He does say he has a space limitation. So he will need to measure from the axle centreline to the furthest point behind that shackles can be safely pivoted from, then work his way forward. He probably could get a pair of custom main leafs [shortened 4-5" behind and the same "percentage" in the front] and remount the springs correctly.
http://www.generalspringkc.com/Leaf_Springs_Ford_Ranger_s/1879.htm Ranger spring is 25 5/8 front, 31 rear from axle centerline. OP flipped this around, so we're at 25 5/8 rear 31 front 2 3/8 width. 1100 to 1750 lb spring capacity depending on chassis. Let's focus on 25 5/8 rear and look at springs that match, considering the front mount is moved. 86- 97 Nissan pickup is 25 1/8 rear 22 1/8 front. 2 3/8 width. Spring rate not listed. So if the front mount can be moved back, these springs will work. Need to ensure that spring mounting does not change pinion angle, if it does pinion angle spring shims can be used. http://www.generalspringkc.com/product_p/69-147.htm 55 t bird springs are 25 1/2 rear and 22 1/2 front, no width listed, 760 lb spring capacity, might be a lititle light. http://www.generalspringkc.com/Leaf_Springs_Ford_Thunderbird_s/1907.htm 66-77 bronco is 24 front 24 rear, width 2 1/4, 1750 lb capacity. if both spring mounts need to be moved. http://www.generalspringkc.com/Leaf_Springs_Ford_Bronco_s/1880.htm This is a quick search, most of these springs are readily available in scrap yards to give them a try. Really depends if the spring mounts can be moved, the bronco spring may be the best shot
Lots of great suggestions! I can't go any further back with the shackles so I guess I need a spring with a shorter front half
The most important rating is lbs/ins [stiffness] You can have a softer spring with a higher load rating. manufacturers increase the load rating by changing the load height [the shape of the arch] so it can take more load for the same stiffness. You will need a spring that is probably 120 lbs/in and simply get the arch reset to the desired height. [ you can re-set the springs yourself with a BFH and deaf neighbours ] I would look at the 55 T-Bird springs for stiffness being close to what you want for desired ride quality. To get a comfortable ride , the car needs approx. 4-1/2" to 5" of load at the desired ride height [more on a luxo-barge] You need to weigh the rear, then pull the front and rear eye bolts to weigh the unsprung weight. once you deduct that you know how much weight is supported. Example a 3000lb car with 55/45 front to rear bias has 1350lbs at the rear 1350lbs minus 200lbs unsprung weight [guessing] = 1150lbs which is 575lbs each side. 575lbs divided by 4.5 [load] = 127.8lbs/in 575lbs divided by 5.0 [load] = 115.0lbs/in Example:Mustangs had rear springs rated between 85 and 153lbs/in
Old "real" traction masters did NOT have a movable front mount. The mount was a hard point, welded to the frame, single mount. And I had them on my OT 1967 390 mustang 4 speed with slicks and actually pulled the mount right in half. I would suggest making the front mount two pieces welded to the frame with space for the bar to be in the middle with a bolt going through both pieces. Made my replacement ones like that and it solved the pulling it apart problem.
Guys, I spent a lot of time on a creeper under the truck and doing anything with the relocation of the springs or attempting to get new springs was just plain too much work (at least right now). So, I decided on the "band-aid" approach, as some of you guys called it. I cheaped out and ordered the James Duff traction bars. I was sitting at my bench with a few Heims, trying to figure out a quick and dirty way of implementing something to stop the springs from winding up when I accelerated, and the $99 bucks they wanted for the kit kept looking better and better. I got the kit in a few days and it has a bushing at the rear end of the bar and a threaded section at the front. Since the bars were too short for my application, I got some 1/2-20 threaded rod, some jam nuts and a couple rod couplings from Mcmaster-Carr. This made it simple to modify the length of the rod. I installed the bars and, they worked beautifully! Since they install above the springs, you can't even see them unless the truck is up on a hoist. The lurch is gone and that Godawful sound of the springs groaning when I hit the gas is gone too. Time will tell if it was the best solution. But at least I can drive without fear of finally breaking a spring by wrapping them up all the time. Thanks for all the advice. I especially liked all the data about the various springs I could experiment with. I had no idea that info was even available!
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