: 1960 Cadillac power brake pedal hard to push after driving a little while

02-05-13, 08:55 PM
Hello friends. Just wondering if anyone would know the cause for my brake problem on my 1960 Cadillac. I was told by some that the brake booster is bad although there is a vacuum valve installed between the carb and the booster that might have an issue. I think that the valve is ok although it is old but the thing is when the car is cold and I start out driving the brakes work fine. After the car warms up some and I have driven it some the brake pedal gets harder and harder to push down. I can't seem to find even the valve to replace it and the brake booster will cost well over $200.00 to send off and get rebuilt. I would do this if this was definitely the problem but don't want to waste the money if thereare other possible causes for this to happen. Any help would be very much appreciated.

02-06-13, 08:47 AM
Hello stotzbotz, and welcome to this forum :welcome: You could try to bypass the valve with a longer hose and see if the problem does not occur to verify if the valve is faulty. Another possibility is that the hose has a leak. If the choke is engaged when the engine is cold, RPM is higher and leak could be counterbalanced. When hot, RPM drop and now the problem is noticed. If bypassing the valve with a new hose the problem is solved I would try then to go back using the valve with new hose in every section to see if the problem came from the hose or from the valve. If after trying this the problem continues, I would get the booster tested.

Some places specialized in old cadillac parts in case you need the valve:

http://www.cadillacville.com/ (junkyard)

You could try to upload some pics of your caddy when you have some time. We love to see these old school cadillacs here :thumbsup:

02-06-13, 11:52 AM
The valve is a check valve to hold vacuum in the booster. With the car off and up to temperature, remove the hose from the booster. Vacuum should escape from the booster. If not then the booster is leaking.