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Rehauling e-body HD drum brakes

Started by kawahonda, June 05, 2020, 02:34:42 PM

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bc3j

Quote from: kawahonda on July 12, 2020, 03:32:07 PM
You may be right about the wheel cylinder...because that's where I'm heading next!

I swapped the rear hubs, and the problem still exist on the driver's rear. I can feel some dragging by coasting in neutral.

The car also pulls left during braking--just more evidence that the driver's rear is the culprit.

My thinking is to order another new wheel cylinder for the driver's rear, and replace both rear adjusters for the hell-uvit.

Obviously replacing a wheel cylinder means bleeding the brakes again. Curious: Does this mean the full bleeding process @ 4-corners?

Thanks!
When I went through my ritual, I only bled the rear since that side of the system was opened.

Mr Lee

I would only bleed the one wheel where you opened the line.
So how many miles have you put on the car since the brake job?   I just took my car to get an alignment and the mechanic said that the brakes need some time to bed in before everything equalizers, so to speak.  I think he said about 50 miles or so.


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JS29

Pulling when breaking is usually front breaks, I have tightened up the opposite side of the pull a little. Maybe a couple of clicks or so. Wheel cylinders I all was change in pairs.    :alan2cents:


kawahonda

Is this driver's side axle housing bent, or is this this area being a little concave normal for the casting?
1970 Dodge Challenger A66

MoparLeo

They are stampings, not castings. Not normal.
moparleo@hotmail.com  For professionally rebuilt door hinges...

kawahonda

Well, this could very well explain the heat build-up.

I could either A) Try out the new wheel cyl and adjusting hardware on both sides, or B) stop now, and remove third member. Ugh, what a pain to have to find this out now.

How the hell does that even happen? Is this repairable, or am I now looking for a new third member?
1970 Dodge Challenger A66

RUNCHARGER

Thats looks damaged but I don't think it wouldd affect the brakes.
Sheldon


JS29

Try a dial indicator on the axle's, That will tell you if the axle has any run-out.  :alan2cents:

kawahonda

Quote from: JS29 on July 18, 2020, 05:30:03 PM
Try a dial indicator on the axle's, That will tell you if the axle has any run-out.  :alan2cents:

Good idea. I was also planning to mark center point of third member, and both axle sides as well and "connect the dots". That may help tell the story with the dial indicator idea.

My axles have been professionally "rebuilt" (if that's a such thing). New tappered bearings were installed. I'm pretty sure the shop would have tested them for straightness. The dial indicator idea would still work to determine a bent housing I would assume.
1970 Dodge Challenger A66

kawahonda

Quote from: RUNCHARGER on July 18, 2020, 05:01:40 PM
Thats looks damaged but I don't think it wouldd affect the brakes.

The PO (a good friend of mine and a member here) was chasing a heated brake issue for a long time. He informed me that he found a bent axle housing, and that solved the issue. Makes sense, because the drum hub connects to the axle (well, actually everything does). For him, straightening the axle housing fixed his issue because he's tried everything prior.

Not information I really liked to hear, but my job is to track down the issue. It gets tiring having to pull off the wheels so much and try little things specific to the brakes....maybe this could be the reason...maybe not. Now would be a good time to check it I suppose.

Would be a big job pulling third member...a good winter project, but a piss-poor summer project. :)

1970 Dodge Challenger A66

kawahonda

#130
Rechecked my thrust play. .016". That's in spec, but a little bit on the big side.

Considering to tighten that a little, but I would suppose that wouldn't be the issue here.

I'll take a look at axle run-out tomorrow.
1970 Dodge Challenger A66


kawahonda

Thrust play: .016"
Drivers rear runout: .007"

I measured to the best of my ability to determine any bending.

Top sticky is laser beam from backing plate to backing plate.
Bottom sticky is tape measure to center to center of tire tread.

These measurements are not showing any abnormalities.
1970 Dodge Challenger A66

kawahonda

Here is picture of new cylinder and adjuster hardware.

Picture is important because is shows which area of the shoes were getting toasty.

Notice it's the rear shoe.

The "dent" in the axle would suggest that the housing would be pushed "backwards" and downwards. This matches the heat profile of the shoe.

However, my measurement methods cannot pick this up as a fact.
1970 Dodge Challenger A66

kawahonda

#133
I made an infographic to help solicit opinions. I wouldn't mind measuring more, but there are obstructions in the way that keep me from running a straight line.

I basically want to assure that there isn't any problem with the axle housing.

It appears that my laser measuring is picking up some discrepancy. We're looking at .08".
1970 Dodge Challenger A66

Bullitt-

 I'm not sure what this means but if I'm understanding the #s relationships
the backing plates at the rear are closer          52.95-52.87= 0.08
while the rear tire centers are further apart     61.25-61.375= -0.125
   the stack of these two differences being 0.205
Is it possible that the backing plate has been bent?     
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