2nd Gen Rear Wheel Cylinder Upgrade
 

This is for changing out your rear brake cylinders from a 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 a ¾ ton Dodge. You will only confuse them. They sometimes will tell you that they have a cheaper cylinder or 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 your there at it because youll 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 dont 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 up and hit the brakes hard. One drum broke loose, but the other didnt. 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 (the RED one in the pic below), meaning the one facing the front of the truck. This will free up the shoe so you can remove the cylinder.


Attachment 60920



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.

Keep in mind guys that this will not work on 05 at least . I know mine has no drums, and I am not sure when this was started.

Does sound like a hell of a fix if you have them though. :up: :up:

2002 Was the first year for disk brakes

so how much better are the brakes after the upgrade?

I would say an aprox 30% gain in braking power

Not correct - 2001.5 was when disk brakes first appeared.

yeppers.........01.5 was the first disc brakes on the rear :U:

This made a night and day difference in my trucks brakes. I just did it here a few weeks ago.

I will have to do that upgrade in the warmer weather. Need to flush the system anyway..

Brake cylinders AND shoes
 

Oops, just noticed this is a pretty old thread. Hope nobody minds the resurrection!
Anybody have any recommendations for brake SHOES? I'll be installing the GM wheel cylinders in my (wife's) '99 this weekend, and I suspect I'm going to need to replace the shoes while I'm in there.
Thx

i got 91 that has sorry brakes will this work

I cant see any reason why not. Its a Dana 70 or 80 isnt it?

Its a good idea to get some speed bleeders - makes flushing the system much easier.

Russell Performance - Domestic Speed Bleeders

A word of caution though - if you have replacement calipers you have to make sure you measure the proper size of bleeder. The bleeders listed on the site are for the OEM equipment.

Rear Drums, Dana 70
 

Related, but slightly off topic. My '01 has a Dana 70 rear end. The previous (orignal) owner said he had to pull the axles to get the drums off. My ancient (1965) Dodge truck was setup this way, but my '99 isn't. Is he mistaken?

To get the drums off? I think hes mistaken. Look at the pic above - the drum is off and the axle is still in place. The "drum" is the outer housing that the shoe presses against to stop the truck.

I was hoping that was the case. On the older 3/4 and 1 ton rear ends, the drum and bearing hub was one piece. That never made any sense to me, but that's the way they were. I believe the '01 Dana 70 drums are just stuck to the hub pretty hard. The bearing hub and drum don't appear to be one piece. Early in this thread (or the other wheel cylinder change thread) The OP talked about breaking them loose by pulling the wheels with sturdy jackstands under the axle, starting the truck and putting into reverse, giving it some go-pedal then stomping the brakes. I'll find out soon enough.
Thanks,
'Dead Stick'

That trick works very well,,,,but keep at least 1 lug nut on or you will be chasing your drums down the street.

I wouldn't even give it no gas, idle speed does the trick just fine. Don't get to crazy on this, don't want bad things to happen here.

Depends on how much rust you have - I had to giver a little go pedal.

When they're fresh I never even put it in gear, just start the truck, give a push on the pedal and off they flop. It's almost sweet how simple it makes em.

Then on the other hand I've had em in such bad shape that they didn't even push hard enough to put pressure on the drums. Out comes the BFH.

It's a New Mexico / Nevada truck. Shouldn't be too tough. I'll be cautious.... probably.:U:

The biggest thing is just to make sure you leave at least one nut in place loose, I prefer one top and one bottom myself. Cause when that drum brakes lose it's enough to take ya off your feet if your standin in the right/wrong place.

I noticed a pretty big difference with the 1 ton cylinders on my 96, made me wish I'd done it a lot earlier.

yep, the removing the axle crap is for the 1st gen axles, only. when my '93 grenaded the ring/pinion I just swapped in a 2nd gen axle. bigger brakes, wider axle and way easier to service the brakes! I have yet to do the 1 ton cylinders on this one, though.

I was going to change the cylinders on my wife's '99, but she's happy with the brakes as they are. My '01, however, is starting to get tiny radial cracks in the front rotors. According to the previous (original) owner, this will be the 3rd set of rotors for this truck, all failing with radial cracks. One question about the 30mm cylinders though: On the '01, the brake lines enter at an angle, unlike the 30mm cylinders, or the cylinders on the '99. I'm a little leery of re-bending the brake lines to fit. Any guidance?

What kind of rotors have been on there? FWIW, the cheapies are made overseas and Ive been told that they do not have the know how to smelt metal properly. Buy American made. As well, you shouldnt have to bend any brakelines to do this upgrade.

The first set of rotors were, of course OEM Dodge. Second set, same. The current set are slotted aftermarket rotors. I don't know the brand, but I doubt they're cheap imports. Based on the longevity of OEM and the (assumed) good aftermarket rotors, I'm going to give cheap Chinese rotors a shot. I'm hoping the 30mm wheel cylinders may help by taking some of the braking load.
So, what about bending the brake lines??

Why would you have to bend the brakelines? You break the fitting on the brakeline (its attached trough the backingplate to the wheel cylinder, remove both springs, remove the old cylinder, throw in the new one, put the springs back on, reinstall the drum and bleed.

Think we got a disconnect here about what this thread is covering. This upgrade is for the rear drum brakes on our 01 and older trucks. Not applicable to disk brakes, front or back.

That may be the case - but some 01's have rear drums and some have rear rotors.

Ya but read the quote in my post there, he's talkin about his front brakes.

Because on the OEM rear wheel brake cylinders on my 2001 RAM 2500 the brake line enters the wheel cylinder at about 30 degree angle. The 30mm cylinder which is the subject of this thread is machined to accept the brake line straight in. Therefore, to mount it, I would have to bend the existing brake lines about 30 degrees.

Ok, I gotcha now. I have not done or even looked at the rear brakes on my 01 - due to having an exhaust brake.

Im suprised the original poster, Whitmore did not mention anything about bending brakelines (he has an 01)

I have excessive brake dust on the front, how much will this cut down on the dust? My brake pedal is really stiff, will this help?

Yes, the 1 ton cylinder will help a lot, it puts quite a bit more braking force on the rear shoes. But you'll still have to adjust them or hit the brakes hard in reverse and verify that they're adjusting properly, just like any drum brake setup.

should i get new shoes for the rear and if so for what truck like dodge or gm since the wheel cylider is gm

No - get the Dodge shoes. You are just replacing the cylinder itself. Everything else stays the same.

ok great and one last ? i think..I have 22" wheels for summer but change back to stock 17" for winter..will the 17" wheels fit over the new bigger hub?:humm:

nuttin changes other than the wheel cylender, its the lil dealie that pushes the shoes out................it all fits inder the brake drum

yes you do need to bend slightly but no biggie man.......its so easy an old man like me can do it

Take a look at the pic in the first post. Youre just replacing the wheel cylinder at the top, The difference is a bigger piston in the cylinder which causes better braking.