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Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
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post #1 of (permalink) Old 04-22-2009, 10:49 AM Thread Starter
 
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spring over axles/or under?

I'm building a 51 willys pretty much from ground up and I'm trying to decide what to do for suspension. It'll be lifted roughly 3" already but what are the pros and cons of putting the axle under the springs as opposed to on top of the springs. Right now I'm only planning on running 33" tires but I eventually plan on moving up to 35's after I get axles that will hold up to that much weight.
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post #2 of (permalink) Old 04-22-2009, 11:11 AM
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When the axel is under the springs, torque applied to it by braking or power has a strong tendency to twist the leaf springs into an S shape, which causes problems with the drive shaft U-joints, and with the steering linkage in front.

The common methods of dealing with that tendency is to build beams rigidly attached to the axels and extending towards the transfer case, using exceptionally stiff spring packs, or extra long spring plates sandwiching the spring pack. Probably the best cure is the torque beams since the other methods reduce spring flex and cause a harsher ride.

Unfortunately there are not many guys on this board that know a lot about modifying the older Jeeps like yours. What I do know is that they're pretty lightly constructed. Anything you do that increases weight, strength or power needs to be engineered carefully or it will cause something else to break.

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post #3 of (permalink) Old 04-22-2009, 03:27 PM
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If you are going to be getting bigger axles, I wouldn't mess with a SOA until then. Even then, what motor trany and t-case are you planning and are you planning full width axles? Your stock axles are narrow and your wheel base is short so I wouldn't go lifting it to much.... Mayby look into coils on the rear or even 1/4 eliptical so you can cick the back axle to the rear of the tub..
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post #4 of (permalink) Old 04-23-2009, 12:58 AM Thread Starter
 
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Thanks for the help, I'm dropping a crate 350 in, a scout t18-a tranny mated to a dana 20 transfer case, its got a dana 44 in the rear and a dana 30 up front but to minimize the short wheelbase a little i extended my 3a body 7.5" and mounted it to a 60' cj5 frame. I haven't decided what to switch the axles to but i want at least a dana 60 in the rear and at least a 44 in the front
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post #5 of (permalink) Old 04-23-2009, 03:33 PM
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You can get a GM 14 bolt a lot cheaper than a D60 for the rear. If the biggest tire you are planning on running is a 35, why not just front and rear 44's from a wagoneer ?

Are the axles in it stock or did you put them in ? Im thinking it should have a D41 rear and D25 front, That's what my 51 M38 has in it.....

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post #6 of (permalink) Old 04-24-2009, 04:32 AM Thread Starter
 
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the axles are out of a 70's era renigade running 3.73 gears so they really arent worth much, got any good places to buy axles?
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post #7 of (permalink) Old 04-24-2009, 06:08 AM
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The D44 is probably good enough unless you plan to beat the tar out of it. The D30 is weak, but I wouldn't replace it until it gave me a reason, unless you plan to explore miles from civilization by yourself. But I wouldn't spend any money on either of them. For 35" tires a D44 front and 14-bolt rear would be a good combo. I don't think you really need a D60 front because your Jeep won't be as heavy as a built CJ7.

As to where to get axels, the junk yard. Ford and Dodge 1/2-ton pickups from the late '70s to late '80s will have a D44 front with passenger-side drop. GMC and Chevy will have 14-bolt rears but you'll need to look at heavy 3/4-ton or 1-ton trucks. Full-width axels are going to be mighty big for a flat-fender. Narrowing a front is easy, a rear is a little more involved but not an impossible home shop job.

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post #8 of (permalink) Old 04-24-2009, 08:00 AM
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Look for a later 70's-80's GM 1ton. Should be able to find a GM14 bolt with a D60 front. The 3/4 ton's had 14bolt rear with a GM10 or D44 up front. Around here we can pic up 14 bolts for about $150 but the D60's are a different story. Just remember when you do a SOA, you are going to want to do a high steer set up and that can run into some $$$$ With a D44/GM10 front you will need to have flat top knuckles on both sides to do that, sometimes you can find the passenger side in junkyards but then you have to have it machined which means more $$$. I don't think the D60's have this problem, might be better off with a D60 front depending how much you can pic one up for. I think by the time I was done with the high steer, I was close to $500 for a GM10 bolt high steer. I had the axle, machined 44 flat top knuckles cost me about $220, high steer arms were about $120, then the tube was like $9 a foot for 12' and the bungs cant remember and then new rod ends and ball joints...
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