Flipping the Rear Springs

[Seth_O]

I am getting ready to drop an SM465 into my '69 FJ40. I will likely be using the classic cruisers adapter since it's much shorter than the AA piece. I am thinking about flipping my rear springs at the same time to move my rear axle back an inch or two.

I am looking for some feedback on the idea - in research on mud I haven't been able to find much about this specifically. The two items I am the most worried about are:

1. do I need to move my shackles to the rear as well? this seems like it would be a deal-killer, but I thought you needed to have a specific side of the spring linked to the shackle
2. would I need to move the shock mounts on the frame? Would this cause an unacceptable angle on the shocks if the axle moved but the shock mounts on the frame did not?

Seems like this would give me a longer wheel-base, re-center my rear wheels in the wheel-wells, and take care of the drive-shaft length issues I was likely to run into.

Anyone done this and know first-hand?

Cheers...

 

[66fj40x2]

Your shackles are already at the rear. You need the military wrap side of the spring to stay at the shackle end IIRC. Some springs have mil wrap at both ends (BDS & maybe CCOT come to mind)

Move the shocks to the other side of the crossmember.

What springs are you running and are you SUA or SOA? I gained about 3" with the flip with 4" BDS springs

 

[Seth_O]

Running OME 2.5" lift, SUA. How much of a PITA is it to move the shocks to behind the cross-member? Correct on the shackle-side, had it right in my head and it came out wrong in the post .

My concern is if there will be a performance issue if I de-couple the long side of the spring from the shackle. Looking at my OME's it looks like neither end has a military wrap - second pic down here: MAF OME Dakkar Leaf Springs

 

[66fj40x2]

Running OME 2.5" lift, SUA. How much of a PITA is it to move the shocks to behind the cross-member? Correct on the shackle-side, had it right in my head and it came out wrong in the post .

My concern is if there will be a performance issue if I de-couple the long side of the spring from the shackle. Looking at my OME's it looks like neither end has a military wrap - second pic down here: MAF OME Dakkar Leaf Springs

OME only have the mil wrap at one end, so your option would be to disassemble the spring packs flip the second spring that has the wrap and redrill it. The shock mount wasn't that bad. I drilled a new hole in the crossmember, ran a long bolt through, welded it to the xmember and mounted the shock. I don't have much experience with OME's so someone may have a better idea of what you'll need.

Goood Luck

 

[Seth_O]

Cheers Mike - appreciate your help......

 

[Cruiserdrew]

If you plan to stay spring under, I wouldn't complicate it further. Just keep the standard spring arrangement and don't move the hanger. If you do spring it over, then run wagon springs and move the rear hanger back.

 

[Cruiser Cruisin]

I have been running 4in Skyjacker flipped around for almost a year now. I had to put wedges under the axle to help with the drive shaft angle and moved the shocks to the back side of the cross member, All in all it was very easy to do and it moved my axle back 3 or 4 inches. It worked out very well with my alum. body wheel wells because they are cut out farther back then stock wells.

 

[AfricanToy]

why would you need to flip the second leaf spring?

what advantage do you get by flipping the rear spring packs?

someone says: it moved the axle back 3-4 inches

wouldn't that require a longer rear drive line?

would you do this on a stock 1973 fj40?

 

[yzftaco]

why would you need to flip the second leaf spring?

what advantage do you get by flipping the rear spring packs?

someone says: it moved the axle back 3-4 inches

wouldn't that require a longer rear drive line?

would you do this on a stock 1973 fj40?

1. Flipping the second spring lets you get the extended wheel base with keeping the mil-wrap side of the spring on the FIXED hanger (not the shackle hanger)

2. Longer wheelbase! Easier time out on the trail...

3&4. yes

5. Do it to any year FJ40...

Obviously if you don't have a rig that you wheel and are not afraid to get dents then you wouldn't do this mod....

 

[nuclearlemon]

while the "correct" way to flip is to move the military wrap and redrill the center pin, many have run for decades without flipping the military wrap. i wouldn't redrill a spring for that, i have seen drilling weaken the spring.

 

[AfricanToy]

If I had a stock 73 FJ40 which I drive around town and sometimes in the mountains; should I do this mod?

would the vehicle drive better on the highway too? @ 70 mph?

 

[mr_manny]

I think increasing a 40s WB is a good thing
checkout the search button when you get a chance, tons of info out there...

 

[hammerhead]

I too did the springflip by redrilling my second spring and moving shocks to the back of the crossmember. Easy to do and works great.

Improves trail ride and street manners.

Yes, requires longer driveshaft...

 

[green40]

Your shackles are already at the rear. You need the military wrap side of the spring to stay at the shackle end IIRC. Some springs have mil wrap at both ends (BDS & maybe CCOT come to mind)

Move the shocks to the other side of the crossmember.

What springs are you running and are you SUA or SOA? I gained about 3" with the flip with 4" BDS springs

I was wondering about the BDS springs, I run them and was thinking of flipping. Not having to disassemble and drill makes it a 1 banana job.
Thanks!

 

[66fj40x2]

...keeping the mil-wrap side of the spring on the FIXED hanger (not the shackle hanger)

Thanks I couldn't remember for sure.... been a while since I've looked at mine.

The disadvantage to a spring flip is you may have to widen the rear wheel opening and as Ige pointed out drilling into springs is not something I cared to do. Luckily I had BDS springs and those Pinnacle's Ige is so fond of .

That said, when I build my daily driver I will flip the springson it ...... if I don't do coils and links that is

 

[66fj40x2]

I was wondering about the BDS springs, I run them and was thinking of flipping. Not having to disassemble and drill makes it a 1 banana job.
Thanks!

I also removed the two smallest leafs out of my spring packs and they really softened up. If you haul a lot of gear or whatever you can try it removing one to see how it feels. Don't know if it'll cause the springs to wear out quicker but I hope to order some longer Alcans for the rear in a couple months.

 

[green40]

I also removed the two smallest leafs out of my spring packs and they really softened up. If you haul a lot of gear or whatever you can try it removing one to see how it feels. Don't know if it'll cause the springs to wear out quicker but I hope to order some longer Alcans for the rear in a couple months.

How long have you been running without the 2 leaves?
And how soft is it? I consider the BDS to be pretty stiff, but I've
never run anything to compare with.

 

[ohrly?]

pics pls when ur done, i want to see wether it has a tendency to love those of the same sex

 

[AussieForty]

Hey guys, why worry about modifying the std 40 series leaves?

Guys that I have spoken to in Australia flip the rear spring shackle hanger, moving the location of the rear shackle further rearwards - right to the end of the chassis rail basically. Just grind out bolts/rivets then flip and bolt back in with a few welds on top. Guys have used spring packs from either FJ55, 60 or 75 series trucks. You could then modify them to suit you application for height and spring rate. The amount of rearward shift then depends on spring used and the location of the locating pin from the front hangar - re drill as you please...

Hope this helps - my first post on IH8MUD!

 

[Chromed]

What about flipped frnts? Opinions???