Rear brakes are not bleeding.

[DentalDart]

The rear brakes aren’t bleeding and I don’t know why. Fronts are locking up and rears are bone dry. I’m not seeing any leaks anywhere. Fluid is getting to the distribution block and draining out of all of the inlet/outlets from the distribution block.

Master Cylinder was bench bled and had no air bubbles in it when installed on the purple car.

Rear discs are taken from a parts car, used the lines from the car as well. When they were still installed on the parts car the brakes worked fantastic. Everything at the front of the car is new, and new distribution block was used for 4 wheel disc brakes.

I feel like I’m just not getting fluid in the rear lines? I believe the distribution block is hooked up correctly, I mean with the sizes of the lines/fittings being different it’s kind of hard to get them in the wrong spots?

I also hate the setup of the rear brakes. The bleeder valve is in the worst spot, makes it to where the passenger side can’t even get a hose on it because the bolt is in the way.

Next time spend the money and just buy a new complete kit from DrDiff for the rears.

I bought a motive power bleeder but I can’t figure out how to get it to work, it seems like it doesn’t seal and it seems like all of the fittings for the top don’t really do much.

 

[harrisonm]

You say the rear is dry? To me, that means there is no brake fluid getting to the rear brakes at all.

Here is what I would do. I would start at the back and work forward to find the blockage. Get the car up on jack stands. Take the brake fluid line off of each rear caliper one at a time (I'd start with the right rear) and have an assistant press down on the brake pedal and hold it down to the floor. Then with your thumb, press against the end of the brake line and tell your assistant to let the pedal up. Blocking off the brake line with your thumb will not allow air to get sucked into the lines when the brake pedal goes up. Then repeat up, down, up, down, at least a dozen times to see if you get any fluid. If not, hook the brake line back up on the right rear caliper and then do the same to the left rear. If you don't get any fluid at the calipers, the blockage is further forward. Crawl under the car and trace the lines to the next connection (most likely a junction block on top of the differential. Disconnect that line and do the same sequence as on the rear calipers. Make sure to block the end of the line while the brake pedal goes up so air doesn't get sucked into the line. As you are doing this, MAKE SURE TO CHECK THE MASTER CYLINDER FREQUENTLY to ensure it always has plenty of fluid. Then follow the brake line to the next connection forward and repeat the sequence again. Eventually, you will be at the junction/distribution block. When you take the rear brake line off of the distribution block, if no fluid comes out, you need to determine which line from the master cylinder and goes into the distribution block. Then take that line off of the block. if fluid comes out of that line now, the blockage is in the distribution block. If no fluid comes out, the problem is in the master cylinder. This will take a while, but it should work.

 

[junkyardhero]

i just had a similar experience. i wasn't getting anything at the rear cylinders, but i still had a mostly hard pedal. something broke loose or came apart and jammed up in the rear drop line from the frame to the block on the axle.

so i'd start there to see if you have fluid getting back there.

i've run those same brakes. the "engineering" leaves a lot to be desired. they take a TON of fluid and are right pain in the *** to bleed out.

 

[Bewy]

If the rear brake lines are original, they are 50+ yrs old. Plenty of time for rust to form. If both rears are not bleeding, you could have a blockage [ sediment ] in the rear hose or the line feeding it.

 

[72bluNblu]

The rear brakes aren’t bleeding and I don’t know why. Fronts are locking up and rears are bone dry. I’m not seeing any leaks anywhere. Fluid is getting to the distribution block and draining out of all of the inlet/outlets from the distribution block.

Master Cylinder was bench bled and had no air bubbles in it when installed on the purple car.

Rear discs are taken from a parts car, used the lines from the car as well. When they were still installed on the parts car the brakes worked fantastic. Everything at the front of the car is new, and new distribution block was used for 4 wheel disc brakes.

I feel like I’m just not getting fluid in the rear lines? I believe the distribution block is hooked up correctly, I mean with the sizes of the lines/fittings being different it’s kind of hard to get them in the wrong spots?

I also hate the setup of the rear brakes. The bleeder valve is in the worst spot, makes it to where the passenger side can’t even get a hose on it because the bolt is in the way.

Next time spend the money and just buy a new complete kit from DrDiff for the rears.

I bought a motive power bleeder but I can’t figure out how to get it to work, it seems like it doesn’t seal and it seems like all of the fittings for the top don’t really do much.

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The rear hose from the axle back up to the frame would be my first check. I've had a brand new hose at that location that was internally collapsed. Beyond that I'll just second the other advice to work step by step eliminating lines/hoses. You have fluid at the combination valve, so, disconnect that rear hose at the other end of the rear line from combo valve and see if you have fluid there. Then check the end of the hose going to the axle lines, then each line. But if both rear disks are dry and you have fluid at the rear discharge of the combination valve it's either that rear line or the hose.

If the rear brake lines are original, they are 50+ yrs old. Plenty of time for rust to form. If both rears are not bleeding, you could have a blockage [ sediment ] in the rear hose or the line feeding it.

Guess looking at the pictures he posted is too much for you? Don't think the original brake hoses were stainless braided, and it doesn't look like any of those lines are factory.

 

[DentalDart]

You say the rear is dry? To me, that means there is no brake fluid getting to the rear brakes at all.

Here is what I would do. I would start at the back and work forward to find the blockage. Get the car up on jack stands. Take the brake fluid line off of each rear caliper one at a time (I'd start with the right rear) and have an assistant press down on the brake pedal and hold it down to the floor. Then with your thumb, press against the end of the brake line and tell your assistant to let the pedal up. Blocking off the brake line with your thumb will not allow air to get sucked into the lines when the brake pedal goes up. Then repeat up, down, up, down, at least a dozen times to see if you get any fluid. If not, hook the brake line back up on the right rear caliper and then do the same to the left rear. If you don't get any fluid at the calipers, the blockage is further forward. Crawl under the car and trace the lines to the next connection (most likely a junction block on top of the differential. Disconnect that line and do the same sequence as on the rear calipers. Make sure to block the end of the line while the brake pedal goes up so air doesn't get sucked into the line. As you are doing this, MAKE SURE TO CHECK THE MASTER CYLINDER FREQUENTLY to ensure it always has plenty of fluid. Then follow the brake line to the next connection forward and repeat the sequence again. Eventually, you will be at the junction/distribution block. When you take the rear brake line off of the distribution block, if no fluid comes out, you need to determine which line from the master cylinder and goes into the distribution block. Then take that line off of the block. if fluid comes out of that line now, the blockage is in the distribution block. If no fluid comes out, the problem is in the master cylinder. This will take a while, but it should work.

I took the rear line off from the distribution block today, and got fluid through each line… used a syringe bleeder to force brake fluid through each line.

The rear ones were the only lines reused since the setup of the calipers are weird and don’t have mounting location for the braided line and the metal line like the ones DrDiff uses.

The braided lines through the calipers needed the most fluid. Almost 3/4 of a syringe for each before fluid started coming through. Picture of the syringe for reference, it works fantastic for pushing fluid through the system.

I’ll fill up the MC and see if I can get it all bled. I know when I was reattaching the lines air got in them.

 

[DentalDart]

Ok I’m at a loss for words…

Using motive bleeder, no air in system, it stays pressurized.

I go around and bleed all the calipers. Take the bleeder off the MC. Put caps back on the MC. When I press the brake pedal it goes straight to the freaking floor.

This is how much I bled through the system without any air bubbles.

 

[Just Send It]

I've never had good luck with those master cylinders. I've had seals be bad right out of the box on several brand new units. If you have access to another MC, I'd recommend swapping it out to see if that's the culprit.

Is your Emergency brake hooked up and functional? When I switched over to rear discs for my D60, I couldn't get the rears to bleed either. Turned out, the E-brake wasn't connected correctly, and because of that, the damn things wouldn't bleed. Once I corrected it, I got pressure and they've worked great ever since.

Another thing to look at is the piston sizes of your calipers. Depending on the bore size of your MC, it may be lacking the volume to push enough fluid to squeeze the calipers adequately. Now, in saying that, this is probably not your issue since you would still get some pressure to the calipers even if there was a volume deficiency. But this is still something to keep an eye on.

If there are no obstructions in the lines, it's either bleeding pressure or a volume issue.

 

[Oldmanmopar]

Loosen the master cylinder at the firewall. I believe you already have the piston partially depressed in the master cylinder. . Let it come away from the firewall until there is no pressure on the push rod. See if this helps . If so make a spacer

 

[DentalDart]

Loosen the master cylinder at the firewall. I believe you already have the piston partially depressed in the master cylinder. . Let it come away from the firewall until there is no pressure on the push rod. See if this helps . If so make a spacer

I have an adjustable pushrod, I left it the same length as it was in the black car. After I read your comment I took it out and shortened it because it was actually a little long. Now it’s the same exact length as the stock pushrod (measured them side by side).

 

[DentalDart]

I've never had good luck with those master cylinders. I've had seals be bad right out of the box on several brand new units. If you have access to another MC, I'd recommend swapping it out to see if that's the culprit.

Is your Emergency brake hooked up and functional? When I switched over to rear discs for my D60, I couldn't get the rears to bleed either. Turned out, the E-brake wasn't connected correctly, and because of that, the damn things wouldn't bleed. Once I corrected it, I got pressure and they've worked great ever since.

Another thing to look at is the piston sizes of your calipers. Depending on the bore size of your MC, it may be lacking the volume to push enough fluid to squeeze the calipers adequately. Now, in saying that, this is probably not your issue since you would still get some pressure to the calipers even if there was a volume deficiency. But this is still something to keep an eye on.

If there are no obstructions in the lines, it's either bleeding pressure or a volume issue.

The ebrake definitely was not tightened properly. I adjusted the ebrake to FSM directions now. I never had an ebrake before so I figured that wouldn’t have made a difference.

I even thought maybe air did get in the MC even though I bench bled it on the vice so I had my son come in and he helped me bench bleed it again while on the car. It had 0 air in it when we finished.

I actually have 2 more brand new MCs. And a brand new rear disc brake setup on my other car… I’m about to take the whole setup off of that car since it’s all brand new. This literally should have been a quick hookup and bleed job and now it’s been multiple days. At some point my time is worth more than the 600 bucks for another rear brake kit.

 

[DentalDart]

Well the only thing I can think is either a caliper is bad or master cylinder is bad. Or long shot, maybe it’s the fact that I’m using a mopar distribution block instead of the Chevy prop valve that was with the original system on the black car.

Oh well, I decided to take it all off and quit ******* with the old stuff trying to make it work. New MC bled with new brake rod. Tomorrow maybe I’ll have some time to swap the parts and bleed the system. I wanted to drive it before heading to Vegas on Monday but I don’t think that will happen.

What does NEED to happen is my big shop needs AC now! The small shop is so nice at a cold 75 degrees with no humidity. I’ve been sweating my *** off for the past couple of days without ac while my small shop is so nice to work in, but the car is non mobile in there.

 

[nutz]

are your rear calipers touching the pads
what i do is jam a screw driver between the pad and the rotor can see if you can compress the rear calpers (like you do on the front to replace the pads )
it should not compress...if it does the p-brake isn't ratching out and make sure your p-cables let the levers sit all the way back ....you don't want any pull on the levers

 

[340sFastback]

are your rear calipers touching the pads
what i do is jam a screw driver between the pad and the rotor can see if you can compress the rear calpers (like you do on the front to replace the pads )
it should not compress...if it does the p-brake isn't ratching out and make sure your p-cables let the levers sit all the way back ....you don't want any pull on the levers

On my Dr Diff 10.7 inch rear disc I had to rotate caliper pistons all the way back in, assemble brakes, then activate / release parking brake like 30 times to get pads up against rotors. Then bled the brakes. That process got rid of excessive brake pedal travel.

Then I had very slight parking brake cable tension which glazed the pads and rotors. Had to adjust some cable tension out then rough up pads rotors with sand paper.

Then the pads on one wheel were excessively tight in the caliper bracket causing excessive drag. Had to use file belt to remove powder coating where pads sit. Then greased up slider pins good and tad of grease where pads ride in caliper mount bracket.

But I eventually got it all sorted out and working perfectly now. Would like to say was a simple bolt on and go. But usually things aren't like that.

 

[DentalDart]

On my Dr Diff 10.7 inch rear disc I had to rotate caliper pistons all the way back in, assemble brakes, then activate / release parking brake like 30 times to get pads up against rotors. Then bled the brakes. That process got rid of excessive brake pedal travel.

Then I had very slight parking brake cable tension which glazed the pads and rotors. Had to adjust some cable tension out then rough up pads rotors with sand paper.

Then the pads on one wheel were excessively tight in the caliper bracket causing excessive drag. Had to use file belt to remove powder coating where pads sit. Then greased up slider pins good and tad of grease where pads ride in caliper mount bracket.

But I eventually got it all sorted out and working perfectly now. Would like to say was a simple bolt on and go. But usually things aren't like that.

This is great because I too had to rotate the caliper pistons all the way in to get the calipers with pads over the rotors. I’ll yank on the parking brake a bunch of times tomorrow morning. It is adjusted now and when I pull it, it actually works and stops the rear rotors from spinning. I’ve never had a parking brake on the car before

 

[Bewy]

72Blu,
Smart a**e. Read post #1. Rear lines were USED, from a PARTS CAR. No mention of low long that car had been sitting...

 

[nutz]

This is great because I too had to rotate the caliper pistons all the way in to get the calipers with pads over the rotors. I’ll yank on the parking brake a bunch of times tomorrow morning. It is adjusted now and when I pull it, it actually works and stops the rear rotors from spinning. I’ve never had a parking brake on the car before

try jamming a flat head screw driver in to take up the space,bleed it ,than once you get a peddle pull out the screw driver ,those square cut seals can behard to get moving and will bounce in the bores

 

[340sFastback]

This is great because I too had to rotate the caliper pistons all the way in to get the calipers with pads over the rotors. I’ll yank on the parking brake a bunch of times tomorrow morning. It is adjusted now and when I pull it, it actually works and stops the rear rotors from spinning. I’ve never had a parking brake on the car before

The undocumented gotcha is if you apply hydraulic pressure to those Cobra calipers in that 10.7 rear disc kit BEFORE activating / releasing emergency brake then you have to spin caliper pistons back in and go through the emergency brake sequence THEN hydraulic pressure can be applied. Otherwise the rear calipers do not function correctly. I have not found anywhere where that is written down and documented anywhere.

 

[DentalDart]

try jamming a flat head screw driver in to take up the space,bleed it ,than once you get a peddle pull out the screw driver ,those square cut seals can behard to get moving and will bounce in the bores

Oh I’ve gotten tons of fluid out of the caliper, I’ve probably used 3.5 of the 32oz jugs through the system.

It’s weird too, because if I pump the system a ton with the pedal the pressure builds in the master cylinder and I have to open a cap to get it to release.

 

[DentalDart]

try jamming a flat head screw driver in to take up the space,bleed it ,than once you get a peddle pull out the screw driver ,those square cut seals can behard to get moving and will bounce in the bores

There’s not really any space between the pads and the caliper. Passenger side is the worst to bleed or try to bleed.

 

[nutz]

Cap shouldn't hold pressure
Should be a vent hole in it
Wonder if that's giving you trouble

 

[nutz]

Are the bleeders on the very top of the calipers
If not then all the air isn't getting out
Sometimes the mount might angle them wrong
Or might have to jack or lower the front to get the bleeding angle

 

[DentalDart]

It barely even wants to gravity bleed. I want a huge steady stream.

 

[DentalDart]

Are the bleeders on the very top of the calipers
If not then all the air isn't getting out
Sometimes the mount might angle them wrong
Or might have to jack or lower the front to get the bleeding angle

I know they are supposed to be at the “top” but these calipers aren’t the same as the others. I do have the bleeder higher in relation to where the line comes in at though. Also when pressure bleeding wouldn’t it force everything out anyways?

 

[nutz]

No air trapped in them
Take a c clamp or block and turn them 90 deg then bleed bleeder needs to be on top of piston....