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OEM brake shoes vs on the shelf at Napa....


63wildcatconvertible

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I was told, original equipment brake shoes are arched to fit the OEM drum specification.  Supposedly, every decade ( or so) either the brake lining was manufactured 'thicker' to accommodate the drums being machined as part of a proper brake job or, the later versions were re-ached to accept the OEM lining thickness.

 

Anyone know about this?

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The only way shoes can fit a drum properly is to measure the drum and arch the shoes to fit.  You could measure the drum and calculate the thickness of the lining needed and still would need to either machine the drum larger or grind the lining down to fit.  No one has ever made linings to all the possible thicknesses to suit every job.

No manufacturer of linings would have any idea how much you drum was worn or how many times it had been turned.

Not "every decade ( or so)"  has anything to do with it.  Linings have always been available in various thicknesses as well as different coefficients of friction.

Shoes do not come in oversize like pistons and anyway you would not use oversize pistons without measuring the cylinder.

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Your answer contains an extremely condescending tone.  Now I remember why I left here years ago. You and others like you are the reason these forums and old car guys are also becoming obsolete.  Perhaps some grammar lessons should have been included.

 

Furthermore, it you were not so full of yourself, perhaps you would have read and comprehended the part where I included the linings made thicker to accommodate machining.

 

I'll remove the Me and My Buick thread and not be back.

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It use to be very common practice in some shops to use shim material of proper thickness between the rivet style brake shoe on older models and new lining of a stock thickness , when drums were pretty worn but still servicable and not to be truned even larger.

 

I worked at a friends Mobile service garage in the early '80s and used the drum and rotor lathe and the shoe grinder( archer). Took off a lot of lining to make fit some bored out drums ..I don't recall oversized lining shoes  comming in for a job on a car.

If a job needed much thicker linings ,they were sold new drums !

 

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2 hours ago, Flivverking said:

If a job needed much thicker linings ,they were sold new drums !

 

Or REQUIRED new drums.   As I remember there was a legal (CA) state standard that you could not use drums that were more than 0.060 or 0.090 oversize. 

 

A drum doesn't get larger with time, only with metal to metal wear (rivets included) or repeated turning to correct out of roundness. 

 

Lining thickness has always been determined by the lining manufacture. It has never been sold in an 'oversize' format.  You measure each drum and arc the lining to that particular drum.

 

YES, for a while they sold "pre arced" shoes, but this was always a gimmick until the public forgot that it was necessary. 

Edited by m-mman (see edit history)
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I used to buy oversize linings in the sixties and early 70's.

Specifically to be used on drums turned to up to .060" OS..... late 50's MoPar Center Plane drums that were maxed out at .090" on legal drum turns always required OS linings that then certainly needed arcing of the shoe and lining.

Those and all other OS shoe/linings required arcing to properly fit the turned drums for a proper brake job.

Today no one but old timers remember OS shoes/linings were offered when needed.

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I guess it is part of the instant gratification generation. It took all of 2 and a half hours to come to the conclusion ALL of us on here are obsolete and for us to FO. Based on ONE response!

 

Didn't he want an answer to an obsolete question? He came to the right place.👍

 

Oh well, another one off to Facebook to get the "right" information ..... NOT! I have no use for that medium as answers to car questions, as there is so much misinformation there on every subject. Reading the Corvair Facebook pages is reading a humor book. Like trying to repair your house with a house repair book by Dave Barry.😲

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  As said by m-mman .060 was the limit that most of us go by, but most drums are stamped for maximum diameter.

The only problem I see is the arching, because in some states arching is illegal, in fact somewhere in the 80's or early 90's we got a edict from the state that we had to get rid of our arching machine because of asbestos. Our machine was a newer type with a recovery bag but it didn't matter, it had to go. Later on we were inspected to make sure it was gone. 

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