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74 Yj Spring Conversion Question

Discussion in 'Intermediate CJ-5/6/7/8' started by Ol Fogie, Dec 15, 2019.

  1. Dec 15, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    I am studying the archives preparing to change over to old man emu yj springs on my 74 cj5. For those who have done this conversion specifically on an intermediate. Has anyone had alignment problems with the factory frame mounted shock mounts being out of alignment with the spring plate mounting pin because of the wider yj springs? Have not seen this mentioned in any of the install discussion threads.
     
  2. Dec 16, 2019
    47v6

    47v6 junk wrecker! 2020 Sponsor

    Washington DC.
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    I did not do this on a intermediate, but I did do it on a 1974 D30 axle. The spring perches are too narrow to fully support the YJ springs, so I cut those off and welded on the correct ones while giving me 7* caster. I did have issue with shock clearance and a stock style spring mount. I had to install my front shocks upside down to get the clearance.
     
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  3. Dec 16, 2019
    bigjohn

    bigjohn Member

    Kelso Wa
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    I did the 76+ cj airings in mine. You'll need the wider spring plate so I did the same, cut the stud off and welded it onto the new one. Also to take full advantage of the softer springs, you may consider the ford f250 shock towers that allow you to run a longer shock and I think it pushes the upper mount out a bit.
     
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  4. Dec 16, 2019
    scott milliner

    scott milliner Master Fabricator

    Seattle Wa.
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    I used the original spring perches from my '73 D30 axle. I just tightened the u bolts evenly. Just bolt and go. I did have an alignment. All they had to do was set tow. Drives great even at 70 mph. I also towed it to California and back.
     
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  5. Dec 16, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    I am thinking I will change the spring perches to wider ones, not much trouble with the axles already off the jeep. Can any type shock be inverted or only certain types?
     
  6. Dec 16, 2019
    47v6

    47v6 junk wrecker! 2020 Sponsor

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    The passenger side perch is gonna need a larger radius cut on one side to accommodate the housing where it rides. As for shocks, I don’t o ow if others can be fun upside down. I decided I didn’t t care and it works.
     
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  7. Dec 16, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    yeah, if they work ok I guess it doesn't matter which end is up. Easy enough to try them both ways. did you use a conv. kit from rocky road?
     
  8. Dec 17, 2019
    47v6

    47v6 junk wrecker! 2020 Sponsor

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    No, I did not, nor would I. I have read here that they aren't always a perfect bolt on operation, and how could they be? The suspension will need a bit of tweaking to get it right where you want it anyway. One size fits all isn't always the best solution.

    If you have the ability to weld on new spring perches, you don't need a kit. I got all the parts I needed from chassis unlimited. Buy the springs of your choice and go. You will probably save 5~600 bucks.

    Also, the kit wouldn't help me anyway, as I fabricated my entire frame from 2x4 tube steel.
     
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  9. Dec 17, 2019
    Norcal69

    Norcal69 Out of the box thinker 2020 Sponsor 2019 Sponsor

    Northern California
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    Ive done two Yj spring installs. One RR kit and one home brew. No real reason to change the spring perches on the axle to wider. Both times I used steel caster shims that were the same width as the 2.5" springs. Bolted all together the springs/axle don't know the difference. JMO
     
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  10. Dec 17, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I have some experience here. A few years ago I installed an RR YJ kit with OME springs. Here are a few things I have trouble with. Shocks: I kept breaking lower mount bolts. Traced it to the shock length not being correct and the bump stops missing each other in full stuff mode. I already had a bump stop extension on the axle. I added a piece of angle iron to the top and made it longer so it will hit the rubber piece on top.

    Second issue. The center of my springs are 28-1/8" C to C. OEM spring perches are spec'd 27-1/2" C- C. While the original perches work just fine the width difference caused one of the U-bolt plates to sit at an angle. This is in the front. RR hadn't heard of this happening and had no answer. The problem seemed to be at the stationary mount end. Anyhow, I purchased a set of Currie perches, in the YJ spring size. I am currently welding them on to my axle this winter at the 28-1/8" C-C.

    As for the rear shocks, yes they are at quite an angle. I have toyed with installing a bit longer top mount that sticks out farther. Just haven't got around to commiting to doing this.. Rear shocks seem to work fine for now.
     
    Last edited: Dec 18, 2019
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  11. Dec 17, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    Thanks everyone for your replies. I am thinking at this point I will fab the stationary spring hangers my self along with some shock mounts and spring u- bolt plates. The shackle hangers and shackles I will get from Jim Crabtree. Self fabrication should make it easier to tweak alignment and location measurements of axles and hangers. Maybe save a few bucks too.
     
  12. Dec 17, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    Zila, I was hoping to here from you. I have read your entire spring conversion thread from start to finish and studied all of photos two times. I has been a great help in planning my spring conv. project.
    That is an interesting observation of the distance between the spring pack centers and the distance between the axle perch centers being different. They should have been the same. The distance between the centers of the frame rails from side to side and the axle perch centers should be the same, whatever that measurement is. I am wondering if the stationary end spring hangers are not centered on the frame rail. A bent hanger maybe. Maybe the axle perches were not properly spaced or located when welded on at the factory. Thanks for all your post and photos.
     
  13. Dec 17, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I dunno. The ones at the front where the shackles are is the correct measurement. The rear not so much. Kinda tapered. I am guessin the RR brackets are not right. I will measure to the center of the old spring hangers tomorrow..
     
  14. Dec 17, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    I will try and get some measurements from my 74 also, they should be the same. And maybe we can compare. My jeep is 30 miles away in my brothers work shop ,I will be over there sometime in the next day or two.
     
  15. Dec 18, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I had a thought in the middle of the night. I wonder if I have my brackets on the wrong sides. Will check later today.
     
  16. Dec 18, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    Well I checked.. The brackets can only go on the side they are made for.. Also C-C on the frame is ~27-1/2" as near as I can measure. I have the OME springs hung without the axle and get ~ 28-1/8 at the rear of the spring, locating studs and front. I have no idea why it is not 27-1/2" Going ahead with welding the new perches on.
     
  17. Dec 18, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    New spring perches will probably true things up well enough. Especially with all three measurements at 28 1/8 It is only off about 5/8 of an inch if I am correct according to your first measurements. Probably not enough to cause any problem. Just a thought, I have not actually seen up close one of the R R stationary brackets. Are they manufactured to mount so that the spring leaf center line will be in line with the center line of the frame rail, it should be. I did see a close up photo on your install thread of a bottom up view of one of the rear stationary brackets after you had mounted it. It looked like the spring would be pretty well centered to the rail, I would assume the front stationary would center up as well. I will be at my shop tomorrow and will measure my jeep, will let you know what it measures.
     
  18. Dec 18, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I do not know why the front doesn't seem to line up.. I am thinking maybe the bracket is a off a bit. 1/4" on each side gets it where I am now. Hard to tell from this pic

    [​IMG]
     
  19. Dec 18, 2019
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
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    Humm, from the looks of the R R bracket it appears it would have the proper offsets to center the spring and rail. You are probably right, a-little here a- little there ,maybe a little bit of twist in the frame rail you can't even see no way to tell. I would think you will never notice any problem when you adjust the locations of the new spring to axle perches. Go- fir-it. BTW just wondering how to know where to weld on the new perches to get the caster angle right without taking it to an alignment shop for the weld on? Maybe just weld them on in best guess location then tweak with shims per alignment shop check. I had looked at one of those caster checking tools a while back, finally decided to just let it be and just call the pros at the shop. I don't know how to handle it when I start my install. What do you think?
    Jim
     
  20. Dec 19, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I use a protractor that I have for my vocation. I am an electrician. I calculated the distance I have to move each perch. Then cut one off and remeasured, then set the angle to match the other perch and tacked it. Then I did the other side the same way. I am going to recheck my measurement with two plumb bobs before weld up. I'll post a pic later. I haven't welded it up yet, just tacked. I make knives and have been buried with Christmas orders..

    As for camber I am going to make some shackles in front that are 1/2" shorter and see how that is..

    [​IMG]
     

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