1937 Plymouth Sedan Rear Springs

[cturboaddict]

I'm in the process of an Explorer 8.8 rear swap during my build and was looking at a fresh set of rear springs possibly. 

Is there any factory springs that swap out with ours? Car is a 37 Plymouth 4 door Sedan. 1 3/4" wide spring. 

Or is there a good place to get a reproduction/aftermarket set?

[sser2]

No personal experience with these guys, but their price is good. Springs come with silent blocks and require later model rear shackles.

Plymouth rear springs

[cturboaddict]

23 hours ago, sser2 said:

No personal experience with these guys, but their price is good. Springs come with silent blocks and require later model rear shackles.

Plymouth rear springs

Yeah, I have this one saved. 

[cturboaddict]

23 hours ago, sser2 said:

No personal experience with these guys, but their price is good. Springs come with silent blocks and require later model rear shackles.

Plymouth rear springs

Which late model shackles are you speaking of?

[Plymouthy Adams]

Late model shackles are too wide for use with the early springs.   One must remember that the shackle bolts are welded to one side strap and open on the other for the strap to slip on and nut up... the shoulder of this bolt is for the diameter of the bushing inner hole...the threaded end is stepped down as is the hole on the matching side strap..the length of this shoulder is specific to the width of the springs...

Edited October 16, 2018 by Plymouthy Adams

[sser2]

OEM '35-39 rear spring rear shackles are screw type U-shape with grease fittings. OEM springs used with these shackles have corresponding threads. Later bracket style shackles do not have threads or grease fittings, they have rubber bushings instead.

OEM shackle

Later style shackle

 

[cturboaddict]

9 hours ago, sser2 said:

OEM '35-39 rear spring rear shackles are screw type U-shape with grease fittings. OEM springs used with these shackles have corresponding threads. Later bracket style shackles do not have threads or grease fittings, they have rubber bushings instead.

OEM shackle

Later style shackle

 

Gotcha, 

So those ebay leaf springs from springking would have to have a later style shackle as the ends are not threaded but bushed. I could just make these shackles instead of purchasing them seeing that they come with the bushings already. Or can you use the OEM shackles on the springking springs? 

[Plymouthy Adams]

I looked in the repair manual, not the best way to view these but all I have to reference seeing as my cars are 41 and up......the rear frame connector may be the limiting factor....and then again, could be modified to accept the later shackes...without seeing how it is made I regretfully cannot advise on how to begin this.  My earlier statement still stand for those springs as pictured, even modified, you need correct shackes and ones that are shouldered so to properly center and provide the proper squish on the bushings...

distances should be 1.980 to 2.000 between the side plates...

[cturboaddict]

Appreciate it Plymouthy Adams. I was just getting ready for the rear end swap, and noticed that the passenger side spring seems to have a wrap covering of sort on it. 
They don't seem to have any issues (sagging), but was curious if there was a factory set that could just be swapped out. In turn, just educating myself incase I decide to go that route. I'm going to get them off and sandblasted to see if there's any issues before I pull the trigger to purchase anything new. 

[Andydodge]

Up to and including 1940 the rear spring shackles are the screw in type....I've seen a number of the rubber shackles from the 1941 onwards supposedly to suit the earlier cars and yes the springs are the same width and yes the rubber bushes will fit however unless the threaded part in the chassis is removed then my thoughts have always been that the thread will chew up the rubber very quickly and thats why I haven't bothered to swap in the rubber in my 1940 car..........but it was interesting to compare the setup between the two years when I had the 1941 Plymouth sitting beside the 1940 Dodge............andyd

[blucarsdn]

I used Posie rear springs on my '39 Plym conv cpe.. They worked great, I have used Posie springs on several cars, with great success.

The original Mopar rear shackles present a problem due to the open U shape. We made up a set of C shaped shackles that gave us the clearance we needed on the rear cross-member and allowed the use of modern shackle bushings.

Edited October 25, 2018 by blucarsdn
spelling

[cturboaddict]

54 minutes ago, blucarsdn said:

I used Posie rear springs on my '39 Plym conv cpe.. They worked great, I have used Posie springs on several cars, with great success.

The original Mopar rear shackles present a problem due to the open U shape. We made up a set of C shaped shackles that gave us the clearance we needed on the rear cross-member and allowed the use of modern shackles.

Those look great bud! Just ordered all of my front end stuff from Fatman, I'll be digging into the rear here soon. 

[Andydodge]

Blucars....when you used the rubber bushings did you remove the threaded bos in the upper shackle that in the chassis?...........I've always been told & thought that the treaded area would chew the rubber shackle bushes out very quickly............andyd

[blucarsdn]

We removed the original shackle parts from the frame, which left a clean bore for the "Delrin" (plastic) bushing, same type in the spring eyes.

The rear axle under my '39 is a HD GM 10 bolt unit, (early Camaro) 54-1/4" backing plate to BP, same as '39 Plym. Engine is 330 hp SBC w/700R4 trans. We were concerned about axle wrap with the added torque of the AT and V8, that is why we used Posie springs.

Fortunately the early DPCD's have open drive-lines so the problems can be minimal going from a 6 cyln to a V8. Closed drive line vehicles can present huge problems with axle wrap when the closed drive-line is omitted and stock springs are retained.

[cturboaddict]

41 minutes ago, blucarsdn said:

Fortunately the early DPCD's have open drive-lines so the problems can be minimal going from a 6 cyln to a V8. Closed drive line vehicles can present huge problems with axle wrap when the closed drive-line is omitted and stock springs are retained.

What is a DPCD?

[Jerry Roberts]

Dodge , Plymouth , Chrysler , De Soto . 

[blucarsdn]

Through the early years of the Chrysler Corp and continuing through the late '50's, Chrysler referred to and marked all of the parts they produced as "DPCD". Mopar did not come into use until the big Hemi's, etc., came on the scene.

When I started to restore my '39 Plym in '96 I discovered that the majority of the original parts were marked DPCD. I did my best to make sure that when possible I would use nothing but DPCD parts.

According to my old Chrysler Corporation Parts & Accessory Books, dating back to 1939 there is no mention of "Mopar". The term Mopar appeared on the cover of the Master Parts List, 1936-1942, printed July 1946.

[cturboaddict]

12 minutes ago, blucarsdn said:

Through the early years of the Chrysler Corp and continuing through the late '50's, Chrysler referred to and marked all of the parts they produced as "DPCD". Mopar did not come into use until the big Hemi's, etc., came on the scene.

When I started to restore my '39 Plym in '96 I discovered that the majority of the original parts were marked DPCD. I did my best to make sure that when possible I would use nothing but DPCD parts.

According to my old Chrysler Corporation Parts & Accessory Books, dating back to 1939 there is no mention of "Mopar". The term Mopar appeared on the cover of the Master Parts List, 1936-1942, printed July 1946.

Awesome info. Thanks for schooling me. 

[Plymouthy Adams]

2 hours ago, blucarsdn said:

Through the early years of the Chrysler Corp and continuing through the late '50's, Chrysler referred to and marked all of the parts they produced as "DPCD". Mopar did not come into use until the big Hemi's, etc., came on the scene.

 

 

Mopar parts and accessories 'name'  had been long in use prior to the hemi arriving on the scene....

[blucarsdn]

On 10/26/2018 at 10:10 AM, Plymouthy Adams said:

 

Mopar parts and accessories 'name'  had been long in use prior to the hemi arriving on the scene....

 

True, "parts and accessories" not Mopar to describe vehicles... Mopar is an abbreviation of Chrysler Corp "Motor-Parts" and/or "Parts Division".

[blucarsdn]

DPCD will generally only appear on hard parts, bumpers, hubcaps, suspension, etc., Prior to about 1932 the letters DB for Dodge Bros can be found on parts used in other DPCD vehicles.

Another interesting side bar, Model T Fords prior to 1914 have a significant number of parts stamped with DB. A friend of mine has a 1913 Ford Model T that was an unmolested original car which he had put in storage for almost forty years awaiting the time to work on it. When he tore it down to restore it, much to his surprise he found that the rear end was all DB, except for the right axle which had been replaced at some point in time. My friend had to look high and low to find a DB axle for the car.

[Plymouthy Adams]

If not for the Dodge Brothers, Ford would not have had parts to assemble the cars ...remember, he did not invent the car...he just perfected to some degree the assembly line...

[cturboaddict]

On 10/25/2018 at 10:33 AM, blucarsdn said:

We removed the original shackle parts from the frame, which left a clean bore for the "Delrin" (plastic) bushing, same type in the spring eyes.

The rear axle under my '39 is a HD GM 10 bolt unit, (early Camaro) 54-1/4" backing plate to BP, same as '39 Plym. Engine is 330 hp SBC w/700R4 trans. We were concerned about axle wrap with the added torque of the AT and V8, that is why we used Posie springs.

Fortunately the early DPCD's have open drive-lines so the problems can be minimal going from a 6 cyln to a V8. Closed drive line vehicles can present huge problems with axle wrap when the closed drive-line is omitted and stock springs are retained.

Does the threaded boss in the fram just unscrew? Looks like I'm ordering a set of springs from fleabay, and I'll need to make this upper rear shackle connection. 
Just curious before I yank it apart..

[sser2]

The simplest way is to drill out the threads to the diameter of shackle's rubber bushings. It is important to properly center the rear shackles and to tighten silent block's and shackle's nuts only AFTER the car wheels are on the ground and full weight of rear end is applied to springs.

 

Oh, and btw, shackles with rubber bushings are service-free, while old style screw shackles need greasing at regular intervals.

Edited April 17, 2019 by sser2

[cturboaddict]

Gotcha. Just didn't know if it was a threaded insert or not. That's gonna need a big drill bit.