What should I replace (rear drums on 14B SF)?

[Hunter79764]

I need to do some work on my rear brakes. They are losing fluid, and the rear has gone from being sticky after sitting a few weeks between driving to completely grabbing/mostly engaged when driving forwards and only mildly grabbing when in reverse the last month or two. I haven't checked which side it is, and due to parking on gravel, have not noticed fluid anywhere in particular. I also just assume that whatever I do to one side, I'll do to the other.
I haven't torn into it yet, but I'd like to order my parts and just dig in once. I'm assuming that I'm getting fluid out of the wheel cylinders and onto the friction material, hence the grabbing. New wheel cylinders, new shoes (surely fluid has soaked them?).
New springs and hardware kit is cheap, so I plan to order that too.
I see that the self adjuster kit is separate and more expensive than nearly anything else. I don't know that I'm having issues with the adjusters (am I?), can I safely skip that unless I see some obvious issues when I pull them off?

What else should I do while I'm there? I'm not made of money, and I'm not having any other particular issues, but I haven't messed with drum brakes that much and this is the first heavier truck I've had.

Also, how do I know which brakes I have (it looks like there's 13", 11" and 11.15"?) I have code C6P, which shows 8600 GVWR on a codes list found online. Does that indicate which brakes I have?


Thanks all. And for reference, it is a stock '87 3/4T Suburban with a little over 110k original miles. No real idea on previous maintenance other than it was a university owned vehicle originally, then bought at auction by the previous owner and used as a hunting truck, generally take care of though. Now the truck gets many more miles flat towed behind my RV than under it's own power, but hunting season is coming and I need it back in shape.

 

[Radiohead]

Consider that until you disassemble and see exactly what is going on, buying parts on the hope you won't need ingredient X is a potential waste of your time.

What you describe sounds like an axle seal has decided to go gunnybag on ya, although it could be brake fluid. Either way, in my mind I would just buy it all and do it all at once and be done with it for the next decade. I get frugal, I am so tight I screw my socks on in the morning, so I get it. But really, just do it all at once - the whole buy once, cry once thing.

In the long run, you will appreciate having done it all right the first time.

 

[fast 99]

Yes, inspection first. Do not reuse springs even if they look good, they aren't. 8600 likely has 13", width varies. If not familiar with drum brakes take pictures or only work on 1 side at a time.

 

[Hunter79764]

I hear you, and if I have some time I'll try to pull one off and take a look, but with 5 kids and 2 house projects ongoing, scheduling an inspection day and a work day separately gets difficult. I can afford to have it down, but I'm usually working outside too. If I tear into it and find something unexpected, I'm ok going to the parts store and buying whatever else I need, I might be ok ordering online and getting it in a couple days if weather permits, but I'd rather not plan on that. Leaving things out ends up with missing pieces, throwing things back together enough takes up time on both ends too. I just try to get the stuff I know I'll need ahead of time, then let it take longer if required instead of planning on it taking longer. Also, I usually buy on Amazon with free returns and just send back what I don't need.

I've done drums before, but it's been a while. I'll crawl under and see if I can measure 11 vs 13 and go from there. As far as "Do it all", that's basically my question. What is "All"? Shoes, springs/hardware, wheel cylinders are all in the plan. Are the adjusters likely bad or should be ok? And if I don't repair them, do I just lose the self adjust? For the 1000 miles a year I drive, that's probably not a big deal.
Wheel bearings? Are those "Due" at 100k? What else?

 

[Radiohead]

You're on the right track man, thinking is sound. As for wheel bearings, again without inspection it's a guess. If you are in for brakes, doing bearings then might be advised. That's a part you could pre-order and not feel too bad about returning.

 

[Hunter79764]

I'll look at seals and bearings and see about adding those to the order.
Since I'm losing brake fluid but not from anywhere up front, that was my assumption. But yeah, could be axle seal too. Thanks.

 

[fast 99]

Spring kits do not come with adjusters. Adjusters and associated parts can be reused if in good condition.

Check emergency brake cables for free movement. If they aren't free the self-adjusters will keep ratcheting up killing the shoes.

 

[WebMonkey]

https://www.gmsquarebody.com/threads/webmonkeys-1985-k20.28635/post-578215

that's my post on redoing the rear brakes on my k20 super double xtra heavy duty C6P optioned.

13" drums, replaced everything including the cylinders.

good luck
'monkey