Just got my last Cougar, a’68 XR7, 302Jcode, C4, SanJose build, power disc brakes. The seller told me it had no brakes and upon getting it home on a trailer I checked the master cylinder, it was bone dry, both chambers. I couldn’t see any leaks there or at the wheels. I filled the mc and tried the pedal hoping for a miracle, O. I watched a video from Don Rush about the Midland booster and he said something about the booster sucking brake fluid past bad mc seals. Am I better off getting a rebuilt mc/booster and from where, WCCC or NPD? It’s getting cold here in northern Indiana so I’m looking at next spring to get on the road. Thanks for any suggestions. Elgato 68
Booster Steve.
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It seems premature to question the booster. If both sides were bone dry, I would first wonder if a prior owner had swapped out the master cylinder possibly without even bench bleeding. In any case simply putting fluid in will not work. The air must be bled from the system for each wheel. Getting all the air out of dry master cylinder requires a separate bench bleeding process out of the vehicle. Since everything is assembled you might try bleeding the wheel cylinders first to check brake function (they won’t work with compressible air in the system). This will detect leaks and prove out basic function and leak tightness. If they seem to work but there are still bubbles or the pedal is spongy then pulling the master cylinder for a more thorough bleed may be needed. Check for videos on brake bleeding. If the brakes work but require too much pedal pressure or there are other signs of vacuum loss it will then be time to question the booster.
It’s possible to bench blead the Master cylinder on the car. I would inspect the system from front to back. Look at all the metal lines and the soft lines for evidence of leaking, Then I would bench blead the M/C. Then move on to each wheal. Maybe you will be lucky and have brakes.
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Badcatt is right on bench bleeding in the car. I’m too focused on my master cylinder replacement that I’m in the midst of, just bench bled on the bench and just installed in the car, getting ready for the wheel cylinders. You don’t want to pull the master cylinder if you don’t have to. On my '70 and I believe on all the earlier Cougars you have to loosen the booster to be able to lift and swing the master cylinder inboard to clear the shock tower. Good luck, hope it is as simple as bleeding the system
You need to figure out where it is leaking first. Remove the master cylinder and look at the distribution block and look behind the master cylinder to see if it is leaking into the booster.
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