Katmandu

Do the axles need to be pulled out a couple inches (for clearance) to remove/replace the rear brake cylinders ??

Or can the brake cylinders be removed with messing with the axles ??

jrs_dodge_diesel

I believe once you get the drum off you have all the access you need to R&R the cylinders.

DL1221

Yup, all you do is pull the drums off, you don't even need to take the shoes off, you may need to disconnect the return springs, or what ever else is in your way.

If the drums won't come off (most of them are frozen in place by rust), start the engine, put the truck in gear, spin the wheels a bit, then step on the brakes. Oh very important, put one or two lug nuts back in a bit, otherwise the drums will fly off the axles, and make sure you're not in four wheel drive, or you'll have more than the drums flying off.

If this doesn't work the first time, try spinning the wheels both forward and reverse, and give a few wacks with a big hammer to brake the rust seal.

infidel

DL1221, you forgot one important step in the spin the wheels drum removal method--
The entire rear end must be jacked up and securely supported.

johnh

i use heat from a propane torch

Mike D

Dodge Rear Brake Cylinder Swap
By Loren Hartman


This is for changing out your rear brake cylinders from ¾ ton to 1 ton cylinders. First thing you need to do is go to your local auto parts store and ask them for GM part #4637337. DO NOT tell them you want GM 1 ton cylinders for your ¾ ton Dodge. You will only confuse them. They sometimes will tell you that they have a “cheap” cylinder and a “higher quality” one. I chose the higher quality one and paid around $80.00 for the pair, but they do come with a lifetime warranty. Might as well grab a couple cans for brake cleaner while you’re at it because you’ll need it.

Go home, block the front tires and jack the rear of the truck up. Place jack stands under the axle and remove both tires. Next you will need to remove the brake drums. They usually don’t come right off. What I did was take 2 lug nuts and spun them back on the studs on each side. I started the truck, put it in reverse, got the rpm’s up and hit the brakes hard. One drum broke loose, but the other didn’t. I had to take a heavy punch between the studs and strike it with a large hammer. It broke loose finally.

Your drums will probably not slide right off. Back off the adjusters a tad and it should slide off. Spray the parts down with brake cleaner and get things cleaned off. Now is a good time to look at your brake shoes while you have the drum off too.

You will need to remove ONE spring from the shoes to allow it to spread apart so you can get the cylinder out. (See Illustration) It is only necessary to remove the “forward” spring, meaning the one facing the front of the truck. This will free up the shoe so you can remove the cylinder.













Take a 3/8 wrench and remove the brake line from the back of the cylinder. Take a 13mm wrench and remove the two bolts securing the cylinder to the housing. Remove the cylinder.




The 1 ton cylinder is noticeably larger.


You will need to reuse the metal pieces that spread the shoes. (You will see when you do it). Put the new cylinder in, tighten the bolts and install the brake line back in. Also secure any springs that you removed. Put the drum back on and adjust the brake adjusters until the just barely drag on the drum.

Start the truck and bleed the air out of the system. Put your wheels back on and you’re ready to go.
I had been battling hard pedal for almost 2 years and figured it was in my master cylinder/booster. After doing this my brake pedal is soft and I have awesome brakes now.

Katmandu

How much difference is there in upgrading to the larger rear wheel cylinders ??

infidel

All 3500s and 2500s '97 up came with 27mm cylinders
Switching from a 27mm to a 30mm (#37337) cylinder increases applied force area from 572.55mm^2 to 706.85mm^2.
That's over a 23% increase.

The pre '97 2500s came with 24mm cylinders, switching to a 30mm cylinder gives an almost 50% increase in rear braking force.

When I first switched mine about five years ago the guy at Napa pulled out three different grades of the same cylinder so we could compare them. They all looked the same, had a hard time putting them back in the correct box...

I've only used the cheapest $13 ones myself on at least 20 trucks, not one problem except on the first stop. Your brakes will finally work right and might throw you into the steering wheel but you get used to it fast.

DL1221

Thanks for the correction Infidel, yeah kind of hard to pop the drums off if the truck is still sitting on its wheels and tires.

However the procedure in Mike D's post leaves nothing to guesswork. . . great description.

jkarner

Can anyone provide more info on how to back off the starwheel for the rear brake shoe adjustment for my 3/4 ton 96 2500? It doesn't move when I apply force from a flat-blade scredriver-how do I access the release lever to it? Also, I am trying to remove the outer bolts that hold the drum on and they are frozen. Can I heat them with a torch without risking damaging bearings? thanks