I've been thinking about flipping my rear springs but had a couple of thoughts/questions:

1. How does it effect daily driving - I assume there is a reason the longer end of the leaf is on the shackle end.

2. I realize you need to move the upper shock mounting - is it best to cut the cross member and rotate it 180 degrees (cut, sleeve, and reweld)?

3. Will flipping the springs change the rear pinion angle enough (or at all) that it will matter?

Thanks for any input.

PS: reasons for the flip:
- Longer wheel base
- I want to keep my 4 sp since it is my daily driver, but, want lower gears on the trail - thinking Marlin toybox if the Orion case never shows up and therefore might want the extra room

1. longer wheelbase is nice. smoother, less bucking.
2. cut and spin tubular crossmember with a sawzall right against the frame bracckets. little kerf, so it is easy to bevel and use some rope to pull the frame together and weld away. No need to sleeve really.
3. yes, pinion angle will be affectively higher if you have already rotated it to aim at the t-case.

Originally posted by osteology
I've been thinking about flipping my rear springs but had a couple of thoughts/questions:

1. How does it effect daily driving - I assume there is a reason the longer end of the leaf is on the shackle end.

2. I realize you need to move the upper shock mounting - is it best to cut the cross member and rotate it 180 degrees (cut, sleeve, and reweld)?

3. Will flipping the springs change the rear pinion angle enough (or at all) that it will matter?

Thanks for any input.

PS: reasons for the flip:
- Longer wheel base
- I want to keep my 4 sp since it is my daily driver, but, want lower gears on the trail - thinking Marlin toybox if the Orion case never shows up and therefore might want the extra room

Brett,
thanks for the reply - for some reason, I thought the pinion would end up lower after the flip, incresing the angle with the driveshaft - am I just on crack or did I misunderstand your reply? Will it change enough that I need to change to a CV driveshaft for a daily driver?

Originally posted by osteology
Brett,
thanks for the reply - for some reason, I thought the pinion would end up lower after the flip, incresing the angle with the driveshaft - am I just on crack or did I misunderstand your reply? Will it change enough that I need to change to a CV driveshaft for a daily driver?


I think I typed too fast on the reply to 3.
there are some variables here, springs would be the first issue, but if you already have the pinion aimed at te t-case, and have flat stock prings it will be pretty close, but if you have tons o' arch skyjackers or something else, all bets are off, and likely it will change things quite a few degrees...

Guess this should have been in the first post: I'm SUA with OME springs, 1.5" shackles in the rear to compensate for the SR in the front. Currently the pinion angle basicly matches the driveshaft.

On the front shock mount, unbolt the shock mount bolt out of the mount. Then put it in the front. You will need to trim your finder well.

Also you may need to get your drive shafts lengthened.

Measure twice, cut once.

HTH,

sorry. im new to the fj40 world too, ( just bought an 81 last week for a 50mi a day daily driver) i want to run 35's and i do a lot of snow and ice driving living in the mountains so needless to say i would love a few more inches in the wheel base.i understand the pinion angle, trimming the fender to the rear and the shock mounts, but how do i do the actuall "spring flip"? i need a total of 4 or 5" of lift for 35's right? now its got 2-1/2" ome springs. any input would be greatly appriciated, j.c.