Bleeding new brakes

[YJJPWrangler]

So, bleeding the brakes on the Willys for the first time. Fronts bled great, no bubbles, rotor locks up good. Rear is a different story. I bled the rears for about 2.5 hours. I have no bubbles and have taken the caliper off the bracket and pointed the bleeder screw up at 12 o clock. I have no bubbles in the rear calipers. The pistons in the rear calipers will not move at all. I'm running 78 Eldorado calipers(with e-brake) on the rear. I have verified that the pistons move by cycling the E-brake lever and the pistons move in and out. The driver side rear has about 1/16" inch of clearance between the rotor and pads and the pass side rear is about 1/8". The pistons do not move at all when the pedal is depressed. Any thoughts?

 

[Jason W.]

Priority valve on master cylinder bad?? Is it a single or dual piston master cyl?

 

[YJJPWrangler]

Dual reservoir master cylinder. Pedal feels good. No valves at all. Just straight lines to the front and to the back and then a T junction on the axle. I'm getting good flow at the bleeder screws.

 

[Fabrik8]

What's the order of connection on the master cylinder, and how's the pedal travel?

 

[YJJPWrangler]

Order of connection is: first port(smaller of the 2) feeds the rear and second port(larger of the 2) feeds the front. Pedal travel is OKish, nothing great at the moment.

 

[Ron]

Did you bench bleed the master?
Have you tried cracking the rear line at the MC?

Ok check that you say good fluid flow at bleeders on rear? Then that points to a system design fluid volume/pressure issue or bad hardware

 

[YJJPWrangler]

Bench bled the master. I'm getting good flow at the rear bleeder screws. Both rear calipers are brand new. I've had them for about 1.5 years installed on the jeep just not hooked up.

 

[Ron]

Then you dont have enough fluid (volume or pressure)...
Noticed it's a willys with rear discs...who selected/spc'ed the master ?

 

[YJJPWrangler]

Then you dont have enough fluid (volume or pressure)...
Noticed it's a willys with rear discs...who selected/spc'ed the master ?

I can't for the life of me remember what master it is but I do know that I found that recommendation off of Pirate in the Willys section. This is my master. It has two casting numbers on the underside 16027 and 1003256 but I was unable to cross reference them.

I talked with @R Q yesterday and he had a good idea of switching the ports(temporarily) to see if the rears would lock up. I switched the ports, re-bled and still couldn't get them to lock up. I now think that its my rear calipers that are the issue. I'm running 78 Eldorado calipers with attached E-brake. When I first did my initial research, these were the calipers to use if I wanted a E brake. I've read a lot more info in the last few days that these calipers are hard and finicky to set up and operate. You have to use the E-brake everytime you park the vehicle so that it adjusts the pads for pad wear. That wouldn't be a big deal if these calipers were working. Right now, I can actuate the E-brake lever on the driver side and the piston will compress and ratchet out. The passenger side will move slightly but will not ratchet out like its supposed to.

All that being said, I'm going to ditch these Eldorado calipers and move to a non-ebrake version. My rear disc brake conversion came from Daves Unlimited Customs and the instructions specify either Eldorado(E-brake) or Monte Carlo(non e brake) calipers Wagoneer Dana 44 Rear Disc Brake Bracket Kit.

 

[Fabrik8]

You could just rebuild the calipers if that's the only thing wrong with them (sticking pistons). Cheap and easy, as long as there's nothing wrong with the caliper bores (scoring/pitting/rust, etc).

 

[paradisePWoffrd]

Have you tried bleeding with the ebrake set?

How does the pedal feel? What happens if you pump the pedal; does it ever get firm?

Do you have residual valves in the rear lines?

 

[YJJPWrangler]

Have you tried bleeding with the ebrake set?

How does the pedal feel? What happens if you pump the pedal; does it ever get firm?

Do you have residual valves in the rear lines?

Ended up swapping out the rear calipers for a set of non E-brake calipers. Locks up nice right now.