Several weeks ago I started driving my '63 Wildcat and noticed the brake pedal felt different--slowly sinking to the floor upon applying pressure. Still had good braking after a few pumps, but I've had a brake hose explode while driving an old car in the past. So with that harrowing experience in mind, back home I went in a hurry. I couldn't find any leaking fluid anywhere, so I suspect the master cylinder and/or booster has gone bad. I've done brake work at the wheels but have never taken apart the MC/booster/pedal linkage before. How does one narrow down the issue and prove it's one or the other causing the problem? I've always meant to swap in a dual master cylinder for safety reasons and now seems a good time. Is anyone aware of one that will work with the original booster (assuming the booster is not the issue)? I found this thread from last year--http://v8buick.com/index.php?threads/changing-master-cylinder-on-63-cat.322816/#post-2752194--but I'm not sure if the MC he used on the '64 will work on my car. Anyone have experience doing this on a '63? Any help is much appreciated! Phil
My 63 Power booster/master cylinder turned to junk so I fitted a Corvette set. Dual diaphragm booster and dual circuit master cylinder. It's not 100% straight forward swap but with a little help from one friend for one small detail I did the rest at home in my garage. Feel free to message me for details. I should add it stops real well now and passed Compliance/Certification for use on New Zealand roads.
Hey guys, I appreciate the replies. Sounds like this is a more complicated job than I had anticipated, and at this point I am leaning towards simply buying a replacement single master cylinder, at least until next summer. Most of the other brake components--wheel cylinders, hoses, etc... were replaced in the last 5-7 years and appear to be in good order. Roadrunnerz, is this the setup you purchased? I'm definitely interested if you have photos of the installation. Phil
Finally got to the car this weekend. So, where to start? You're going to need a double flaring tool! Dual cylinder Corvette booster and master cylinder, can buy them almost anywhere. Must be a 1"bore master cylinder. Putting the two together should be self explanatory. The four booster bolts fit the firewall perfectly BUT the large hole the booster fits through will require a few minutes with a file to open up a faction. I used a thin rubber gasket I made. Don't bolt it up YET. The tricky bit was making the joint to go on the end of the shaft to the brake pedal - I used a rod end type joint and there was no off the shelf part anywhere. The brake pedal hole is larger than the threaded shaft, I'm guessing but lets say the pedal is 7/16" and the rod is 3/8" - not on any shelf. What I did was locktite a bolt into the rod joint, cut the end off and drill and retap the insert to fit the threaded shaft. Get the length correct, thread it onto the shaft and feed it through the firewall and onto the brake pedal. NOW you can bolt to the firewall. Wont work any other way. Now for the plumbing. I left the distribution block in place but undid the rear brake line and input line. Where the rear line went is now your INPUT for line1 from the master cylinder. Line2 from master cylinder attaches to the rear brake line. (I used residual pressure valves (purple bits) that were supplied with the cylinder.) And the final input line to the distribution block gets filled by your brake light sender unit. Then two plugs in the remaining master cylinder outlets and hey presto a sealed system. Now bleed everything, twice. Your going to need at least a quart of fluid, probably more. I made up a DIY one-man bleeder using a spare oneway valve. Finally, connect the vacuum hose to the manifold, or via the vacuum tank if you want. This system damn near put my head through the windscreen first test stop. optional - I removed the firewall mounting plate, buffed and two-pot painted it before reinstall. It's a bitch getting all the bolts out and back in but looks so much neater now it's finished. Brake4 by roadrunnernz posted Oct 7, 2018 at 1:17 PM Brake3 by roadrunnernz posted Oct 7, 2018 at 1:17 PM Brake2 by roadrunnernz posted Oct 7, 2018 at 1:17 PM Brake1 by roadrunnernz posted Oct 7, 2018 at 1:17 PM
Roadrunnernz, I really appreciate your last post, that was really above and beyond. If you have any photos of the situation you describe with the brake pedal connection, that'd be the only other thing I'd like to see if possible. Since my last post I went ahead and removed the master cylinder and wow, the connection to the booster was really nasty and crusty. Take a look: I'm not sure this is the original factory master cylinder, but it's certainly been on there a LONG time. You think there's any point to cleaning up the booster and mounting a new single MC just to have the car back on the road before winter? Or is full replacement the only way to go here? Phil
I'd do it once, and do it right, the way you want it to end up. Dual master. I did it on our '62 in an afternoon. I don't have the part numbers of the master/booster I used. They stayed in the folder that I gave to Les, the guy I sold the LeSabre to. He's been on here, but haven't heard from him for awhile. His screen name is Les C. Message him. He's a nice guy and I'm certain he would give you the part numbers.
I went down that road, twice, before I gave up on rebuilt or so-called new parts - had two master cylinders leak exactly as your one did and the rebuilt power booster never worked like it should. In the end it's your money and your decision. You might be luckier.
