Has anyone done this to their springs? (1 Viewer)

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Joined
Nov 17, 2003
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Location
South Pierce County, WA
I'd like some input and pro's/con's on the following ideas please? I value all I've learned from y'all.
I have a 66FJ40, 2F, 4spd, stock t/c, ps, extended shackles, air shocks, uncut, mostly stock and cleans up nice. I'm considering spring options for the next phase of my build which will include a set of 78 FJ40 axles with 3.73 gears and 33 x 10.5 or 9.5 tires if I can find them. Best options I've read about are the Skyjacker 4" lift or maybe HFS from CCOT. Favoring Skyjacker due to what sounds like a bit more flex and a bit softer ride for long trips to the trail heads. The other option I'd like discussion on mostly is whether anyone has put FJ60 springs under a 40. I've read about 55 springs, but I own a set of 60 springs. Thinking of putting a .080" strip of UHMW material between each spring for more flex ...seems like I read about someone doing that but could'nt find it in search. Search brings up a lot of good reading but not quite the details I'm looking for. So, who'se done this or has opinions on it? thanks tons!
 
Hi All:

I'd suggest swapping in a pair of later model axles that have 4.1 ratio diffs - 3.7s will be too high with a 33 inch tire, unless you plan on driving all day on the highway at 70mph!

Check-out the LCML archieves over at www.birfield.com. Jeff Zep of Colorado posted a cheap lift option that should work for you. He lists the part number for an inexpensive Rancho brand add-a-leaf insert that will firm-up and increase the arch of your truck's saggy stock leaf springs, and gives enough lift to clear 33s.

Good luck with your rig!

Alan
Seattle
 
There are several guys in my club that are running the FJ60 springs on their 40s and are very happy with them.
 
fj60 packs are a little wider, this makes them difficult to work with as the original hangers on your 40 are too narrow. I don't know exact numbers but I do know they are wider.
 
"Thinking of putting a .080" strip of UHMW material between each spring for more flex ...seems like I read about someone doing that but could'nt find it in search"

Not sure what UHMW means but a couple of spring makers, including the maker of the HFS springs, put a thin strip of some plastic material between the leaves. It's more like .030" than eighty thousandths, and someone, possibly JT, sells a kit of supposedly 'Teflon' strips to put into existing springsets. It should help a little for as long as the stuff lasts. I think .080" is too thick and would require a longer centerpin to keep it all together.
 
I tried the UHMW strip thing for a while. The problem with these strips is that the individual leafs in the spring pack also move laterally. After a short time the stips work out from under the springs or get all bound up at the spring clamps. I took mine out after a month.
 
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just call alcan and quit messin around. And do not get the 78 stuff. bad ratio and the birf's are morfidites...
 
The springs are not wider. the eye bushings are..
 
the teflon strips between the springs will shift out and be pretty worthless in a year....

painting with slippery paint (grain chute paint or the like) lasts the same amount of time, but at least ya don't have to keep cleaning up piece of teflon strips all the time :D

33 x 9.5 on stock rims won't need a lift, and stock springs flex great once the wraps are opened and the shackle hangers are relocated for improved angle...you "may" not need a lift to fit the 10.5 wide tires on stockers either...

78 IS a morph year (76-78 all are) but use what ya got....the 78 should have 4.11 fine spline tho, not 3.73...discs, odd birfs and knuckles, and is a good axle for 33's.

As a rule, extended shackles by themselves don't do diddly for flex....relocate the shackle hanger and they can help a ton tho.
 
I used this paint on stuff callled Slip Plate that is graphite dust mixed with paint stuff. It goes on thick as you like. I havent had my rig on the road enough to know really how well it works, but so far it seems pretty good. Its used in the rail road on the tracks, as well as on things like hoppers, dump truck beds, on the table and rollers that converyor belts slide over, etc. Read more here:

http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611786938&ccitem=

-Dustin
 
woody said:
78 IS a morph year (76-78 all are) but use what ya got....the 78 should have 4.11 fine spline tho, not 3.73...discs, odd birfs and knuckles, and is a good axle for 33's.

As a rule, extended shackles by themselves don't do diddly for flex....relocate the shackle hanger and they can help a ton tho.

I know I've read it a bunch of times that these 78 axles SHOULD have 4.10's in them, but upon inspection...3.73's. I got them from a real decent guy who had no reason to bs me when he said he removed them from his 78. So, could they be a late 78 type transition axel? He was pretty sure they weren't swapped by the po, but anything is possible. What should I look for to ID these. Most of my concern at the time of purchase was that there were disc brakes on the front. Can the axles be upgraded very easily or is it even worth it for trail use, light crawling stuff?

Got a line on some 4.10 thirds over on pirate. What years will swap into the asumably 78 housings? I can't confirm spline count at the moment as the axles are at the eastern wa shop, but they did look finer that the ones on my 66 pinions. Are there ony two styles?

OK, Bag the UHMW (ultra high molecular weight) material akaTeflon strips. Paint coating info appreciated! More info on the 60 springs???
 
two spline counts for pinions...

4.11's to "drop in" outta be from a FJ62 series....those'll be fine spline then...it's possible you've got an early 1979 axle in there.....

60 springs = 7" increased wheelbase, fender cutting, more....IMO, for 33's not worth the time/expense....if ya do, plan on 4" lift and 36's :D
 
Mace said:
The springs are not wider. the eye bushings are..

So what's the best mod for the 60 springs..wider hangars or narrow the spring eye? Or am I reading that it's just a bushing issue? Can they be modified or another type used? thanks!
 
woody said:
60 springs = 7" increased wheelbase, fender cutting, more....IMO, for 33's not worth the time/expense....if ya do, plan on 4" lift and 36's :D

I could be sold on that idea...I'll concentrate on axles for now maybe. These springs just kinda keep lookin' at me...maybe 35's, i'm kinda short! Thanks!
 
honk said:
Not sure what UHMW means...

ultra high molecular weight...polyethylene
 
amandap said:
So what's the best mod for the 60 springs..wider hangars or narrow the spring eye? Or am I reading that it's just a bushing issue? Can they be modified or another type used? thanks!


I have been working on mine. The 60 spring is 2 3/4" (if i remember right) wide. We cut a piece of 4x4 .250 wall box tubing. We made it extra long so that it could extend out of the already 2"longer rams by doing the 4x4labs power steering box set up. we made it overextend the horns by 2 1/4" so the front bumper (2x4 box tubing) can sit on it. We cut the spring hangers at nearly a 45 degree and am putting 1/4" plate on the front of this. Basically, no more blasting the front of the springs.

The idea is it will act as a slider for the spring hanger. Just got it welded up and will try to post a pic later. Good luck :D
 
amandap said:
I know I've read it a bunch of times that these 78 axles SHOULD have 4.10's in them, but upon inspection...3.73's. I got them from a real decent guy who had no reason to bs me when he said he removed them from his 78. So, could they be a late 78 type transition axel? He was pretty sure they weren't swapped by the po, but anything is possible. What should I look for to ID these.
Count the teeth on the pinion. If its 9 it is a 4.11:1, 10 its a 3.70:1. Both ring gears should have 37 teeth.
 
They're not right in front of me now but I believe they were stamped 3.73? Is this possible or is my memory fer s***? I'll check it out next week at the shop. thanks!
 

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