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Cj-5 Verses Cj-6 Ride Quality

Discussion in 'Early CJ5 and CJ6 Tech' started by oldtime, Apr 12, 2022.

  1. Glenn

    Glenn Kinda grumpy old man Staff Member

    Seems like there must be some unknown/underlying problem that exists with the shackle reversal since they stopped building them that way?
     
  2. oldtime

    oldtime oldtime

    Only two problems I can think of with shackle reversal.
    1) Nose dive when braking from high speed when on road.
    2) Increased off road speeds because of the smother ride leads to increasing damage.
     
  3. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Are the c-shackles set into the frame at the rear mount?

    Suggest it's a cost-reduction move. The military config was likely more expensive and time-consuming to produce than the familiar front-shackle mount with the stamped steel shackle plates. Plus it "solves" the dive-on-hard-braking problem, which may have been worrisome to civilian drivers. Possible the original rear shackle config was more about durability (ie no bent springs) and the better ride was only coincidental. Anyway, purchasers expected a Jeep to ride like a buckboard in those days. Military wrap went away too, as I recall. Part of continuing de-mil.
     
  4. fyrmn

    fyrmn Member 2023 Sponsor 2022 Sponsor

    I believe that my early 6 with shackles in the rear of the spring for the front, rides better than my 5. Could be wheel base, both have stock springs that I am sure have seen their better days. All possible contributing factors?
     
  5. Glenn

    Glenn Kinda grumpy old man Staff Member

    I'm sure eliminating the problems that arose far outweighed the benefits of them.
     
  6. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    De-mil to cut costs. Uncle Sam has deeper pockets and different priorities than the civilian purchaser. Different incentives for the two markets.
     
  7. oldtime

    oldtime oldtime

    Fyrmn,
    You have a very early CJ-6 with factory shackle reversal ?
    I expect those were only around in 1956 and 1957 ???
    Now that’s a rare frame indeed and I would certainly expect that it should give the best possible ride for a leaf spring Jeep.
    Maybe put a new set of BDS leafs on it and some soft shocks and wow that should be real nice on the road.
     
  8. fyrmn

    fyrmn Member 2023 Sponsor 2022 Sponsor

    Yes, it is titled as a 56. And had BDS on it for a short while. It sat nose down because of the reverse shackle. You loose a few inches in front due to the reverse shackle set up, being in the frame. The ride was good with bds, just didn’t want to go to the work to weld new spring perches on the rear front to level it. My stock spring packs are, 11 and 13 iirc.
     
  9. oldtime

    oldtime oldtime

    Awesome !
    I’m pretty sure the reversed shackles were all gone by 1957…
    1956 was the first year for CJ-6 and also the first year for the original rock crawler transmission ( Borg Warner T98).
    That might be the rarest of CJ’s if it had a T98A.

    If I was to build a reversed shackle cj-6 then I’d opt for a Dauntless and T18 Tera Low D20 with center flanged D44 in the rear. A truly road worthy and expedition over lander.
     
    Last edited: Apr 18, 2022
    givemethewillys likes this.
  10. jbjeeps

    jbjeeps Member 2022 Sponsor

    This is interesting. I have a '56 CJ6 with factory shackle reverse. I've been considering putting the BDS 2 1/2" lift spring and shock kit on it. I wasn't aware that the front end would be so nose down.

    When you say, "didn't want to go to the work to weld new spring perches on the rear front to level it", can you help me understand what that means?

    Also, are you using aftermarket stock springs or did you go back to the original factory springs that where on it?

    Thanks. Jack
     
  11. fyrmn

    fyrmn Member 2023 Sponsor 2022 Sponsor

    84B3644F-6104-4DC1-9BED-3701A95FF90B.jpeg ECF39614-B415-4668-A5B8-A3B8B6DC4F61.jpeg
    The left image of a 56 cj6 with front spring “reverse” shackle. Note that the pivot point is in the frame.
    The right image, 64 cj5 with “standard “ shackle” both pictures are of the front spring, the rear shackle.
    As Charles stated the “reverse” was around in 56 and gone by 57, or at least it changed. The solution would be to purchase and weld the attachment point to the bottom of the frame as in the bottom image. My guess is that since this difference only occurred for a short time, the spring companies were not aware of it, or chose not to address it. IIRC there is about a 3”’difference from the top to bottom image, in height. I chose to go back to the stock springs. Now with all that said. I don’t claim to be an expert, so it is entirely possible I have missed something. All I can say is that secondary to installing the bds springs, my front sat low. Welding the perch on the bottom of the frame is a quick fix, I just didn’t want to go there.
    I swear, with this stock set up and reverse shackle it rides pretty darn well. I hope this clarifies, that somewhat. Top=left. bottom=right. I guess it matters if your logged in or not.
     
    Last edited: Aug 19, 2022
    jbjeeps likes this.
  12. oldtime

    oldtime oldtime

    I notice that the 1956 has a set of the original “Eaton” springs.
    These two pics show that the distance from the bottom edge of frame to the pivot center appears to be essentially the same.
    Yes the reversed shackle design was changed after serial # 57548-25559 for cj-5
    and # 57748-12044 for cj-6.
    More importantly these early frames used different
    front leaves than those on the later frames.
    Presently I don’t know why they changed the suspension design and also the front leaf spring.
    I would have expected that the same front spring would suffice but apparently not…

    If anyone has an early cj-5/6 with original leaf springs we would like to know about those springs and how they differed from later front springs.
     
    jbjeeps likes this.
  13. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Do the post '57 leaves have the military wrap & grooved leafs?
     
  14. jbjeeps

    jbjeeps Member 2022 Sponsor

    Thanks for the great reply. I was thinking that was what you meant, now I understand. I appreciate the pictures.

    I have a Jeep with the BDS kit on and really like the way they ride. I have another one with a different brand of 2 1/2" lift springs that are horrible, ride like a buckboard. The springs that are currently on the "6" are pretty well shot, plus some homemade extended shackles by a p.o.

    Thanks again! Jack
     
  15. fyrmn

    fyrmn Member 2023 Sponsor 2022 Sponsor

    My 64 Cj5 are grooved but not military wrapped. I believe them to be original to the jeep.
    Question, were not the m38a1 “reverse” also and wouldn’t those springs interchange with the early civilian models with front “reverse”. ???
     
  16. jbjeeps

    jbjeeps Member 2022 Sponsor

    My '56 CJ6 is 57748 10xxx. It's led a pretty hard life so I'm not sure if the springs are original. I'll get some pictures next time I'm up there. Jack
     
  17. oldtime

    oldtime oldtime

    The original springs with a groove or channel through middle of the leaf are always Eaton brand springs.
    Personally I do not like the Eaton springs for a couple reasons.
    I very much liked the Mather springs.
    Yes military m38-A1 are reverse shackled so the springs would be interchangable to early cj-5/6 springs but likely be stiffer; having more leafs.
     
    Last edited: Aug 19, 2022
  18. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    To the best of my knowledge M38A1 units were the same as the civvy '55/'56/'57.5 "heavy duty" spring packs.
     
  19. fyrmn

    fyrmn Member 2023 Sponsor 2022 Sponsor

    Not sure if any of this matters, but here are the numbers that were on the springs of the 56 cj6 547DA569-DE7A-42F1-85BD-68B2E0911868.jpeg 9C1510A1-2E3A-43D6-BD66-DF054B6A75D0.jpeg 463CC741-7516-4AC3-B7BE-7D58DC82DF55.jpeg 9BA40B66-92D1-4FA3-962C-E359917FE8D3.jpeg
     
  20. danielbuck

    danielbuck Uncle Buck

    were the fronts originally grooved? I have grooved springs in the rear, and non-grooved in the front of my 56, the grooved ones seem to have held up better, the flat ones definitely are sagging, no sure if they are original or not.