QuestionI just replaced the master cylinder on my 67 Caddy,now the brake peday goes nearly to the floor, and does not pump up pressure. I also hear a sucking sound behind the dash when I pump the pedal. I know that I will still have to bleed the system at all 4 wheel cylinders, but it does not seem right to me. Any suggestions?
AnswerHello Dennis,
It sounds to me like you've got 2, possibly 3, related problems. The first is the new master: for the future, you should bleed both reservoirs on the new master before or during installation to avoid injecting more air at the head of the brake lines. Not a fatal mistake but it will take quite a bit of brake fluid now to make sure all the air is out of the system.
Second, once you've thoroughly bled the system, check brake adjustment. I don't recall if Calais' had front discs but I know they had rear drums. Check to make sure that any drum brakes are properly adjusted. Low pedal can result from poorly adjusted brakes.
Finally, the underdash noise you hear is likely a vacuum leak at the power brake booster. It is possible the booster itself coincidentally failed when you replaced the master or, more likely, the hose from the engine to brake booster is cracked, broken or loose or the connection is the same. If you choose to replace the hose (I'd recommend this if you're unaware of when it was last replaced), make sure you specify a power brake hose vs any type hose. The reason is that PB hoses have thick, reinforced walls for the direct engine vacuum they connect. And , if you've ever tried to stop a heavy, non-power brake operational car with a collapsed hose, you'll not need to use your stairmaster that day!
Try these suggestions and I think you'll have the Caddy back on the road quickly!
Good luck,
Bob
