Rear Drums: hot & smelly!

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SD_R/T

SD_R/T

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Not long ago, I noticed a burning smell after getting home from running errands (40 minutes of stop-and-go city driving). Followed my nose to the rear driver-side wheel. Touched the wheel and it was hotter than hell!

A few months back I had re-done the rear drums (both sides) and hadn't noticed any issues since that time. Now normally I don't take the Valiant on anything longer than a 10 minute jog to work or the grocery store, so this recent 40 minute stop-and-go trip was probably the hardest they've been tested. It's possible the issue's always been there and I just hadn't noticed it.

When I did the rear brakes, everything was new: drums, shoes, hardware (springs, adjusters), & wheel cylinder. Haven't had the Valiant long enough to know the full history so figured it was best to just change everything out.

Anyhow, pulled off the drum to take a look and here's what I found:
View attachment DSCF0953.jpg

View attachment DSCF0954.jpg

View attachment DSCF0955.jpg

Can somebody see something that I can't??? I half expected to find something detached or for the drum to be seized on. Looks like there may be a little glazing of the shoes, but otherwise nothing jumped out at me. My findings:

-Drum was not seized on. Came off with just normal force.
-Was able to spin adjuster freely in both directions.
-Compared everything against the shop manual and other photos and everything (springs, etc) seemed to be in the right position.
-I have experienced no 'pulling' while braking nor do I notice any drag. Before pulling off the drum I confirmed it spun fine and wasn't hung up. I don't really use the parking brake ever.
-It did appear the top edge of the front shoe was worn a little further than the rest of the shoe. Not sure if it's significant enough? Circled in yellow in this photo.

View attachment brakenotes.jpg

I did notice there was some minor play at the top where the front shoe rests on the top anchor. It wasn't much, but I couldn't get it to 'stay' solidly against it by fiddling with the springs. Took the passenger rear drum off for comparison and was able to manipulate the shoes at the post as well (ever so slightly), so not sure if that's even an issue or not.

Hoping someone out there with more experienced eyes than mine can see something I can't! Thanks guys....
 
Did you replace the rubber hose between the block and the car body? I have seen these where fluid wouldn't release back because the inside of the hose was deteriorated.
 
I like to put the drum and wheel on and pop the plug to the adjuster off the backing plate and spin the adjuster wheel until there is just a little bit of scrubbing while turning free....both sides equally.

I'm thinking maybe you have them adjusted too tight, the parking brake is hung up or quite possibly the backing plates have deep grooves worn in them where the shoes slide while moving during braking.
I also lube up the star wheel adjuster threads with anti seize and put white lithium grease on the contact slider pads where the shoes slide on the backing plate.

Pull the parking brake with drums on then release it to see if it is hanging up then step on the brake pedal then release to see if that is causing problems.
You can also get a helper to lightly step on the brake pedal while you watch with the drum off and see if it all snaps back in place like it should.

Have you bled the system properly yet?

We're the drums a ***** to get off of the car or did they come off easily?
 
Oklacarcollecto said:
Did you replace the rubber hose between the block and the car body? I have seen these where fluid wouldn't release back because the inside of the hose was deteriorated.
Click to expand...

Might have to check again, but I think it was a hard line directly into the backing plate and wheel cylinder?
 
Hard to tell in the 1st or last picture, but is the strut bar properly engaged on the rear shoe?
 
This is an example of what the line would liik like. Look at the steel line leaving a wheel cylinder and follow it to where the two steel lines meet from each wheel cylinder. There will be a block that is bolted on to the rearend housing and this rubbr line will be going from that block to the brake kine that is attached to the body.

h24717-007.jpg
 
cudaspaz said:
I like to put the drum and wheel on and pop the plug to the adjuster off the backing plate and spin the adjuster wheel until there is just a little bit of scrubbing while turning free....both sides equally.
Click to expand...
Wheel turned freely after install. Dumb question perhaps, but aren't the adjusters 'self adjusting'? I'm full of dumb questions :D

cudaspaz said:
I'm thinking maybe you have them adjusted too tight, the parking brake is hung up or quite possibly the backing plates have deep grooves worn in them where the shoes slide while moving during braking.
I also lube up the star wheel adjuster threads with anti seize and put white lithium grease on the contact slider pads where the shoes slide on the backing plate.

Pull the parking brake with drums on then release it to see if it is hanging up then step on the brake pedal then release to see if that is causing problems.
You can also get a helper to lightly step on the brake pedal while you watch with the drum off and see if it all snaps back in place like it should. .
Click to expand...
Didn't notice any serious grooves on the backing plates. There was still grease on the 'contact points'. I'll have to check the parking brake again, but I didn't notice any hanging up.

cudaspaz said:
Have you bled the system properly yet? .
Click to expand...
Yep, bled right after install. Got a decent pedal. Have noticed no deterioration or change in braking (besides the smell and heat that one time).

cudaspaz said:
We're the drums a ***** to get off of the car or did they come off easily?
Click to expand...
Originally, before installation: yes. After I re-did the brakes: no, they came off with normal force.
 
SD_R/T said:
Ahh! Will have to take a look at that. Thank you.
Click to expand...


You are very welcome. Glad to be able to offer a possible solution.

With age they can collapse inside and when the pressure is applied to the brakes the brake fluid will work but when you release the brakes all the fluid may mot be able to be pushed out of the wheel cylinders by the brake springs. I have ran in to this numerous times.
 
I always thought that the spring just above the adjuster was a small thin that went from side to side.
 
Oklacarcollecto said:
You are very welcome. Glad to be able to offer a possible solution.

With age they can collapse inside and when the pressure is applied to the brakes the brake fluid will work but when you release the brakes all the fluid may mot be able to be pushed out of the wheel cylinders by the brake springs. I have ran in to this numerous times.
Click to expand...

Indeed. It is much appreciated. I thought I followed the FSM to a 'tee' so this had me scratching my head. Looked back through the entire 'brakes' section in the FSM and didn't see one reference to it.

Just went out and looked underneath: yep - I see the line you are talking about. Looks like both hard lines from the rear wheels join up to the single rubber line near the exhaust? Looked on Rockauto and mostly I see 'hoses' for Front Brakes, but there are two that are identified as 'Center' hoses. Assuming that's what I'm after? (Car is '68, slant, 7.25, 9" drums all around).

Looks like I'll try replacing that line, seeing as how the odds are good it's never been changed. Another dumb question: Since this rubber hose feeds both rear brakes, would I expect to see the release problem on both drums? The passenger did not exhibit the same symptoms.
 
Snake said:
I always thought that the spring just above the adjuster was a small thin that went from side to side.
Click to expand...

Looks correct for that application........GM's use a small spring that way though.
 

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OldmanRick said:
Hard to tell in the 1st or last picture, but is the strut bar properly engaged on the rear shoe?
Click to expand...

Hmm, I think I see what you're talking about. It didn't catch my eye while inspecting the set-up, but in the photo it almost looks like it isn't seated properly.
 
OldmanRick said:
Hard to tell in the 1st or last picture, but is the strut bar properly engaged on the rear shoe?
Click to expand...

Have you checked this? These are not a exact photo, but..... Sorry, this post was late.
 

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OldmanRick said:
Hard to tell in the 1st or last picture, but is the strut bar properly engaged on the rear shoe?
Click to expand...

OldmanRick: here is a photo of the 'before':
View attachment DSCF0883.jpg

Although the angle of my 'after' photo doesn't show it clearly, it seems as if there are two plates (the strut bar rests on the 'inner' while the return cable attaches to the 'outer'). Does that sound right? I will still take another peak just to verify.
 
SD_R/T said:
Indeed. It is much appreciated. I thought I followed the FSM to a 'tee' so this had me scratching my head. Looked back through the entire 'brakes' section in the FSM and didn't see one reference to it.

Just went out and looked underneath: yep - I see the line you are talking about. Looks like both hard lines from the rear wheels join up to the single rubber line near the exhaust? Looked on Rockauto and mostly I see 'hoses' for Front Brakes, but there are two that are identified as 'Center' hoses. Assuming that's what I'm after? (Car is '68, slant, 7.25, 9" drums all around).

Looks like I'll try replacing that line, seeing as how the odds are good it's never been changed. Another dumb question: Since this rubber hose feeds both rear brakes, would I expect to see the release problem on both drums? The passenger did not exhibit the same symptoms.
Click to expand...

A slight bit of difference in the adjustment could cause just one side to do this. It is obviously letting brake fluid back in the system but is it letting it all back like it should? It may not be the hose at all but based on experience I would start there if you find nothing else that is evident.
 
SD_R/T said:
OldmanRick: here is a photo of the 'before':
View attachment 1714512816

Although the angle of my 'after' photo doesn't show it clearly, it seems as if there are two plates (the strut bar rests on the 'inner' while the return cable attaches to the 'outer'). Does that sound right? I will still take another peak just to verify.
Click to expand...

Looks right to me from memory. I would have to pull the service manual out to be 100% sure.
 
That arm behind should be the emergency brake lever. Could be a issue if not correct. The before pic looks just right to me.
 
Do you have an Oreilly's? If so call them and ask for this part number. It should be correct.
BrakeBest - Brake Hose

Part # BH24717

Line: BHH
 
OldmanRick said:
That arm behind should be the emergency brake lever. Could be a issue if not correct. The before pic looks just right to me.
Click to expand...

Confirmed: strut is sitting on the e-brake lever, similar to the 'before' pic.
 
SD_R/T said:
Confirmed: strut is sitting on the e-brake lever, similar to the 'before' pic.
Click to expand...

That's good. At least there are some good suggestions posted for you to check.
Good luck and if something else comes to mind i'll chime in, Rick

P.S. Thanks for the pics, they were really helpful.
 
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