Joined: Jan 27, 2014 Posts: 151 Location: West Palm Beach FL area
Posted: Mon Aug 17, 2015 9:09 am Post subject: Rear Leaf Spring replacement problem
I bought a set of 9-leaf rear springs for my '51 restoration project, from a reputable source. They were marked "Crown A-614" so they are China repops.
One eye on each spring was small, and the other end slightly larger, but both were small compared to other replacement springs I have seen and used on my CJ2A. In the larger end was a proper M38 style of concentric metal and rubber pivot bolt bushing that accepts the 7/16" pivot bolt. The small end was too small to accept the M38 style pivot bushing, and way too small to accept the U-Shackle threaded bushings.
Is there a known problem with this Crown spring on M38's? Is there a better source for M38 rear springs where the spring eyes are properly sized??
BTW, the Crown A-612 front springs worked OK on the same M38 with the concentric metal and rubber bushing and the standard U Shackles.
Jeff _________________ 1951 M38 restoration project - Flightline Jeep MC 23923 DoD 6-51
1954 M-100 Trailer USMC Dunbar Kapple s/n M-750759 DoD 1-54
1947 Willys CJ2A - Harvest Green
1954 Ford F-100 Parts chaser - blueprinted Y-Block
Southeast Florida
I do not know of anyone to date making proper M38 repop 10 & 11 leaf spring sets. The pivot bolt size has always been the big problem between the M38 and the CJ's springs. The only solution is to make the bushing fit the bolt or the bracket fit the bolt.
When not interested in restoration accuracy I have always preferred simply going to a modern aftermarket performance spring set which generally has a modern spring rate curve giving a better ride. Also they will come with hard plastic bushings and you simply adapt the hole size to the bolts used. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Shackles are usually updated straight sided H type. The 1.5" lift Rancho system would be a good choice. Modern steel spring technology results in less leaves and a better ride while retaining the needed strength.
Jeff, I used those exact springs on my M38. I solved the problem by having them drilled out to the correct diameter. I don't remember what it cost but it was not very expensive. So that may be an option for you.
Joined: Jan 27, 2014 Posts: 151 Location: West Palm Beach FL area
Posted: Mon Aug 17, 2015 9:44 pm Post subject:
32sbct wrote:
Jeff, I used those exact springs on my M38. I solved the problem by having them drilled out to the correct diameter. I don't remember what it cost but it was not very expensive. So that may be an option for you.
Do you recall to what size you enlarged them? I imagine they need to be a little under sized to allow for the spring to "give" and also to allow for the bushing to cut the thread. I would just have to make a SWAG....
Jeff _________________ 1951 M38 restoration project - Flightline Jeep MC 23923 DoD 6-51
1954 M-100 Trailer USMC Dunbar Kapple s/n M-750759 DoD 1-54
1947 Willys CJ2A - Harvest Green
1954 Ford F-100 Parts chaser - blueprinted Y-Block
Southeast Florida
Jeff, I used those exact springs on my M38. I solved the problem by having them drilled out to the correct diameter. I don't remember what it cost but it was not very expensive. So that may be an option for you.
Do you recall to what size you enlarged them? I imagine they need to be a little under sized to allow for the spring to "give" and also to allow for the bushing to cut the thread. I would just have to make a SWAG....
Jeff
I don't. I took them to a local machine shop and they did it. I may have taken measurements from the original springs or I may have taken shackles with me for them to measure. I do remember that they said it was not easy and they broke several drills on the spring steel.
Joined: Jan 27, 2014 Posts: 151 Location: West Palm Beach FL area
Posted: Wed Sep 02, 2015 7:38 pm Post subject:
Here is an update on my spring eye problems...
I took the springs to a local truck repair facility that primarily works on large trucks and diesel engines, in Athens GA. They have a general machine shop in the back that does work like driveshaft shortening, and general engine machine work.
They looked at the springs and bushings and shackles and said that they would heat the eye and attempt to press in the pivot eye bushing on one end , and resize the other end of the spring to accept the U-Shackle. They warned me in advance that if it didn't work, or the spring broke, they would not be responsible. Given my dead-end situation with these spring, I gladly agreed to proceed at my risk.
Each process required heat applied to the eye to a dull red glow, then the eye was reshaped with a piece of steel tubing that would slightly open the eye. The spring was not quenched, and allowed to cool at room temp.
After the spring cooled, the pivot bushings were pushed in with a hydraulic press. I then took the springs back to my shop and the U-shackles engaged and threaded their way home perfectly. All seams well, although I have not put the jeep back on the road yet due to other issues.
The mechanic had done similar work to leaf springs before, and had not experienced any issues with temper or localized weakness. I guess time will tell, and since this M38 is not going to be a rock climber, I think the risk/ reward proposition is acceptable.
All the best,
Jeff _________________ 1951 M38 restoration project - Flightline Jeep MC 23923 DoD 6-51
1954 M-100 Trailer USMC Dunbar Kapple s/n M-750759 DoD 1-54
1947 Willys CJ2A - Harvest Green
1954 Ford F-100 Parts chaser - blueprinted Y-Block
Southeast Florida
Jeff, Thanks for coming back and telling us how it went! _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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