Re: 1940 Super 8 160 Model 1803 Project
Posted by Jim On 2010/9/10 1:13:14
So after some digging and comparing info. a buddy provided to images on the Bendix website it became apparent the 12" X 2" shoes used front and rear on a 1940 160 are Bendix R-33 webs. Sourced two sets of relined R-33's at Carquest for about $65 bucks, no core charge.
The lining was nicely fit, and of proper length for primary and secondary shoe application. The primary lining looked to be about the thickness I would expect for a Bendix self energizing brake system. The secondary lining is normally thicker, but in this case it was substantially thicker. The lining on the secondary shoes appeared to actually be fitted with oversized lining.
A common practice that seems to have been lost with time is to fit the shoes in the respective brake drums and check for at least 90% friction to drum contact.
In this case, I had about 90+% contact with the primary shoes in the rear drums. That figures, the rear drums measure darn near standard. However, the secondary shoes fit with only contact on the very edges of the shoe. The center of the shoes stood off the drum about .050" to .090" thousandths. With the miles most of us put on these cars, it would take about 10 years to bed that in. Until then, the brakes would substantially under-perform.
The answer is to arc the shoes on a brake shoe arcing machine. This was common place in any competent auto repair shop years ago for reasons mentioned above. Pictured below is a pictorial of the process and equipment to arc brake lining to conform properly and completely to the circumference.
A before and after of the friction to drum contact is very telling. I hope this is informative and gives folks an idea of what arcing brake shoes was (is) all about.
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The lining was nicely fit, and of proper length for primary and secondary shoe application. The primary lining looked to be about the thickness I would expect for a Bendix self energizing brake system. The secondary lining is normally thicker, but in this case it was substantially thicker. The lining on the secondary shoes appeared to actually be fitted with oversized lining.
A common practice that seems to have been lost with time is to fit the shoes in the respective brake drums and check for at least 90% friction to drum contact.
In this case, I had about 90+% contact with the primary shoes in the rear drums. That figures, the rear drums measure darn near standard. However, the secondary shoes fit with only contact on the very edges of the shoe. The center of the shoes stood off the drum about .050" to .090" thousandths. With the miles most of us put on these cars, it would take about 10 years to bed that in. Until then, the brakes would substantially under-perform.
The answer is to arc the shoes on a brake shoe arcing machine. This was common place in any competent auto repair shop years ago for reasons mentioned above. Pictured below is a pictorial of the process and equipment to arc brake lining to conform properly and completely to the circumference.
A before and after of the friction to drum contact is very telling. I hope this is informative and gives folks an idea of what arcing brake shoes was (is) all about.
Attach file:
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