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cturboaddict

1937 Plymouth Sedan Rear Springs

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The threaded boss in the chassis is attached to the chassis with rivets.........because the "threads" are the very shallow style that are also found on the front suspension bushes you could install the rubber or neoprene bushes and 1941 style shackles although as I mentioned earlier the threads would probably chew the bushes excessively..........but using the 1941 up style  bushes is certainly better than nothing for a short term fix...........andyd  

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Last year replaced the real springs on my 39 Ply. business coupe using Eaton Leaf Springs. and stock type shackles from Andy.  Were a perfect match with the stock springs.  Also purchased the U bolts from Eaton, were a little long and had to cut after installation. 

 

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Alright, I'm in a bit of a pickle here guys. I can't seem to figure out what is going on here, and maybe you guys could provide some insight. I'm sure it's something silly, but I gotta reach out for this one. 

 

So, when I swapped rears, (I put an Explorer 8.8 disc in) the Passenger side of the car was all of a sudden much higher than the drivers. I couldn't get the factory springs to settle for anything. I can't remember exactly how much higher, but was something like 2"+ higher. The passenger side U bolt shackle wouldn't rotate further into it's angle to stretch the leaf spring flatter for the life of me (I tried Jacks, extra weight, jumping on it, prying it, beating it, NOTHING). I spoke to McVey's Springs (the springking on ebay), and we chummed it up to be bad leaf springs. So, I purchased a new set. I got new polyurethane bushing for the rear portion of the spring. Drilled out the threads and put the poly bushing in both the back of the leaf and in the body. Made some custom shackles (well, 2 sets because the first ones were too large with too big of a radii) similar to the other ones in this post. Got them all bolted up slowly today, not tightening anything until I could put weight on the car. And here I am with the SAME ISSUE.

The passenger side of the car sits 1 1/2" higher than the drivers as seen in the photos below. Note the frame rail relationship to the top of tire. 
The passenger side shackle will not rotate any further with the spring attached. (Not the passenger side shackle photo and the drivers side behind it with much more angle).
When I jack up on the drivers side, the shackle rotates, the spring get's flatter and the axle advances vertically into it's travel. The passenger side will get to a point of rotation (where it sits now) and essentially just beyond that rotation it will begin to lift the entire car off of the jack stand. I'm sort of lost right now trying to figure out what to look for. 

I was going to bring the port a power in from work and try to force the rotation of the shackle thinking it's binding somewhere, but I can't see where. It was doing the same thing with the original U bolt shackle. Regardless---- HELP, what do you guys think?

 

Passenger Side

Passenger Side rail above frame

Driver Side

Drivers Side Tire Above Frame

 

Drivers Side Shackle Angle

Drivers Side Shackle

 

Passenger Side Shackle Angle (Note angle of Drivers in background)

Passenger Side Shackle Note Drivers Angle

Drivers Side Spring FLAT when jacked. 

Drivers Side Spring Flat

 

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I read this several  times and looked at the pics. It stuck me after many other thoughts , maybe the rear frame is bent??

It's is Not heavily reinforced on this frame in the rear.  Check for straightness, measurements, strings, etc. Find the original frame specs? Are the poly bushings lubricated?

Did not change much into the 50's Mopars that I have seen.

Other thoughts were to loosen all spring attachment bolts including the U-bolt shackle and try again.

 

Just my thoughts.  Best of luck!

 

DJ

Edited by DJ194950

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10 minutes ago, DJ194950 said:

I read this several  times and looked at the pics. It stuck me after many other thoughts , maybe the rear frame is bent??

It's is Not heavily reinforced on this frame in the rear.  Check for straightness, measurements, strings, etc. Find the original frame specs? Are the poly bushings lubricated?

Did not change much into the 50's Mopars that I have seen.

Other thoughts were to loosen all spring attachment bolts including the U-bolt shackle and try again.

 

Just my thoughts.  Best of luck!

 

DJ

The thing is, it was never this way until I pulled the original rear out of the car. Leaving the original leaf springs bolted in when I did it. Then shimmying the new rear in and bolting it in resulted in the variance. I've looked over the frame before, and never noticed any issues with anything. It's one of the reasons I specifically purchased this car. 

So, I went out just now and pulled a rough measurement of the front of the front bolt to the front of the rear bolt (to give me CL to CL of the leaf mounting holes in the frame). 
Drivers Side is 51 13/16", Passenger side is 51 15/16". I'm gonna chock up the 1/8" difference due to the vehicle being produced in 1937 and the standards weren't up to the same snuff that things are today in the terms of precision. (As I've discovered with other Frame measurements along this process. 

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I just went back out there and started with basics. I checked all tire pressures, Drivers side front was really low. All tires at the correct pressure, and I jumped on the car with no shocks attached on either side. The passenger side is now only 1" higher than the drivers. And when jumping the shackles functioned as they should rotating when the springs were compressed/bounced on. So the shackle isn't binding. 
Does anyone have an accurate frame dimensioned drawing I can start inspecting with. I'm just not drawing to conclusion how this passenger side isn't at the same height. The only additional weight that I would have in the car on that side right now is a steering column. The gas tank is a bit offcenter by design, but I don't think an empty gas tank or the steering column is going to cause 1" variance in rear suspension only. The front suspension matches perfectly. 

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Have you taken a good look at the front? If for some reason the front driver side is sitting lower then the front passenger side it would cause your rear passenger side to sit high. You stated you had to add air to the front driver side and that brought it to 1". What about the front tire size, Is the DS smaller than the ps? What's the current weight distribution of the front? Could be a couple things working against you like low ds tire pressure plus slightly smaller tire plus a little more weight on the front ds.....

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6 hours ago, Bbdakota said:

Have you taken a good look at the front? If for some reason the front driver side is sitting lower then the front passenger side it would cause your rear passenger side to sit high. You stated you had to add air to the front driver side and that brought it to 1". What about the front tire size, Is the DS smaller than the ps? What's the current weight distribution of the front? Could be a couple things working against you like low ds tire pressure plus slightly smaller tire plus a little more weight on the front ds.....

Yes, I checked the front. The front is level and everything checks out. Atleast from what I seen. I'm going to fine tooth comb it tomorrow and see really take a look at all of it. 

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Frame alignment charts and measuring procedures are in the factory service manual.

Did you try to settle springs without shocks? If pass. side spring hits something when you jack up the wheel, and won't flex any further, it is very important to determine what stops the flexing.

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2 hours ago, sser2 said:

Frame alignment charts and measuring procedures are in the factory service manual.

Did you try to settle springs without shocks? If pass. side spring hits something when you jack up the wheel, and won't flex any further, it is very important to determine what stops the flexing.

Shocks are not attached.  

Dont have the factory service manual

Shackles swing when bounced. It just returns to the higher height on the passenger side only. 

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Cturboaddict:

i have a pdf service manual, but cannot append it to a pm because it is 13+ mb, but only 3 mb is allowed. I will try to make a smaller pdf of the relevant chapter and send it to your forum mailbox.

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5 hours ago, sser2 said:

Cturboaddict:

i have a pdf service manual, but cannot append it to a pm because it is 13+ mb, but only 3 mb is allowed. I will try to make a smaller pdf of the relevant chapter and send it to your forum mailbox.

Received. But If by chance you could send me the whole thing, that would be great. I'll send you my email in PM. 

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2 minutes ago, Sharps40 said:

is one spring installed backwards?

No sir. They are correctly orientated. 

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well, then Id go back to pulling it all and checking relaxed arch and swing/binding in the shackels.   Also compair old leaves to new, etc, perhaps one old spring was dearched a bit for a bent frame, etc.   you problem is likely in the last change you made to the rear of the car.

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I'm at 7/8" difference after they have sat and multiple jumping/bouncing sessions. When I pull the body, I'll give it a good overlook for squareness. But I may have to adjust the passenger side only to get it to set right. Oh well, all in the fun of restoration. 

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Reviewing you May 25 posting to this thread I noted that your rear shackles are not in a "C" shape like mine. I would also be suspect in the quality of the springs you used, compared to the Posie springs I used.

If you review my original posting to this thread on 10-24-18, you will note that my rear shackles are "C" shaped which places the spring close to it's original position, just barely clearing the frame crossmember.

Edited by blucarsdn
added info

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Eaton Detroit Springs on Michigan Avenue right off Rosa Parks Blvd.  These guys are artist and can make the originals.  We used these guys (we could pick up so no shipping) and they called us to confirm all the modifications for weight changes and then asked us how we wanted the hight to ride relative to OEM before making the front coils and the rear leaf springs.  Highly recommend if your still looking for springs.

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Eaton Detroit Springs on Michigan Avenue right off Rosa Parks Blvd.  These guys are artist and can make the originals.  We used these guys (we could pick up so no shipping) and they called us to confirm all the modifications for weight changes and then asked us how we wanted the hight to ride relative to OEM before making the front coils and the rear leaf springs.  Highly recommend if your still looking for springs.

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Eaton Detroit Springs on Michigan Avenue right off Rosa Parks Blvd.  These guys are artist and can make the originals.  We used these guys (we could pick up so no shipping) and they called us to confirm all the modifications for weight changes and then asked us how we wanted the hight to ride relative to OEM before making the front coils and the rear leaf springs.  Highly recommend if your still looking for springs.  I see I'm late on this now.  Sorry

Edited by NickPickToo

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