Packard Forum Index » V-8 (1955-56)

This will probably show my age but I apprenticed at a Studebaker -Packard dealership and finished my apprentice ship at a Chrysler dealer. I have literally replaced hundreds of rear axle bearings in my lifetime and have always preloaded them with zero failure.To each his own. Also free advice is exactly what its worth.

from Timken direction for taper bearing installation I have no horse in this contest
https://www.timken.com/wp-content/uploads/2016/10/5556_Bearing-Setting-Brochure-1.pdf

Still no luck. I completely released the hand brake tension at the equalizer (fully slack) and made sure that the rear service brakes were adjusted and then took her for a spin with the exact same results as before: grinding at braking speeds of 25-30 mph or above. The braking behavior was normal and pulled the car down steady and straight.

My thinking in leaving the hand brake essentially disconnected was to isolate potential mis-adjustment in the hand brake and ensure that nothing would impede the shoes from seating on the anchor pin. And then I hoped for the best but to no avail.

Attached are pictures that I took after my latest test drive. You can see the "polished" edges of the shoes with the heaviest contact occurring at the bottom of the secondary shoe and lighter contact at the top of the primary shoe.
The second picture shows the "polished" rivets on the underside of the drum. These points of contact do not seem to be getting any larger, if that makes a difference.

Again, I'm open to any thoughts. The shoes are probably the next suspect although I'm not sure how to identify a slight twist as they pass a visual inspection. After that, I suppose looking at the drum for warp is next.

Attach file:

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  Drum1.JPG (200.88 KB)


  Drum2.JPG (286.95 KB)


  Drum3.JPG (194.01 KB)


  Drum4.JPG (271.68 KB)

Maybe the brake backing plate is slightly bent, or not seated fully on the axle tube. That would hold the shoes slightly out of alignment with the drum, and could cause the light interference you're getting.

Do you have the problem on both rear brakes, or only on one side?

The brake drum needs to be straight and it needs to fit tightly and evenly against the axle flange.

The primary and secondary shoes are often different. The lining composition and length of the lining often differ. It may be that the offset is also slightly different. I've had problems with taking brakes apart and then finding that some parts will go on more than one way, with only one way being correct.

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Interesting thought. The grinding started about a year after I bought the car. During that first year I drove the car frequently with no problems and, until the noises started, I had never taken the rear brakes apart so if something didn't fit right it was like that before the grinding started. Also, when I performed the rear axle service I cleaned the axle flange and the backing plate and installed new shims. None of that changed the nature of the grinding for better or for worse.

As for a bent backing plate, I can't think of anything that would have caused damage to the plate in my first year of ownership. Again at the time the grinding first began I had never taken the rear brakes apart.

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The problem is only on the left (driver's side) rear brake.

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That really sums up what is so maddening about this. Basically the brakes were fine and then they weren't. I tried adjusting them, then replacing all the hold-down hardware and return springs, then checking axle bearing clearance (with new bearings and seals), adjusting everything again, and, most recently, disconnecting the hand brake just to make sure it wasn't pulling things out of place. So far nothing has changed the nature of the grinding one bit. At least if I had put something together wrong I could blame myself and then fix the problem.

****"The problem is only on the left (driver's side) rear brake."****

I would look very carefully for evidence of a bent or misaligned backing plate.

Also: Be sure the brake drum is not somehow bent or distorted. You might switch the right and left brake drum.



If one brake works properly and the other does not, it might be helpful to compare one side to the other, looking carefully for any disparity.

If the drum does not seat correctly on the axle, due to problems with the key/keyway, axle taper, or any other issue, it could cause the problem you're having.

**** Another problem that can occur with a tapered axle/hub is that the hub can sometimes seat TOO FAR onto the axle, due to having been run loose, heated with a torch, or some other reason.

Should that be the case, it could cause the issue you are having.

**This may be the most likely cause of the problems you're having.***

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This has been in the back of my mind as well. Over 70 years a lot of different people have been in and out of these brakes.

What I can't figure is, if this were to be the case, why were the brakes fine for so long? Maybe I'm thinking about it wrong, but with the force the hub seats onto the axle, I would think that, if the hub seated too deep onto the axle, the grinding would show up immediately at the time of reassembly. In my case, I bought the car and drove it without ever opening up the rear brakes for more than a year with no problems.

It may be that when you replaced the brake drums on the axles, one of them seated further onto the axle for some reason. It may have been slightly loose before. They have to be tight, or they will not go far without giving problems.

It might help to switch the right and left drum.

People have resorted to shimming the axle taper to correct problems with fit. It's not a good practice. It's not uncommon to find shims on Model T Ford axles. You can even buy shims ready made for them.

The Packard, being a heavier and more powerful car, would be less likely to get good results using the shim fix.

In you case, I'd try switching the rear drums. That might eliminate the problem.

Running the hubs loose is not an option.

If switching the drums moves the problem from one side to the other, it points to a problem with the the hub bore.

Measuring a taper accurately might be a challenge.

If you try shimming the axle/hub, use a very thin shim that is free of wrinkles and burrs and that fits as closely as possible, covering as much of the contact surface as possible. It might be possible to fabricate a shim from a steel beercan or soft drink can.