brakes binding part deux
 

Several days ago, I posted a query about what the reasons might be behind the moderate/light binding of the brakes on my newly restored '83 SC after a several-mile drive. I got a number of replies, but they were all of the replace-the-old-swollen-brake-lines variety, and I obviously neglected to make it clear that this was a _complete_, $50,000-in-parts-alone restoration: the only thing on the brakes that isn't brand-new is the master cylinder and caliper bodies. All of the internals of all five units were replaced, as well as all rubber and some steel brake lines, pads and hydraulic fluid. And all four wheels are binding evenly, judging by their warmth (not really "heat") after I stop the car. Knowing this, does anybody have any new ideas? Has anybody had a brake vacuum-booster problem that would cause this? Is the fact that the booster is now getting its vacuum from the left bank of PMO carburetors rather than the car's original CIS a possible problem? There is no rust, no old brake fluid, no swollen lines or anything else of the sort in the car's brake system at this time.

thanks,
Stephan

I posted the same problem. See http://www.pelicanparts.com/ultimate/Forum3/HTML/008621.html
This should solve your problem. I think It's going to solve mine.


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Randy
71 911E

did you check for sufficient freeplay in the pushrod? if the m.cyl. doesn't return fully, the fluid can't get back to the reservoir, and will drag all the calipers. the vacuum from the carbs wouldn't do it, however you probably won't get vacuum assist after repeted pumps of the pedal. you may need to mount a vacuum reservoir tank. i've used sportomatic vacuum tanks for this.