Outer Limits 4x4 Board

Fj40, rear springs are stuffed.

grafting on fj55 rear springs, 3.5 inches longer (eye of the spring to spring perch is where teh extra length is)

measured up, if i move my axle back3.5 inches, diff pumpkin will hit the gas tank.

so,

there are 3 bolts/ rivets on the bottom of the chassis rails, which hold on the solid spring mount (not shackle mount) 1.5 inches apart, so if i remove these rivets, make the further most hole on the spring hanger line up with the middle hole in the chassis, redrill the front hole, effectively moving the spring mount 1.5 inches forward.

this only moves the axle back 2 inches once the 55 series springs go in.

this will clear gas tank.

rear shackles are vertical now, so the 2 inches further back will make them out to about45 degrees, so no prob there. no problem trimming the guards behind the wheel. the trimming in front of the wheel may allow for 35's once the axle is moved back 2 inches.

the front driveshaft on the 55 series is 1.5 inches longer than the rear shaft already in the rear of the 40, so i could use that untill i get my other one retubed/ lengthened, and the slip joint in the middle of the shaft should be able to cope with the extra .5 inch length.

bolting the front spring hangers on with strong bolts. i have read alot of US sites, SAE grade 8 sounds like the go, do we have the same bolt ratings?, if not, what is our equivelent bolt strength, so i know what to ask for at the bolt place.

new bushings, spring pins, u bolts etc is a given.

the spring clamps were buggered during the pulling apart of the springs, the plan is to get 4 mill thick box section, 75mm x 75mm, cut the top off it, making a U shape, to use to locate the spring (stop it splaying sideways). a hole will be drilled at the top of this, and a bolt/ pin used to limit spring separation onroad.

exaust should clear, if not, i'll cut it off behind the muffler, and have it exit into the wheel wells, or move the mount in a bit, it'll clear.

anything i have forgotten, this is my only car/ DD so i really want to plan for most eventualities, and this is the first time i am doing anything more than putting part A where part A should go

and i won't be around for a couple of days, so don't think i'm being rude by not responding, assume i know nothing, if there is something obvious, don't assume i knew it, and just didn't post

Grade 8 bolts are Imperial.If you want to use Metric go 10.9 grade.

Any mods to the chassis will require engineering. By re-drilling the chassis rail, you run the risk of moving the stress points, and ultimately cracking the rails.

I was looking at the 60s rear springs and moving the front shackle mount to suit, plate the chassis and go from there.

pics would be great when you get around to it.

sounds like a hell of a lot of unnecessary work. Leave the fixed front mounts alone. Get some springs that are longer than the 40's but shorter than the 55's. Check a toyota workshop manual or go to the wreckers with a tape measure and you should find some. They will bolt straight in. You can adjust leaves to suite your weight and flex. And dont forget that as the spring compresses it gets longer so it moves the axle further back. Keep this in mind for clearance with your gas tank. Or simply relocate the gas tank...
What is wrong with your curent springs? Longer springs are better, but 40 series springs can be made to work quite good.
Busiboy - dont touch the fixed front mounts!!! If you install 60 series springs in the rear remove the shackle mount at the back of the chassis, turn it around and weld it back on.

Redrill centre bolt hole on top leafs.

Bazzle

ok.

the 55 springs are about the shortest 4x4 toyota springs, that are longer than the 40 springs. i also have 55 series packs sitting here, for free, otherwise the swap won't happen.

the dif will clear normally, it's under compression (when the spring is at the longest point) that the gas tank will affected, if i retain the original frame hanger. moving it forward 1.5 inches will stop contact on full compression.

as i'm reusing 3 out of 5 original mounting points for the spring, i would have thought bracing with some plate would be enough.

the old springs are past flat, the rear is really low, and the springs below have worn 1/2 way through the main springs.



if i redrill the main leaf 1.5 inches forward of the original hole, will the original hole be any cause for concern strengthwise in the main spring.

sounds like an easier way to skin a cat (minus the little bit of lift i would get from moving the hangar forward) <--- i like this new idea.

or, would redrilling the spring perches to move the axle back forward be an OK option? i have read a little on breaking redrilled springs.

can anyone tell me how far i could relocate the axle by drilling the spring perch?