Builds 77 FJ40 Build, It begins...and may take a while (2 Viewers)

[franklin40]

so i'm doing a little planning tonight. i need to build a new crossmember over the transfercase output shaft. the atlas hits it so i'm just going to move it. i want to build an antiwrap bar and wonder how close to the transfercase output the front shackle mount needs to be. i'm assuming as close as possible so it follows the geometry of the drive shaft. am i right in assuming this.

 

[White Stripe]

I ignored leaf spring arch geometry and hoped the soft long springs would somewhat conform to the traction bar ach. Their are a lot of write ups on traction bars on all the offroad forums to help u come up with a plan.

 

[franklin40]

i read a bunch of stuff and think i know where i'm going with it. i'm going to get the ruffstuff kit. easier than fabing it myself and frankly steel is expensive so this won't cost much more. i'm just trying to figure out where to put my crossmember so i can hang the front shackle. i know the top bar needs to
be horizontal and the bottom bar should be parallel to the drive shaft. i guess ill see where my crossmember will sit as far forward as possible without causing any interference.

now with a short rear drive shaft and centered rear diff the traction bar will be off set quite a bit to clear the diff housing. one bar is still adequate no? i'm not going to need something on each side am i?

i was thinking of mounting it on the drivers sideand ill put it right up against the diff housing.

 

[SuperBuickGuy]

Have I ever mentioned the issues I had with my rig until I fabricated a steering brace? no? my rig has a rigid frame that extends from the front links to the back links - thus boxing the entire center of the frame. Not just that but I fully welded the seams.... problem is, while not as weak a Jeep, it's still not strong enough.... don't lose the braces because you'll think your vehicle is a wandering pig (and it is) but it is soooo much better with the extra bracing. Why do I bring this up? put that cross member back in - maybe add some more strength by putting in a fully parameter bolted skid plate....

 

[franklin40]

oh for sure skid plate going on for sure. that cross member needs to be moved. not removed. my transfer case hits it so i'm just moving it. totally agree it's needed. i'm just trying to figure out where to put it so i get the best position to hang the anti wrap bar from

 

[64Rotorhead]

Are you planning to box your rear frame?

 

[franklin40]

no (maybe) because i was planning to build a bumper that is built like the 4plus ones for the 60 series. it would fit inside the frame rails and have a built in crossmember. i might just box it though and go with the actual 4plus bumper that bolts on the the crossmember. an extra crossmember might get in the way of the fuel tank i am using (downey plastic one)

 

[franklin40]

some parts showed up today. hopefully the rest tomorrow.

i got some new super beefy spring plates and and heavy duty antiwrap bar from ruffstuff. looks very strong.

 

[franklin40]

just pure beef!!

 

[White Stripe]

Wow that is beefy

 

[SuperBuickGuy]

that looks really nice

 

[franklin40]

little by little. mm by mm. noticed my spring hangers weren’t perfectly parallel so i’m working that today so i can get my spring perches in place. i’m going to buy some tube tomorrow so i can bend up a new cross member and then i’ll be able to start mocking up the antiwrap bar! a friend lent me his tube bender!! new toys to learn to play with

 

[franklin40]

rear axle mocked up. has anyone ever mentioned that the pinion center isn’t the center of the diff housing? my center bolt on the housing is perfectly centered between the springs but the center of the pinion flange is 1.5 cm off set!! this makes my rear drive shaft a both drop and offset a little. i guess the only way to make it perfect will be to shift my engine over 1.5 cm. not sure that’s all worth it.

i also pointed my diff right at the transfercase. high angle says they like 2 degrees down but i’m hoping with weight on the truck that’ll work
out to about 2 degrees down. i’m just racking things for now so once i get weight on the frame i can adjust. i’m hoping to avoid castor shims but they are always an option should i have vibration issues

 

[franklin40]

opinions please. should i mount my shocks on top of my axle as in the picture (stock top mount). or move my top shock mounts behind my cross member and mount them lower on my axle tube? big concern is if my fuel tank will fit if i move them. ill have to check

 

[Bripars40]

opinions please. should i mount my shocks on top of my axle as in the picture (stock top mount). or move my top shock mounts behind my cross member and mount them lower on my axle tube? big concern is if my fuel tank will fit if i move them. ill have to check
View attachment 1577544

I would mount them even with the bottom of the axle and as vertical as possible. Allows for longer shocks and better use of the shock valving.

 

[White Stripe]

I would probably wait until you get it running b4 doing shock mounts. Then you can see what room you have left for them after everything else is all set.

 

[franklin40]

thanks white stripe. that was kind of my thought too. i just want to cheat a little and get everything welded up so i can paint them. i don’t really want to assemble,disassemble,assemble etc etc. i guess with this kind of build i have to be willing to do that. i don’t think there’s room for them behind the crossmember once i set the fuel tank in place. ill leave them for now

 

[franklin40]

new crossmember bent up. it’s fun using a bender. as my first bend there are a few small wrinkles but nothing i’d be worried about. i used 1 1-2 inch tube because that’s the size die i have. it’s still pretty stout and shouldn’t be any weaker i’d think than the stock 2 inch one.

 

[franklin40]

cutting some plates to weld the new crossmember into for in and outside the frame the frame. my hole saw broke tonight so i’m stuck for now.

can someone tell me what bolted to the drivers side of the stock crossmember? you can see the bracket still on mine

i also tried to clock the atlas up a bit but it points upwards so it’s staying where it is. my rear drive line angles are about perfect. i was doing some reading of high angle drive line and they say a freeway driven truck shouldn’t be more than 22 degrees working angle. my workin angle is 22 degrees dead on. my diff is pointed up 2 degrees less than my drive shaft too. this is what they suggest. now my next question is should i keep it this way or will the antiwrap bar stop that 2 degrees of upward turn under power or is 2 degrees enough to worry about?

 

[franklin40]

ordered some new frame gussets for the rear corners. that should now be all the parts i need to get the frame done and ready for refinishing. im so glad to finally see this think moving along. just need a couple little tools and i’ll get that crossmember in and the frame gussets then mock up the front ford shock towers and then i’ll get all the welding done. maybe by the spring i’ll have the frame ready!!