Ron42Dodge Posted February 15, 2017 Report Posted February 15, 2017 I was forwarded a question regarding a 1942 Plymouth convertible folding top operation. Apparently this gentleman has a 1942 Plymouth Convertible where the top is not hooked up. I'm assuming that means it does not work. He first wanted to verify that it was a vacuum system which I was able to confirm from my 42 Plymouth parts manual. Next he was looking for a diagram that might show the vacuum lines and how they are run.. My 42 Plymouth parts manual does not have any diagrams of that. I found a weak diagram in the plymouth service manual but it really did not show the vacuum lines. I'm guessing the same vacuum system was used on the P15 46-48 convertibles but I don't know that for a fact. Does anyone know? My 46-48 Dodge Parts manual has a wonderful schematic showing the convertible top mechanism and wiring but that is electric. I was wondering if the P15 Parts manual had an equally nice schematic of the Plymouth folding top and all the vacuum lines? Quote
Robin (UK) Posted February 16, 2017 Report Posted February 16, 2017 (edited) The convertible top system is very simple in the P15. Just a couple of days ago, I replaced the top control valve in the dash, and the rubber hoses. I've attached a picture of the control valve. And another showing its position when fitted in the dash. The single outlet is for vacuum supply - hooked up to the intake manifold. When the plunger is in the mid-position, it shuts off that supply. Pulling the knob out allows a vacuum draw to the lower chamber of the top cylinder at the back of the car. This will pull the top cylinder plunger down and open the top. Pushing the knob in allows a vacuum draw to the upper chamber of the top cylinder at the back of the car. This will pull the top cylinder plunger up and close the top. If there are no leaks in the system and the leather seals in the top cylinders are OK, there's not much else to go wrong. My car's top opens and closes really smoothly and quite quickly. Edited February 16, 2017 by Robin (UK) 1 Quote
Ron42Dodge Posted February 16, 2017 Author Report Posted February 16, 2017 Thanks Robin. Great information. I will pass it on. 1 Quote
Mark D Posted July 6, 2017 Report Posted July 6, 2017 This thread is a few months old, but I am currently in the process of servicing the vacuum power top system. If needed I would be happy to email photographs. - Mark Quote
Ron42Dodge Posted July 6, 2017 Author Report Posted July 6, 2017 Mark, It would be great to upload them to this thread for future access. 1 Quote
Ward Duffield Posted August 14, 2017 Report Posted August 14, 2017 Hello I am reassembling my P-15 after three years of restoration. I have added a double-acting fuel pump but find that despite decades of experience with postwar Mopars, I have no reference materials for the plumbing under the hood. Can anyone point me to a source or supply as few photos? Ward Duffield Pine Plains, NY Quote
Ron42Dodge Posted August 14, 2017 Author Report Posted August 14, 2017 Ward, I don't know if this diagram helps or if you need more detail as the actual route for the lines. Quote
greg g Posted August 15, 2017 Report Posted August 15, 2017 Ward, vacuum wipers or electric? If vacuum you just tie into the vacuum line on the intake. The vacuum pump was also used to augment the vacuum wipers operation while climbing hills or accelerating, both times of low intake vacuum. The hose from the fuel pump can just t into the manifold vacuum line and could then power the wipers or the top by splitting it again to feed the top and wiper switch. Most modern cars use vacuum for climate control, selecting vent air paths etc. So many feature vacuum accumulates some where under the hood. The come in many shapes and sizes. You could source one new or used at a pic and pull for a few bucks. Manifold vacuum and pump vacuum could both be routed to the canister and then wipers and top plumbed from it. You would probably still need the car running to operate the top, but the reservoir might provide a decent boost to operation. Most would have a check valve on the suction side to keep the reserve between uses. Source source 1 the pump and source 2 the intake manifold would be joined by a t or y fitting, that single line would go to the check valve fitting of the reservoir. The other fitting of the rest would go to a t oy y fitting and then to top switch or wiper motor switch. Electric wipers would negate the split and a single line would then go to the top switch. Leaving out the reservoir would have the single line from the sourcrs combined hoses at the t directly to the top switch. Can you visualize that or do you need to see a schematic??? I got straws and salt shakers I can mock up and snap a pic or two. Quote
Ward Duffield Posted December 7, 2017 Report Posted December 7, 2017 Well, there is a tube from the intake manifold to the vacuum pump, then a tube from the vacuum pump to the convertible top dashboard control valve. I have seen photos where there appears to be a cylindrical check valve or something in that tube leading to the valve, but installed ahead of the firewall. I was wondering what that cylindrical part is and was hoping that a ragtop owner still had one installed. Then Iam unsure which outlet on the valve goes where, but I can figure that out. Thanks Ward Quote
Plymouthy Adams Posted December 7, 2017 Report Posted December 7, 2017 (edited) are you sure you have vacuum cylinder on the P15? per the book they are electric driven hydraulic since 1941 with Mopar per Plymouth manual and the Motors manual for the era. There are three basic designs, vacuum, hydro electric and electrical mechanical. Good description of the three in the Motors book. My copy is a 17th Edition.....1940-54 Perhaps your local library will have a copy on the shelf. The vacuum boost fuel pump is for the vacuum wipers, stock on early P15's, not so on later models. I do not know the cut off date....this helps to keep wiper speed when loss of vacuum occurs, WOT or pulling long grade. Best used with a check valve and reservoir. Edited December 7, 2017 by Plymouthy Adams Quote
BobT-47P15 Posted December 7, 2017 Report Posted December 7, 2017 That line coming from the manifold to the firewall includes a hollow tube that looks like a miniature muffler....and in fact, the parts manual calls it a "muffler". I have always had that item in place, but cannot see or hear that it does anything particular. Have never tried going without it. Might not really be all that crucial, unless that section of hose might want to collapse due to vacuum. I have wrapped a couple pieces of chrome looking tape around my "muffler" simply for looks. . Quote
BobT-47P15 Posted December 7, 2017 Report Posted December 7, 2017 A P15 vacuum top cylinder is made like this. The end on your right goes toward bottom of the cylinder. Basically, by activating the dash switch, the system vacuum sucks the cylinder either down or up. Some have said a small moistning around the edge of that bottom disc with neatsfoot oil (a footwear leather softener/conditioner you can find at walmart or the supermarket) helps limber it up to make better contact and hold the vacuum. Quote
Ron42Dodge Posted January 31, 2019 Author Report Posted January 31, 2019 On 12/7/2017 at 12:28 PM, Plymouthy Adams said: are you sure you have vacuum cylinder on the P15? per the book they are electric driven hydraulic since 1941 with Mopar per Plymouth manual and the Motors manual for the era. There are three basic designs, vacuum, hydro electric and electrical mechanical. Good description of the three in the Motors book. My copy is a 17th Edition.....1940-54 Perhaps your local library will have a copy on the shelf. Plymouthy Adams. I am not an expert on Plymouths but I believe Plymouth Convertibles from 1939 to 1948 had Vacuum operated Folding Tops. I just happened to be digging into this subject again and saw your comment was not really addressed. My 42 Plymouth Parts book in the folding top section referes to the Vacuum Cylinder, Vacuum Cylinder pivot, Vacuum Cylinder Piston rod, etc. The Folding top Control valve that was used for the 42 Plymouth folding top was also used in 41 - 48 Plymouths.. Later ones became electric. Quote
Plymouthy Adams Posted January 31, 2019 Report Posted January 31, 2019 (edited) Page 264 of my factory manual states that the P15, P18 and P20 got a electric-hydraulic and the electro-mechanical on later models. If you look again, this comment was in question form and addresses the P15 which is 46-first series 49 and is in regard to post #9-vacuum on a P15...thanks Edited January 31, 2019 by Plymouthy Adams Quote
Ron42Dodge Posted January 31, 2019 Author Report Posted January 31, 2019 10 hours ago, Plymouthy Adams said: Page 264 of my factory manual states that the P15, P18 and P20 got a electric-hydraulic and the electro-mechanical on later models. If you look again, this comment was in question form and addresses the P15 which is 46-first series 49 and is in regard to post #9-vacuum on a P15...thanks Now I wish I didn't sell the 2 Plymouth shop manuals I had. This morning I checked with a friend that has a P15 Convertible (1947 I believe) and he replied "P15s used solely vacuum. Huge vacuum cylinders." It appears they switched to an electric hydraulic in 49. My 1935 - 53 Parts List has a diagram of the Hydraulic system (see attached). Some of those parts referenced came into use in 1949. I will try and post a schematic of the electric mechanical used in Dodge Desoto and Chrysler from my D-24 shop manual. Quote
Plymouthy Adams Posted January 31, 2019 Report Posted January 31, 2019 thanks for the picture and hopefully many folks will be aided with this drawing......I have to again state that this was the very reason I placed my response to the man in question form as I have an original Plymouth shop manual for reference that in no uncertain words states contrary.....as this manual is specific for 46-54...and shows the electro-hydraulic and the electro-mechanical systems....and has NOTHING on the vacuum operation...to say the least, this is a huge oversight for the factory when writing this book... Quote
Ron42Dodge Posted January 31, 2019 Author Report Posted January 31, 2019 I'm hoping someone has a P15 Parts List manual and hoping that it has a schematic of the Folding top showing the vacuum setup as there appears to be little information available on it. Quote
Plymouthy Adams Posted January 31, 2019 Report Posted January 31, 2019 now on that I totally agree...however I think that our forum member Bob Toft did just that one time in the past. Probably available through a search of the forum. I do feel that the book is in error as based on the original date of this thread two years ago...I do not have a convertible of this vintage....this would make a great technical sticky where the facts, diagrams and repair procedures for the vacuum operated system could be found all in one place. Quote
Ron42Dodge Posted February 1, 2019 Author Report Posted February 1, 2019 D24 Convertible top schematic with electric motors. Basically the same for 42- 48 Dodge DeSoto and Chrysler. 42 had helper springs to assist in lifting the top but they determined they weren't needed. Quote
Ron42Dodge Posted February 1, 2019 Author Report Posted February 1, 2019 (edited) duplicate post removed Edited February 4, 2019 by Ron42Dodge Quote
Ron42Dodge Posted February 1, 2019 Author Report Posted February 1, 2019 I just learned something else. The 1940 Dodge also was Vacuum and used the same control valve 859914 as the 1940 Plymouth. Desoto does not show a convertible switch for 40 and I don't have a chrysler book to know. 1941 Dodge used the same switch as 42-48 Dodge DeSoto Chrysler however the knob was different for 41. Interestingly the knob that came with my 42 Convertible is a 41 knob and so was another persons. I'm guessing they were using up old inventory first. Quote
Thomba48 Posted February 2, 2019 Report Posted February 2, 2019 By the way. Does anyone know what the original colour was for the frame? I am currently getting a new top installed and the frame does not look too good. And also where might I get the gasket strip towards the front. It is a 1949 Plymouth by the way. If that was to matter at all. Thanks Quote
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