Packard Forum Index » Post-War (1946-54)

Installing the new brake rebuild kit on the 47 Custom today. Interesting thing noticed with the new kit vs old install. Brake shoe springs. New kit has two identical (blue) whereas old used the primary and secondary (orange and yellow) springs. Parts book says the 47's used different springs.

Didn't see a mention in earlier manuals but 55-6 manual specifically states springs on the junior cars are the same (blue) while seniors had different. Curious as to why they would be the same on some models and different on others for one thing. Assume most of the juniors would have come with standard brakes and seniors would have had power and slightly larger shoes but what else other than lining composition would dictate a difference. Manuals do say there is a difference in friction materials primary vs secondary but wouldn't that hold for all?

The question now is should I reuse the old springs with the new linings or use the new springs figuring they were supplied for a reason and there might be something in the lining composition that dictate spring type. Don't see a specific designation other than length of lining as primary vs secondary shoe on the new ones.

I don't know how this might mesh (or not) with what Packard might have done on a particular model or models, but with Bendix floating anchor brakes one spring is typically weaker than the other and the weaker spring goes on the primary shoe, the logic being that the primary shoe engages the drum first and forces the multiplication of force to the secondary shoe which should also have the greater lining surface. Not sure if this helps you or not.

Dave, Thanks for the response. Which spring to use is a moot point now.

Not sure I could say I felt a difference between orange and yellow springs but the ones with the kit are most definitely considerably stronger than either. My brake spring tool didn't even want to put them on and tried to get even for the attempt by wanting to take a chunk out of my arm. Fortunately I moved fast for once so it wasn't successful -- and neither was I in getting them on in spite of another attempt. Lesson learned, the old ones went on nicely and I'm sure will do just fine.

I'm thinking now that the springs sent were meant for smaller diameter shoes. Still begs the question of why the same strength on some applications and different on others. Would like to be educated if anyone else has theories.

Howard,

Where did you purchase the kits?

Not sure it helps or not, but the my 54 clipper uses springs that were the same. But '54 Clippers were the same setup up as '55-'56s which use smaller drums than the 53 and prior models.

It was Kanter's deluxe brake overhaul kit. New master & wheel cylinders, hoses, shoes and hardware. Only thing I think they skimped on was not including new copper washers for the master cyl banjo fitting. They did include washers for the wheel cylinders.

I did have to reuse my old piston to shoe connecting pieces and in my case, the springs as well but that was about all. If I had wanted to shop around, might have found some things cheaper but not that much less for what was needed for that model car. That particular master would still have been unavailable aftermarket.

Overall, I'm pleased. It seems to be a decent kit and was all in one place. Not having an aggravation factor trying to find any adapters or coordinate various brands and items meant a lot in this instance so worth a little extra.

Here is my take on the subject.

Back in the day the original equipment engineers went to great pains for achieving smooth, effective, and easy braking. They used different lining materials and spring rates for primary and secondary brake shoes.

Over time the nuances of the specifics of engineering designs and materials faded and rebuilders started using common lining materials and springs for the primary and secondary brake shoes. They did this as the new way all seemed to work well and was less expensive. Besides, no one could remember how nicely a new Packard braked.

What do you think?

Paraphrased comment from a supplier of the brake springs,

Brake springs. Orig seniors had yellow sec and orange primary as did replacements industry # 122/130. Wire diam on ours .118" and we supply all 4 same as did most all aftermarket companies offering "heavy duty " springs, all 4 in a set were the same.

Blue springs were for 11" junior brakes, wire diam .100

we supply all 4 same as did most all aftermarket companies offering "heavy duty " springs, all 4 in a set were the same.

Thanks again. Looking at the springs they are probably more gray than blue so that would fit with being "heavy duty". All I can say is they were heavy duty enough my tool didn't like them. Not sure which type tool is needed to install them but obviously I don't have that type. For now will keep with the orange and yellow springs -- unless there is some reason the new cylinders and linings want the heavier ones.

OD is correct--as usual. The lighter weight springs were to go to the primary shoe so it would go out away from the anchor pin when the brakes were applied. In forward braking, the secondary shoe is never to leave the anchor pin so having the weaker spring on the primary avoids a clunk. They thought of everything.