Another Rear Drum Dragging Thread

300cruiser

300cruiser

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I have been struggling with a dragging & overheating right rear drum issue for a while. Last year I decided to rebuild all four corners, new shoes, drums, cylinders, springs, etc. The new shoes made the issue worse even on short rides.
I eagerly followed Zymurgy's thread about the same issue. I borrowed a gauge and checked/set the end play...no love.
Tonight I pulled the drum and had my assistant slowly apply the brakes so I could observe the action. The cylinder deployed the leading shoe but it does not retract. Problem identified.
So, since all parts are new, I suspect that there is a pressure release issue. Next steps will be replacing from center flex back to cylinders, including a very rusty looking t-block.
Any other suggestions would be appreciated.
Mike
Shoe.jpg
T Block.jpg
 
300cruiser said:
Thanks for the link. I’m having difficulty locating the block, seems that many sources are out of stock.
Click to expand...

I would take yours off and inspect it. There isn't much to it, someone may chime in if there is more to it than just a simple T block. It would be clear or not mine was brass. If you do have an issue with yours I should still have my original, I would just need to locate it.
 
There is probably a piece of crud from a deteriorated hose caught in the block. There is not anything to wear out on the block so take it off and check it for debris. Also check the brake line on that side for obvious dings or dents that might reduce fluid flow. Quick check, have the helper deploy the brakes as in your previous test, while the cylinder is still extended, crack the bleeder screw, if the cylinder immediately retracts, the problem is in the line or the block. If the cylinder stays deployed, the cylinder is defective or something is blocking the shoe from retracting.

Dave
 
Thank you gents. I will pull the block and clean it up and probably replace the lines while everything is apart.
 
what about parking brake cable adjustment? I see no mention about this in the thread of conversation here.
If it is stuck in the applied position then it will cause the shoe to sit exactly as pictured.
Disconnect that first and see if it returns to the proper position.

If this doesn't do the trick then with every thing in place as shown crack the brake line loose to see if it pops back into place.
If it does then it's a hydraulic problem.
If not then it's a mechanical issue at the wheel.

One last thing that it may be is if the backing plate is worn badly, it will cause the shoe to hang up in the grooves worn into the backing plate.

On my brake plates I had to weld up the worn section and grind it flat to fix the problem of the worn grooves.
 
mr. fix it said:
what about parking brake cable adjustment? I see no mention about this in the thread of conversation here.
If it is stuck in the applied position then it will cause the shoe to sit exactly as pictured.
Disconnect that first and see if it returns to the proper position.

If this doesn't do the trick then with every thing in place as shown crack the brake line loose to see if it pops back into place.
If it does then it's a hydraulic problem.
If not then it's a mechanical issue at the wheel.

One last thing that it may be is if the backing plate is worn badly, it will cause the shoe to hang up in the grooves worn into the backing plate.

On my brake plates I had to weld up the worn section and grind it flat to fix the problem of the worn grooves.
Click to expand...

Could the parking brake cause an issue if never applied? I rebuilt them last year and have never actually used the PB. I can compress the shoe/cylinder by hand, takes some pressure, which makes me think it's hydraulic related. The shoe appears to move smoothly on the plate but will confirm the above this evening.
 
300cruiser said:
Could the parking brake cause an issue if never applied? I rebuilt them last year and have never actually used the PB. I can compress the shoe/cylinder by hand, takes some pressure, which makes me think it's hydraulic related. The shoe appears to move smoothly on the plate but will confirm the above this evening.
Click to expand...
If the cable is pulling on the pb lever it will do what you have shown above
If you can compress the shoe back in then there’s a better chance it is hydraulic
 
Check and make sure your equalizer bar is seated properly. (Little cross bar with spring on RH side). It looks like it is holding that side open. I did that the other day when I replaced my wheel cylinder. Pull the anti rattle spring back towards the center and push the cross bar up into the slot. The spring may be holding it down and not allowing the brake spring to pull the piston back in.
I will see if I have a close up of what I am talking about.
EB473180-8DF0-4E1E-9D82-8E9EC9F10485.png
 
This is the other side but you can see how the spring on the equalizer bar (don’t know the right name) is supposed to sit. If it is resting on the spring it cannot retract.

C1A85264-2447-47B7-A443-12029E59AD20.png
 
HWYCRZR said:
Check and make sure your equalizer bar is seated properly. (Little cross bar with spring on RH side). It looks like it is holding that side open. I did that the other day when I replaced my wheel cylinder. Pull the anti rattle spring back towards the center and push the cross bar up into the slot. The spring may be holding it down and not allowing the brake spring to pull the piston back in.
I will see if I have a close up of what I am talking about.
View attachment 291763
Click to expand...

It looks good from what I can see here but only eyes on the actual drum can verify that
 
Yes, the latest picture looks correct. The last one must’ve been the angle.
 
BC06C1C3-3D51-4534-B3B0-DF5C45979C48.jpeg
4737E6DD-E91B-4C49-9E28-F59F9A97B80B.jpeg
D6D956A9-281D-4EC9-9A39-4B0935656025.jpeg
Hey Mike, guys, I am having the same problem now with my 67 Polara. I replaced EVERYTHING (some things twice), asked 4 “specialists” and no one can figure out! Drove it to get them hot again, RT worse than LT, jacked it up and cracked the bleeder...no pressure which means it mechanical, not hydrolic.

Got my hot gloves, pulled everything apart and noticed heavy gouges in the shoe sliding pedestals (where you put the anti-seize) on both sides. Also, left and RT side of stud on backing plate where brake guide and upper springs attack are warn shinny! So shoe frames are definitely rubbing!
Could this be it for some of us?
-I have 11x2 brakes
-Centric drums-As far as I know the only company that makes them
-I think I have Raybestos shoes (may be centric...my records are at work).

Questions:
-could this be it for some of us or Mike’s 300?
-are aftermarket backing plates available?
-anyone recommend a good shoe and drum? (if it’s that?)

See pics...thanks all!!!
 
Pauly's67Polara said:
View attachment 294489 View attachment 294490 View attachment 294491 Hey Mike, guys, I am having the same problem now with my 67 Polara. I replaced EVERYTHING (some things twice), asked 4 “specialists” and no one can figure out! Drove it to get them hot again, RT worse than LT, jacked it up and cracked the bleeder...no pressure which means it mechanical, not hydrolic.

Got my hot gloves, pulled everything apart and noticed heavy gouges in the shoe sliding pedestals (where you put the anti-seize) on both sides. Also, left and RT side of stud on backing plate where brake guide and upper springs attack are warn shinny! So shoe frames are definitely rubbing!
Could this be it for some of us?
-I have 11x2 brakes
-Centric drums-As far as I know the only company that makes them
-I think I have Raybestos shoes (may be centric...my records are at work).

Questions:
-could this be it for some of us or Mike’s 300?
-are aftermarket backing plates available?
-anyone recommend a good shoe and drum? (if it’s that?)

See pics...thanks all!!!
Click to expand...

If the shoes are hanging up in the deep groves in the backing plate, that could cause your brakes to be dragging although I would not expect that to happen on more than one brake set at a time. I usually either replace the backing plates at this point or remove them and use a wire feed welder to build the tabs back up. Not difficult, just takes some grinding with a small angle grinder to get everything square again. Unless you new brake shoes have gotten so hot that they have cracked, they are probably still ok.

Dave
 
Try this.

Back off the tight drum adjuster after putting it all back together.

Install and tighten the wheel.
See if it rotates.
If not, then perhaps the shoes are too wide or incorrect.
I had this happen to me when I first bought my Polara. Was told I had 2 1/2" rear shoes but in reality they were 2".
all was good until I tightened up the wheel

Any mention again in the thread about a tight parking brake cable or has that been addressed?
Having a look at that picture you originally posted appears to have the parking brake lever engaged slightly...
 
Last edited:
I’ve been away for two weeks so no chance to work on it. I’m proceeding with the hydraulic issue first and have ordered lines from the flex back. The flex itself looks rough so I’ll feel better having new lines. I will report back once that’s complete.
As for parking brake, the wheel turns freely after sitting for a day or two so (assuming a slow pressure release) so I don’t think that’s the issue.
I cleaned the backing plate and put grease on the contact points during the shoe replacement.
 
Ok guys,

Put it together, went on test drive...hot again... drove it into garage, jacked it up, cracked the bleeder, no pressure, so it's definitely mechanical.

Thank you Dave! Yes, I already spoke with my buddy last week...he is going to build up weld and grind the perches of the backing plate. I believe they are so warn, the top of the shoe's frame edges are even rubbing against the top pin seat where the guide and springs install...on both sides! That's why I believe that's it. Both sides hot initially made me think that it was hydraulic! Also, I actually removed ALL the E break components completely...still hot.

The dingle berry I bought it from (that's a whole other story), 110% would have drove this car continually with the hot breaks! He was not familiar with any type of cars at all. He wanted to "turn" this car. He was oblivious to the mechanical questions I had. (Got it on Ebay...shame on me for trusting him over the phone!!! Shame on me for using Ebay!!! lol). Shocker, he was watching Velocity channel classic car turning shows when I got there. The negative effect of those shows on that channel! A shame.

-I will report back on how it goes guys...May be a few weeks as my buddy is a busy guy

-Anyone have good luck with a specific brand of 11x2 shoe? Or drums for that matter...are their any other brands out there? Thank you all!!!
 
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