1950s '54 series 62, major brake adjustment (final update)

[Julien Abrahams]

Dear all,
Because one of the wheel seals developed a leak, I changed both wheel seals (one side looked like the original seal which I find hard to believe). Ofcourse the diff oil had contaminated the brake shoes on the driver's side, so those needed to be replaced as well. I found what I believe to be the original brake shoes (do they contain asbestos?). I have tried to heat them to get the oil out. I put them in the oven at 350 degress for about an hour. But it seemed that no matter what I did, the diff oil would continue to seep out (when heated with a blow torch. It was just test because I already had ordered new brake shoes.
Installed the shoes yesterday, but now have a question with regard to the major brake adjustment as described by the manual. The manual states to loosen the anchor pit nut about 1/2 a turn then tap the anchor pin up with a hammer, then all the way down. Then adjust the shoes with the start wheel and check clearance with what looks to be a feeler gauge.
But the anchor pin is not moving at all. I think it is rusted in place. I loosened the nut and hit it with a 7 pound hammer. I don't want to damage anything, so I did not use "stupid" force.
I am tempted to just retighten the nut to the prediscribed torque and adjust the brakes with the star wheel (tightening them, them turn the drum with a tire iron, then loosen the star wheel until there is very little drag).

Any words of advice is highly appreciated.

[Dave Shepherd]

Usually if the major adjustment is out of whack, you would see uneven wear on the shoes, I would leave it alone, unless you see evidence of a problem.

[Caddy Wizard]

I consider that one of my special areas of expertise is brakes.  On your car, the major brake adjustment is a critical step in the brake job and needs to be done any time that the brake shoes are changed.  This adjustment centers the shoes in the drum and ensures maximum effectiveness of the brakes.  In some instances, the improvement in effectiveness of the brakes after performing the major adjustment is startling, while in other instances it is slight (depending on how far out of being in the right position the shoes are to start with).

I find that most folks working on these old Cadillacs don't bother with the major adjustment.  But trust me, it is worth doing.

In addition, your 54 is supposed to have grooved brake linings on the primary (leading) shoes.  These grooves are about 1/2" wide and extend nearly to the steel backing of the shoes.  They provide cooling of the primary shoes.  As you may imagine, the primary shoes do more of the braking work than the secondary shoes and tend to get hotter.  This cooling groove keeps the primary shoe from overheating and becoming glazed.  I cut the grooves in the primary shoes myself using a carbide router bit and a router table with some guides attached to it to allow me to swing the shoes in a gentle arc.  It is a nasty process and I do it outside, with a fan blowing the dust away, and wearing a protective mask.  I'd like to find a way to do this with a grinding wheel, instead of a carbide cutter.

I also find that the Chinese made brake shoes generally available online and through various suppliers have good friction material, better than what we have had put on by brake specialty shops in relining shoes (like the kind of brake shops that reline big truck brake parts).

[PHIL WHYTE CLC 14192]

I agree with Art. The major adjustment is essential. My brakes are great, no disc conversion for me on my 54. Follow the manual diligently and believe me you will be pleased with the results. If things are seized then dismantle and free everything up. And yes, you do use a feeler gauge for adjustment.
Phil

[Dave Shepherd]

I've never had to do this on many GM cars of that generation, if it is the factory setting, and no one has played with it, and shoes are evenly  worn heel to toe, you should be good.  That said if you follow the procedure, you can't go wrong. We have followed this working procedure in my restoration  shop for years, only had to do it twice. Caddy Wizard is on target, but again, it is not always required.

[Caddy Wizard]

I've never had to do this on many GM cars of that generation, if it is the factory setting, and no one has played with it, and shoes are evenly  worn heel to toe, you should be good.  That said if you follow the procedure, you can't go wrong. We have followed this working procedure in my restoration  shop for years, only had to do it twice. Caddy Wizard is on target, but again, it is not always required.

The reason that this major adjustment is such a good idea is that when you change shoes, the new shoes are not 100% the exact shape as the old ones, so they will sit in the drums differently (and not be centered).  Back in the day, if you bonded or riveted new friction linings onto the old shoes and returned them to the same wheels that they came off of, the major adjustment wouldn't matter.  But when we change out the steel backings of the shoes (as we typically do since we buy new shoes and don't reline the old ones), the new ones inherently won't be exactly the same shape 100%.  Thus, I believe it is prudent to follow the book and do the major adjustment.  Of course, sometimes it won't make much difference.  But sometimes the difference is quite dramatic in pedal feel and braking effectiveness.

[Dave Shepherd]

Agreed, Art, we have the shoes we use relined by White Post restorations, so this could be the reason we haven't  run into issues with shoe concentricity. Same mounting surface.

[dn010]

The pin on my 57 was also rusted in place. Pretty much had to take it all apart, spray it down, etc and then hit it free. The brakes were also "ok" in that car, it would stop but I felt I had to nearly stand on the pedal if I really wanted good braking. I replaced some components like the shoes, rubber hoses etc., got the drums cut, and then decided I should do the major adjustment - it was night and day difference afterwards to where it stops with little effort now.

[Julien Abrahams]

Alright, an update from my side. I unbolted the anchor pin, cleaned it,and putof copper paste on the shaft that goes through the back plate to prevent it rusting.

Then put everything back together to do the major brake adjustment as describedid by the.manual. it states to adjust the brakes until clearence atthe bottom of the secondary shoe (the bigger on towards the rear of the car, right?) is 0.015 inch at which point upper clearance should be 0.010 inch.
However, I cannot get the upper clearance at 0.010 (it is more that twice that). The manual states to loosen the anchor pin nut somewhat and tip the pin upwards. Pin is now completely up, but upper clearance is still greater than specified. Lower clearance  is about 0.015. Any tips? Could.it be that the shape of the new linings is different from the old ones?
Tips are appreciated.

[Caddy Wizard]

Alright, an update from my side. I unbolted the anchor pin, cleaned it,and putof copper paste on the shaft that goes through the back plate to prevent it rusting.

Then put everything back together to do the major brake adjustment as describedid by the.manual. it states to adjust the brakes until clearence atthe bottom of the secondary shoe (the bigger on towards the rear of the car, right?) is 0.015 inch at which point upper clearance should be 0.010 inch.
However, I cannot get the upper clearance at 0.010 (it is more that twice that). The manual states to loosen the anchor pin nut somewhat and tip the pin upwards. Pin is now completely up, but upper clearance is still greater than specified. Lower clearance  is about 0.015. Any tips? Could.it be that the shape of the new linings is different from the old ones?
Tips are appreciated.

If I recall, before you start the major adjustment, you are supposed to adjust the parking brake cable.  Did you do that?

[Julien Abrahams]

I did not do that yet. The manual states to first adjust the service brakes, and thereafter the parking brake.
The main 'problem' I am having now is that I cannot get the clearance between the secondary shoe ( specifically at the top of the shoe) and drum to be equal to what is stated in the manual (0.015 inch).  The clearance is now about 0,025 inch. It should be 0,015.
The manual also states that the clearance should at no point be less than 0,010 inch.

[Roger Zimmermann]

If I recall, before you start the major adjustment, you are supposed to adjust the parking brake cable.  Did you do that?

As the parking brake is dependent to the service brake, in my opinion it's unlogic to adjust the parking brake first.

[Julien Abrahams]

Alright, so here is an interesting one.
On the passenger side, the bottom clearance of the secondary shoe is according to spec, upper clearance is too much (about twice the clearance described in the shop manual). Tried tapping the anchor pin to get it within spec, but to no avail. Anchor pin is in its upper most position.

On the passanger side, the oppsosite happens. The upper clearance of the secondary shoe is too tight. It is about 0,005 inhces. It should be 0,010. I have tapped the anchor pin all the way down.

Any ideas anyone?
I am thinking about just swapping the secondary shoes side to side, just for the fun of it.

[dn010]

Dumb question but are you sure you have the primary and secondary shoes in their proper locations ("short" one with the groove towards the front of the car)? You might take one side apart and compare the shoes to the other to see if you have any variations. One problem I had on my 57 - there was chunks of what looked like rust in the pin holes that prevented it from moving all the way up or all the way down. I had to dig around with a file in order to remove chunks that were keeping the pin from moving. Does your gap measurement change if you rotate the drum with the feeler gauge installed? Do you have a ridge on your drum that may be engaging the shoes (if they're slightly wider than the old shoes)?

At this point if everything checks out, I would put it all back together, loosen the star wheel, the pins and start all over. I recall it took me a few tries on the rear brakes to get the anchor pins "in the central location" with the pin being loose and I'm tapping on the backing plate. It was a real PITA with no lift and working on the ground but I was finally able to get them to spec.

[J. Gomez]

Julien,

Although the points provided above are good there are two key items that have not been pointed out which are not well documented on the Service Manual.

It is logical that "the major brake adjustment procedure" is done when new shoes are installed and/or drums are replace and/or recondition. In addition back them it was practice to "arc the new shoes" to match the new or recondition drums. This practice of "arcing brake shoes" is long gone in today's procedure.

When I replace all of my shoes after recondition the drums with new hardware and well cylinder I had to make sure the new shoes where properly arc with each drum.

I place the new shoes inside the drum and visually checked for any "high/low" areas and mark them.
There is an "old mechanic trick" of placing a sand paper sheet around the drum surface area and rotate the new shoes against it to check for correct arc level between both drum and shoes. This will show you if there are any high/low areas that would need to be corrected.

My new shoes were not too bad "but" they needed to be sanded in a few areas (mostly on the middle).

The 0.015" clearance is done against the secondary shoe (top and bottom) and is adjusted by the star wheel. The 0.010" clearance is done on the top of the secondary shoe and adjustment is made by the anchor pin. This is per the 1956 Service Manual and I believe the same applies to the 1955 as well.

NOTE: The "E" brake cable would need to be loosen before performing the "major brake adjustment" once this is complete there is a step to perform the "E" brake cable adjustment.

Good luck..! 

[J. Gomez]

It was a real PITA with no lift and working on the ground but I was finally able to get them to spec.

Dan,

I bet is was your best time spend in getting them aligned,      as I remember my trials and tribulations while doing them as well.   

[Lexi]

Very good write up by Jose and the sandpaper trick. Regarding the placement of the shoes yes the big one on the side farthest away from the front of the car. Wasn't there an old motorcycle aphorism used as a reminder of where the largest shoe goes? Think it went something like, "Fat girl rides on the back". Clay/Lexi

[Julien Abrahams]

Thanks for the tips, especially the one on the sandpaper and checking the arc of the new shoes against the drums.
I also am just curious what happens if I change the drums (put the one that is now on the passenger side on the driver's side and vice versa).
And yes, I have disassembled the anchor pin, cleaned the hole in which the pin is located, cleaned the contact points of the pin and put a little copper paste on it, so that it can move freely.
I have also completely started over again by removing the shoes, springs etc.
I will now go and try the arcing of the shoes with sandpaper today. Even though these are old bluky cars, the tolerances on these brakes are very small (0,25mm (or 0,010 inch) makes a big difference.
Will keep you guys posted.

[J. Gomez]

I also am just curious what happens if I change the drums (put the one that is now on the passenger side on the driver's side and vice versa).
 

Julien,
If you have the original drums with the original lug nut studs be aware these were/are key threaded and should be stamped on the tip LH and RH, so I would not recommend switching the drums around if someone other than you works on your car.

The old theory back then was having these lug nut keyed on the correct side was to keep the nut from become loose "BUT" later it was found this theory did not hold water if they are correctly torque, that is why today we have the same threaded lug nuts on either side.

Good luck..! 

[Julien Abrahams]

OK. So I had another crack at it today. I removed the shoes from the backing plates. With the "arcing" tip in mind I put the drum on the table and lay the new shoes in the drum to check the "fit". Then I found that the new shoe does not perfectly follow the drum (when holding it tight there was about 0,035" gap between the friction material and the drum on the top of the shoe. That explains!
I then visited a local garage that only works on vintage cars (from say the '70's right down to the '10's). I asked the long term owner for advice. He stated that it is possible to get the drums turned and then the new shoes ground to match the drum. However, he did not recommend it, find it necessary. His advice was to adjust the brakes as close to the measurements the shop manual gives as possible, then drive the car for about 50 miles or so, so that the new linings can break in and to wear off any high spots. Then adjust again. If necessary, repeat the adjustment after another 50 miles or so. Then it should all be good.
I tend to trust his opinion, as he has been working on these kind of cars for about 30 years and does restoration work on cars which are in a different category (AC Cobra's, Lancia's and Maserati's). Also some acquaintances bring their cars to him (for example a guy with a Mercury comet, and another guy who has a Ford Thunderbird).