M1028 - Rear brake "lock-up" / Drum Removal

[Makincold]

So of course I have searched here and cant find description of my specific problem
I also have the 20P in front of me as I type

When I got the M1028 The drivers side rear tire locked up a bit but would go away after driving. I attributed it to a rusty drum and not being driven
After driving it more the problem has gotten worse, driving over the weekend on pavement it would lock up at parking lot speeds and drag 2-3 feet
There is no leaking fluid out the back of the drum area (differential fluid or brake fluid) that I can tell
My assumption is I need to remove the drum and see whats going on, but not sure what I need to have at hand when I get in there.

Any ideas on what it can be? Should I have everything I need for a total brake job before I tear into it?
Must I replace seal #14 (page 8-12 in the 20P)

Thanks for any input, just like to be as prepared as I can before I start into something!

 

[doghead]

I have had a very similar issue before. Only at slow speeds, like at the end of my driveway, of just before coming to a stop at a light, it would skid one wheel(same one every time).

It was a bad oil seal. The shoes were wet with oil.

I replaced the seal, turned the drum(the oil allowed grit to stick and create grooving) and replaced the brake shoes.

All fixed.


You could have a shoe that the lining is bad or fallen off of. Or you could have a brake shoe hardware failure.

Get in there and see what you have. Replace the seal, at least, while it's apart.

 

[BKubu]

I concur with DOGHEAD. I had the same problem with my M1028A2.

 

[Makincold]

Thank you gentlemen, I'll get a seal and pull it apart and let you know what I find!

 

[Barrman]

Might as well buy new wheel cylinders and the rear axle brake hose. The brake parts might cost you $20 total, they will be new and you will only have to bleed the brakes a single time.

I had the same problem on a 14 bolt Suburban and it was the wheel cylinder seeping. Either way, same problem and same fix.

Just remember to read the TM about brake bleeding. The proportioning valve is very picky about bleeding procedures.

 

[Makincold]

So.....
I pulled the axel and drum this afternoon...
And Dogead and BKubu win the cupie doll! Leaking oil seal
I'll pick one up tomorrow, it wasn't leaking enough to run out the back, but enough to ruin the brake shoes, lots of oil inside
This truck shows 26k miles on the odometer and after pulling the drum I'm sure it's correct, all the internal parts ave bright paint, blue springs, orange springs, orange wheel cylinder. Just like the day t left the GM plant in 1985
Brake job and new seal and she will be good to go

 

[truck1]

I had the same issue on my 1028.Left rear oil seal failed and ruined the drum and shoes.It was a good excuse for a complete brake job.I was surprised how inexpensive the wheel cylinders and spring kits were.

 

[4x4 Forever]

Do yourself a favour and have the drum turned if it looks bad. At the very least grab a couple (or more) brake clean cans and douse is good to get the oil off.

Have FUN!

 

[truck1]

If your drums are shot,Saturn Surplus has NOS drums CHEAP!

 

[Makincold]

OK drivers side done! Took a lot longer to clean the oil off of everything than to actually change the brakes
Passenger side next
Then I am going to change the differential fluid, it didnt look all that good when I pulled the axle

 

[Makincold]

So I got the passenger side done, brakes and wheel seal
The wheel seal on that side hadn't started to leak much yet, but it would have been leaking soon
It had a coating of oil and a little "fuzzy" from brake dust and dirt
Everything had a healthy coating of surface rust, looked 25 years old to me!

 

[Shrapnel]

Looks like you got everything taken care of with little trouble. Have you test driven it yet?

 

[Makincold]

Test drive done! All is good. Lots of forward, backward, start stop to make sure the adjusters adjust out!
Front differential fluid and king pin bushings are next!

 

[doghead]

I remember how happy I was to not have my brake grab! Glad you got it fixed.

 

[Makincold]

Thanks for the advice DH!
Yea, much better to put on brakes and not drag the tire 3 feet down he pavement!

 

[4x4 Forever]

Yup, looked 25 years young. Glad you are through with it!