Front brakes shoes not advancing - do I bend the arm..?

The front drums on our '65 Satellite are not advancing,

I've had them open and all the parts are there and moving freely, not binding, the advance gear rotates willingly.. the advance gears haven't been swapped side to side.

I've also compared the '65 to the fully functioning '67 drums I have and the major difference I notice is where the 'advance arm' touches the 'advance gear'...

The arm on my '67 engages the gear much lower down than on the '65, it easily catches a tooth on the gear to rotate it. The arm on the '65 is higher and "misses" grabbing a tooth to rotate the advance gear.

If I use my fingers to press on the '65 cable, simulating a brake advance situation, the arm just pops past the teeth without rotating the advance gear.

The same holds for both sides brakes.. OK, so far so good -

The length of the cable hooked to the arm and the upper pivot pin is what dictates the positioning of the arms on the gear... If the cable was longer, the arm would drop lower, and engage the teeth correctly.

I can't stretch the cable, I can't move the "eye" of the cable any better... so do I just go ahead and bend the 'arm' so that it moves lower on the gear to engage the teeth? That's kind of destructive, but I can't fathom what else to do.

What else might help move the arm down to engage the gear lower down where it grabs a tooth?

I've thought of filing the teeth not the advance gear to be sharper, but that won't do it.
I've lengthened the cable as far as possible.
Could there be an issue with the two shoes being swapped "lead and lag".. if you know what I mean? But I recall checking that against the '67 and they're identical.

What would you do?
Thank you,
- Art

I bent the arms many times. Tilt it in at the bottom. Sometimes that's still not enough. You may have to bend the tip in towards the backing plate. Test afterwards as you can go to far. The friction against he teeth when the arm returns can turn the adjuster backwards.
Doug

Any chance the arms/cable length is just wrong?

Assuming same size brakes on your 67, how do the cable lengths and arms compare? If someone before you did a brake job and installed new wrong hardware ie cables that you are assuming to be OEM, it might explain the difference.

Kevin

Wasn't mentioned.
Is this a new set-up?

If not new parts I would assume you checked the adjuster wheel for free movement, no?
I've had the grease dry up and then they don't want to rotate.

Thanks guys,



That's the thing - these are pretty idiot-proof setups.. everything is original except the cylinders.. and both sides of the '65 have the identical problem. Whatever I did, I did to both sides.. hmm.. so that's kind of an indicator.

I went through something similar on the rear of the '67, on one side only, it was driving me nuts.. I went from side to side comparing everything.. It turned out to be the cable's eyelet at the top pivot pin was positioned wrong... That was a "Slap to the Forehead" moment, for sure.. and I found *that* problem by sticking to basics, looking at every single part of the set up one at a time until I found it. I feel like i've done that this time too over and over. I'll try again before I give up.

Yeah, I could measure and compare with the '67, that's a good idea. But if the common practice is to bend the arm, and I can't do anything else, I'll go ahead and do that..

For now I'm crawling underneath and advancing the wheel with a little screw driver manually. ..PITA... but it's a hazard to NOT advance them.. I can feel the rears doing all the work after a while.

Thanks,
- Art

Sorry missed that some how.
It's just this is what I usually find when I get into the drum systems.

Speaking of things that are new: The brake shoes are new of course..

And you know how there is a "curved slider plate" with a groove for the cable to rest in as it travels from the top pivot down the bracket with the actuator arm?
...Remember how that "curved slider plate" is held by round pin that sits in a hole drilled in the brake shoe's gusset plate?

You put the plate in that hole, then you insert the keeper spring with a hook on the end that holds the place in place...

What if that hole was drilled in the wrong place? ..by whoever produces those shoes. Then the cable could be pulled shorter.

I'll check that.
- Art

Unless you've owned the car since it was new, that could be a faulty assumption.

You mentioned something about what if the hole that locates the doodad the cable slides over was in the wrong place. Is there a difference in hardware locations between say the same size 10" brake on B-body vs an A-body or if we're talking 11" brakes, a C-body?

Can you post a pic of your setup? Maybe someone will see the problem.

Kevin

This was a common issue back in the 70's/80's when these cars came into the shop for brake work. Many didn't work when dissembled. This issue was happening even when using the old hardware. This left only one option. The holes in the shoe were in a different location for either the cable guide/return spring or the hole for the self adjuster arm. No biggie, bend the arm correctly and it'll work fine.
Doug

The holes the pivot points the adjuster bracket stud goes into is a factory positioned hole. The odds of getting 2 with the holes improperly located are pretty slim I would guess. Brake shoes are mounted with the shoes with the longest lining is always on the rear side. The backing plate that the shoes mount to have raised pads the shoes sit against. I've seen those pads have groves worn in that that won't let the shoes move freely against them. Those 6 raised pads needs to have perfectly flat surfaces. The top of the shoes also needs to sit tight against the top post. If the shoes are not fully seated, it can make the adjusting cable hold the adjusting lever in the incorrect position.

The cable also needs to sit in the recess of the cam at the center of the shoe, that is held in place by the return spring. That cam also needs to sit flat against the shoe. If it is out of position, it effects the position the lever rests in. The cable end also needs to be fully seated in the lever, and the lever has to be fully seated in the grove in the pivot stud.

If you have replaced the cable, you want to be sure the new cable is the correct length. There isn't much difference in the cable length between the 10" brakes and the 11" brakes, I have seen more then a few cables incorrectly tagged or in the wrong boxes.

I have been doing drum brakes for 45 years, both personally and professionally and I have only had to bend the adjusting lever a dozen or so times in all those years. Most of those times have been replacement parts, and many were more recent. New parts these days leave a lot to be desired. Gene

Thanks all,

I do think the answer will be simple - once I find it. Another head slap, probably.



Thanks, Gene, everything you wrote makes sense.
This gets at the root of the problem - the curved plate you are calling a cam - that's the part that is held in place by sitting in a hole on the brake shoe gusset (and its held there by the return spring)... that hole in the gusset is punched by whoever makes the shoe - which is a replacement part that could have been produced with the hole in the wrong place, making the cable the wrong length (and then the whole production batch would have been wrong, so thousands would have the same problem)... or it's remotely possible I have swapped the shoes front/rear, but I'll see that once I open it up..

In short, I'll scrutinize everything you wrote here. I'll share some pictures here too.. I had to put it back into storage for a week to take care of another car issue..
Good times.
- Art

Agreed I failed to list that stamping as a cause. Bottom line, bend the tab and move on. If it adjusts, it adjusts. It's not rocket science.
Doug

I found the problem.

It's happening on one side of the fronts only.

The curved plate that guides the cable... it has a round "pin" that inserts into the hole on the brake shoe gusset. That "pin" is about 1/8" around - and it has worn down so much that the plate has moved and allowed the cable to sag.

Time to talk to my local 'Mopar Hoarder' and see if he's got some spare old drum brakes kicking around..
- Art

Art that was too easy!

Art...post a pic of what you need...I may have several just laying around here too...If it's what I think it is they're the same for LH or RH applications...

Thanks skicker,
It’s the steel plate with the curved groove that guides the cable.. yeah, I’m thinking they are interchangeable LH to RH.. there should be a photo attached, trying this frok my iPhone..

- Art

Correct

If you don't get one local send me a pm with your address...I have several sets laying around...

Trying this again with reduced file size engaged...

Now that I have the hang of reduced pic file size, I can show you all what was going on...

The top photo is the RH side, which worked fine - notice the blade or "arm" comes to about the center of the advance wheel.

The lower photo is the LH inoperative side - notice the 'arm' is too low, so it won't lift enough to grab a tooth on the advance wheel...

Figured I'd share the final outcome for y'all to know....

I found basic rebuild kits online for $19.99 and used the one part I needed... you can see the shiny new cable guide here [EDIT: The photo absolutely refuses to load properly, sorry]... and a pic of how the old one wore out and slackened the cable so it stopped working..

Cheers,
- Art

Art that was too easy.

Yeah it was easy once I saw what the problem was... but dang I had to look real long and hard at it before I saw it ..
Always remember to start looking at the simplest possible answer FIRST.
- A

That was driving you bonkers for quite awhile & I ain't never seen a guide plate do that ever.

I've seen that before. The most likely cause is that when the brakes were assembled, and the spring was pulled up over the show anchor post, The "cam" probably became unseated and the spring held enough pressure against it to hold it in the wrong place. The self adjuster worked until enough of the seat was worn away.

After the shoes are secured to the backing plate, I usually hang the eye for the cable on the shoe anchor post and lay it across the top of the brake show. Then I hook the return springs over the anchor post and make certain the cam is seated. Then I hook up the bottom spring and insert the adjuster. The adjusting cable is hung over the cam, and I pry the adjuster up with a small screw driver until I can connect the end of the cable into the adjuster arm. Any time I tried to connect the cable before installing the return springs, it often will unseat the cam. Gene

From that lesson comes the old adage of KISS, Keep It Simple Silly or Stud, your choice on words used