60 springs on rear of 40 question (1 Viewer)

[youmustbecrazy]

Need opinions / suggestions. I have 60 rear springs that I am planning on using when I switch axle to a 60 axle and do a spring over. Have any of you done this and if so have you removed any of the spring leaves? How long a shackle did you use? I'm aiming for articulation, but don't want to have it too soft and deal with roll while driving on road. Thanks in advance

 

[Bret]

I just picked up a set of 60 springs for the same thing, but keeping the 40 axles. I'm curious about the same things. I am hoping to start by flipping the rear spring hangers and remove enough leaves to make them flat and and still account for a wrap bar. I am hoping the front springs will help with the body roll and the rears will provide the flex and softer ride.

 

[TBIFJ40]

Yes, the 60 springs will ride and articulate a lot better. There is no magic formula (weight of the truck, age of the springs, etcetc) when it comes to number of leaves and shackle length; youre just going to have to play around and tweak it a bit. DO use an anti-wrap bar, the kind with a shackle fab-ed into it, or you'll tear the springs up, especially if you take leaves out. Turns them into a nice "S" shape in no time! Dont be afraid to change things around if they dont work perfect the first time. Dont over weld stuff on intial fabs, in case ya gotta go back and grind the welds off and move stuff.

 

[TBIFJ40]

Bret has the right idea with the stiffer springs in the front limiting body roll. The wider 60 axles will also help with stability. When you position the springs, make sure that when under load the shackle isnt standing straight up and down; the eye of the rear of the spring should be further back than the shackle mount on the frame. Good time to move your rear axle back a bit, too. If the spring goes into a negitive arch during compression, the rear axle will move forward slightly, and the tire can hit that big square body crossmember. Just a few issues I dealt with.

 

[Cruiserdrew]

I'm running FJ62 springs on the back of my FJ40. It works great. There is some creativity in the bushings you need at the frame hanger. I posted part numbers way back, so they are here somewhere!

Don't take out leaves unless you travel with no gear. I actually added a load leaf to mine, since I travel pretty heavy (fridge, week's worth of gear, lots of spare parts etc).

I used stock FJ60 spacing for the distance between the spring hanger and the shackle hanger. That works perfectly. In fact, I left the frame hanger alone, and only replaced the shackle hanger which I moved back the proper distance. For the rear hanger, I used the hanger that Ruffstuff sells. Really high quality parts. I used this one: Way Back Shackle Hanger [0690070] - $46.00

 

[youmustbecrazy]

Thanks for the info, I usually travel light, but looks like experimentation will dictate. Appreciate the help

 

[mtweller]

Just dealt with Dan at RuffStuff for some parts - A++

Great service, great product. Will definitely use him again when I get the chance!!

 

[candograge]

fj60 sprigs all around

Ok guy im currently in the middle of putting fj60 parabolic springs on my sons 73 fj40 i will post pics . front is done and im working on the rear doing just as it has been suggested flibppbibng bthe brear hanger. Although i was going for more lift so i basicly droped the front spring 3 3/4 inches with a shakel flip.

 

[candograge]

sorry thats my squirrel must of slected wrong pic.

 

[youmustbecrazy]

Thanks for the pics!

 

[youmustbecrazy]

for those of you who have removed a leaf which one did you pull? Which should stay?

 

[csd1982]

I'm running FJ62 springs on the back of my FJ40. It works great. There is some creativity in the bushings you need at the frame hanger. I posted part numbers way back, so they are here somewhere!

Don't take out leaves unless you travel with no gear. I actually added a load leaf to mine, since I travel pretty heavy (fridge, week's worth of gear, lots of spare parts etc).

I used stock FJ60 spacing for the distance between the spring hanger and the shackle hanger. That works perfectly. In fact, I left the frame hanger alone, and only replaced the shackle hanger which I moved back the proper distance. For the rear hanger, I used the hanger that Ruffstuff sells. Really high quality parts. I used this one: Way Back Shackle Hanger [0690070] - $46.00

How long are your rear shackles and how long are the spacers? I just did my SOA with FJ60 springs and to get my rig level my rear springs I have mocked up are stupid long.

SOA Fj40 Questions - 55 Springs - "Measure twice cut once"

 

[Bret]

When I SOA'd with 60 springs in the rear to match my 2.5 SUA w- S/R in the front I cut the spring perch deeper where the axle tube rests and lowered another 1/2". Started by removing short leaves while running with no top, doors, etc. but put them back as soon as I put anything in the back due to draggin a$$ and horrid axle wrap. Final version was wrap bar, reversed rear hanger and 3/8" flat bar rear shackles. Also used spring perches with 3 mounting holes to allow a little adjustment front to rear.