Brake Bleeding Problem

I just converted a 66 cj5 to disc brakes and installed one of herms dual reservoir master cylinder kits. i have bled the brakes the normal way, used a vacuum pump and reverse bled them from the calipers and wheel cylinders and it still takes 8 to 10 pumps to get any pedal. Can't find any leaks, tried with and without the proportioning valve and nothing has worked. bench bled the master twice. This is the third one of these conversions I've done and I've never had this sort of problem. I'm out of ideas. Anyone have any thoughts about anything else i should try? Thanks

 

Check the freeplay at the brake pedal. Sounds like there is still pressure from the brake pedal on the master cylinder.

 

yep have 1/2 to 3/4 " of freeplay

 

Have you manually adjusted the rear brake shoes? If the rear brakes are not adjusted correctly, this can cause this type of problem.

 

yes adjusted them up still nothing. Pulled the master and disassembled it and everything looks good. Bench bled it again. Will try it again tomorrow

 

I had to take my calipers off, get the bleeders straight up vertical, 2x4 in the caliper to get the air all out.

 

I had a Beazatch of a time with my set-up ,too. I just kept at it........ I learned, toward the finish, that a semi experienced helper helps big.

 

If the rear brakes are adjusted properly, then you still have air in the system.

You said you pulled the MC again. Anytime you open anything in the system you introduce more air.

I cobbled up a DIY pressure bleeder using a M38A1 bleeder cap (has no vent and has a hose barb) and a 1 gallon weed sprayer. I bench bled the MC, installed and hooked it up, pumped up some pressure, then starting with the right rear brake I attached a clear bleeder hose with a check valve submerged in a mason jar so I could watch for bubbles. Just open the bleeder valve wait till a clear stream of fluid with no bubbles comes through shut the valve and move clockwise to the other three brakes.

Disc brake pistons hold a lot more fluid and air than drum brake wheel cylinders.

 

I fought bleeding brakes till I used speed bleeders. Was done in one evening

 

I went through this for many hours. I finally got some help from someone mysterious. I called this person and they said to never call again and wouldn't give me a name. Told me to lose the number after. Anyway here is the process.
Remove the driver caliper and place a block of wood between the pads. Raise the caliper as high as possible. Bleed the brakes as you normally would. Replace the caliper. Repeat on the passenger side.
Worked for me perfectly.
Hope it helps.

 

You called the CIA??

 

It was a very strange phone call to say the least. But it worked for me!

 

wanted to say thanks for the help. Took the calipers off, got the bleeders straight up and it worked. Never had that problem before, but I had never used cj calipers before and never noticed where the bleeder was located.

 

Glad to hear it worked for you

 

Ya know...... Thank You fellah's.
I recall , along time ago, some old school mechanics using that same trick of the Trade.

 

......Again??? ( ... )

 

What is the number? I may have an issue I need help with.

 

Too many years ago, that number is long gone