eurojoe

So I have been posting on these forums for a but trying to figure out different issues with my truck and making it into the perfect work vehicle for what I do. I am working on this specific truck because I inherited it from my grandfather so it was free, If I could choose any truck I wanted from the get go and had a million dollars I'd choose exactly what I wanted (like anyone else) I had another thread that was very general and after many weeks I finally decided exactly what I want to do. I got a few questions so I can make the most cost effective and resourceful decisions. My goal is to increase my payload and safe handling for my work. I am not trying to haul tons and tons on a 4 cyl gas engine, but I do want to be able to carry semi-heavy loads without worrying about damage on my car or my self. I want to overbuild my truck to carry 1,500 MAX and 2,000 on a rare day driving slowly a few miles.

Speaking about the chassis, what is the main difference between 1/4 ton and 1/2 ton and 1 ton toyota pickups? Is it stronger axles and beefier springs? Are all the frames the same? I dont want to convert my truck to a 1 ton and the frame or engine cant take it and I dont want to change my rear axle to a 1 ton if my 7.5" diff axle is almost as good.

My trucks specs are 22re automatic trans 1989 DLX cab
I have a F304 axle (7.5" - 3.7 - 4 Pinion) It's what my sticker says (see pic)
I have the 121.5" wheelbase (the longest one Toyota pickups have I believe)

Here is what I want to upgrade
1) Lengthen wheelbase so my rear wheel is at the center of my flatbed or past it ~6 inches
2) Chevy springs (via this write-up http://www.pirate4x4.com/forum/toyot...-swap-faq.html)
3) 1 ton axle swap?? not sure if I should or could do this

Here is where I need some answers
-Is there Toyota driveshafts measuring around 55"?
-What about a chevy or ford driveshaft at 55" and using conversion Ujoints? (I'd rather not spend the money on getting a custom one if I can just pick one up at a junk yard.)

I have a 4pinion 7.5" differential on my rear axle. Is upgrading to a 1ton toy axle (or a Ford 8.8) worth it for the marginal gain? Is the axle swap a MAJOR gain?
Should I just weld on an axle truss on my existing rear axle and call it good? Will that even help with downward force of weight on my bed?
NOTE: I have 5lug axle shafts and I plan to keep my rims and tires as they are NEW.

Basically, Im trying to find a driveshaft at the right length and trying to figure out what increases the payload on these trucks. Is it the springs? Axles? of course shocks and bearings need to be upgraded along with these things.

eurojoe

I realize having a diff at 7.5" with four pinions at 3.73 is rare or im just decoding wrong or have the wrong info

so i did the tire spin test, i'm even more confused now.

one 360 spin of the tire is 1.8 spins of the driveshaft. is there 1.8 gear? It seems so high.

flg8r22

iTrader: (1)

Joe, spin the tire two complete revolutions for gearing check. Also I had an 88 2wd that I put wheelie bars on for a truck show. The parts house didn't have wheelie bars for a Toyota so I bought a set for a Ford axle. The housing on the Toyota axle was about 2.5 inches in circumference larger than the Ford. I don't know if this translates to strength but it certainly was bigger than Ford or Chevy

mchapter

Have you weighed your truck empty? Your GVWR is 4550 right now, with the stock axles. Subtracting the empty weight from the GVWR will give you an idea of how much more capability you want.

Another thing to think about, if you do make changes to the rear axle, is that the front axle is also load bearing and may need improvement. My sense is that your truck probably weighs around 3500 or 4000 pounds, and that gives you a payload capacity around 1000 to 500 pounds. You may be able to do something simple like adding a leaf before needing to go whole hog for new axles and so forth.

eurojoe

Yes I believe my truck weighed in at 3550, from what I can tell my axle is the half ton. I probably wont be changing the axle unless someone gives me a real good reason. I might just weld on an axle truss to beef up what I got, is the truss even worth my time or is that for more direct damage on the trails?

I am going to be getting 3leaf chevy springs tomorrow for $100.

I also have a 1997 4runner in my backyard, going to go measure the driveshaft and see if its the size I need.

highonpottery

iTrader: (1)

These old trucks will hold 1500lbs

Personally if I were pulling lots of weight all the time I'd look into these mods:
- v6 or 1-ton rear axle assembly off a 2wd, to get 8" diff with stronger 4-pinion carrier and 30-spline axles. You could even do the 1-ton dually axle, which is a full-floater and 5-lug. If the 4runner is 2wd, you could use that rear axle.
- new leaf springs and possibly airbags to support different loads when empty/loaded
- brake upgrade to safely stop your heavier loads - larger brakes, possibly rear disc swap, larger bore master cylinder up front, adjustable brake proportion valve accessible in the cab, etc.

The front will also take more load, but luckily we have t-bars that can be adjusted or swapped for beefier or simply new ones.

Axle truss won't help you much - those are more for bracing the axle when you have heavy impacts like dropping off a boulder onto the axle or tire, which can obviously bend it. Your concern is from vertical loads capacity, most of that is a straight transfer downward through the bed supports, springs, perches, wheel bearings and tires, etc.

eurojoe

Ok i sort of figured the axle truss is for sudden impact rather than deadweight.

ive been looking for dually axles and i cannot find a one!

is the 4runner axle really stronger than the pickup axle? Seems surprising as one is a SUV and the other is a Truck.

i just bought Chevy Springs.

what about the 4runner driveshaft, is that one-peice? Is it ~55"?

eurojoe

Should I have gone with 3+1 springs instead ?

highonpottery

iTrader: (1)

Its up to you. There are many reasons why people would choose the Chevy leafs -- the main reason is their extra length and flexibility for offroad articulation, not really for weight capacity. The major downside is you have to weld on new spring perches to install them.

For extra weight capacity I personally would have went the route of 1) add airbags between axle and frame 2) install an "add-a-leaf" or 3) make hybrid pack with full extra leaves from a donor leaf pack

eurojoe

I actually have an add a leaf on there already it causes my Springs to make a W shape .

I loaded maybe 600 pounds of steel and I was almost at the bump stops already . The stock springs are probably extremely old and overused. I figure these Chevy springs are going to be a whole hell of a lot better than what was on here before .

I own a family welding shop, so for me to re-fabricate is just another day. And while I'm there cutting off the perches I want to lengthen the driveshaft and put my wheels halfway on the beds depth.

I also like the fact that the springs reach out further back helping support weight that might be on the ass end of my bed limiting my steering control.

that's the thought process anyways, I appreciate the ideas you got though.

The forerunner I have in the backyard is a RWT and it's got a slightly larger tires with Six Lugs.

eurojoe

So i finally got around to it. Here is a day of dismantlings pics

eurojoe

PICS

the last one is the yoke i need to swap from the existing to my old driveshafts yoke. lets hope they fit up

ewong

There was a commercial truck repair shop near me (FlowRig - Conshocken PA) back in the 1990s

THey did "dump trucks" and stuff like that.
Anyway - they built a custom drive shaft using Spicer U Joints. Took at day or so. Really nicely built.

It might now be that difficult to source

http://www.rjflorig.com/contact.htm

eurojoe

So, Ive been having a hell of a time removing these damn bushings! Wow what a pain in the ass.

I just took my shaft to driveline in Sacramento, they did a wonderful job. Ill have pics tomorrow, and I am repainting my axle, also pics tomorrow.

I am building my spring hangers tomorrow as well, my questions is this.

When installing the axle, how should my shackle hang if my car is jacked up by the frame and the axle is hanging on the springs. So basically full droop, tires off the ground, axle weight on the springs. Should me shackle be vertical? Remember, i am not making this for rock-crawling but for carrying heavier loads comfortably.

Also, should I install my shackle upside to help carry more weight? Or is that a bad idea for such a small truck?

eurojoe

more pics

repainted the axle
got my upgraded driveshaft in and grease up
driveshaft installed
spring plates fabricated and primered

i extended my frame before and I made a weak joint so I am beefing up my joint with a 3/16" x 3" plate steel that I hammered a 45degree bend in to overlap over the materials drop in thickness

I ran into an issue. My U-bolts are too short!!!! I am so annoyed, will be running around town to get a new pair that is at least an inch longer

eurojoe

So i bought some u bolts for autozone, they wre 1/2" shank and i was a bit iffy about them being so thin. I tried to fit them and i dont like them, they dont fit snug on the axle. Too much play so i will return them and go to a real local truck hardware store.

its hard finding 2-7/8" diameter and 9/16" shank locally.

what is the stock toyota pinion angle? 0 dead level or is it pointed a degree or two upward?

upcoming pics of my spring hanger fabrication andfinal installation

eurojoe

I had custom U bolts made, really nice and they were a good price. I built some ugly spring hangers aswell since i dont have a press brake I had to weld them square but they came out great, they make full contact to the sides of the bushings which is real nice. Super tight fit. Tomorrow is the day i finally hang the springs.

eurojoe

Cleaned up my worksite so i can start the next phase with a clear mind

connected my welder to 220

patching my weak seam

eurojoe

I had stop and help my dad CNC out some lettering for a front door they are making. I took advantage of setting up the CNC machine and decided to design and cutout some blank shock mounting tabs.
I left the tabs extra long and no hole so I can drill press them and cut them to my needs. The tabs for the shock to frame will simply be flat bar cut to length with a hole drilled in them. If I don't keep getting stopped to help everyone I might actually hang these god damn springs today.

Pics and video included

eurojoe

So I have put on the ubolts and I began shimming the springs upwards until the hangers I made have met my frame.

I now notice my driveshaft is offcenter (from left to right) because my axle is offcenter (the actual pinion coming out of the pumpkin). Also it seems that my pinion is lining up at a 0 deree angle with my rear driveshaft.

Should I change my hanger height so that I can change my pinion angle to be parallel with my front drive shaft? I am not sure what works best for my application.

Should I be worried that my rear driveshaft is angled to my passenger side 2-3"??