Air or Vacuum Operated Convert?

[Lou Earle]

Began working on 47 convert. The service manual has nothing about a set up like mine Seems like it has copper lines leading from under dash and some sort of valve to the rather large cylinders in the back. Also appears to be some vacuum plate on the carb -under the bas with the line cut off and sealed.

Anyone know where I can get info on this system - all advice welcome I actually have a 6 volt hydraulic pump from the old caddy hydraulic windows. I might use that if I cannot find info on the vacuum?? system

thanks

Lou

[Plymouthy Adams]

The P15 is an electric over hydraulic system..pump with forward/rev control, reservoir, operating switch with circuit breaker and the hydraulic cylinder. The later units were electro-mechanical with for/rev motor and twin cable drive out.

[JohnS48plm]

My 1948 p-15 convertible was a vacuum system. A tube from the manifold brought vacuum to a valve on the right side of the dash. The valve had a knob that said top on it. The valve sent vacuum through tubes to the top cylinders to make them extend or retract to raise or lower the top. The cylinders had leather cups to seal the pistons in the bores, I used neetsfoot oil to soften up the leathers. John

[Lou Earle]

Not so sure = I have a push pull knob on the right corner of the dash and it has 3 tubes going to it- no electrical at all and Tim u remember how the vacuum tube was large and had a huge muffler? I am wondering if some of these had some other operating system- very strange indeed- I find no motor, no by passed wire and no mounting bracket for a motor

Lou

[Lou Earle]

My 1948 p-15 convertible was a vacuum system. A tube from the manifold brought vacuum to a valve on the right side of the dash. The valve had a knob that said top on it. The valve sent vacuum through tubes to the top cylinders to make them extend or retract to raise or lower the top. The cylinders had leather cups to seal the pistons in the bores, I used neetsfoot oil to soften up the leathers. John

That is exactly what I have- do you have any pics? whee did the vacuum line enter the car? or was it spliced off the wiper? What a system?/ I haven't a clue how this works any help wanted and appreciated

Lou

[Plymouthy Adams]

I was just quoting from my book..I do think Bob T. spoke of vacuum on his convertible...funny that the book does not mention vacuum at all. page 264 body section, para. 28. So went to my Motors manual

Dodge

1940 vacuum

41-48 Electric

1949-52 and 55 Hydro Electric

1953-54 Electric

Chrysler/DeSoto

1940 Vacuum

1941-48 Electric

1949-55 Hydro-electric

Plymouth

1940-48 Vacuum

1940-50 Deluxe Electric

1949-50 Sp Dlx Hydrao Electric

1951-54 Electric

1955 Hydro-electric

per 1955 Motors manual...has good description of vacuum operation and service. Lou..I think you have this book at home in your back room...check out general repair, power tops.

[BobT-47P15]

They are totally vacuum operated, Lou. I wondered when you would get around to that part. Vacuum line off the manifold to the dash push/pull switch on the right.

Does yours have the little muffler in the line? No one seems to know exactly what it's function is, but they are listed in the parts manual.....as "muffler, folding top vacuum line, assembly". Parts for the top cylinders are listed on page 326 and 327.

Then two tubes from the switch to the back under the step plate edge. Under the rear seat some lengths of tube which ultimately connect by hose to the top and bottom of each cylinder. Vacuum either pulls the plunger up or down to operate the top. Pretty simple. Will work if cylinders and lines are in good condition. Connects off the wipers.

Here is what's inside the cylinder. The leather part is a leather pump cup. I once found a pump service in Kansas somewhere that had those for about $10 apiece....but have now lost the info.

The cylinders can get a little rough on the inside from moisture, so may need to be slicked up. Leather may need attention too as previously mentioned. It is weird that they don't show the system or hardly mention it anywhere in the litereature.

I have been putting the top up and down by hand for some time, and it's not all that tough. Probably the hardest part is when ready to put it up, I have to stand in the back seat and pull it up from the well and get it about halfway up.....then step out of the car once it's balanced and finish closing it. The thing I really try to watch is when lowering the top, I tuck the material in on the sides so it won't get pinched and make a hole in the top. It got in a bind once and I have a real small hole on the right side.

Had the upholstry guy make me a boot.....he did a pretty good job for $250. Attaches to top edge of back seat with velcro.

[claybill]

hi bobT....i like the boot....what did you use for a pattern? local upholstery shop wants a pattern first!!!!! cant find one. help?11!!

i have a 41 and a 46 convert..BOTH HAVE THE SAME VACUUM POWER TOP.

no electric or hydraulic whatsoever!!! as you say///dash switch has 3 lines...vac going in..an up and a down line. connecting to the cylinders just under the rear side panels. on the 41 the vac tubes are steel and go around the back thru the trunk area.??

i am not sure if one cyl is up, and the other ,down...or both operate as same.

i think so just a different location of the vac line coming in. am i correct???

on my 41, my top goes down...but needs assisstance pulling it up..

i am thinking there is a crack in the hose or something simple.

bill

what i did figure out.............if it comes up easily with manual help when you operate button, then it might be a leaky line as you are not fighting the friction of the cyl.............if it is a bitch to pull up, even with the button pressed, then you are fighting friction of the cups in the cyl....meaning that the 'up' vac line is not operating at all....line is probably disconnected someplace.

[BobT-47P15]

Hi Bill. Those cylinders both work together. One pair of vacuum lines connects to the top, to pull the cylinder up. The other pair of lines goes to the bottom connectors, to pull both cylinders down.

If top does not work well in one direction, it may be a vacuum line leak somewhere, or the leather cups inside the cylinders may be dried out causing air to leak by them. And the inside of the cylinders can get a bit of surface rust on them from condensation.....and may need to be cleaned up.

New cylinders can actually be purchased from (I think) Hydro E Lectric Co in Florida.

Re: the boot - I had an old boot that came in the car. Looked sort of right for the vehicle, but was not quite large enough, so was either wrong or had shrunk a bunch. The upholstry guy used that as a partial pattern, then just measured and winged it the rest of the way. Guess I could take it clear off and measure it. (Just tossed out a roll of kraft paper that might have been big enouth to draw a pattern....darn.)

[claybill]

ok bob.....i also have a shrunken boot from my old 41 'vert. i was hoping that he coul;d make adjustments...sounds good.

now i have to figure out how to attach it with those snaps..or cn the upholsterer do that?

bill

[Lou Earle]

Bob

Got the cyls out and now starting to work on them. I am havinb a hard time getting theplunger mechanism out of the cassister- How did you acomplish that? Thanks to all for the help.

Lou

[BobT-47P15]

Lou.. Mine would move up and down before I opened the cannister. So no problema getting them out. Are yours frozen up? Try some seafoam or whatever you use for rusty stuff.

[Frank M.]

As usual , Bob T is right on ! I have never seen anything but a vacumn op.top on Ply. since its first intro in 1939. That incidentally was the first Amer. Manuf. car with a automatic top. Ply tops '39 thru 48 were ALL vac. operated. The cylinders are very powerful when in good condition. The tubes under the carpet AND under the boot well were STEEL. The 1/2" outlet on the manifold was used for volume that the large cylinders needed. The small muffler half way between the carb and the firewall I would guess was to stop debris from the top mech. from entering the fuel intake. Thats just my thought tho and until -if we ever find out for sure- its a guess situation. Chrysler,De Soto,and Dodge in those years ( 42-48 ) all used the same lift mech. Two motors with gear reduction attached to two long screws raised and lowered the top. All electric. They drew so much juice that it was suggested that the engine be run during operation. Ply changed to Hydo-Electric in 49 and later to just electric as was formerly said. Had to jump in here guys ---hope no one minds. Frank M.