Author Topic: started with rear drum brakes.. then grew out of control...  (Read 1747 times)

Offline BillWill

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started with just wanting to bleed rear drum brakes so I could get comfortable enough to get my truck to a friends shop for help working on it and it's still on side of my house on jackstands...

bleeder valves won't budge (started to strip so just went a bit further..)
ordered new cylinders for drum brakes (never worked with drums and this was what I was told to get)
removed rear drums (torch, sledge and pry bars for the win here..sorta)
realized I needed to drum brake pads.. ordered those
figured I might as well get new springs too.. ordered those
found 'sludge' leaking from rear differential so figured I might as well change fluid while under there (Youtube showed it to be simple enough)

pics of brakes after removing drums...


on the passenger side the drum brake 'contraption' fell apart and I have some questions about if I need to get some other parts replaced (asking not because I don't want to spend the money but if I do one side I need to both.. and I really really really do not want to take apart the drivers side brakes again if I can help it).  The emergency brake lever and the help brake bar lever seem to be able to function okay but did get some damage to them so are these 2 parts critical to any type of exact specs?  I am assuming no..

drum brake backing plate has some decent grooves in it where the 'touch points' for the pads would normally sit so I'm not sure if the brakes will just hang or not but I can't seem to find these backing plates anywhere either.  I heard some guys weld over them and grind them down but I have no clue how to do that or have the equipment so looking for advice on what to do here.

if/when I can get this to a friends shop I'm hoping for help to do all rear seals and bearings or at least get them all checked..  I have never done more then basic car work and am enjoying learning.. just wish I had someone nearby to show up and help show me what to do (or in the case of drum brakes really show me an easy way to do them.. they suck)
1986 chevy K10 Scottsdale
305 w/700r w/np208 w/AC
3.73 gears 10 bolt rear
3" lift on 33's

Offline JohnnyPopper

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Re: started with rear drum brakes.. then grew out of control...
« Reply #1 on: June 15, 2020, 05:20:30 PM »
Wow! what a mess!

I feel your pain, rust can be a real problem.

Use the side that didn't fall apart as a model, just reverse.

Always take pics before removing anything.

Was there any oil in the diff? You're going to need to rinse that out good.

I've used Air conditioning line flush for tight spots like that.
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline BillWill

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Re: started with rear drum brakes.. then grew out of control...
« Reply #2 on: June 15, 2020, 05:51:37 PM »
I found a youtube video that was awesome from 'milkcrate82' which I'm sure most of you have heard of and got a great picture (without the axle even which was a great help) and I was able to get the first side put back together again.  Attached the pic from him as well as mine after I got drivers side back together..

I am finding another issue though where I know i have the right size pads but the drum brake adjuster is completely closed on mine after I have the brakes back together and I'm wondering if that may cause issues.  The drum fits back on and does turn without issue as far as I can tell but the pads sit pretty far out on the touch pads on the back plate.

1986 chevy K10 Scottsdale
305 w/700r w/np208 w/AC
3.73 gears 10 bolt rear
3" lift on 33's

Offline bd

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Re: started with rear drum brakes.. then grew out of control...
« Reply #3 on: June 15, 2020, 06:39:41 PM »


The secondary return spring is missing.

After you install the missing spring, make sure that the self-adjusters are fully retracted then back off of the parking brake until the shoes on both sides are firmly seated against their anchor pins located at the top of the backing plates.  Install the drums and adjust the shoes on both sides.  Adjusting the parking brake is the very last step before road checking.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline BillWill

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Re: started with rear drum brakes.. then grew out of control...
« Reply #4 on: June 15, 2020, 06:52:46 PM »
I did get that last spring attached but it was just not in the picture as I had a lot of problems getting it in place, but thanks for the catch as I should probably take a new picture.

I went ahead and replaced the emergency brake cables as well since it didn't cost too much and seemed like a good idea anyway with as much of a mess everything else was.  I am assuming however that before I do any brake adjustments, bleeding etc.. that I need to get both sides put together?  Which leads me to the issue of the backplate having gouges in the touch pads and not sure if I need to replace the backing plate (can't really find them) or getting someone to weld/grind them down properly.  Hoping someone can help with this as well as it would mean taking the drivers side apart again and then removing the axles.. which might get me into more trouble with seals/bearings which again, I have no idea how to take care of.


regarding the rear differential.. there was maybe a cup or 2 of fluid in there but as you can see was more like mud.  I wiped it out as best I could and used a can or 2 of brake cleaner to spray it all out and keep wiping it down, then filled again with clean fluid which is also how I know the front seal is bad and leaking.  Trying not to feel like it is more then I can handle or that the wife is willing to let me spend. 
« Last Edit: June 15, 2020, 06:56:00 PM by BillWill »
1986 chevy K10 Scottsdale
305 w/700r w/np208 w/AC
3.73 gears 10 bolt rear
3" lift on 33's

Offline bd

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Re: started with rear drum brakes.. then grew out of control...
« Reply #5 on: June 15, 2020, 07:47:09 PM »
Yes, both sides should be assembled with drums installed and firmly seated against the axle flanges before performing adjustments and bleeding.  Regarding the thrust pads, if the pads are worn deeply enough to catch the edges of the shoes then they can be filled with braze or weld and dressed down flat and parallel to the axle flange.  If the grooves are fairly shallow, the pads can be burnished and the edges smoothed.  Either way, sparingly dab some brake grease onto the pads during reassembly.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)