vpifarmer@b2xonline.com Posted November 22, 2011 Report Share Posted November 22, 2011 Can anyone help with my understanding/knowing the differences between the standard car's front suspension and the 7 passenger front suspension. I know there are differences - but I need to know precisely the differences. Will they interchange in any manner? Dimensional differences? Are there effects on front suspension alighnment/dimensions/etc.? If there is a reference source online - please refe me to it. Thanks Dan Quote Link to comment Share on other sites More sharing options...
Olddaddy Posted November 22, 2011 Report Share Posted November 22, 2011 Dan, I've been emailing you regarding disc brakes upgrades, but email is returned, mailbox full.......let me know how to reach you. Quote Link to comment Share on other sites More sharing options...
Andydodge Posted November 22, 2011 Report Share Posted November 22, 2011 My info says that 7 passenger stuff is bigger/thicker etc.......check your service/workshop manual for specs, mine says kingpins are slightly larger diameter, upper inner pivots, arms, etc all have a different measurement........what have you got?...............andyd Quote Link to comment Share on other sites More sharing options...
1940plymouth Posted November 22, 2011 Report Share Posted November 22, 2011 Contact Jim Benjaminson, the last I knew he had a seven passenger 1940 Plymouth. Quote Link to comment Share on other sites More sharing options...
greg g Posted November 22, 2011 Report Share Posted November 22, 2011 Most likely the pieces from the large and heavier Chrysler were used on the Plymouth. You probably have the 11 inch brakes, upgraded sway arms and mounts, Those would have been off the shilf and bolt on pieces, perhaps the spring also. Can't be mush more of a difference elsewhere. Quote Link to comment Share on other sites More sharing options...
vpifarmer@b2xonline.com Posted November 22, 2011 Author Report Share Posted November 22, 2011 We have a '40 Plymouth coupe - not the 7 passenger / heavier stuff. I am having difficulty in getting front alignment as needed - I was wondering what the 7 passenger parts might do under the coupe - in other words, can those parts possibly help with alignment issues. Can not get camber to needed position and caster is a BIG problem. Caster is in the wrong direction. Camber not too bad on right side (but not correct) - left side is not good. Toe-in is fine to adjust. Steering geometry seems well within usable specs. The camber eccentric just does not have enough adjustment to get me there. The assembly of the front suspension is the onlu caster adjustemnt I see and we tried to use all tolerences to the best advantage? I get the "heavying up / bigger kingpins/arm pivots, etc. - which would not really help me, but if there were length to vertical differences in the parts. That MAY help? But do not really see how - yet. Coupe drives terrible. Back to the drawing board - I think? Also having front spring problem of those springs are "settling". That I can addresss - AGAIN But a pain since it is the third set of springs that have settled too far after driving/sitting. Tried different springs & tried a rubber base spacer toraise the car - just have to find a little longer spring and a bit "heavier" coil spring rate & try again. Quote Link to comment Share on other sites More sharing options...
Young Ed Posted November 22, 2011 Report Share Posted November 22, 2011 I would suspect you've got something worn out or perhaps accident damage not allowing the proper adjustment. It also sounds like you are trying to align yourself? Have you tried taking it to a shop with an alignment rack? Are you installing different used front springs or new? Quote Link to comment Share on other sites More sharing options...
Andydodge Posted November 22, 2011 Report Share Posted November 22, 2011 Dan, I have an Australian built 1940 Dodge, but its based on the 1940 US plymouth as you can see the Plymouth sheetmetal.......what I did was used 1941 onwards upper control arms which used the same upper outer pin & bush thru to 1956, the upper inner pin & bush fits into the 41-56 upper arm. As an aside I actually do have a pair of NOS 1940 Plymouth upper arms and outer pins but as I am in Australia shipping would be prohibitive, the 1940 design was similar to the 1939 but am not sure if it was identical, either way the 39/40 design only lasted for 2 yrs and as it was replaced by a design that lasted for 15yrs I'd say that there was something to be said for the later design. So I'd suggest getting the 41-56 upper arm & pin/bush.......it will fit the 1940 spindle as thats what I used. I also used 1941 onwards stub axles as they were easier to adapt the disc brakes onto......regards, andyd Quote Link to comment Share on other sites More sharing options...
vpifarmer@b2xonline.com Posted November 23, 2011 Author Report Share Posted November 23, 2011 All parts are NOS/NORS/NEW from Mopar parts suppliers No wreck damage anywhere on coupe. There was only one very small area of rust in the rear floorboard where some chemical had eaten the metal - on the entire coupe. Professional alignment only. This shop is widely known for being THE place for older vehicles. I have used them for 40 years for all types of vehicles. I frankly wish it were parts or damage - that could/should/might be able to be found and be fixed.(by a pro) All springs are brand new - from Mopar suppliers of front end/suspension parts. The older springs removed matched new dimensions and probably were newly installed by previous owner? In fact - every piece of this front suspension is NOS/NORS by me and installed professionally by others under my watchful eyes. Do I know the parts and how they work - think so! Camber adjustment is limited to the excentrics at the top of the vertical. there is no factory caster adjustment. (I did figure out that a very minor amount of caster could be gained by careful assembly or the vertical.) Toe-in is obvious. Extra NOS verticals & arms were also tried/fitted. I supose the verticals could be heated & bent to gain some caster - but not yet! Other comments about using '41 parts - that is interesting and deserves follow-up. Never thought they might fit frame holes/etc.. I had wondered about differences between std & 7 passenger parts. Trying to figure a means of gaining adjustment for camber and caster via a safe and reasonable means. Old Daddy - please try email again & let me know if it fails. Dan Thanks folks Quote Link to comment Share on other sites More sharing options...
Andydodge Posted November 23, 2011 Report Share Posted November 23, 2011 Dan, just reread your initial post and new reply.......caster or lack of it is the problem.......my 1936-42 Oz manual states that for 1939-40 "Caster angle is not adjustable but proper setting is obtained when assembling the camber eccentric bushing"...as you have found out.........dunno what to say........I have had no problems with mine over the past 40yrs I've owned the Dodge......are you still using the original style upper arms with NOS bushes & pins?...........or have you replaced the actual arms themselves as well as the bushes & pins?.........andyd Quote Link to comment Share on other sites More sharing options...
fstfish66 Posted November 29, 2011 Report Share Posted November 29, 2011 andy very intresting info...ill follow along Quote Link to comment Share on other sites More sharing options...
39Plymouth Posted December 9, 2011 Report Share Posted December 9, 2011 I have a '39 so don't shoot me if the '40 is different. On the '39, the upper, inner control arm attaches via two threaded bushings. The rear bushing is dual threaded, the front is internally threaded and externally smooth with a guide groove in it. Remove the rear one completely, loosen the clamp bolt on the front one and tighten the bushing to gain positive caster then re-install rear. I had the negative caster problem you describe on one side of my '39 and this technique solved it. The service standard range for caster on the '39 is minus 1/2 degree to positive 1 1/2 degrees. Plymouth may claim the caster is not adjustable, but there are two points on the upper control arm (inner and outer) which can be used to set caster. I guess setting and adjusting were two different things according to 1930's engineers. From the shop manual: "Camber adjustment is made within 1/2 revolution from the point where correct caster setting is obtained." Hope that helps. Quote Link to comment Share on other sites More sharing options...
Randy4840 Posted October 28, 2019 Report Share Posted October 28, 2019 So I am having a similar problem with my 1940 Plymouth. It has the single side attachment on the upper control arm. I have a set of 1947 Plymouth x style upper control arms . They don't seem to interchange at all. The upright is not centered the same as the single side attachment control arm. Any suggestions. I have a set of fat man dropped spindles for a 51-56 mopar but the upper concentric doesn't fit . Any help? Quote Link to comment Share on other sites More sharing options...
Andydodge Posted October 29, 2019 Report Share Posted October 29, 2019 (edited) See my reply to your other thread........soon...........err, done........lol.........Andyd Edited October 29, 2019 by Andydodge Quote Link to comment Share on other sites More sharing options...
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