Packard Forum Index » V-8 (1955-56)

56 Exec. has loss of power brake assist about once in every 200 or so applications. Anything to look for? The BTV was rebuilt about two years ago and everything seems fine except for this rather scary problem.

lostcause Quote:

"scary" is an understatement! I personally had 4 different, professionally rebuilt BTVs fail over several years -- one was complete failure, i.e., not just no power assist, but no brakes, period.

My solution was to replace the BTV with a modern dual master booster. Several others on this website have done exactly the same or adapted another type modern booster to the firewall. See for details on what I did:

http://www.1956packardpanther.com/Panther/powerbrakes.html

In the 9 years I have had this setup installed, it has been 100% reliable.

Craig

Perhaps a sticking vacuum check valve. Follow the hose from the booster up to the intake manifold and you'll find the valve. Pretty simple little thing, often can be fixed by just cleaning, sometimes replacing the spring or ball.

EDIT: You said the power assist failed, not the brakes. Thus my guess on the vacuum check valve. If you can't repair it or find an NOS one if needed, they are still used on cars today so you could adapt a modern functional equivalent easily.

If just assist and not entire brakes, one easy place to get to and look is the check valve at the back of carb. If it has a bit of rust or somehow stays open, sometimes the vacuum available in reserve is not sufficient for an application.

If you are losing entire brakes, another matter entirely and a different issue. Other than a bit of cleaning and lube for the piston leather, I don't think rebuilders spend a lot of time (if any) on the vacuum section when doing a rebuild. If the check valve cleaning doesn't help, you would need to have that vacuum portion looked at by someone known to do good work.

G'day Tim,
to PackardInfo and good luck in solving the brake problem with the '56 Executive. Was going to ask you to include the Exec in the Packard Owner's Registry when I noticed your signature line of "EIGHT IN A ROW, THE ONLY WAY TO GO!!!". So, besides the Exec, could you also include your '39 120 4 Door Sedan?