i have swapped GM 10Bolt and 14Bolt FF axles with the big 3/4 ton brakes into my 80 CJ7,
converted the 14Bolt with K20 rotors and Eldorado Calipers to disc brakes,
and also installed a Blazer K5 MC on the stock CJ booster,

my 1st problem is after bleeding several times, i must push the brake pedal 2 times to get a presure and the Jeep stops, the 1st one i can push it to the floor, and the 2nd one i have brakes,
i have pumped about 2 quarts of fluid throu the brakes, so i think there could not be air in the system,

the second problem is that i used the stock CJ prop. valve, and what i searched i had to remove a valve or spring to reduve the presure to the rear disks, but i can not verify where i had to remove it,

i hope you can give me some tips what could be wrong

i have pumped about 2 quarts of fluid throu the brakes, so i think there could not be air in the system,


You are mistaken...you still have air in the system. Eldorado calipers are impossible to bleed completely. Trust me you still have air in them suckers.

Take them off the axle and rotate them around and tap them with a hammer while bleeding. Spend 10min on each caliper.

ok,
and what about the prop valve ?

take it out.

its better to remove it than attempt to defeat it and risk losing your brakes entirely.

run one hard line from the MC to the fronts, and one to the rears

First off read this and your answer is there.

http://pirate4x4.com/forum/showthread.php?t=292583

Second I wish people would stop saying to yank out the prop valve. If you do that you might as well put on a single stage m/c, it would actually be safer. ALL propotioning valves have a safety bar in them (Law by DoT) so if one half of your m/c fails it gets blocked off. Removing the valve removes this feature. The valve also keeps pressure to the rear and stops too much fluid from going there. There's a ton of reasons to keep your valve and not 1 to get rid of it.

From my continued aggrivation of those rear caddy calipers on my 55 chevy, I'll repost this saying.... EL DORADO REAR CALIPERS SUCK!!!!! After the initial 3 trips to the parts store to get a set that didn't leak, one will start leaking again at lease once a year. :mad3:

ok, so i think my setup is ok, i had only bleed this caddy calipers,

but one more question, where is this residual valve ?
in the MC or prop. valve

The valve also keeps pressure to the rear and stops too much fluid from going there.

yup. and his stock valve is metered for the flow necessary to operate drum brakes.

is he running drum brakes now?

at the very least, he needs to swap it out for one designed for use with rear discs.

The residual valve is in the prop valve. It's in the section where the rear line goes into it. Commonly refered to as the "o-ring" people like to remove all the time. Grapehead has a point, using a 4wheel disc prop valve would be better. However it's not the reason he has air in them.

Chances are there is still air in the system. You must have the bleeder screw pointed up. You'll also find out you need to tap the caliper with a hammer (plastic) to get the last of the bubbles out. It usually takes 2 quarts to bleed an entire system. Don't forget cheap or old brake hoses are notorious for expanding a significant amount.

Lastly, I'd put a combination valve out of the K5 in it. I'd also consider the powerboost diaphragm also because you'll find that the itsy bitsy one in the CJ isn't nearly as nice as a K5 one. You'll also end up running an adjustable proportioning valve.

are there pics available of the oring ?
or would i directly see the oring ?

i tried the K5 Booster also, but it would not fit really good

i am running a similar setup, and the problem i had bleeding was that the stock combination valve wouldnt flow enough to the rears to get the air out, so i removed it and ran separate systems.

if half your MC fails you still have the other half, and with 4wheel discs either end is just as good as the other.

i am running chevy calipers though on the rear instead of caddy. ive heard nothing good about the caddy's as far as difficulty in bleeding.

i am running a similar setup, and the problem i had bleeding was that the stock combination valve wouldnt flow enough to the rears to get the air out, so i removed it and ran separate systems.

if half your MC fails you still have the other half, and with 4wheel discs either end is just as good as the other.

i am running chevy calipers though on the rear instead of caddy. ive heard nothing good about the caddy's as far as difficulty in bleeding.

Caddy you're misinformed buddy. A duel m/c needs the prop valve in the vehicle if half of it fails. I posted this a few times and save a copy to make it easier on me.


First off is the duel job of a proportioning valve. I explained the how it holds pressure but it has a much more important job that I like to stress. You guys remember the old vehicles that came with single piston master cylinders. As we call them, suicidal master cylinders. Problem with these is once the 1 cup failed all your brakes failed, time to downshift and hit the e-brake and pray.

So along comes the duel master cylinder to solve this problem. If 1 cup fails then half your brake system failed and the other half will stop you. All good in theory but it’s only half the story. Those 2 pistons in the master operate together. If 1 fails they BOTH fail to the point where you can’t stop the vehicle. You guys have all heard this story right?

“I was driving down the road and was coming to a stop when my brake pedal hit the floor. I panicked and pumped my pedal and was barely able to come to a stop. Scared the crap out of me”.

This is what happened.

1. A master cylinder cup failed and both pistons followed each other and you lost all brakes.
2. Both master cylinder lines are attached to the proportioning valve; these lines put pressure on both sides of a piston inside the valve that’s sole job is to do nothing when you have pressure on both sides.
3. One side of the master cylinder had pressure (the good side) the other side did not (the failed cup). So the piston’s second job came in. That’s to be slid over by the pressurized side to block of the port to the bad side.
4. Now your good side of the master cylinder will operate enough to stop the vehicle. The bad side is blocked off and the good side can put the pressure out to your brake system instead of through the bad piston.

I stress this for a reason. I see many guys removing their proportioning valves and replacing them with metering valves. When you do this you just went from a duel master cylinder to a single (suicide) master cylinder. If you feel you have too much pressure and would like to put on a metering valve to fix it, go ahead. Just please leave the proportioning valve on, don’t remove it.

Note: If you need a metering valve there’s a reason. They where designed for racing vehicles not as a “fix” to your brake systems problems. Best bet if your modifying your brake system is to do what GM, or Ford, or the like did. Decide on a front caliper, see what the manufacturer used for the rears and use the same sizes. They did all the testing and engineering for you, take advantage of it.

The only TRUE duel master cylinders that do not need the saftey feature of a prop valve is a side by side. This is where 2 single m/cs are mounted side by side to one brake pedal. Used in racing a lot. When you use one m/c with 2 pistons you need a prop valve.

if half your MC fails you still have the other half, and with 4wheel discs either end is just as good as the other.

This is the other part that is wrong. 80% of your brakes is on the front. Also the back calipers are smaller (or should be). It's all about foward motion and weight transfer. All the weight and transfer is to the front, the backs are mainly stabalizers. Unless of course you're driving backwards.

1. ok then explain why my 88 ranger came from the factory with one line going from the MC to the front, and other line going to the back.

2. with a mc designed for 4w discs such as the 68 vette the bias is not 80/20 like a disc/drum vehicle.

1. ok then explain why my 88 ranger came from the factory with one line going from the MC to the front, and other line going to the back.

2. with a mc designed for 4w discs such as the 68 vette the bias is not 80/20 like a disc/drum vehicle.

1. Without looking this up. Was there a stoplight switch on the m/c on that Ranger? Many M/Cs come with the prop valve built into it. Tons of GMCs did, I can see Ford doing it too.

2. Yes, the bias is the same, especially on that corvette M/C. All those corvette m/cs from 68-82 are set up for 2 wheel disc or 4 wheel disc with the proportioning valve correcting the flow. If you don't believe me go order a 75 (pick any year) Corvette 2wd mc and then order a 75 4wd m/c and look at the numbers. They'll be the same thing.

3. I don't meant to upset you or argue with you. I hate correcting people online, makes me feel like an ass. However, there are a lot of misconceptions about brakes I'd like to see go away. Especially the one about not needing a prop valve.

you arent upsetting me in the least, if i am misinformed i would like to clear it up before my brakes fail..;)

and yeah, the prop valve is in that MC on the ranger, but ive always been under the impression that one side of a MC will work even if the other side fails.

so i bleed the caddys again and now it works perfect,
stock CJ prop valve,
stock CJ booster,
K5 MC

Good to hear.

and what a difference compared to the CJ Brakes