need brake help

BRUISER

BRUISER

silent.. but deadly
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Mar 17, 2005
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Raleigh
ok here is the deal.. I have been fighting my brake issues for two weeks with no luck and need some help

I have ford 9" front and rear axles with chevy 3/4 ton disc on all four corners.

I have installed a 99 dodge 2500 MC and kept the yj Booster.. I have also gutted the stock proportioning valve for the rear brakes. we have bleed the entire system atleast 3 times and no matter what I do I can not get a firm pedal.

any ideas?
 
I'm no Brake man, but I do see a lot of Different parts! Guys usually ask first, did you bench bleed the MC. Doubt the proportioner has much to do with it. Is the MC for "All Disc"? Sometimes if it was used for rear drums, you have to pull a check ball or something out. How would you get the proper length push rod, to match the Dodge mc, to a YJ booster? I expect all these to be addressed, as others read this post.
 
rodney eppes said:
I'm no Brake man, but I do see a lot of Different parts! Guys usually ask first, did you bench bleed the MC. Doubt the proportioner has much to do with it. Is the MC for "All Disc"? Sometimes if it was used for rear drums, you have to pull a check ball or something out. How would you get the proper length push rod, to match the Dodge mc, to a YJ booster? I expect all these to be addressed, as others read this post.
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yup I bench bleed it.. the MC i used is the one 100's have used on PBB including some guys in cnc4x4 local. I pulled the inside out of the proportioning valve as others have done to get better rear brakes..as for proper lenght you have to make one as directed by others on other builds,, you really just have to figure out how much is sticking out of booster and make new one that lenght.

Man reason why I am confused is I have done exactly what others have done with no luck at all

does anyone know how to chevk a booster?
 
On my Ranger I could not get an acceptable pedal no matter how much I bled the brakes. I ended up making my own pressure bleeder as a "test". I was able to get air out that was trapped in my cutting brakes. I made mine out of a garden sprayer by attaching a hose from it to a spare master cylinder cap I had laying around. My Welfare YJ had the same issue. After adding rear discs and a gutted prop valve I had to pressure bleed it as well.

Then I bought a Motive pressure bleeder with multiple attachments for customer vehicles. This process allows you to get air out that you won't be able to any other way.

As far as the MC swap goes, just gotta make sure the pushrod travel is enough to fully actuate the master. I have always used the 1986 E350 master (same theory as the Dodge 2500 one) and measured the difference in depth from mounting surface to where the pushrod first touches. But you're no dummy and I'm sure you and the CNC crew did the same.

I'll bet you a sixxer of Brevard Brewing against Lone Rider that you need to pressure bleed it.
 
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Are all the bleeders on the calipers on top?
 
BRUISER said:
does anyone know how to chevk a booster?
Click to expand...

The booster will not make a soft pedal. If the booster is bad it will have a hard pedal as if the engine is off and the brakes have been pumped til the vacuum is gone. Your problem sounds like an incorrect sized master for the calipers, incorrect pushrod, or air. If others have used the same master on the same calipers with no problems and your sure the master cylinder pushrod is long enough then you've got more bleeding to do. I'd try a mighty vac or similar and see if you can push fluid from the bleeders to the master. I've had luck pushing air out that way before.
 
Tim C said:
The booster will not make a soft pedal. If the booster is bad it will have a hard pedal as if the engine is off and the brakes have been pumped til the vacuum is gone.
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This. I've also had them seize, so the pedal goes down, but doesn't come back up.
 
well good news is I found the issue.. it was the rear passenger caliper.. the calipers came with the rear axle and what I found was the previous owner drilled and tapped the bleeder screw.. so i am pretty sure it was not holding pressure.

replaced caliper and we now have brakes..
 
I hate to bring this thread back to the top of the forum, but I am having similar issues. 91 xj with a D44hp front and 9inch rear. All-wheel Ford disk brake calipers. Front calipers are brand new. Rears are used, but still only a few years old. I'm running a 04 wj brake booster with a 99 ram 1500 MC. Everything has been laying on the shop floor for a year until I was able to start the swap. I have replaced 90% of my brake lines. I have extended the push rod on the booster till it just barely touches the MC. I bench bled the MC and have been bleeding the calipers using a mityvac for a few days. I pump the brakes with the jeep off and the pedal gets so hard I have to lay on it to compress, but as soon as I start the jeep the pedal goes to the floor. It will return and if I pump the pedal it get slightly stiffer. When I'm bleeding the brakes I will do the "catch-can" way as well with a tube down into a jar of fluid. While pumping the brake with the jeep off I see zero bubbles and can't even see the fluid moving through the tube, but it is rising in the jar. Its the same on all the calipers. A wheeling buddy is running the same setup and he complains about his pedal being too stiff. *Edit* He is running chevy calipers*. Anyone know how Bruiser was able to figure out his bleed screw issue? I would think that a bleed screw issue would result in fluid leaking out. I may just need to bleed for a few more hours. Which is what I'll be doing again tomorrow unless someone has an idea. When I drove it a few hours ago I was able to stop but I'm gona need as much room as a fully loaded train.
 
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Red Rover said:
wheel Ford disk brake calipers. Front calipers are brand new. Rears are used, but s
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Which calipers? How big are the pistons? You could have calipers that are too big for the volume of fluid that the MC displaces.
 
Red Rover said:
1979 Ford d44
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Those are notoriously crappy. I believe Thunderbird/LTD/Mark VII?? calipers from the same vintage were the "upgrade". @UTfball68 might remember...

If it were me, I'd stick with a known-good recipe. I've always liked the Chevy calipers for stuff like that.
 
I can't tell if you have a bleeding problem or not, but as far as the long stopping distance you can do some simple math and find out what's going on. I'm not a fan of randomly mixing and matching brake system parts without knowing if the MC is going to be too small, or if I have massive amounts of rear brake bias because of the caliper size or rotor diameter, etc. You can figure that stuff out beforehand, or figure it out after you realize it takes 4 football fields to slow down or it wants to swap ends in the rain.
 
shawn said:
Those are notoriously crappy. I believe Thunderbird/LTD/Mark VII?? calipers from the same vintage were the "upgrade". @UTfball68 might remember...

If it were me, I'd stick with a known-good recipe. I've always liked the Chevy calipers for stuff like that.
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Yes the t bird calipers are single piston and go right inplace of the truck calipers other than a small issue of the banjo bolt thread I think. The single t bird piston gives it the same piston surface area as the two piston d60 calipers. The upgrade on the old Ford f150s and Broncos was to install tbird calipers f350 wheel cylinders on the 9" and then put a matching f350 master cylinder on it.

Hard pedal engine off, dropping to the floor with it running is a classic air in system symptom though. If the parts were mechanically or hydraulicly mismatched it would be doing it either way.

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New development today. I bled a bit more yesterday and today. However, today when I went to pump the brakes and stick my 2x4 in between the pedal and seat I noticed that the brake pedal is not as stiff as it was the previous days. Its still hard to push but its not rock hard anymore. I can't push it to the floor, but I have rechecked all my connections and they are not leaking.
 
A proportioning valve if you have one may have recentered itself. That would mean both sides of the master are working again. You may have only had half your brakes initially. I might bleed it once more and test drive again.

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I have not gotten a chance to mess with it today. Been getting semi-prepared for Hurricane Florence, but I was thinking I may unbolt all my calipers and let them sit on the axle. Then I will pump the brakes and see what happens. Hopefully, they all close a bit.
 
Recently, at the end of my build, there was issues with my brake lines. Like all things Jeep, it snowballed. First it was the hard lines, replaced them. Then couldn't get them to bleed. Issue was the MC. No idea what MC was on it, so it was replaced with a Dodge 2500 MC. I have never had better brakes!
Stock pedal, stock 87 Booster (87 YJ), Dodge 2500 MC, Chevy one ton calipers in the front, 3//4 ton calipers in the rear.
 
I have not been messing with the Jeep much. Like many of us, I have been swamped with service calls after Florence. I wanted to ask if anyone could give me a correct way to bench bleed a MC. I ask because I talked with a guy today that asked me how I primed my MC. I told him that I clamped it in a vice. Then threaded some old flares on with clear rubber hose running to the reservoir. I then pushed the piston in and out until bubbles were no more. He asked if I pushed the piston all the way in? I said yes and he said that was incorrect and that I'm only supposed to push it in as far as the push rod would go had I been pushing the pedal down. Any pointers? It is possible that I inadvertently broke 2 Master Cylinders while bench bleeding them? Thanks!
 
I bolt them up to the booster and run some random tubes back into the reservoir. Pump the pedal until no air.
That way you can't overstroke. (The master)
 
Jody Treadway said:
I bolt them up to the booster and run some random tubes back into the reservoir. Pump the pedal until no air.
That way you can't overstroke. (The master)
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I thought about that to. However with the Jeep where it's at and the angle of the MC, I'm wondering if the MC needs to be flat...guess I'll need to dig out my big floor stands.

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Ive been using used Masters until now so I ordered a brand new one. Maybe by some chance I ended up with 2 bad ones in a row? Fingers crossed.

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I don't trust used MC's at all. Even new ones I've had bad out of the box & I've never heard of over stroking a MC. I'll have to go look that up.
 
a_kelley said:
I don't trust used MC's at all. Even new ones I've had bad out of the box & I've never heard of over stroking a MC. I'll have to go look that up.
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Me either. I don't use used OR reman masters unless there is absolutely no other option. We've been bit by more reman masters at work than I can count. If there's a new option, even at double the price, thats what the customer gets from us or they can tow it somewhere else.

The only time I've seen over stroking a master cylinder be a problem is on an old or used master. They will get debris or corrosion in the unused part of the bore and it'll tear the piston seal or the dirt will mess up the seal. On a new or reman master cylinder, unless it's a shitty reman, overstroking won't be a problem because the bore is clean and any corrosion has been honed out.

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