Hot rear brake

SixBanger

SixBanger

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Hey,

I still have problems with the right rear brake of the car.

I have already replaced every part of the drum setup (Drums, Self Adjuster setup, hardware kit, wheelcylinders + new brake line to L/R distributor). Problems started with replacing new shoes. it is strange that only the right one warm up after a while and start bogging when accelerate. But it seems braking oke, but not great brakes and it has to be working well.

Drums self seems okay not to much wear and are round (10 inch). Self adjuster seems working. Have some play in the parking brake line. Springs installed at the right way (like shown in workshop manual).

Do someone have tips?

Thanks.
 
I'd say you have it adjusted to tight, park or service breaks.
 
If the linings are dragging the drum (other than VERY slightly), as you drive, the heat will actually cause the brake to get hotter, which makes it drag more, which causes even more heat so it drag more yet...……………… Vicious cycle. Once everything cools down its fine until the car is driven the next time.
If it was a front brake, it could be the hose collapsed internally and not letting the pressure release. As the fluid gets hotter it expands and applies the brake more and more. Since it's the rear, it's probably not the hose of course since it's only one brake with the problem.

I'd try backing the right brake off a few clicks and see if it still gets hot and drags. Just to be sure it isn't a pressure problem, apply the brakes and then release. Crack the bleeder loose and see if there's any pressure release. The fluid should only barely dribble out from gravity.
 
Thanks! Last weekend I have reduced the tension on the right parking cable and it seen move freely as the left side (I can fit 2 fingers easy between line and car floor).

I would backing the right brake adjuster and check if the bleeder.
 
You might check the park break cable and see if it moves, you might have slack in the cable but the sleeve will not let it slide.
I would think removing the drum will tell you what you need to know.
 
I just went through this last year on the same side after having to replace the shoes due to a leaky wheel cylinder. Never did figure it out. Finally I ran the adjuster all the way in and verified the shoe wasn't contacting the drum at all - drum still fried after going down the street. Must have had it apart a dozen times. Eventually I said 'piss on it' and swapped to disc with the new rear axle.

Can you post a photo with the drum off?
 
Park brake cables freeze up all the time from lack of movement, then they get applied and the cable will hold the shoe against the drum.
 
And sometimes the cable may not be completely frozen but tight enough to hang the brakes up.
 
Seems that the old park brake caused the brake problem. I barely use the parking brake here on the flat lands here in Holland. But when I remove the drum I saw that the parking brake cable spring was retracted and it doesn't move easily. Had to see this before, but that's learning things on the way.
 
Given the amount of friction of the right drum brake, this has caused some friction in the suspension bracket / mounting of the leaf spring and differential.

Until recently I noticed some mechanical noise coming from the rear right.
Apparently the right bracket of the leaf spring and the mounting strip on the differential had failed. I think this result in some wear on the right side of the mounting location between the differential and the mounting strip (which is what keeps the differential in place between spring and diff).

[leaf spring bracket]
IMG_20190715_210735.jpg


So time to weld a new mounting strip on the differential and a new set of brackets for the leaf springs.
Exactly last year, only the bracket for the leaf spring broke for the left side. But this is still looking good.

I was already planning to come up with a different type of bracket and mount it for both sides of the rear springs. Which includes a bracket for mounting the OEM shock absorber and get rid of the ISO delete rubber blocks.

IMG_20190726_210426.jpg


Today mounted the new brackets for the left side of the car. However, a piece of rubber was used between the brackets and leaf spring (originating from a rubber floor of a 2CV). Use two 1/2-20 U-bolts to fix the brackets.

IMG_20190726_234805.jpg


Install the right side tomorrow
 
Those brackets look great, but what about the locating pin and the hole in the spring perch? The hole on the perch needs to be the same diameter as the pin.
 
I noticed that as well.
You either need to weld a piece in the spring perch to make the hole smaller or, make a bushing of some sort that goes over the spring center pin and into the large hole in the perches. Otherwise your axle will shift all over the place.
 
Good point guys. I can see that the hole of the spring perch should match the center pin diameter. But why this is not done with the old type bracket?

Yesterday I have install both sides. Test drive it. For now looking great so far. Shaft and spring perch centered in the middle of the brackets by hand before tighten the nuts. Used first 1/2" 'normal' nuts. These torque down to 30 Nm, take some turns to fasten them. Then used locking nuts and torque to 100 Nm to lock the assembly.
I hope that this is good to go. Or had to modify the spring perch.

IMG_20190727_140932.jpg


IMG_20190727_181625.jpg


Old poor right bracket, someone did a weld job

IMG_20190727_180030.jpg
 
If you were to make a plate that covered the axle pad with the appropriate locating hole in the center you can then weld it to the pad.
 
The rubber pads took up the gap around the pin and spring perch. They will probably move some if you don`t do something about it. I have never did it but I have seen some weld a thick washer in the perch hole.
 
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