Coil-Spring Conversion
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Bits and pieces to make me go further before I get stuck
After several years with modifications on the leaf springs, I decided that something radical had to be done to get what I wanted. The leaf springs suffered from a lack of articulation that I felt could not be achieved without extensive modifications and much custom work. Also I had a serious problem with axle wrap in the rear that only could be helped with locating arms or stiffer springs. And stiffer springs are not any good if articulation is the goal. |
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I though of several things that could help me get what I wanted like custom made soft leafs in a spring-over setup in front, and soft springs with relocated revolving shackles in the rear. Also quarter-elliptic springs in the rear together with trailing arms could do the trick.
Common for all the setups where that they required heavily modifications and I would still have a leaf sprung Jeep with all the limitations that leafs have.
Coil Springs
I have always liked the way coil springed vehicles handled and I decided that I wanted a coil-spring setup on my Wagoneer. I also came to the conclusion that it wouldn't be any more work converting to coils than it would have been getting leafs that worked the way I wanted them to do.
The ideal would be to use coil-over shocks like Bilsteins , Fox or King, but the price tag on those quickly made me look for another solution. I had already installed Rancho RS 9012's that I was very pleased with, so I decided to continue using them together with coils. Maybe I can switch to coil-over's at a later stage, but for now a regular setup will have to do.
I did not want to make all the work on my Dana 44 axles, feeling they were a little bit too weak for my driving habits. After searching for a while I found a set of Dana 60's that I felt were strong enough. They guy I bought them from had began a coil spring project on his own so I got some springs from him that I though I could use.
The coils I got with the axles where Old Man Emus for Toyota Landcruiser #OME 851 and some for Mitsubishi. The Mitchu coils where to wide to use but the OME 851 where OK for the rear. I found some OME's for Range Rovers that I could use up front. They are # OME 764. The spring rate for both front and rear is 220 lbf/in.
The Front
The springs are placed on the outside of the frame both front and rear. To make thing a little bit easier I used Range Rover trailing arms in front. This also makes the front suspension a bit more stable than 4-links would do because the design of the arms doesn't let the axle articulate too much.
I made location point on the underside of the frame for the arms and on the axle side they are located on the underside of the axle tube just like they are originally on Rovers. I could have made the arms longer to allow more flex, but I wanted to keep them original to aid getting licence plates on the Wag.. I intend to use this setup for a while and then rethink if I need (and want) a 4-link in front.
I moved the axle forward as much as I could without relocating the steering box to increase the break over angle. The panhard rod is homemade using 1 1/2 inch DOM tubing with 0,22 inch wall thickness with ¾” chrome-moly rod ends like I use in all the other linkage on the Wagoneer.
I spent many hours cycling the front suspension before I got the location of the shocks and the steering right, and I ended with the Ranchos mounted straight right in front of the coil springs. This will give me the travel of the Ranchos that have 13” between compressed and extended. The hoops that I fastened the shocks onto are the same that I used with my leaf suspension but the points where the shocks bolts to the hoops are changed. The hoops are also connected with a rod over the engine for stability.
Rear Suspension
In the rear I custom build a 4-link setup to have more articulation. The lower arms are 38,5 inches long and are fastened on the bottom of the axle without getting under the axle tube. On the frame side I made some brackets that are positioned right in front of the third crossmember so that I could weld them both to the frame and the crossmember to get more rigidity. I use National 3/4 inch chrome-moly rod ends for the linkage. I also boxed the frame from the brackets to the fourth crossmember.
The upper arms are located at the same brackets on the frame and goes to the top of the diff housing on the axle side. The upper arms are 36,6 inches long. With this setup I can make the axle stability sideways without using a panhard rod. The geometry of the arms is designed to let the pinion angle slightly difference as the axle moves up and down. Both the upper and lower arms are made from the same 1 1/2 inch DOM tubing with 0,22 inch wall thickness as the front panhard rod. Also, 3/4 inch crome-moly rod ends is used here
The coils are located on the outside of the frame and the upper mount is made so I can run without any bolts. This will allow the spring to move from the frame at full drop. I don't know yet if this is the way I'm going to end up with, but at least I have the choice.
The shocks are located at the top of the axle and goes through the floor and to a hoop that goes from frame side to frame side. They are setup at an angle to further help travel. It is designed so I will get xx inches rear axle travel. I also moved the rear axle 3 inches further back.
Steering
The steering linkage is made from 1,3 inch DOM tubing with 0,33 inch wall thickness (overkill again) and I made new steering arms from 1" stainless steel. This was done to help angle of the steering rod when the axle is at full drop. I also located the tie-rod to the new steering arms so that it was a little more protected from rocks and such. The steering arm has two bends to further help angles. I used the original pitman arm but bored it out to use rod ends instead of ball joints. 3/4 inch chrome moly rod ends is also used here.
I intend to use a hydraulic ram to aid the steering at a later stage, but mechanical will do for now.
Did I Like It ??
The suspension turned out to be very good. I had some trouble with the front suspension at first, but after I adjusted the caster down to 6 degrees instead of 9 it turned out OK. It flexes very well off-road and behaves civilized on the street. The only real problem is the Swamper tires, they are the worst tires I've ever driven on the street. They can't be proper balanced and they take forever to warm up so the flat spots disappear. They are very good off-road, so I think I'll keep them for now. I have not driven it alot, but during 2003 I hope to get some major testing done. And get some pictures of the Wagoneer in action..
Questions ?
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