1961 rear brake heat

[johnstrow]

I have replaced all brake hardware and hoses on all four corners. The brakes are adjusted well (maybe toward the loose side).
Emergency brake is adjusted also. All new fluid and system is bled. It brakes well with a slight pull to the right (maybe following road crown).
Problem is after a five to ten mile run the left rear brake drum is about 60°F hotter than the right rear or any other drum on the car.
Both front drums are around the same temperature between themselves.

Could it be a bad left rear wheel bearing?
When I pull in and out on the hub there is about 1/32" play.
When rotating the wheel by hand you can hear a bit of a "rumbling sound".

Possible cause: When I had new tires mounted and balanced the shop adjusted the brakes (unrequested} and had the left rear so
tight when I drove about five miles I had smoke. After everything cooled down I found I could barely rotate the wheel.
Maybe at that point the extreme heat generated by the brakes cooked the bearing(?).
I have since torn down the left rear and checked everything; it all seems in order except the hub play and noise.
I have hit both brake shoes and drum with 60 grit in a cross hatch pattern to address any glazing.

Another thought I had is that this extreme heat event somehow damaged the rear wheel cylinder?

As it stands; the wheel rotates freely with just a touch of drag. After a drive, same thing. Nothing seems jammed or seized.

I am looking for some collective wisdom here. I am greatly appreciative of any assistance.

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[74 Harley]

If you're getting any noise or roughness change the wheel bearing.

 

[johnstrow]

Thank You…I will look into replacing both rear wheel bearings.
Could this rumbling bearing with the axial play be the cause of the increased heat in the drum?

 

[aa010175]

What part of the drum are you measuring? Remove the hub cap and measure the axle end. That should be hotter if it’s your bearing. Now what is the temperature of the other axle end?

 

[johnstrow]

Thanks for your help.
I am measuring (with an infrared heat gun) the edge of the drum from under the car. The hub isn’t that hot. When I measured last yesterday the hub was about 135 degrees while the drum measured around 195 to 200 degrees.
It does seem like dragging brakes but when I jack up the car and spin the wheel there is no resistance.
Frustrating for sure.

I understand the drums can heat up, expand and cause this issue. Maybe I just keep backing off the adjuster(?).

The wheels spun well and seemed to be adjusted well after things sat overnight. So, I wanted to check how much the drums inside diameter constricted with heat.
This morning I checked the wheels after several miles of driving in the July heat.
Everything had tightened up, with the left rear and right front being the tightest. I backed off all of them when they were still warm until I was satisfied.
I took another test drive after that adjustment; the pulling to the right upon braking was somewhat better but the left rear drum is hot again.
Data after today’s second drive:
Both front brake drums were around 160 degrees.
Right rear drum was 150 degrees, left rear drum was 200 degrees.
The right rear hub measured 126 degrees while the left rear hub was 148 degrees.
I’m not convinced it’s the hub. Could the parking brake be contributing to this just on the left side? It is adjusted fairly loosely.

Would switching drums from one side to the other in the rear make sense as an investigative tool?

 

[74 Harley]

You need to look at the metal line that runs across the axle. It may have damage creating a situation where the brake drags from a slow bleed off. A dent, kink, or even rust inside the tube.

 

[johnstrow]

Interesting idea.
As part of the brake system overhaul the rubber hose was replaced in the rear.
Also the metal line to the right rear broke off and was replaced with a new brass line. The metal line from the tee off the rubber hose which runs to the left rear is an original steel line. No kinks but if it’s original it could well be rusted inside….

 

[74 Harley]

If you have a brass line on the right please replace it with steel. Brass is not rated for the pressure of the brake system.

 

[johnstrow]

Installed all new stainless steel lines on the rear axle; same issue (one drum is about 50/60 degrees F hotter than the other side). I triple checked the parking brake, all is well.
The wheel bearing of the subject wheel is “rumbling” and has about 0.250” of play when pulling/pushing on the wheel.
I honestly think it is time for new rear wheel bearings. The hub on the problem side is about 25 degrees hotter than the other.

 

[johnstrow]

UPDATE:
New wheel bearings on both sides.
I also switched the drums side-to-side after the new wheel bearings to check if one may be warped or defective in some way but the heat stayed on the driver side; left drum is about 50 degrees hotter than the right. I will persevere…

 

[Kultulz]

Did the bearing replacements eliminate the noise?

If one side is hotter than the other, it indicates shoe drag resulting n overheating. The LS brake cable may be sticking/frozen (in cable housing @ the rear brake end) causing the LS shoes to drag. It could also be a bad wheel cylinder (sticking).

The backing plate pads where the shoe rides/slides, are there wear marks/gouges possibly causing a shoe to hang?

Did you rebuild the OEM cylinders or replace with aftermarket? You installed all new retracting springs. Were they quality or cheap aftermarket?

When you adjust rear brakes, raise the car by the rear axle housing and sit the housing on stands as it lifted and the car is supported on stands on the frame, the axle assy drops, and the cables will apply the shoes slightly preventing correct adjustment.

Does the front brakes or rear brakes pull? Where did you source the shoes?

 

[johnstrow]

New bearings are good.
I installed new aftermarket cylinders on each wheel.
Springs are quality.
Thank You for the advice on the adjustment.
No brake pulling. It is weird that just the one corner is hotter while the other three are within a few degrees F of each other.
I will give it another look tomorrow.

Shoes came from Pat Wilson’s Thunderbird Parts. They seem decent(?).

 

[Kultulz]

Let's try this again as I have found several threads relating to the same problem/vehicle.

I think I have figured out what I have: It looks like someone took 1963 and newer style backing plates and mounted them on the reverse side(s) they were intended for. 1961-62 parking brake cables entered the backing plates from the rear. The 1963 and newer Thunderbirds had the cables entering the plate from the front.

To make the 1963 and up backing plates work with the 1961 set up they had to reverse the plates. This would result in the adjuster slots be I guess too forward of the adjuster to be useful. Everything else would work well, I believe. I just need to make a second adjuster slot in each of the improper backing plates so the adjusters can be accessed. I don’t know if anyone else has run into this situation but this is about the only that makes sense to my simple mind.

The brakes are assembled incorrectly. Someone (previous owner) mixed different year parts on the wrong model year.

Is this one of the cars being discussed as having a 62/63 year axle housing swap into a 61 model year?

In addition you mentioned the adjusters would not correctly fit the backing plates. This design uses self-adjusters and the adjusters are unique to the design. If the wrong or aftermarket parts are used (or assembled incorrectly - car side to side), the self-adjusters will not function properly and in some case will cause shoe adjustment over tightening.

This may sound crazy but do you see any ID STAMPING CHARACTERS on the backing plates?

I think the answer is going to be finding the correct year backing plates and all new quality hardware. Do you see an ASSEMBLY ID TAG on the rear axle differential?

The play on the axle shafts seem normal. Did the noise(s) go away?

The TECH who decided to adjust the brakes without prior customer approval was wrong. Did they charge you?

 

[johnstrow]

Yes, thank you. This is not the posting about swapping rear axles amongst bullet bird years.

I got my car back in April and have been sorting through things. I noticed the backing plates were reversed as were the adjusters, etc.
The markings on the adjusters (L and R) showed they were on the wrong sides! As a result, the back brakes were effectively inoperable.
The front shoes were cracked and tired, probably from overwork.
After setting up all new hardware as per the shop manual on those rear backing plates I had to cut new slots in the plates to access the adjuster wheels.
I have three corners running well, each about 160 degrees F.

When I went through the whole system originally I sanded down the raised areas on the backing plate and lightly greased those to facilitate shoe movement.
Very recent reassessment has me suspicious of the one "hot" corner having a secondary shoe which seems to be hanging up after reversing.
I'm suspecting this is the case as I ran the car without reversing it for about five miles; all drum temperatures were darn near equal.
I then reversed the car, hitting the brakes and drove about the same amount; driver side rear drum was about 50 degrees hotter than the drinker side drum.
I will be pulling that apart tomorrow and trying to smooth out the raised areas better once I get a better look at where it may be hanging up.

To answer your questions:
The bearing noise seems to be normal after new bearings and seal on both sides.
Thank You again for confirming the axial play seems correct.
I didn't see any ID on the backing plates but will look at that closer tomorrow.
I will also see if I can find the differential ID plate info. at the same time. It would be nice (crucial?) to know what year the rear differential is....
And yes, the folks who adjusted my brakes of their own volition and started this whole party did full charge me.
Their task was to mount five new Diamondback radials; they went above and beyond.

Again, thank you for your help on this. I greatly appreciate it.

 

[johnstrow]

FINALLY!!!! I believe I have effected a positive change…I kept at it (smoothing out shoe contacts, etc.) today, and by the grace of God I noticed the rear-most return spring seemed a bit longer than the other one.
I fished out two new return springs and immediately noticed they were shorter; a little more effort was required to put them over the anchor pin too…
After a couple test drives, reversing while applying brakes and such, the driver side drum and hub are roughly equal in temperature to the right side (actually about 15 degrees cooler).
I believe the secondary shoe was getting hung up after reversing due to the weak spring not pulling it back away from the drum.