2nd Gen Non-Engine/Transmission Rear Drum Brake Questions

[brn2fsh]

Hello,



Last weekend I decided to adjust my rear drum brakes because I had noticed a considerable loss in braking power and my parking brake was no longer holding the way it should. To begin, I jacked up the rear of the truck so both tires were off the ground. I then pulled the four rubber plugs from the wheel assembly on each side of the truck. My truck has 118K miles on it with the original brakes and I was surprised to see that all four shoes had about ¼ inch of pad left on them.



On the driver’s side, the rearward shoe was close to the drum while the forward shoe was about 1/8 inch away from the drum. I turned the star wheel to adjust the shoes until I felt a slight drag. At this point, the forward shoe was still a fair distance from the drum while the rearward shoe was in slight contact with the drum. I go in the truck and pressed on the brake pedal a few times to try and re-center the shoes. I went back under the truck and the forward shoe was still far away from the drum while the rearward shoe was slightly dragging on the drum. Is this OK? What can I do to correct this if it is a problem?



On the passenger side, both shoes were an equal distance from the drum and the adjustment went well. However, the star wheel and associated hardware appeared wet. The drum and shoes were dry. The wetness was not from water but appeared to be something leaking from the truck. I assume this is either axle or brake fluid that is leaking. Whatever is leaking is not leaking very much because there is no sign of leakage except for what can be seen around the star wheel. What should I do regarding this leakage? I guess I should pull the drum and see for sure where the leakage is coming from.



Any advice would be appreciated as I am not a brake expert.



Thanks,



Scott

 

[Bart]

Mornin' Scott. I learned from my Dad, who was a brake and frontend mechanic, that adjustments were made by adjusting the wheel until you couldn't move the wheel with all your strength of one arm (while adjusting the star wheel with the other one). That will force both shoes against the drum. There's an equalizer bar in there that pushs the second shoe outward after the first one contacts the drum. It's called the line of least resistance. Then you'll need both hands to back off the star wheel. I use a long thin screw driver (6-8") to push the adjusting arm away from the star wheel so I can use the brake spoon to back the wheel off 3 to 5 clicks. This way both shoes will be up against the drum. When you do the second side, take into account the added friction of the newly addjusted brake that you just finished.

Next, if you supect a wet star wheel PULL the drum. A leaking wheel cylinder or axle seal is right above the star wheel and that'll be the first thing to see the leak. It's worth the time. Replacing the axle seal is not a fun job. It's been several years since I had to replace one of my seals and frankly I'd have to review my shop manual first. I can see in my mind the full floating axle, drum assembly, but I don't remember just where the seal is right now. I'm at work and books are at home. Seems to me that it's inboard (close to the differential) but I'm not sure. Let me know if you'd like me to check the manual and let you know tomorrow. Maybe someone else is close to their book and can also give you some input.

If the leak is from the wheel cylinder, it's a good time to up grade to the GM wheel cylinder that's larger diameter and gives a little better brake. It goes without saying to replace both wheel cylinders. By the way, since you've prefessed to not being a brake mechanic, changing out a wheel cylinder involves removing most or all the brake mechanism. That requires about 5 hands for someone familar with brakes. A novice should takes some digital pictures, have a second set of hands (preferably a friend). Wives don't work well here (trust me on this). :-{}:-laf#@$%! and lastly :{(wife).



Edited, one other thing, don't look inside side opening at the gap between the shoe and drum for clearance. That's to tell how much linings are left. The drum wears some and leaves an edge out on the edge of the drum. You can't really see the surface where the shoes hit the drums. Good luck

 

[San Felipe Bob]

Get a book

Get a repair manual.

Read through the section on rear brake cylinders.

The problem you describe fits a worn out brake cylinder.

Do not start the project unless you are prepared to bleed your brakes.

If you have not changed your brake fluid "ever".

You should have a professional or a well equiped shade tree mechanic flush your brake fluid.

You will be amazed at how well your brakes work when brought back to factory new specs.

You may also consider going up one size on the diameter of the wheel cylders as well.

This will help your front brakes last a little longer at the expense of slightly shorter lifespan of the rear brakes...



Get a Repair manual.



SFB

 

[brn2fsh]

Bart and SFB,



Thanks for the responses!!



Bart, I will try what you suggested about tightening the shoes until both contact and then backing off. Hopefully this will work. I will also pull the drum. If the axle seal is leaking I may get back to you regarding the repair procedure.



SFB, when you are referring the the worn out wheel cylinder is this in reference to the leakage or the uneven shoes?



Thanks,



Scott

 

[San Felipe Bob]

Wheel Cylinder Leakage

BOTH Wheel Cylinder Leakage and uneven shoes.



"SFB, when you are referring the the worn out wheel cylinder is this in reference to the leakage or the uneven shoes?"



When the wheel cylinders get old they start to leak.

Check out the rubber boots on the wheel cylinders.

They should be nice and dry.

They are all gooowy and you can't tell where the goo came from?

Simply peel back the boot check for signs of fluid.

Since you are in Montana my guess is your cylinders are shot.

The fact that your shoes appear to be uneven tells me that your wheel cylinder is froze up / rusted on one side.

Be sure to let us know what you find.

Us arm chair / shade tree mechanics have inquiring minds and would like to know.



Thanks

SFB

 

[Dave M]

If you have a leak in there then its likely the brake shoes are no good due to the fliud leak. I did this on my 97 dually about 2 years ago. I replaced the wheel cylinders and axle seals and brakes. Do a search on "dave m" and you will find my post regarding the axle bolts shearing off when I tried to pull the axle.



My axle is the floating type and I can't remember if yours is. If it is the wheel bearings are lubed by the rear end fluid and the axle seal is under the bolts holding the axle to the hub.

 

[Bob Cochran]

On the seals in a the floating type. I don't know if this applies to the newer trucks I have not had the need to replace mine yet. In my old 1975 Dodge 3/4 ton I had leaking rear seals on my then new under warranty truck. Took to dealer for new brake shoes and seals both sides. Shortly after the work was done it started leaking again!!! OK this time I am going to do it myself and here is what I found. Inside the axle housing was a ridge that the seals was suppose to bump up against all around that kept the seal square. To get the seal to do this the seal was recessed a little inside the axle housing. If you did like the dealer and just put the seal flush with the outside of the axle housing the seal would slowly tilt and start leaking. When sit properly against the ridge inside the axle housing the seal did not tilt and it never leaked again until I gave the truck to my son. He wreaked it but it had a lot of miles on those seals. Maybe someone can comment if this is the case on newer trucks. Hate to see anyone have to do multiple brake pad and axle seal replacement in a short period of time. There was no mention of this in the Dodge service manuals I had for the truck back then. Yes even back then dealer work was always suspect!!!!

 

[jelag]

As a guy in the profession I agree with Bart in that we were taught to get them snug... . I don't personally agree with as tight as Bart is suggesting but other wise I fully agree.....

On the other hand I DO NOT suggest the change to oversize wheel cylinders. Some great engineers designed your truck and who ever suggested the move to larger diameter wheel cylinders needs to consider the overall engineering of the truck... . your front brakes do somewhere between 65-75% of the braking based on the engineers design..... this leaves the rear empty bed doing 25-35%... . lets say that you change those cylinders as suggested and now the rear brakes do, oh say 40% and every time you hit the brakes they lock... . in a skid and force the ABS system to function... . any skid is loss of control and longer braking distance..... now lets say your in an accident and someone finds out you, a non professional modified the brakes..... I'm guessing your AS* is sticking out a country mile, and maybe if your lucky your insurance company will still cover you for the liability of this foolish act... . but the other guy finds out, and I'm betting he going to own your home when he's done... ... ...

And I'd suggest that Bart ask his dad if he's still alive... . if he would make that wheel cylinder change..... to oversize cylinders!!

 

[brn2fsh]

Thanks for all the responses, tips, and suggestions!!



Last night I pulled the drums. On the passenger side, everything under the drum was covered in what I would describe as a black grease. I was expecting brake fluid or gear lube but instead there was a black grease. The brake shoes are shot because they are covered in grease so I will be replacing them on both sides. I am taking the drums to a brake shop today to have cleaned and turned. There was very little wear on the drums at 117k.



I could not tell what was leaking. I will pull back the boots on the cylinder to see if they are dry as SFB suggested.



Anyone have any ideas on where the black grease came from and what to do to repair the problem?



My truck is a 1997 3/4 ton, 4x4, 3:54 gear ratio. I believe is has a locking differential as both rear wheels turn forward at the same time when only one wheel is rotated forward while the vehicle is jacked up off the ground.



Thanks,



Scott

 

[San Felipe Bob]

Wheel cylinders

Jim,

Dodge has a TSB on the larger cylinders.

I'll try to find it and post a link.



I see your a Pac-Brake dealer.

An exhaust brake would be the first and best "brake" system up-grade.

Our 2nd gen automatic equipped trucks have little to none engine braking and our brakes are asked to do allot of work.

I bet with "proper" maintainance and an Exhaust brake the brakes would actually last more than 25,000 miles.



As far as getting into a wreck and being held responsible?

Well I guess these days they'll sue you for whatever they can.

"I'm sorry Sir your truck was modified and we are taking you for everything"



I guess that's where we get these companies with the "For off highway use /racing purposes only" disclaimers on all there go fast stop quick goodies.





Oh well... ... ... .....



I'm done ranting.



SFB

 

[San Felipe Bob]

Brake fluid.

My 4,000 miles away guess is still brake fluid.



Brake fluid is more or less water soluable.

When your pads wear they produce black dust.

That dust mixes with the leaking brake fluid and tends to make a "grease like " mixture.

Your next "to-do" should be to wash off the brake assemblies with water.

IMPORTANT

DO NOT USE AIR to "Blow" off the brakes.

USE WATER... ... .



When the axle seals leak it makes more of an oily mixture.



Good job !

Keep the info coming.

I almost feel like I'm standing there with a beer in my hand pointing out what to do next. .



Cheers,

SFB

 

[San Felipe Bob]

Tsb

I found the TSB.

Probably the best brake TSB on the planet!

It gives very detailed info on a proper brake job.



Please read ... .



Lots of great stuff!!!!

TSB 05-04-97



TSB 05-04-97





SFB

 

[brn2fsh]

SFB,



So if I understand you correctly you are saying that brake fluid is water soluble and gear lube is not. Thus, if I wash the assembly with water and it comes clean then the leak is from brake fluid. If I wash with water and it does not clean up then the leak is gear lube because gear lube is not water soluble and will not wash off with water.



I will try this tonight and let you know. I'm glad you pointed this out because I was going to clean the assembly with brake cleaner today when I got home from work. Now I will try water first.



Thanks a bunch!



Scott

 

[San Felipe Bob]

Water?

Scott,

The brake fluid is water soluble.

However... .

You may find that the greasy mess may not just "wash" off with relative ease.

You can try using a brush to scrub it off but it gets messy.

More than likely you will end up using brake cleaner to get it squeaky clean.

How many miles did you say you had?

Wheel cylinders are NOT designed to last forever.

If you have over 80,000 miles you may want to just go ahead and replace them even if you are not sure if they are leaking.

As far as going to a larger size?

Well I have tried 1 -ton Dodge size and the 1-ton (largest) Chevy size.

I prefer the 1 ton Dodges over the Chevy's.

As mentioned by others

You will need to replace those gummed up shoes.

I recommend you replace the "hardware" (springs ect. ) too.

They lose there strength from getting hot.

Your brakes should be checked every time you rotate your tires OR every 5,000 miles whichever comes first.

BUT you drive in extreme conditions in Montana.

You should be checking and lubricating your front calipers and checking your rear brakes

SEASONALLY. SPRING ,SUMMER, FALL and WINTER.

Regardless of milage.....

Your front calipers like to get gummed up start to stick and prematurely wear the inside pad.

Check out my readers gallery here on TDR for some other great photos, tips and tricks.



By the end of this you will better understand why brake jobs cost soooo much these days.



SFB

 

[jelag]

SFB

I am a pacbrake dealer, and sell a lot of the TDR guys exhaust brakes..... But don't go out of my way to push the product... I'm very pleased with those guys who come to us for their products, and would like to take this space to say THANK YOU... .

And your right that the pacbrake would solve part of the issues here... . more so than the oversize wheel cylinders... I was not aware of a TSB...

For Scott the simple answer, is if you can wash it down with water its brake fluid if it won't wash with water its oil from the floating rear end and either the axle is over full, or the wheel seal is bad... . or both... .

If Scott pulls the plug on the diff housing and the oil pours out. . he knows someone put too much in it... . and bringing it down to the correct level will help... But since he's going to pull the hub and bearings he should replace the seal as part of the job... .

I would add you your last post... any signs of a loose boot means the calipers need to be dealt with NOW so that sticking piston doesn't wear out the inner pad and rotor when you don't expect it... . your comments are well on target... .

We expect our trucks to last 500K before we sell them... . my 04 listed below now has 240K miles, it (04) went with an exhaust brake 160K miles before the first brake job, an F550 has 500K and we are waiting on a new 5500 to replace it... . we bleed and flush all the brakes every 12-15 months... I like a master cylinder and clutch master with nice clean brake fluid... .

And remember if your changing pads, open the bleeder and dump the fluid and don't do as some of the dealers do... and push the piston back in and force the old dirty brake fluid back to the master since its so much faster and easier... .

I had a Honda Motorcycle dealer do it to my goldwing... . saw the tech through the window when he was changing pads and tires... . you can't even believe how up set I was to see that dirty fluid pushed back into the master cylinder... but that's a whole other story... ... .

 

[fest3er]

For what it's worth, brake fluid is akin to cutting fluid. If it gets on your drum brakes, the brakes will work *very* well. And wear very quickly. I had this happen on my F150 years ago; stepping on the brakes made it pull to one side. Turns out one rear cylinder had failed and brake fluid was everywhere.

If it's gear lube, braking will be lessened, since gear lube counteracts friction. Last October, one or both rear seals were leaking. Badly - the wheel wells, tires, underside, tailgate, bumper and the trailer were quite damp with gear lube. I'd had the seals and bearings replaced and everything cleaned up, but one started leaking again. The most likely cause was the key in the big nut that holds the hub nut in place had failed, along with half the plastic it is tapped into. For the second repair, the shop used new nuts and keys.

The wheel cylinders still seem to be just fine after 237K miles. It might help that I change the brake fluid every 100K miles or so; brake fluid attracts water, which rusts brake components, so it must be replaced periodically.

General R&R steps:

• remove wheel
• remove drum
• remove brakes
• remove axle cap and axle
• remove key and hub nut
• remove hub
• remove seals
• check/replace bearings
• check/replace cylinders
• check seal 'seats'
• install new seals
• reverse initial steps to reinstall hub, brake and wheel

N

 

[brn2fsh]

Hello,



Last night, I disassembled the brakes on the leaky side. I discovered that the wheel cylinder was obviously leaking. When I pulled the metal plunger from the rubber boots, the rubber boot on one side was full of brake fluid. I then looked at my brake fluid reservoir and noticed it was down about 1/2 inch. So I will clean everything up and buy new wheel cylinders, brakes, brake fluid, and a brake hardware kit from NAPA and replace the rear brakes.



The thing that is still somewhat confusing to me though is that there are some things that would lead one to believe my axle may be leaking in additon to the wheel cylinder. For instance, my brakes were not grabby at all as was mentioned would occur with leaking brake fluid. In fact, the original reason I checked the brakes was due to a loss of braking power. Loss of braking power may occur from a leaky axle as the result of gear lube on the brake shoes. Also, the greasy mess did not wash off with water as I had expected it to if the leak was from brake fluid. I used brake cleaner to clean everything. So I am hoping the axle is not also leaking.



One thing that makes me think that the axle is not leaking is that the brake shop I took the drums to said that gear lube would smell while brake fluid would not. There is really no smell at all coming from the leaking substance so I guess I am comfortable concluding that the axle is not leaking in addition to the wheel cylinder. Also, my rear brakes were not properly adjusted as I have not adjusted them in the 70k miles that I have owned the truck. This probably explains the poor braking performance and why the brakes were not grabbing with the leaking brake fluid.



Thanks for all the replies and help on this problem. You guys are great!



Scott