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Rehauling e-body HD drum brakes

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

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kawahonda

#105
I did one wheel at a time, so I did not mix up the star wheels.

Let's confirm the correct direction.

Here is the offending wheel. Rotating the star wheel upwards lengthens (tightens). Same if I where to pull upward on the adjustment cable. This appears logically correct.

The star wheel on the offending wheel threads moved to 14.25 from 14.00. So it did tighten incrementally--it did not over-tighten. So I think the adjuster operation is correct here.

I rotated the wheel, stepped on the brake, then spun the wheel again. I couldn't reliabily tell if spinng the wheels was harder after breaking. So if it's "dragging", it must be dragging during heated operation.

On the shoe backing contact surfaces, I used regular synthetic  heat resistant "racing" grease. In-fact, according to the data sheet it is rated for 160F constant temp and 180F peak temp. This grease is applicable for wheel bearings. So I don't think this was the wrong grease to use.

Maybe pad contact surfaces are rough and/or shoe contact surfaces are not smooth and should be filed?

On both rear wheels, the parking break "bar" is loose and is not under any pressure.

The only thing I know to do next is dissemble each rear wheel and to inspect pad surfaces.

1970 Dodge Challenger A66

kawahonda

#106
How much fluid do you guys recommend being in the master cylinder? Mine fill level is a little under 1/4" to the top of the bowls. Edit: Manual says within 1/4" to top, so I have this right. Hmmm.
1970 Dodge Challenger A66

kawahonda

#107
Sorry for the influx of posts, but I think I found an issue. It may very well be related.

I decided to start yanking on the e-brake cables. The passenger side cable I can get to "move" when I pull on it. The driver's side cable is seized...I cannot get it to move by "pulling" on it.

It's probably time for a new parking brake cable. For the meantime, I may spray some PB blaster and lubricant in the hose to see if I clean it out for the meantime.

Even though the cable has some slack, I can easily see during chassis movements that the cable could "expand" itself (the primary end of the cable rests on the chassis), and then get "stuck" in certain positions if it's corroded. That's probably what's happening. That's why you can lift the car, and not see an issue, but after road use, with enough flex/force that cable can move, and then easily get stuck.

Confidence is about 80% that is what's going on.
1970 Dodge Challenger A66


73440

Would switching drums from side to side , in case there is a different drum thickness , be something to try ?

kawahonda

That would definitely be a way to see if the hub is out of round or something strange! Good idea. I may try that. For now, the ebrake kit is on the way!
1970 Dodge Challenger A66

kawahonda

OK, who has knowledge of how the heck to install the front brake cable starting with the linkage?

The pedal assembly looks pretty closed off. I can see a pivot pin, but how the heck do I swap this? Am I supposed to remove the entire parking brake pedal assembly?
1970 Dodge Challenger A66

RUNCHARGER

Yes: I demount the pedal from the cowl to hook it up.
Sheldon


kawahonda

Thank you! WIll do that over the next couple days.

Man, the underneath of this car is really clean, especially with brand new lines and cables across the board!

1970 Dodge Challenger A66

MoparLeo

It is in the Factory Service Manual that you have downloaded.
moparleo@hotmail.com  For professionally rebuilt door hinges...

kawahonda

1970 Dodge Challenger A66

MoparLeo

The procedure to install the parking brake cable.
moparleo@hotmail.com  For professionally rebuilt door hinges...


kawahonda

I do have the hard manual (just so you know), and it actually does not accurately say to remove the parking brake assembly. Take a look!

It's an incredibly poorly written section. Hence, why I posted.
1970 Dodge Challenger A66

kawahonda

Completed replacing parking brake cables.

I drove for about 6 miles. Didn't notice any drag while coasting the entire time, unlike before.

Top speed was 45. Did a lot of hard breaking. Probably 20 miles total break in so far.

Pulled into the garage, and driver's rear is still 30-50F hotter depending on where I point my gun. Could still smell break shoe smell when I pulled in. No steam this time though. Some spots through the wheel measured 300F. I have not shot the back side of the brakes yet (brake plate). The driver's rear hub cap definitely felt "hot" compared to all other wheels. Could keep my hand on it for about 3-4 seconds, then too hot to hold...

Am I worrying about nothing here? My thoughts were to swap the rear drums and to re-test. If problem carries over, then perhaps I should install my brand new rear hubs.

I need to know if I'm screwing around about a whole lot of nothing. Trying to do it right and do it safe.

Definitely not a problem with anything with the hydraulic system. Push break, release brake, wheel spins just fine, hot or cold. I don't think wheel cylinder is at fault. Adjuster is not over tightening either.
1970 Dodge Challenger A66

bc3j

There was a post on another forum with the right rear hotter. Everything was replaced including the drums. The poster took his right drum off and found it was out of round and the shop had to make three passes to get it round. That solved his problem. I also have a hotter right drum, but not as hot as yours. I'm also going to have it turned. Both my drums are Bendix, but I think there made in China. I'd be willing to bet the 'made in China' drum is the problem. In my rebuild, I blew out three Chinese made wheel cylinders before I got one to work.

kawahonda

#119
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!
1970 Dodge Challenger A66