Packard Forum Index » V-8 (1955-56)

I know there are several specific threads on the treadle vac brake booster but rather than try and sift thru all the posts to try and pry out info on my problem I figured I would just start a new thread. On my wifes Patrician, when we got it some years ago 2004-5, we drove it around before accepting it. Most of the mechanical stuff was done except for the brakes. As soon as the car was in place for a lengthy time I removed the brake booster and shipped it to Ed Strain in Florida for rebuild. Skip forward a bit and the unit was reinstalled and functioned quite well. After the restoration was complete, we drove the car to a couple of shows and all functioned well. We then embarked on buying land and a new home. When we moved into the new home we transported the car to the new home and garage. There it sat. Several attempts to start it failed. A friend of mine and I tore the carb apart and cleaned it and reinstalled it. Fresh gas and it started up almost immediately. In moving the car out of the garage I almost drove it into the side of the house because pushing on the brake pedal was like trying to push on a block of concrete without much reaction on the brakes.

As of yesterday I have removed the treadle-vac and opened it up. What should I look for? The vacuum hose appears to be intact. However that does not mean that it does not leak. Is there anything I can check while it is on the bench, or is my only option to send it back to Ed. There is no way he will work on this unit under his warranty after all this time, and I would not even ask him to. I have tried to push the plunger by hand and it will not move. What possibly could have happened to make the unit useless just from sitting? I could understand the engine being balky from sitting, but the brake booster?????

ALK

I'd be very interested in hearing some opinions on this problem.... My '55 Patrician that does not get driven very much has the same problem....(it also had a rebuilt BTV from Florida).......My very hard pedal seems to be a lack of vacuum boost.....I still have brakes IF I push the pedal very forcibly. However IF I let the car sit at idle for 10 to 15 minutes to warm up....the vacuum boost returns and is fine for the rest of the day..... any thoughts? PS...I check the fluid almost every time I start the car....and for the past 4 yrs I never seem to lose a drop....its always up where it should be....

One thing worth looking at in both cases is the amount of vacuum available. Make sure nothing is disconnected or leaking at a connection, no pinholes in the reservoir and verify the condition of the check valve at base of carb where the vacuum source connects. The valve sealing pieces could be stuck closed or even rusted away providing no vacuum or an insufficient supply..

If you run the engine and then turn it off, is there vacuum in the system for a length of time or does it disappear as soon as the engine quits. If vacuum is good then it gets more involved as to deteriorated or gummed up components in the power section or hydraulic issues.

Good advice as always from HH56. All I can add it to drive your Packards more frequently, Treadlevacs don't like long periods of inactivity.

Al.

For how long did your car sit?
I am a bit curious, as I also have a BTV.

Tom

AL Quote:

Short answer: replace it with a different used dual master system. Long answer: replace it with a different new modern system. You're right; there are many threads on this subject -- and for good reason.

JMHO after having had 4 BTV failures. I think the original BTV is a fatal accident waiting to happen. There are few subsystems on any car that one should NOT screw around with; the brake subsystem is one of them. You don't want to T-bone a school bus due to BTV failure (almost worst case scenario -- worst case is you and your passengers also die).

Craig

Thank you for the responses......Yes, my first thought was low/leaking vacuum source.....I guess I should have mentioned that I did change the check valve on the end of the carburetor with a known good one without any change (still hard brake pedal upon start up)... I have read (over and over I might add) all the posts on this site of the BTV discussions and controversy.... Like many others I am trying to keep my car as original as possible (but I am not adverse to updating in the name of safety). I have had a '57 Lincoln with a BTV for 27 yrs...rebuilt it once and its still doing fine. I have a '56 Nash Ambassador with a BTV (also rebuilt) doing fine....Recently sold a '57 Buick with the Moraine unit...rebuilt it once and it was just fine for years....its just with my Packards that I seem to have a problem.... I realize that just posting a fault symptom on here cannot always lead to a cut and dried solution...that the correction is quite often situational....I just thought perhaps someone else might have the same problem...of a hard pedal only upon start up....Again, I appreciate all the responses and if and when I correct it...will post what the problem was and how I was able to correct it....I'm 99% sure its a vacuum problem.. either in the BTV or the associated hoses/parts with the system.....

Well I have been in the new house since 2006. The car has sat idle most of that time with only a few outings. I would say continuous idle for at least 4 years with only infrequent starting. However here is the curious thing. MY 55 patrician which also has an Ed Strain rebuilt T-VAC unit is fine. I make sure that the fluid reservoir is topped off and I have never had a problem.

OK, this claim of "never had a problem" reminds of a very recent show on Smithsonian Channel about Air Disasters. In 1989, United Airlines flight 232 suffered a SINGLE middle engine failure of the turbofan blade (made of titanium, BTW) which severed ALL 3 of the airplane's hydraulic systems. The DC-10 has a TRIPLE REDUNDANT system that is professionally designed and maintained by the best crews in the world. The resulting crash ONLY killed about half of the passengers due to heroic efforts by the flight crew to defeat the phugoid curve induced oscillation. See for details:

http://en.wikipedia.org/wiki/Phugoid

My point is that this DC-10 had triple redundant HYDRAULIC system. The BTV is a single point of failure HYDRAULIC system. One can claim that they've never had a problem UNTIL YOU DO. At least with a double redundant system, the odds are pushed further down that your "problem" will occur and kill you.

Craig

Al -

If your talking about a lack of power assist, make sure the vacuum supply to the power brake unit is sufficient and that there are no leaks. Then, follow the shop manual instructions for disassembly as regards removing the end plate from the vacuum section. HOWEVER, you need NOT remvoe the compensator port valve or the outlet fitting to do this much (that is, less than a complete overhaul). All you want to do at this point is make sure that the internal vacuum hose is connected to the tube fitting on the shell and the tube fitting on the piston assembly.

Next, understand that for vacuum to provide power assist, there must be a way for atmosphere to enter the upper end of the vac chamber (to help push the power piston down the cylnder). So, make sure that the little air cleaner (packed with horsehair) isn't plugged up; not sure about your area, but wasp build nests (of mud) in the darndest places.

Beyond that, I could only suspect an intenal problem with the power piston mechansim (e.g. - poppet valves) that would require full disassembly. If you wanna take a stab at that, I recommend that you download and review the "How To" article provided by member Ross.