Mushy brakes 4 life...

Mopar92 said:

Agreed it shouldn’t have this mush. Should be granite.
-1 shoes fit the drum radius very nice
-2 they are adjusted so tight they smoked after 1/4 mile
-3 Then would catch fire this tight. I can see wearing them in like this.
-5 Ha. Can’t even build enough pressure to make it flex if I wanted.

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If all this is true then you have air........somewhere...........

How are you bleeding? I've always like PRESSURE bleeding. I know people preach gravity and vacuum, but they both "encourage" the entrance of air.......because atmospheric pressure!!

67Dart273 said:

If all this is true then you have air........somewhere...........

How are you bleeding? I've always like PRESSURE bleeding. I know people preach gravity and vacuum, but they both "encourage" the entrance of air.......because atmospheric pressure!!

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I used my mighty vac to get the lines refilled. Then we pressure bled it. Lots. As for air in the ports... the first 6/7 slow pumps we had a few bubbles but that stopped. I still wonder about the rear drums. I’m beginning to think I’ve got something wrong back there. Seeing that I had to put 1/8” thick washers between the axle flange and the drum to keep it off the backing plates on both sides... the plates aren’t bent, the drum goes on “ too far” and rubs in the drum recess. I’m obviously not going to drive it around like this. When I pull the e brake, my pedal is substantially better. I have a little drag in the shoes. In fact probably too much as the LR was smoking for a few seconds after a very short trip. I wonder if I have some truck drum or something and it’s smashing or cocking the shoes, and the e brake straightens up the shoes somehow. I’ve never experienced anything like this before. Although I don’t care for drums, I’ve never really struggled with them as an adult.

This is the groove where the backing plate goes in that’s rubbing down in the bottom of the groove. Sure the green bearings didn’t narrow my axle flange to axle flange too much and have a major issue there. Ugh.

Red line is where the backing plate rubs.

Mopar92 said:

This is the groove where the backing plate goes in that’s rubbing down in the bottom of the groove. Sure the green bearings didn’t narrow my axle flange to axle flange too much and have a major issue there. Ugh.

Red line is where the backing plate rubs.

View attachment 1715138524

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Something definitely wrong with that drum/backing plate combo. If everything with the 8 3/4 is B body then you shouldn’t have any issues like what you’ve got.

So, the next deal is to look at the backing plates. The thing is that there are 3 different 11” backing plates. The plates for the 11x2.5”, 11x2”, and 11x3” rear drums all have a different backing plate offset. They all use the same axle flange offset, so, the plates have to be different. You can’t use 11x2” plates with 11x2.5” shoes and drums, or any other combination of parts.

Here’s a post on how to measure them and what the measurements are for each one. Ignore the title, it has all the BBP measurements you need too.
Converting rear drum brakes from SBP to BBP

This is my thread while going through my parts a while back.
11x2.5” drum/backing plate ID?

72bluNblu said:

Something definitely wrong with that drum/backing plate combo. If everything with the 8 3/4 is B body then you shouldn’t have any issues like what you’ve got.

So, the next deal is to look at the backing plates. The thing is that there are 3 different 11” backing plates. The plates for the 11x2.5”, 11x2”, and 11x3” rear drums all have a different backing plate offset. They all use the same axle flange offset, so, the plates have to be different. You can’t use 11x2” plates with 11x2.5” shoes and drums, or any other combination of parts.

Here’s a post on how to measure them and what the measurements are for each one. Ignore the title, it has all the BBP measurements you need too.
Converting rear drum brakes from SBP to BBP

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It almost seems like the green bearings have set the axles in too far. But not by much. I have the thick gaskets installed from dr diff as well. Surely that’s not enough to cause my issues. I wish I had a set of 11” backing plates and drums that I know worked off another car. Ugh.

So people don’t have to click the link and go back and forth.

Mopar92 said:

It almost seems like the green bearings have set the axles in too far. But not by much. I have the thick gaskets installed from dr diff as well. Surely that’s not enough to cause my issues. I wish I had a set of 11” backing plates and drums that I know worked off another car. Ugh.

So people don’t have to click the link and go back and forth.

View attachment 1715138558

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Aww crap. Sorry, I post that stuff so much I forget who I’ve talked to before.

Man the green bearings shouldn’t change anything offset wise. Do you have a sure grip? If there’s a thrust button in there from using the tapered bearings it has to come out for green bearings, sometimes they can hold the axles out too far with the green bearings. Just throwing ideas out there, you probably knew that too.

Indeed I removed the thrust button. There’s no way I could remember posting! I guess my next move is to take the wheel and drum off and take a bunch of measurements and pics for you guys. I’m sure it’s something dumb. I’m wondering if all 11” x 2.5” backing plates are the same. Ie trucks, B body’s, C body cars. I’m almost convinced I have some sort of lateral alignment / mismatch of parts deal going on. I almost think I have no air in the lines but I’ve got the shoes cocked and in the drum wrong. So even though I feel them drag after adjustment... they aren’t seated flat on the drum friction surface. Pulling the hand brake forces them closer, but still not correct. If I’m barely touching if not .030” off the backing plates... I bet I have interference with the shoes and the flange side of the drum.

"If" you can find someone these days with a brake lathe, you could measure and have some material turned off the drums so they clear, but make sure, first, that the shoes are gonna "hit" the proper shoe/ lining area in the drum, and are not going to interfere in the back of the drum

See that’s where I think I have issues. I think the shoes are crammed into the drum on the flange side. Something is allowing that drum to go too far to the center of the car or toward the backing plate. If it’s letting the drum seat that close to the backing plate... I have to have interference inside there.

.............Check to make sure the shoes are against the pin at the top, if not ur e brake cables are sticking and not allowing the shoe to return...this is y u have a better pedal when u pull the e brake on and a crappy pedal w/o e brake on. I have only did a few sets of green bearings but i think i seen a thread on where u can press the bearing on too far creating the problen u have,............kim......

oldkimmer said:

.............Check to make sure the shoes are against the pin at the top, if not ur e brake cables are sticking and not allowing the shoe to return...this is y u have a better pedal when u pull the e brake on and a crappy pedal w/o e brake on. I have only did a few sets of green bearings but i think i seen a thread on where u can press the bearing on too far creating the problen u have,............kim......

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Thanks for the reply... I didn’t know you could press it on too far. There’s a shoulder there. I emailed Cass and what a guy... he emailed me back on a weekend. We emailed back and forth and he gave me measurements from the backing plate to axle flange to start ruling out the problem. Thanks all.

If the bearing is not up against the axle shoulder, there is something wrong with the combo/ hardware/ bearing. That has a lot of force on an "inside corner" and you don't want it moving.

It’s for sure against the shoulder. I didn’t kill it but I pressed it on. Cass said that I should be 2.4” from the snap ring on the bearing to the flange face. I’ll measure it and see. If it’s 2.4”... then I have a backing plate, shoe, or drum problem. Eliminates axle placement that way.

You probably know this, but just in case:
first; I will assume the hydraulic system is fully bled and fully functional.
Next, assume the rear wheel cylinder pistons are free to move waaay out,past their design range, but not so far as to fall out.
>The master-cylinder is now operating as if the rear system has failed. So the entire guts of the M/C has to be pushed to the end of it's travel, until the frontmost piston hits bottom . Not until that moment does the fluid begin to move out to the front calipers.
If the front system is in perfect working condition, it will now have a hard pedal, and braking can begin, using the front only system, allbeit with a very low pedal.
>But if the pedal does not get hard, then there is additionally,something wrong in the front system. Remember I assumed the hydraulic part was perfect.
So, I know that now I am in deep chit, because I assumed the hydraulics are perfect.
So now I have to find out why I can't get a hard pedal, down near the floor. At this point I no longer care about the back. I have a decision to make; Do I; A)continue to believe that the hydraulics are perfect, or do I. B) take everything apart again, and go hunting for a mechanical issue?
Well I'm gonna go with A) on account of I have already bled the chit out of it.
So, off with the wheels and off with the calipers. Now, I take big C-clamps and force the pistons all the way back and lock them there. Then I retest the pedal. >If I now have a hard pedal, then I know that in fact the front hydraulic system is fully functional, and therefore I must have a mechanical problem. And we'll get to that later. But for now, I can continue on the rear diagnostic, leaving the calipers so locked.
>But if the pedal is mushy with the pistons clamped, I have some more work to do on the front system.And it's gonna be a hydraulic issue. I go find it, fix it, and retest the on-the-floor pedal. I can't attack the rears until the pedal is hard.
________________________
So let's say you finally have a hard pedal
Now we move to the rear, Take it all apart,including the push-rods, to access the W/Cs, and put clamps across the metal pistons, preventing them from popping out of the bores. Now go look for a hard pedal again. The pedal should take a couple of pumps to pop up, and then get hard. This proves that the compensating port is open and working and most importantly, that the hydraulics are indeed 100% working. But if the pedal doesn't get hard.......now you at least know where to look. And if the pedal doesn't come up, you look to the pushrod length and why the C-port is not working.
>But suppose you did get a hard pedal. Now we go to the back, and have a good look at the parts, and why they don't like to be adjusted up tight.
And the guys have covered that pretty good already.
Once you get the rears up to speed,and everything assembled in their proper working relationships, and the pedal gets hard....... then you return to the front. Reinstall the calipers and check the pedal. If hard, put all the wheels back on, and roadtest.
But if not hard now, then you know exactly where to look. You have a mechanical issue, and very likely it will be easy to spot. In all likelyhood one of the calipers is flexing. It could be a bent pad or a problem in the caliper mounting system.
In any case,you're on the home stretch, and you will find it.
Do not drive it until you have a hard, high, pedal, please.

Can u post some pics of therearbrakes

Thanks for taking the time to write that. I appreciate it. I am going towards the mechanical side of this because I have an obvious mismatch of parts or axles in too far. I have mechanical interference. Once that’s resolved... I am going to do another hard pressure bleed. If that fails... that master is coming off. I replaced a brand new GM master on a buddies Silverado last year. It was leaking internally and out the back. Back to the dealership and #2 worked. I put a Disc conversion on my wife’s 1960 F100 last winter. Bought the best quality 1960 Ford master I could find. Dead on arrival. Similar to this. We couldn’t get it fully bled ever. Put an Oreilly special on it and it was perfect. Bled in 2 minutes. We took that first master apart and the seals were gummy. It was the most sorry China rubber I’ve ever felt. It was smearing on the bore. I really don’t think it’s the master but my master cylinder DOA out of the box is pretty high lately.

Mopar92 said:

Thanks for taking the time to write that. I appreciate it. I am going towards the mechanical side of this because I have an obvious mismatch of parts or axles in too far. I have mechanical interference. Once that’s resolved... I am going to do another hard pressure bleed. If that fails... that master is coming off. I replaced a brand new GM master on a buddies Silverado last year. It was leaking internally and out the back. Back to the dealership and #2 worked. I put a Disc conversion on my wife’s 1960 F100 last winter. Bought the best quality 1960 Ford master I could find. Dead on arrival. Similar to this. We couldn’t get it fully bled ever. Put an Oreilly special on it and it was perfect. Bled in 2 minutes. We took that first master apart and the seals were gummy. It was the most sorry China rubber I’ve ever felt. It was smearing on the bore. I really don’t think it’s the master but my master cylinder DOA out of the box is pretty high lately.

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Well now that's curious.
Not to be an azz, but with your bad luck, I have to ask; Are you confident that the brakefluid you are using is up to speed? Maybe it too was made in China,lol.

Is the pushrod the same from an auto to manual? I think... I kept the same pushrod from my Auto pedal. I should have probably stated this earlier in my thread that I put in a 73 4 speed pedal setup and kept my 73 pushrod.

AJ/FormS said:

Well now that's curious.
Not to be an azz, but with your bad luck, I have to ask; Are you confident that the brakefluid you are using is up to speed? Maybe it too was made in China,lol.

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Ha. Well I got a bunch of Motul fluid from my father in law. I’d say it’s pretty quality stuff.

So ur just gonna ignore my request for pics to be better able to help u? I’m done. Kim

oldkimmer said:

So ur just gonna ignore my request for pics to be better able to help u? I’m done. Kim

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I’m going by the shop where the car is in the AM. I’ll post up what I take and you guys can just rip me to shreds then... which is ok... that means we get this fixed and I learn a lil sumpin’.

The drum is killing the backing plate. That one shoe is cocked out where I pulled the drum off. It easily seated.

If I’m not misreading Cass’s email reply he said this should be 2.4. The pic is hard to see but I’m damn close to that.

If you have a soft pedal, Def flex brake lines, Def master cylinder or out of adjust shoes or AIR in the system. To bleed out the air in the MC, just mount it in the car, leave the lines off, use the little red nipples and clear tubing, and use the brake peddle to bleed it. Put shop towels under it to catch drips, when no more bubbles, remove the nipples, and screw on the lines, clean up any drips, there wont be many, and refill MC, all done. EZ PeeZe. Brakes are not that difficult IMO.