2nd Gen Non-Engine/Transmission Never-ending rear drum brake saga...

[Rogan]

Ok, here's the dealio.
My '96 2500 4wd has a D70 rear with drums. Tires are 265-75-16s on stock steelies, and 3. 54:1 LSD diff.

I had a huge issue with the Right-Rear brake dragging heavily. I pulled it apart to find an all-but-worthless axle seal leaking, completely caking all the brake parts and drum with axle grease.

I ordered a new seal, hardware kit, brake shoes, and Wheel cylinders for both rears, and got to work.

Replaced both sides with everything, and cleaned up all the nastiness.

Brake would still drag, and seemed almost worse.

Removed the parking brake cable, and that took care of the dragging. Ordered a new RR park brake cable (still waiting on it. )

NOW, the same wheel locks up on slight pedal pressure, mostly when it's been sitting for a few hours. I've taken it apart, and it all is still clean, and nothing looks effed up, so I don't know why this is still doing it.

Doubtful, but would air in the brake lines cause this? The action seems to be more common when it's damp outside, like early morning, and the likes. All the back-plate plugs are in place... Or is it more of an adjustment issue? I searched here this morning, and found some info regarding lockup due to maladjustment. .

 

[The patriot]

are you sure you got all the gear oil off? Sounds like you missed some.....

 

[Rogan]

3 cans of brake clean, 10 rags, 2 wire brushes, and dry cracked hands. . I'm pretty sure

 

[Mishkaya]

If it's anything like the issue I experience with the drum brakes on my truck, it's likely corrosion causing the issue. In my case the rear brakes lock up the first time I use them for the day; now that I know it I make sure to apply enough pressure first thing before I leave the driveway. After that I have not had any issues. Hope it's something simple!

 

[GAmes]

When you replaced the wheel cylinders did you also completely flush the brake fluid? Any chance there is debris (rust) in the line causing a blockage? If you can easily remove the drum it is not an adjustment issue IMO, unless one side is adjusted tighter than the other.

 

[Rogan]

the last two times, it took a punch and a hammer to get the drum off. I'll try it again this evening, or tomorrow.
Thanks!

 

[Joe Mc]

Yo Rogan - I'm a member of the "I hate my friggin rear drum brakes" club.



Now that I installed a locker in the rear it's even more fun trying to get an even side to side brake adjustment #@$%!



I hope you followed the correct bearing pre-load procedure. While turning hub, torque nut to 120 ft lb and back off 1/8 turn then lock in place. I'm thinking the 96's have the same as the 99's.



Sounds like you did everything right tho

 

[fest3er]

The only thing I can think is you got the front/rear (short/long, thin/thick) shoes switched. Look for a thread on that topic; someone described the problem quite lucidly.

https://www.turbodieselregister.com...cked-up.html?highlight=short+long+brake+shoes
https://www.turbodieselregister.com...1998-5-2002/40761-rear-brake-shoe-update.html

If Jelag stumbles in here, he might comment.

 

[Rogan]

When I put them on, I put the long shoe on the back.
well, the shoes were the same size, but the liner on one is longer, which is the one I put toward the rear

Thanks for the links. I'll check'em out.

 

[WilsonF]

I am sure most of you know about the easy way to get the rear drum loose. If not try this: Put the rear end on jack stands, wheels off, put a couple of lug nuts back on loosely, put the truck in gear and spin the drums about 5-10 MPH slam on the brakes. First time I tried it they came off so easy I had to laugh to myself.

Floyd

 

[SRath]

Make sure to also clean and check the backing plates on the pads where the shoes sit and slide. They need to be free of grooves and need some grease on them, too. My truck came with the shoes on backwards on one side (I might be the guy that posted about that).



These drum brakes are about the most touchy I have ever found when it comes to adjustment. It may be crazy, but I adjusted mine out until they just barely dragged, then drove 1 mile to the boat ramp parking lot down the road, checked them for heat (not much), adjusted another couple clicks, and drove home. In that mile, they got pretty doggone hot.



I then backed them off equally to where they just barely did not drag. My idea was to try to seat the shoes and drums to each other. It could easily be over-done, and the smoke as I neared home freaked the guy behind me out, he followed me into the driveway all excited, but it did seem to help once I backed them off. My only real fear was possibly glazing them instead, but I haven't seen any indications of that.



Just a word about the parking brakes (climbing up on my soapbox now): Besides fixing the factory parking brake pedal so it stays down when I set it and so it never pops off on its own anymore, which was a terrible problem on my truck, also a '96, but a manual transmission, it is vital even for auto transmission truck owners to USE the parking brake regularly if you don't want it eventually freezing up, usually in the cables.



There is a very old post here that shows how I fixed the parking brake pedal once and for all. It's very simple, and it works very well, but does require the removal of the pedal.



Most drum brakes self-adjust only when you 1> back up and apply the brakes firmly and 2> when you use the parking brake. So using it religiously is a win-win deal, besides the extra safety factor and the stress it takes off an automatic's parking pawl. Nothing makes me cringe like folks who park an automatic on a hill relying only on that pencil-thin pawl to hold the vehicle, and then get in and have to force the thing out of park. Sooner or later, it won't take that anymore.



I have ingrained in my wife and sons to 1st set the parking brake while the vehicle is still in gear (with your foot on the brake), then shift the transmission into park. When leaving, put it in gear 1st, (with your foot on the brake) THEN release the parking brake. P-brake is first thing on; last thing off. Your auto trans will thank you and it quickly becomes habit to do it right.

 

[jelag]

I can only assume you have an excessive amount of grease in the pores of the metal. .

Go find someone with a bake off oven... . have them throw your drums in the over for a bake cycle and than turn the drums... .

The oven will bake the drums over a 3-4 hour cycle at 700*F, this temperature will not harm the metal but will turn all grease in the pores of the metal to dust, and might change the configuration of the drum... usually this type of heat cycle will normalize the metal and allow it to return to its original shape... so you need to take a clean up cut. .

We clean air compressor, brake parts, clutch parts in this manner all the time... our oven holds a cubic yard at a time... . we than usually shot blast the parts to remove the ash. . than machine as necessary.....

You might find that the new shoes are now contaminated with the grease that was left in the drums... .

Hope this helps... .

 

[The patriot]

3 cans of brake clean, 10 rags, 2 wire brushes, and dry cracked hands. . I'm pretty sure

I have a 4 foot extension on an air chuck. After a good dousing, I blow them clean. It does a better job than cleaner and elbow grease alone.

I hit the drums too.

 

[Rogan]

thanks jelag. I'm picking up a new set of shoes this afternoon, as well as a drum. I don't have the affordability of the downtime to do the baking, even though i have access through a friend who works at a huge machine shop/fabrication place.

Patriot, I did blow everything clean with my air compressor, as well, but apparently I missed something. I also brake-cleaned and blow-dried the drum, as well. .


I can best explain the brake issue as this:
Imagine the RR brake was electric, like a trailer. When applying the pedal, even ever so slightly, rather than feeding the signal but a variable resistor to apply brake pressure, it was hooked up to a toggle switch. That's how it acts, ON or OFF, no medium. And it's only the RR one that's doing it.

Makes me look like an idiot who can't drive.

 

[SRath]

Is the left rear working at all? Is it possible all rear brake fluid pressure is being diverted to the right side only? A pinched line on the left or similar?

I'm not sure, but I think my heating of the shoes and drums by intentionally dragging them a mile to seat them might have a similar effect to baking them. See what jelag thinks.

 

[jelag]

It takes over 500*F to remove the grease... . some synthetic oils and grease burn off at 650*F... if you were to expose the shoes to that temperature you'd cook the resin (bonding agent) out of the lining and they would crumble..... only ceramic pads can withstand that kind of heat and not give you problems later...

The process is also called thermal cleaning, and parts normalizing... . its just a heat process to allow the metal to return to size and during this process all the tramp oils, grease's will burn off to an ash...

We than use an airless shot blaster (like a glass bead machine) that throws steel shot at the metal to clean and peen the surface... . when we're done with this process they look brand new... .

Hope this helps... .

 

[KBrennan]

Ever thought about converting to rear discs? I have heard it greatlu improves breaking but have not found a kit

 

[Rogan]

I have thought about it. A local guy, here, has a D80 axle with discs, but I'd need to regear it (or regear the front )


jelag, if I drag them a short distance, they stop grabbing like a villain, and act like normal brakes... ??

 

[Rogan]

Is the left rear working at all? Is it possible all rear brake fluid pressure is being diverted to the right side only? A pinched line on the left or similar?



I'm not sure, but I think my heating of the shoes and drums by intentionally dragging them a mile to seat them might have a similar effect to baking them. See what jelag thinks.

yeah, the LR works.

 

[Will24]

Rick, just found your thread. We can look at it this weekend. Did you get the new drum? A slightly out of round drum will cause more problems than you can ever imagine... .



Will