Spring flip Q's

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Joined
Aug 8, 2008
Threads
3
Messages
18
Location
Edmonton AB
alright so...first things first, the reason....was wheeling my dd ('81 BJ42) came down a steep rock face and almost endo'd my truck so...for my FJ40 that i currently have apart for upgrades i am thinking i would like to do a spring flip on it...questions are:

-what are the best springs (rears), i have: 40, 55 and 60 springs kicking around my place...i would have to mess around with the bushings on the 60 springs but not with the 40 or 55 springs correct?

-when doing a spring flip in the front to i HAVE to go to a ford shock tower, or will stock ones suffice?

-the military wrap...how critical is it for this wrap to be on the fixed end of the spring. i have read conflicting opinions in my searches.

-what are the pro's and con's of a shackel reversal? again, have heard conflicting opinions on this...some people who are knowlegable about cruisers dont really like them, though i cant remember why.

will i have to replace my shocks?

rig this would be going on is a '74 FJ40 with stock engine, SM420/3sp case going in, saginaw steering in already, stock height and a tendency to cut instead of lift...will be fitting custom tube fenders as well...

i have searched...for a few hours and will continue to search. Im trying to build this thing on a "budget" as in....im a student and have scrimped, saved and kept my eyes open for the cheapest parts i can find, been gathering parts for over a year to do these mods...i dont want to half ass it together...but at the same time if i can hold off on things like ford shock towers, all new shocks ect...i will until the summer when im working again.

thanks
 
front shock towers will work fine. simply mount the shock to the front insted of the rear of the tower . the rear shock mounts will take a little more work. stock shocks should be fine also. you will need custom fenders or cut the stock ones alot. i did this front and rear about 4 years ago. i love the performance but hate the look of my hacked up fenders:hillbilly:
 
I did the rear and left the fronts alone just flipped the shock mounts to the rear of the tube and stretched rear wheel openings.

Kyle
fj40 016.webp
fj40 014.webp
fj40 022.webp
 
ooops, thats actually my rig, question nd post....i was on a differnt computer nd i have recently gotten my sisters bf hooked on this site...he was still signed in.

for reference...here is what my truck looks like now...pulled apart

https://forum.ih8mud.com/hardcore-corner/235356-my-slow-40-build-up.html

thats as it has been for a few weeks now....

Kyot4x4- ur rig looks awesome, im thinking i might just cut the old crossmember out and weld in a new piece of 1 3/4 tube in...im pretty sure the po butchered mine doing his "restoration"

thanks
 
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alright so...first things first, the reason....was wheeling my dd ('81 BJ42) came down a steep rock face and almost endo'd my truck so...for my FJ40 that i currently have apart for upgrades i am thinking i would like to do a spring flip on it...questions are:

-what are the best springs (rears), i have: 40, 55 and 60 springs kicking around my place...i would have to mess around with the bushings on the 60 springs but not with the 40 or 55 springs correct? 40s are most common as that is what everyone has. 55s are a good swap, no need to flip (i believe) to get the WB.

-when doing a spring flip in the front to i HAVE to go to a ford shock tower, or will stock ones suffice? Ford towers are a cheap and easy swap. Extra travel is always nice. Not necessary, though.

-the military wrap...how critical is it for this wrap to be on the fixed end of the spring. i have read conflicting opinions in my searches. Personal preferance. I don't see the need for it, but I do see the reason for it. If you break a spring the wrap will keep the pack attached to the truck. If this happens would you rather have it attached at a fixed point or the shackle?

-what are the pro's and con's of a shackel reversal? again, have heard conflicting opinions on this...some people who are knowlegable about cruisers dont really like them, though i cant remember why. Cost is high, can be rock finders. Will need a long travel d-shaft to keep the t-case from being broken in half. They are in the front for a reason, keep the shackles stock length and you'll be fine. Lift springs do require longer shackles, though. Of course if its done right they can ride very well.

will i have to replace my shocks?

rig this would be going on is a '74 FJ40 with stock engine, SM420/3sp case going in, saginaw steering in already, stock height and a tendency to cut instead of lift...will be fitting custom tube fenders as well...

i have searched...for a few hours and will continue to search. Im trying to build this thing on a "budget" as in....im a student and have scrimped, saved and kept my eyes open for the cheapest parts i can find, been gathering parts for over a year to do these mods...i dont want to half ass it together...but at the same time if i can hold off on things like ford shock towers, all new shocks ect...i will until the summer when im working again.

thanks

Budget does not bode well for shackle reversal unless you can do it all yourself.
 
In regard to the shock position after flipping the rear springs, would it make any difference in moving the LOWER shock mounts instead of the upper ones? Right now they mount rear of the axle tube, so couldn't that mount either be moved on top of the tube or in front of it?

Just wondering, because I have an aux. tank and can't really move the upper shock mounts.

Thanks!!
 
Hi All:

Yes, I moved the bottom shock mounts after installing "flipped" rear 60 Series springs under my FJ40.

See post #8 in this thread for pics.

https://forum.ih8mud.com/40-55-series-tech/244901-any-pics-shock-mounts-rear-spring-flips.html

Regards,

Alan

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In regard to the shock position after flipping the rear springs, would it make any difference in moving the LOWER shock mounts instead of the upper ones? Right now they mount rear of the axle tube, so couldn't that mount either be moved on top of the tube or in front of it?

Just wondering, because I have an aux. tank and can't really move the upper shock mounts.

Thanks!!
 
i really dont know to be honest.... i think i will put my 55 springs in the rear at least....and then the question is kinda...do i want to open another can of worms and go at the front also...this truck is not a DD, it hasnt seen the road for a couple months now...its been apart and plans are to go for trail ability while keeping it street legal...ish, im thinking flipping the fronts as well would be benificial to off road performance...
 
Flipped my rear springs a couple years ago - neat tidbit- if you install an SM420 with a plate adapter, AND flip your rear springs, a 3spd front driveshaft fits the rear perfectly.

With my skyjacker 4" springs, my rear pinion angle improved to nearly perfect with the spring flip.

I'm flipping the front springs this week while I do a u-bolt flip primarily to reduce the rock-finding capability of my front shackles, and to transfer more weight onto the rear axle.
I also drive my 40 a lot on the road, and length helps highway handling.

Question- It's hard to tell by eyeballing, but does anyone know for sure how a front spring flip will affect pinion/caster angle? It doesn't matter if I find out the hard way, but it would be nice to know ahead of time.
 
In regard to the shock position after flipping the rear springs, would it make any difference in moving the LOWER shock mounts instead of the upper ones? Right now they mount rear of the axle tube, so couldn't that mount either be moved on top of the tube or in front of it?

Just wondering, because I have an aux. tank and can't really move the upper shock mounts.

Thanks!!

Make sure there will be enough clearance btwn the diff cover and the aux tank.


Yotawheeler: Take a look at the steering linkage with the sag box you put in. That will tell you how much you can move the axle forward before it binds the linkage.

The 55 rears will be about equal length WB to flipping your 40 springs.
 
i reversed the springs in the rear and do not have enough clearance for the rear tank. I will have to use the cab tank only. I think it is a good trade off.
 

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