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Shortening Ford 8.8 axle

Discussion in 'The Hokey Ass Message Board' started by 23dragster, Aug 10, 2011.

  1. 23dragster
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    23dragster Member

    My T bucket has driveline vibrations. Turns out my rear-end pinion is off-center to the right (3") that it's causing driveshaft harmonics. I forgot about the offset when I built it. I am running an early 90's Ford Explorer 8.8" rear axle. I did some research and found that it "may" be possible to have the "long side" (left) of my axle-tube shortened by 3" and then just use two stock Explorer "short side" axle shafts. This almost sounds too good to be true. Anyone ever done it or seen it done? [/B][/FONT]

    P.S. The rear wheels are centered in comparison to the frame rails in my rod... The pumpkin and pinion are both offset in the original Explorer so the drive-shaft would clear the fuel tank. My driveshaft is about 20 inches long; this offset is too much for the u-joints. I am not sure yet if I have 28 or 31 spline axle shafts. I want the pinion centered and don't mind having the pumpkin off-center. I can't afford a Ford 9" axle. Thanks!

    Attached Files:

  2. Salty
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    Salty Member

    Yup totally possible....My pops used to do it on I believe Dana's out of....crap I forgot....an older SUV 4X4 of some sort....unfortunatly I was a kid and dont recall all of the specific details.
  3. 23dragster
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    23dragster Member

    Glad to hear it's been done before.
    I just measured the drive shaft and it's 14.5" inches with a current operating angle of 12 degrees. If I shorten one axle tube side by 3" and move the axle over 1.5" it will reduce the operating angle to 6 degrees. I wonder if that would vibrate or not.
  4. bobscogin
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    bobscogin Member

    I think if you do some research, you'll find that the recommended maximum angle is 4º or less. Not saying 6º won't solve the problem, but if you're doing all that work you may as well get it to within the recommended spec.

    Bob
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  5. 58fed
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    58fed BANNED

    Is it me or wouldn't you be moving the axle over the full 3" if you're only removing it from one side, in order to center the yoke? Make sure you're overall will fit between the body taking the 3" out of the width of the axle. I know that you could split the difference to the 1.5" to each side but that wouldn't center the yoke.
  6. aaggie
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    aaggie
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    I have a 2000 8.8" from an Explorer in my '40 Chevy and I think the pinion is only 1.5" offset. You might measure the later rear end and it will be easier to center after cutting 3" off. At least you will have disk brakes and 31 spline axles.
  7. 1950ChevySuburban
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    1950ChevySuburban Member Emeritus

    If you're in Tucson, I have an early '90s Ranger diff I'm not doing anything with.
  8. shagg'n
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    shagg'n Member

    did 2 short axle deal on my latest creation,worked out perfect...still ways from road test,but otherwise ok.Mine has 3.73/disc from exlplorer.I had people tell me to use c clip eliminators,but with disc's,even if axle breaks,cant really go anywhere,especially on street carGood luck:cool:
  9. need louvers ?
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    need louvers ?
    ALLIANCE MEMBER

    I have never done this with an 8.8, but it shouildn't be any different than with the 9" and 8" rears and I have done that several times. I'm sure you know that you will have to relocate all of your brackets and such on the axle for suspension and radius rods; right? after cutting them off and welding a second time, I would really recommend taking the housing to a good machine shop or axle shop and having it checked and corrected for straight... You would be suprised how much they warp from the heat of welding brackets.
  10. 23dragster
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    23dragster Member

    Thanks for the recommendation Bob; I'm actually planning on turning my panhard bar out just a tad to maybe remove 1 more degree, but that's as far as I can go; giving me 5 degrees u-joint angle, in order to still (theoretically) use stock axle shafts.

    58Fed: Well, I guess I mis-wrote that as I "want" my pinion centered, but I don't think I can move it all the way like this. I'm trying to figure if I goofed on the moving 1.5" or the full 3"?

    Thanks a bunch for the axle offer 50ChevySuburban, but I'm about 9 hours away, sadly.

    Shagg'n: sounds good, I like the positiveness here. =)

    Louvers: My brackets aren't a problem, I can re-do those easy enough. Once I cut them all off, I would have it straightened at a local shop (I don't have the machinery for that).

    I just talked to a guy that runs a frame shop, and he says he'll do it for $300, but I have to strip the axle housing, including taking the pinion out; which means I'd have to re-set my gears... This guy pushes the tubes out of the diff housing and re-does them. He said there are other guys that will just cut the tube and re-weld it; which means I don't have to remove my pinion shaft, which would save me $, but may not be as strong. Any thoughts on the strength issue if done the cheaper way? Choices choices.

    P.S. I'm running approx. 540 hp, but the rod is light and I can't mash the pedal all the way as it'll self destruct or go out of control.
  11. 23dragster
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    23dragster Member

    Oh and 58Fed: You are correct, the right axle will move inboard 3", which means I'll be moving my pinion 1.5". Thanks for checking that.
  12. 55chieftain
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    55chieftain Member

    Removing and reinstalling the pinion and carrier will not change the gears to where they have to be reset, only with a new crush sleeve the rolling torque will need reset. 6-15 in lbs on used bearings, 15-29 in lbs on new pinion bearings. Keep the caps and pinion shims in order and nothing will change. I always kinda glue the shims in first with some thick grease in the housing than install the carrier.

    If you spending that kinda money replace the axle ends with 9" big bearing and buy new axles. Recut and splines axles aren't as strong. Also the 31 spline is the same dimensions as a 9". Most van & truck 9" axles from the 70's used a 32 " axle" and cant be shortened less than 4"
  13. Jalopy Joker
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    Jalopy Joker Member

    so, you can't use another rear axle set up that is the correct width and pinion location?
  14. yule16met
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    yule16met Member

    The explorer axles are all 31 spline, ranger and mustang 8.8s were 27. I have a 8.8 in my car, runs great. Don't push the tubes out, way to much work. Just cut and weld in square. The 8.8 axle shafts are stronger than Dana 60 axles. Check out a jeep forum about them. The 8.8 explorer axle is a perfect fit in a wrangler and they make tons of aftermarket stuff for them now. If u get one from after 1995 they are disk and possibly posi.
  15. Safari-Tracker
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    Safari-Tracker Member

    I cut one down for my 64 falcon, I can say it was easy. I got a short side axle cut 3" off the long side put new spring perchs on and its been under my car now for two years no problems.
  16. 55chieftain
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    55chieftain Member

    Wouldn't it be easier and cheaper if possible to move the engine over? I have a 91-94 8.8 explorer in my 55 and don't have any driveline vibrations because of angle. Both my pinion and trans angles are equal and the side offset doesn't affect mine any.
  17. bobscogin
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    bobscogin Member

    Do the math. His driveshaft is 20" long. I'd think your's is quite a bit longer, thus reducing the angle.

    Bob
  18. Atwater Mike
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    Atwater Mike Member

    "Two short axles". I recall this trick. Some customers of mine in the '70s had some Galaxie rears they wanted to narrow "the easy way".
    One shortened the housing's long side and the short axle slid right in...he had a 460" with a 1/2" crank, DOVE heads, Crane, Edelbrock, etc. in a '56 Ford Vic.
    I told him to watch out, those axles had a 'set', and would 'unwind'. He said, "Oh yeah, right."
    He peeled off the axle in a week. (on the street) Another axle, another unscrewed spline. He and his bud then ordered axles from Summers Bros. ( $200, when Summers Bros. still had the shop)
    My illustrious brother peeled BOTH axles in his roadster pickup's Olds rear. (he switched them left for right, then had oil leaking from the axle seals. Removed the axles and the splines were twisted 3 splines, in the splined pattern. This made the side gears push the axles outward, bending the outer bearing plates.
    Stubborn brother insisted the splines were machined like that. "You can see it!" Hmmph.
  19. 23dragster
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    23dragster Member

    Thanks 55Chief, I can do preload as I've done it before lots of times; I just haven't set backlash in a long while.

    Jalopy Joker: Yes, I could, but I already rebuilt my brakes, I like my gear ratio and posi, the width is good, and this axle is strong enough (so far), so I limited myself to a Ford 9" or keep this 8.8. If there are other choices, that might work out too, but I don't know of any yet. If you do, I'd be up for more knowledge. =)

    Yule: The expensive shop-guy that would redo the axle-tube for me was going to push them out of the housing. He said others would do it cheaper than him if not his way, but he recommended doing it his way; he said it was a bunch stronger. I'm leaning toward just having a different shop do it and have them weld square like you suggested; then I don't have to strip my gears. If it's strong enough the "cheaper" way, it would save me a lot of time setting up my gears.


    Safari: Sounds good.

    55Chief: I would move my motor, but I can't as my headers already hit my tie rod when I turn, plus, my frame doesn't allow that movement in the rear (my steering box is .75" from trans). I think yours works well because your driveshaft is longer; mine turned out to be 14.5" from joint to joint, around 20" total.

    Right on Mike. I had that thought last night too, about stock axles having the forward rotational force make them only useable in one direction. At least I can order new shafts from Moser/Strange/Currie or some other axle-shaft place when it's finished.

    Thanks so much again guys; this really helps me out.

    So I'm thinking about just having a tube cut on the outside of the diff, shortened, squared up, and welded back up; instead of pushing a tube out. I woudl still be using C-clips and the original axle bearings so I can still use my brakes. Anyone know if doing it that way is "weak". and by weak I mean not able to handle 450hp with an occasional "punch" of the go pedal.

    The pic is old, but it's still the same axle.

    Attached Files:

  20. Kenneth S
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    Kenneth S Member

    If you were close to San Antonio Texas, I have a friend that has the jigs to shorten any just about rearend. He cuts the ends off, cuts a section out, then re-welds it, and never had any problems (even on 10 second drag cars).
  21. greazy john
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    greazy john Member

    i have a good friend that has done short axle 8.8 on several ... works great , currently have a 40 ford vert in the shop with a shortened 8.8 beautiful..

    GREAZY HUBCAPZ CC EAST TN
  22. 23dragster
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    23dragster Member

    Thanks Kenneth S! That's very reassuring as that's what I want to do. I'm in California though (which stinks).

    Perfect Greazy, glad to hear that works well. I'm just about sold on this plan. Now all I need is the dough for the new parts.
  23. yule16met
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    yule16met Member

    The only thing I would think of is the drum brakes, I have disks so I dont need the c clip eliminator. If you broke an axle your shaft "Could" walk out and leave the car with the wheel and the tire. If you hit the brakes hard you will blow the wheel cylinder and loose brake presure. Do you have a dual master cylinder for your brakes?

    I have an 8.8 in my rod and my jeep, I have done alot of work with them and abused the hell out of both. I run 35" boggers on one and I have done my best to twist an axle apart. There is an after market axle company that built an axle test machine, they twist an axle shaft until it breaks. They put out reports and the 8.8 shaft out of the explorer 31 spline shaft is stronger than the dana 60 which is super strong.
  24. Kenneth S
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    Kenneth S Member

    You could also talk to Moser Engineering as I know they would make you one axle short enough to where you can get the pinion exactly centered which I think you will really need since your driveshaft is so short. If the driveshaft angle is more than 3 degrees you will all ways have a vibration no mater what.
    Last edited: Aug 11, 2011
  25. coolbreeze1340
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    coolbreeze1340 Member

    Works great. The Mopar guys do them to use under A-bodies. It can be done at home if you can weld. You can check it all out at forabodiesonly.com. I don't know who first thought of using 2 short axles from the Explorer but they sure saved a lot guys a lot of money!
  26. 23dragster
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    23dragster Member

    Yule: True about the discs... I'm looking for a disc rear now and shorten that one while using what I have in the car for now. Are the disc brakes more powerful than the drums on these axles? I only have rear brakes on my rod (it's pretty old school). I have single-circuit master cyl with 1" bore. Currently requires a slightly-heavy foot to stop... then again that may be because of the 871 blower and stock torque converter... gotta give to get I suppose. Oh, and I think the drum rears have a "safety"-stop built into the slave cylinders to prevent them from exiting the bore should a shaft break.
    Nice about those shafts being so strong. Should handle anything I can dish.

    Kenneth: I would do that, but then I would have to have 2 custom axles made, have both tubes shortened, and it would end up being too narrow to use. I wish I could, but I think I'll have to live with a 1.5" pinion offset and 5 degree operating u-joint angle... until I save enough someday for a centered 9". I'm also going to turn my panhard rod out a bit and get it a tiny bit less angle that way too. No one will be able to tell that it's 1/4" off center... I hope.

    coolbreeze: I was thinking of doing it all at home; I weld well and my brother is a certified welder, but I'm not 100 percent sure I can line it up perfectly, so in the long run, it may save me having someone else do it. I hate sending stuff out, but I'm not 100 percent on the line-up.

    So far my steps are:
    1. Find a disc brake Explorer axle (which should all have 31 spline I think).
    2. Shorten one tube.
    3. Order one new Moser short axle for that side, then re-weld my axle brackets.
    Question on a new axle: Will a new Moser twist less than a stock shaft and send me sideways? As in; should I get 2 new ones? Or will it be fine?
    Also, with discs, that means I don't need a C-clip eliminator kit, since the discs would hold it on if it broke, right?
  27. Kenneth S
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    Kenneth S Member

    The stock axles are harder than the Moser axles so the stock axles takes less twist before they break. Racing, or street strip axles softer than stock axles. A stock axle may break with as little 1/2 of a turn of twist, while a racing, or street/strip axle usually can go 2 or more turns of twist before they will break. Racing gear sets are same way, they are softer than stock gears so they will bend quite a bit before they break, where a stock gear set will shatter. Moser will make you a custom set of 31 spline axles for $345.00, you will break the stock gears before you would an axle.
  28. 23dragster
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    23dragster Member

    Good to know, thanks.
  29. 23dragster
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    23dragster Member

    So now I'm looking at gear ratios.
    Currently I have:
    Stock converter in TH350 trans.
    Supercharged small block Chevy (lil over 500 horsies).
    Car weight: around 1700lbs.
    Rear tires: 28" steamroller tires.

    I want it to be able to take off without feeling it; like it currently does with the 3:73 gears. I have a choice though when I build the next axle: 3:73 or 3:55. It's about 5 percent change, around 140rpm, (3:73= 2909 @ 65mph. 3:55 = 2769 @65mph).
  30. Safari-Tracker
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    Safari-Tracker Member

    I got my short side axle from a supplyer on amazon it was around 100 doller shipped

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