Packard Forum Index » V-8 (1955-56)

After reading through my '55 service manual, I still have a couple of (rookie) questions about reinstalling the rear drums on the axle shafts.

First, is there a recommended practice for keeping the drum from rotating while torquing? I chose to use a wedge between the frame and the wheel locating stud on the drum to keep things in place. The passenger's side tightened 'OK' with this method but, frankly, I was a bit concerned about the leverage I was applying to the wedge (a steel bar). On the driver's side the wheel locating stud bent at about 225 ft-lbs of torque.

Second, neither nut lined up with its cotter pin hole. On the passenger's side I have a castellation partially over the cotter pin hole at 200 ft-lbs. and directly over the cotter pin hole at 270 ft-lbs. On the driver's side, the cotter pin hole is just barely clear at 200 ft-lbs. and partially obstructed at 225 ft-lbs. Is dressing the nut worth the effort or should I be looking for new grade 8 washers? If it makes a difference, the original washers appear be a bit less than dead flat.

Third, when re-torquing the axle-nuts at 100-miles post-install, can I use the weight of the car on the installed tire-wheel ass'y to keep the axle from turning, or should I re-torque the nuts with the car off the ground?

Last, regarding the bent wheel locating stud on the drum, should I be concerned about its long-term viability given that I had to coerce it back to position with a few taps of a hammer?

As context to the above questions, my car is 1955 Clipper Constellation that is driven regularly and is in reliable mechanical condition. I pulled the drums to locate a slight grinding noise that would arise under hard braking conditions. I found that the secondary shoe was just barely contacting the inner face of the drum which I believe can be corrected with a brake shoe adjustment.

I've done plenty of drum brake jobs in the past but they've all been on cars with axle flanges so this certainly has been a learning experience (and quite the physical workout!) As such, I apologize if these questions seem overly basic. I did read through multiple threads using the search tool, but I could find no reference to these particular issues.

Thanks in advance,
Scott G.

Any reason to not use new hardware where you can?

You are making your life entirely too miserable. Relax a little.

The locating stud is for your assistance while installing the tire. It has no structural or locating job once the lug nuts are tight.

Snug up the center nuts,(I zip them on with an impact gun) install the wheels and put the car on the ground. Don't be overly concerned with the exact torque; get it in the ball park then proceed to the next slot to install the cotter pin. I can assure you the mechanics at the dealership did not use a torque wrench. A self-locking taper makes a very reliable and accurate joint. That is why it was used on machine tools. You will find that the washer is soft and the nut will pull it down. If you like, lay it on the back of your vise and beat it flat.

Ignorance and misery often go hand in hand, or so I've been told.

After looking at the washers again, I decided to just replace them with two new SAE grade 8 washers. This, along with your advice to draw the nut tight with an impact wrench, lower the car and then tighten to the next open castellation, took care of the cotter pin alignment issue. I did double check the torque once aligned and I was north of 250ft-lbs on each nut.

Unfortunately, while the brakes stop smoothly and straight, the left rear secondary shoe is still grinding on the inside of the "hat" of the drum. I had thought that a maintenance adjustment of the rear shoes would eliminate this, but I'm now at a bit of a loss. Could the hold-down springs be allowing the shoe to creep outboard on higher-speed (30mph and up) stops or should I be looking somewhere else? (The rear hardware all looked to be in good shape but it's age is unknown).

ScottG

During the rear axle bearing clearance adjustment there are shims placed between the rear axle housing and the backing plate. The wisdom found in the various shop manuals suggest both sides should have about the same thickness of shims left to right. If the shims are all on one side there is the possibility that the thrust block masked the true bearing clearance. I would start by double/triple checking the bearing clearance check for A.) is the clearance is close to the correct value, and B.) is there anywhere near an equal amount of shims on each side. A wildly high amount of bearing clearance is likely to result in some interference. A drum with axial run-out could also result in rubbing. Your question about hold-down springs reminded me of the subject as to whether the brake drum is a cylinder or worn into a cone shape. If all of scoring and wear could not be ‘turned-out’, and that wear was favoring the out-board side the shoe could be (emphasis on vague) pulled out-board.

Would you say the noise appears when the car is going straight ahead, or are you in a shallow turn?

You wrote that ‘the rear hardware all looked to be in good shape . . . ‘, how far did you disassemble the rear-end?

dp

The grinding noise occurs while decelerating in a straight line from speeds of 25-30mph or greater. I can't say if it occurs while turning as I'm usually under those speeds when entering a turn.

As for my comment vis-a-vis the hardware, I was referring to just the brake hardware. I only removed the rear brake drums to inspect the shoes and springs after the grinding noise started. After seeing that the shoes were not visibly worn, the retaining hardware was intact and the drum braking surface was not scored, I put everything back together and adjusted the brakes per the manual. I hoped that the shoes simply needed adjusted and that a bit too much travel was allowing the shoe to move outward and contact the inner face of the drum. Unfortunately, the noise never changed although braking performance improved a bit.

I can identify the two points of contact from where the sound is emanating: one, is a relatively small shiny spot on the steel edge of the secondary shoe; and, two, the heads of the little rivets that are found along the circumference of the drum "hat" are polished to a shine. I just don't know what's leading to the contact.

Could it possibly have the wrong shoes, maybe from another model where they are wider or could the drum itself be from one with narrower shoes?

I doubt the equipment installed is incorrect. I've put about 2000 miles on the car with no problems and the previous owner was driving it as well. Unless I missed something, the car was braking fine and then starting grinding out of the blue. That is why I pulled the drums expecting to find something overly worn or broken. All I found was the rear shoe with a rub mark and those small rivets (I think they're rivets...) on the drum rubbed to a shine.

That said, I'll take some measurements just in case.

They could still be too wide, hence the rivet rubbing. Which is not normal.

I recheck the width and compare that to the correct size that is called for. A simple check to make sure everything is apples to apples.

Barring that, id make sure the correct hold-down hardware was used when it was put back together before. Perhaps it was replaced or swapped out with incorrect hardware.

On the topic of installing rear drums, I've mentioned this in the past but will mention it again, applying a thin layer of Milk of Magnesia on the tapered shaft, letting dry, prior to installation will aid removal later without compromising the integrity of the tapered fit. This doesn't address your noise problem but can make life easier.