the metering valve. Well, since that has not probably been pushed in since the car was new, it was frozen. A little help from the flat head screwdriver and now the 1/16" movement that it was supposed to have is now 1/8-1/4" and the pin is stuck inside the metering valve. This all started cause of an ugly looking rust trail at the 6 o clock position on the power brake booster. graemlins/sad.gif As soon as this car is done getting put back together, I am going with the adage, If it ain't broke, dont fix it. I will keep everyone posted on this folly. graemlins/clonk.gif