SOA Fj40 Questions - 55 Springs - "Measure twice cut once"
- Thread starter csd1982
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- Thread starter
- #22
Understood, thanks
Their are a lot of ways to attack a soa. I vote for the fj60 springs. As far as axles, stock fj40 axles are very narrow. If you compare a stock fj40 axle to body width ratio to modern trucks, the axles were much narrower than todays vehicles. It seems the trend is, if you take a new jeep for example, they have really wide axles, and then make up for that width so that the tires don't stick out by wheel back spacing. I personally like this concept because if you want a wider track width, you just change your wheels and then they stick way out. Right now I am at 63" wide rear, and like 61.2" front. I have wheels with only 2" backspacing. The stance is perfect for me, but I wish I didn't have to run wheels with that much backspacing. I think I would like to have ideally 64" front and 66" rear. Then run wheels with less offset, which would make for less scrub, and less stress on knuckles and trunions. As is though, I am nice and stable off camber.
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- #24
I assume you have fj80 rear? Is that true? Is the fj80 rear diff in a location that will work for my Orion T-case? Someone told me the Fj80 diff is a bit off from where the t-case output is. Is that true? If so do I need to run a double CV rear shaft?
Yes I do, it was the cheapest route to get disc brakes, a wider axle, and selectable locker. It is off by about 3 or 4 inches. I am using a common Toyota truck driveshaft that's been shortened. It's actually out of a gx470. Pretty much the same as a fj80 or 4runner driveshaft. It has single ujoints on each end. I used it because those vehicles have high angle ujoints compared to the stock fj40 ujoints. It would bind with 40 joints at full droop. I get a very slight vibration from the rear driveshaft between the transition of deceleration and accel. Its compressed length is about 19" with my sm465 using stock rear leafs that aren't flipped backwards. If I flipped the springs and lengthened the shaft 3 more inches, it would probably reduce operating angle enough to have no vibration. Ideally I should use a double CV rear shaft-it would fix the vibration totally and help reduce ujoints wear. But that could be a pain to fix on the trail. My operating angle is 22 degrees not including the offset angle. The vibration is barely noticeable and only by me not passengers and only between shifts at certain speeds, so I'm sticking with it. If u can keep the operating angle at or less than 22 then I would not use a double CV just for cost and simplicity. Plus I only drive my 40 3 or 4000 miles a year. Ujoints are easy to replace.
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- #26
Cool, I'm using the fj60 springs so I'll have 3" extra in the rear like you mentioned. I'll let you know how that works out next month.
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- #27
What did you do with the 80 e-brake? Remove it and use the fj40 e brake it did you hook the puller to the fj80 setup?
I'm just using the 40 transfer case parking brake. I never removed the parking brake from the 80 axle. Some day I may hook it up.
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- #29
Hi man what kind of shackle is that on the back there or how long is it?55 springs use different bushings than fj40 and different from fj60. My only real comment here is to try to match the springs so you don't have to go around collecting a bunch of weird sizes of bushings. SOR has them all though. My rig has fj55 rears in the front and fj62 rears in the back. It's silly-flexible at the expense of about four different bushing sizes.
If you move the axle back, I've got a set of these fender plates that will recenter the fender opening.
Here you can see the axle has been moved back:
Here you can see it recentered with the fender plates:
I'm looking at what shackles I want for my fj60 springs. I like my HFS greasable shackled for the 40 springs and SUA lift it has now.
So I'm thinking maybe to use them again but the fj60 version that are 2.5". I assume they are long enough to angle like what you have in the pick to accomidate the long fj60 springs when flat.
Any thoughts?
Sent from my iPad
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- #31
So I'm depacking and cleaning up these Fj60 springs I got now (sucks, takes forever but figure might as we, everything else on my FJ40 has been cleaned up a lot).
While doing this I wanted to see how much wider the Fj60 spring eyes are than the current springs I have on my Fj40. But when I put the Fj60 eye up to the current springs to see how much wider the 60's are they look as if they are the same width as the current springs.
I don't know what the PO did but my rigt is SUA and has 34's with no trimming. Lots of room.
See the pictures attached of the current front and back shackles. It even looks like the PO added some washers to make the hangers work with these wider shackles. Or am I just confused....I should have crawled under the rig to see the hangers on the frame rail as well.
While doing this I wanted to see how much wider the Fj60 spring eyes are than the current springs I have on my Fj40. But when I put the Fj60 eye up to the current springs to see how much wider the 60's are they look as if they are the same width as the current springs.
I don't know what the PO did but my rigt is SUA and has 34's with no trimming. Lots of room.
See the pictures attached of the current front and back shackles. It even looks like the PO added some washers to make the hangers work with these wider shackles. Or am I just confused....I should have crawled under the rig to see the hangers on the frame rail as well.
Cruiserdrew
On the way there
FJ40 and FJ60 springs are the same width. It's the spring eye and bushing sizes that differ. If you want to run 60 springs on an early 40 rear there is a special bushing that works-I can post Specter part #s if you need them. I think the bushing was originally for an FJ45 PU, but it has all the right specs for inside diameter, flange width and sprig eye.
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- #33
OK so the inside diameter of bushing and shackle where the bolt goes through is smaller on the fj40 stock hardware?
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Cruiserdrew
On the way there
So this is a long time ago, but what I remember is this:
If you use the OME spring pins, which are 15mm, there is 1 particular bushing with that inside diameter, the 1 3/8 spring eye diameter and a narrow flange width. But you have to use the OME FJ40 spring pins, which I think I got from Cruiseroutfitters.
The issue is the stock FJ40 spring hangers are narrow, and require this combination to all bolt up OK.
Mine have been running like this close to 10 years, and the bushings are finally wearing out, and will be replaced this winter.
If you use the OME spring pins, which are 15mm, there is 1 particular bushing with that inside diameter, the 1 3/8 spring eye diameter and a narrow flange width. But you have to use the OME FJ40 spring pins, which I think I got from Cruiseroutfitters.
The issue is the stock FJ40 spring hangers are narrow, and require this combination to all bolt up OK.
Mine have been running like this close to 10 years, and the bushings are finally wearing out, and will be replaced this winter.
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- #35
I can pick up a 96 rear Fj80 Drive Shaft I assume it will work with the 98 rear axle, right? I guess I will have to get it shortened?
You got a 98 axle? Out of a 100 series??
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- #37
Misstype it's a 97 LC not 98 or a Lexus, so yes fj80.
The rig has solid axles front and back, ABS and 4.10 gears.
I just got the rear axle and can get the drive shaft as well for 60 bucks.
The rig has solid axles front and back, ABS and 4.10 gears.
I just got the rear axle and can get the drive shaft as well for 60 bucks.
Yes that drive shaft should work. But if your operating angle is any steeper than mine, you may get too much vibration. You will have to get it shortened obviously but no biggie. I have weaker aftermarket ujoints in my rear shaft to act as a fuse. You will have to drill the tcase drum with new holes and move the studs to those holes. I just clamped the ujoint flange to the drum and drilled the holes. If you drill it just the right size, the splines in the studs will bite into the drum nicely and wont spin. One thing I did on the rear spring pads to keep ride height low is I ground the "c" to almost the flat of the spring pad but with still enough room for the spring center pin to not push into the axle housing. I also used a fj60 master and and booster. You may want to see if you can get the fj80 master and booster-that would work. You will be pleasantly surprised with the braking. Rock auto has cheap fj80 caliper hardware and boot kits(not the piston seals, just the slider pins and boots and brake pad clips), put new hardware and boots on and lube everything well, fj80 calipers get gummed up if neglected. I also bought a nice proportioning valve from racer65 to dial the brakes in here on the forum. Don't forget you will have to deal with steering also.
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- #39
Thanks, I pick up the rear axle tomorrow and was told the brakes are shot, all rusted up as you said from neglect.
Why would have to worry about steering? In going with widened fj60 front axle and lukes high-steer. So I should be OK there.
I'll look at the fj80 booster and MC. Would my fj40 booster and cylinder be strong enough for fj60 front disks and rear fj80? In 75 my rig was all drums. I have GM disk all around now in the stock 40 axles
Thanks again
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Oh that's right I forgot u mentioned your getting the FJ60 high steer so your good. If you already have discs you may be fine as is. You will likely need longer brake hoses from frame to axle too or just double them up with 2 short hoses.
