Air Brakes

[amasciarelli21]

Well kind of I hope someone can help. Three week ends of trying to get air out of my brakes has me at my wits end. I'm running a 90 degree under dash master cyl/booster combo w/ FFR frt calipers and cobra rear calipers. Replaced all lines a second time, inspected for leaks and found no visible leaks, proceeded to use gas pipe leak detector at every fitting and hose and found two lines at first w a few air bubbles, tightened lines- problem solved I thought, found that every line and the threaded rod of the wildwood proportioning valve were leaking air. I tried to tighten lines but leaks wouldn't stop , replaced valve w/ SSBC valve/ no more leaks there. I have bench bleed master cylinder three times and again no pedal. There is air at all four wheels. I have bleed brakes by pumping and holding down- pressurized master cyl etc. and after bleeding a caliper to where there is no air I shut the bleeder screw pump the pedal twice, open that same bleeder and I have two full pumps of air in the fluid. I am stumped am I missing something obvious?
Any thoughts would be greatly appreciated.

Ang

[Arrowhead]

There are a couple of tricks, but they may or may not work. When bleeding the front calipers, remove the caliper bolts and tip the caliper back and forth while pumping (keeping it on the rotor of course). The caliper is tipped slightly (more so that it should be) when bolted on so there is a small air pocket at the top of the caliper that the bleeder can't bleed.

You are using a power master cylinder so it's not the supplied dual adjustable Wilwood one correct? If it was there are some tricks for that too. One is to bleed the front and rear at the same time. This makes sure you have full pedal travel when bleeding both ends. That might help here too. I just take a couple of small coffee cans, put a hose on a front and rear bleeder with enough fluid in the bottom of the can to submerge the hose and pump away with both bleeders open (keeping an eye on the reservoirs of course). This gives me full travel, no air is entering when I release the pedal and it a one man operation.

Other than that it could be your master cylinder/booster. Just because it might be new doesn't mean there's not something wrong with it, happens all the time.

[amasciarelli21]

Thanks Arrowhead, I was able to clear the back lines last night finally but frts were still giving me a problem. I had a friend come over tonight and we reverse bleed the frt. brakes and that did the trick. You were probably right about the air pocket in the front calipers what a relief. Now to go over my checklist and hopefully go cart tomorrow. Thanks for the response.

Ang

[maczter]

Also make sure you have the calipers reversed...L on R and R on L, otherwise you will have an air pocket and never get a pedal. Had a similar issue on a 72 Nova SS that I converted to front power discs. Had it to two different shops, power bled, and still no joy. One day while I was working , my Dad was tinkering with it and he noticed the bleed screws were not at the top, I had the calipers reversed. FFR actually needs them reversed to get the bleed screw at the top.

[amasciarelli21]

Thanks Maczter, Thanks to this great forum That was one issue I was aware of from the start. But happy to report power brakes are working great and was able to finally put her on the ground and go kart around my yard, everything went well but I did find one leak the inlet tube of the coolant over flo bottle. My street is way to busy to attempt a road test so i'll probably trailer it up to our school parking lot and make a video to post. I can say I am defin. going to go w/ the power steering set up, I don't know hoe anyone can drive this car w/ out it.

[Arrowhead]

I can say I am defin. going to go w/ the power steering set up, I don't know hoe anyone can drive this car w/ out it.

The power steering is nice, I have it and do like the ease of effort. That said I did run it for about a year without it. The trick is to reduce you caster angle to about 3 degrees when running manual. It steers easier but you give up a little straight line stability. When you have power, you can lean the wheels back to a bout 6-7 degrees and increase your stability but still be able to turn easy at slow speed.

[amasciarelli21]

Thanks Arrowhead that's a great tip i'll work on the alignment part of it this weekend I have already printed out Dan Ruths alignment instructions and ready to tackle that job. I'm going to have to save up for the power steer. not in the current budget. Once alignment is finished I can't wait to start on the body work, thanks again for the info.

Ang

[4wheelspin]

Do you have any pics of your power Brake set-up?