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On 11 Aug 98, at 7:07, Toby B wrote: > Hmmm > I'll freely concede the 'residual pressure' argument- I always thought > that's what the adjuster was for! But many systems do have them for the > drums (Volvo 122, for example, has one in the equalizing valve to the > rear drums) Many early cars, including VWs, had them, but I'm not sure what the purpose was, or even if there ever was a good, well thought out purpose. It is quite possible that the way these brakes operated was improved by a bit of residual pressure. I have always thought it was telling that when VW introduced disk brakes they deleted the valves even in the rear circuit, even though nothing else in that circuit had changed. > But I've always been told, and have always set, my rear, adjustable, > drums to brush the drum slightly. With new shoes, it makes sense, as > there's a bit of wear as the shoe beds in. And every time I work on the > drums, I adjust 'em so they JUST brush. Enough resistance so that > they'll check a free- spinning wheel in a turn or two, or three. Never > had a problem with overheating yet... With new shoes this is indeed a quandry. I prefer to let them seat in and then readjust in a couple of weeks. The concern is that the heat may cause things to expand in such a way that the rubbing gets worse. In the end any rubbing parts should wear away, so it just becomes a matter of how much shoe you are willing to sacrifice, as well as how much chance you are willing to take on brake failure. Obviously, the less rubbing you have, the less likely you are to have any trouble. > On older disk setups, the wheel usually spins freely. On more modern > discs, tho, the caliper maintains a bit (similar to how I set the drums) > of scuff. I always figured it was to keep pedal travel to an absolute > minimum. I don't find that any calipers in good repair will ever drag, however I seldom encounter calipers as old as ours that are still in that good a shape. One thing I do to check a brake system is to drive a car for awhile, using the brakes as little as possible, then stop gently and go around to all 4 wheels to feel the temp of the rotors and drums. Calipers and wheel cylinders that are becoming sticky will produce drag that will burn your fingers. A rebuilt brake will not. Keep in mind that some warmth is natural since you did just use the brakes to stop the car. PS- I'm sure you'd agree that changing your brake fluid every couple of years is cheap life insurance! Well, I have used Silicone Brake Fluid for over 18 years now and it never requires changing. For those who are still using DoT 3/4, changing is essential. Jim - ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ------------------------------------------------------------------- Search old messages on the Web! Visit http://www.vwtype3.org/list/