Rear brake shoe side rubbing on drum

[JohnSaylor]

Hey all,

Had to make a new account as I haven’t posted since mtfca switched to the new forum. Anyways, I am having trouble with my left parking brake shoe (stock brakes, no RMBs or anything) rubbing on the drum and making a nasty intermittent squeak (video here: https://twitter.com/horselessage/status ... vulVw-zCbQ). There is an obvious wear mark on the side of the shoe about 1” from the oval actuator thingy. As you can see there is also a fair amount of daylight between the shoe and the end of the axle fairing: [image] https://i.postimg.cc/GhsJL8BV/81-CD2-DA ... 0-DFA3.jpg [/image] although the other side (which doesn’t squeak) was hardly flush either. I took the shoe off and it does not appear to be obviously warped, and the oval actuator thingy likewise does not have any obvious wear that would keep the shoe from fitting properly against the end of the axle.

Suffice to say I’m struggling to identify the issue. The spot on the axle housing where the mounting bolt goes seems like it might be a bit crooked (well it’s definitely crooked - but is it crooked in a way that would make the bottom shoe jut out?) but it’s hard to tell:

Does anyone have any solutions? I could shim the wheel on the taper to take it a bit further away from the drum, but (correct me if I’m wrong) I think the wheel needs to be pressed up against the axle bearing dust cap, right? My other idea was just to grind down the edge of the brake shoe until it stopped squeaking - after all, it’s just a parking brake right?

Thanks

[Mark Gregush]

Use your grinder or file to fit. Most all T's show daylight between the drum and backing plate, adding a shim would only make for more daylight.

[Moxie26]

Grab the axle shaft, push in and pull out , if there's any significant play , the thrust washers are worn.

[Norman Kling]

4
things could cause this:
1. Worn thrust washers causing axles to move from side to side, however, most likely on the right side, because the ring gear would help to hold things in place and it would move out on that side.
2. Worn disk in differential between the ends of the two axle shafts. That could cause the axle to move inward and drag on drum.
3. Worn axle shaft taper and taper inside the drum. This would cause the drum to be pulled farther in toward the brake shoes. Or if you have rocky mountain brakes and the brake drums are bolted inside the rock mountain drum, it would take either a longer axle shaft or a shim at the end of the axle inside the taper to push the hub farther on the axle.
4. Shoes are moving outward by being warped or the lining is too wide.
Norm

[JohnSaylor]

Hopefully not the thrust washers as I rebuilt the rear diff like 6 or 7 years ago and put in nice bronze ones.

[Craig Leach]

Hi John,
Have you looked at the return springs? That sounds uncannily like something is scraping the springs like the nuts on the wheel. If not the springs the harmonic tone sounds like some thing vibrating. Maybe the nuts are loose & the drum is vibrating or even cracked? I just don't remember ever hearing a sound like that coming from anything that turns that freely. Hope you find it.
Craig.

[Erik Johnson]

Before resorting to a shim, I would swap things around.

1) swap the brake shoes - left to right, right to left

or

2) swap the rear wheels - left to right, right to left

or

3) swap both the brake shoes AND the rear wheels

If none of the above cure the problem, then grind down the edge of the brake shoe that faces the rear axle housing backing plate.

The poorly designed two-piece lined break shoes that the vendors use to sell would flare out away from the actuator instead of remaining parallel to and resting against the backing plates. I solved that problem by installing a large diameter washer between the brake shoe bolt and the brake shoe. Don't know of that trick works for the single piece brake shoes like you have.

Otherwise - try a pair of NOS factory issue unlined brake shoes.

[Norman Kling]

One additional thing. If the shaft is loose in the drum, You need to replace and sleeve. Sometimes when the clevis pulls against the lever, it will tilt the cam to one side causing the shoe to shift. But usually that would only happen when you apply the brakes, not while the wheel is spinning freely.
Norm

[JohnSaylor]

Thanks all - I’ll give it a try tomorrow. Norman, which shaft are you referring to? The shaft between the cam & lever that runs thru the axle housing?

[Allan]

It could be as simple s the retaining springs being fitted the wrong way around.They need to be fitted with the open end of the hook facing outwards. This will align the straight portion of the spring to the backing plate side, pulling the shoes towards the backing plate rather than away from it.

Hope this is the case, for an easy resolution.
Allan from down under.

[speedytinc]

It could be as simple s the retaining springs being fitted the wrong way around.They need to be fitted with the open end of the hook facing outwards. This will align the straight portion of the spring to the backing plate side, pulling the shoes towards the backing plate rather than away from it.

Hope this is the case, for an easy resolution.
Allan from down under.

This is one of my thoughts also.

Secondly, the shoe pivot bolt appears to be a little too tight. Try backing it off.
Thirdly, these repop shoes take a lot of fitting. A little grinding here & there may be necessary to get the shoes to fit against the backing plate after dealing with the springs & anchor bolt. Good luck.

[JohnSaylor]

Oh! Well my hooks are definitely facing inward…

[richc]

Have you tried backing off the brake shoe support bolt a bit so it isn't pulling the shoe towards the axle backing plate? It might help the alignment of the shoes.

Rich C.

[Norman Kling]

Yes, between the lever and the cam where it goes through the backing plate. The shaft should be free to turn, but not to wobble back and forth.

[JohnSaylor]

Re the spring hooks, they are a fully circular hook design (that is, the spring looks perfectly centered no matter which way the hook is facing). I did try backing the bolt off a bit without obvious improvement. Gonna try different combos of wheel/brake shoe to see if that makes a difference

[speedytinc]

Re the spring hooks, they are a fully circular hook design (that is, the spring looks perfectly centered no matter which way the hook is facing). I did try backing the bolt off a bit without obvious improvement. Gonna try different combos of wheel/brake shoe to see if that makes a difference

The springs will pull the shoes & it matters how they are placed. If I remember correctly, the springs on the front sides of the shoes causes the shoes to want to move away from the backing plate. The springs on the back side tend to pull the shoe edges toward the backing plates.
Try them in different positions for the differences.

[JohnSaylor]

So… with a bit of mix n match, I found a combo that did not squeak on the left side:

Left wheel + right brake shoe + left mounting bolt (for some reason I have a 3/4 bolt on the left side and a 5/8 bolt on the right… the big bolt drags on the right wheel hub but not the left)

The right wheel now has a slight rub against the topside shoe where it meets the cam, but it’s only metal (no brake material) so I feel pretty comfortable just grinding it down.

Two questions before I do that & wrap stuff up:

1. There’s a small amount of grease that’s got it’s way behind the dust caps on each axle and have coated the tapers. Should I wipe that off completely? In theory the hubs supposed to be completely fixed on the taper, so no point in having any kind of grease/oil film on there, right?

2. The one-piece shoes I have are slightly narrower at one part of the cam end: for the shoe I took off the left side, the end that rides on the top of the cam is 0.9” while the end that rides below the cam is 1.0” - the right side shoe looks similar. Since I’ve switched the right and left shoes, the fat end is now on top - there’s no clearance issue, but I’m wondering if this is going to affect parking brake performance. I imagine that putting the fatter end on the bottom gives you better braking performance rolling forwards, right? Because the side that expands against the direction of rotation will have more bite? Then again, these are just parking brakes…

[speedytinc]

The small headed 1/2" bolt is correct/original. The 3/4" headed bolt is a hardware store replacement. The head is thicker also.
Grind/machine the head to match the original bolt. That bolt is sized smaller for a reason as you may be discovering.

[JohnSaylor]

Never mind, the actual brake pad material is 0.9” wide at both ends - only the shoe is different widths. Unless someone thinks otherwise I imagine it won’t matter going upside down.

[Scott_Conger]

John K

from my experience, you are right, and it's valid advice. Whether or not anyone cares or pays any attention to that advice remains to be seen.

[JohnSaylor]

The small headed 1/2" bolt is correct/original. The 3/4" headed bolt is a hardware store replacement. The head is thicker also.
Grind/machine the head to match the original bolt. That bolt is sized smaller for a reason as you may be discovering.

Well as I said the head doesn’t rub at all on the left wheel so I’m inclined to leave it be. This is hardly a concours car.

[Allan]

When I looked back at the photo to check the gap, I noticed something else. You might check how straight the backing plate is with a straight edge. If it is bent, and it looks like it could be, the pivot bolt .ay not be square to the backing plate. Another check, by winding the pivot bolt out with the shoe in place, does it flock the shoe against the backing plate? This will tell you if the pivot bolt is bent.

Allan from down under.

[JohnSaylor]

Sorry, just double checking - should the rear axle taper have any grease on it at all when I put the rear wheel back on?

[RajoRacer]

No grease, oil or never-seize - bone dry !

[Mark Gregush]

No grease on the taper, none zip nada.

[JohnSaylor]

Follow up question - for the one-piece shoes, are the springs even necessary? Seems like the steel shoe has enough flex?

[speedytinc]

The spring closest to the cam is necessary for the shoes to return. The spring closest to the pivot is necessary to hold the shoes in place WHEN the shoe breaks @ the pivot point.

[JohnSaylor]

Ok. I am having a problem with the front return spring not having enough clearance against the nuts holding on the wishbone. The spring loops are rubbing on the nut and pushing the shoe sideways into the drum

[speedytinc]

Ok. I am having a problem with the front return spring not having enough clearance against the nuts holding on the wishbone. The spring loops are rubbing on the nut and pushing the shoe sideways into the drum

There are no nuts inside, under the shoes, holding the RADIUS rods on the inside. The CASTLE nuts go outside, a top the radius rods.
Welcome to the dance to get these repop lined shoes to fit.

[Allan]

I believe the shoes are made in one piece because it makes it far easier to line/machine/drill them during manufacture. Henry's originals were cast in on piece also, and also had provision for two springs. The one on the cam side keeps the shoes firm on the cam. The other does nothing, so why is it there?
An earlier responder mentioned it holds the shoes when they break at the pivot bolt. That's fine if that is where the break occurs. I cut them almost in two at the pivot point, so when they do break, it happens where you want it to. Then the second spring does its job. I would like to know if this was recommended for original shoes back in the days. I have seen many originals broken in all sorts of places, especially once they were worn and had to flex more to work
.
Allan from down under.

[DanTreace]

Ford Service Bulletin gives some good info on setting brake shoes to the backing plate, Oct ‘19 , para # 259, “run the bolt through the flange, … when bolt is tight, add the lock nut and cotter, then back the bolt off 1/8 to 1/4 turn”. This helps to give the shoe a bit of wiggle so it can spread open for engaging the drum.

As for ‘dry fit’ of the hub on the axle shaft taper, my experience is that increases difficulty in removing a rear wheel. Sure a dry fit of a morse taper chuck in the drill press is proper, but if the axle shaft is new, and a good hub, and the key fits tight, the grasp on a lightly lubed shaft gives good results.

For the taper shaft, I apply a tiny smear of grease, extremely small amount, on the surface and then install the hub. Likely a tiny bit of anti-seize would do also.

Others can disagree, that’s ok, lots of ways to maintaining the T. Service Bulletin does state to use a bit of grease.

[Mark Gregush]

Sure maybe that was written when cars were new and axles were to be had at most any dealer, re grease on the taper. It is still like a Morris taper, just with a key, dry (stirred not shaken ).

[JohnSaylor]

Apologies for reviving this thread from the graveyard … unfortunately my de-squeaking didn’t survive contact with the asphalt and after a 5 mile drive this weekend the squeak has returned. I have a new theory for the culprit - as I mentioned earlier and others have pointed out, the backing plate is not very straight. Specifically, where the retainer bolt attaches to the plate the surfaces on either side are pitched inwards (towards diff) slightly at the top and outwards at the bottom. So when I fully tighten the bolt it squeezes the bottom part of the shoe outwards- more importantly, even when I back the bolt off, when I tighten it up with the lock nut it tilts the bolt ever so slightly upwards (there’s a little slop in the threads, unsurprisingly) causing the bottom to poke out again.

I made a little wedge shim out of a washer to sit between the fairing and the shoe, and that now allows the bolt to tighten all the way without bending the bottom of the shoe outwards. However the surface the nut goes on is still slanted, so with the nut locked tight it squeezes the bolt upwards again. Unfortunately I don’t think there’s room for another shim - I can already only barely get a cotter key through it.

I want to ream, grind or sand down the outside of the axle fairing until I get it flush with where the nut needs to snug up. Anyone have a suggestion for a tool that would do this better than my little dremel’s cone grinding bit? Thanks

[Allan]

The bolt must be straight. The backing plate must be straight also, so the bolt hole is square to the backing plate. The backing plates will take bending to correct any deformity. You might need a couple of large crescent wrenches to manipulate the backing plate into shape.

Allan from down under.