94 Crawler's sas thread #1

[94 Crawler]

Progress

I got the 9" built and under the truck. No thanks to the HF sand blaster last weekend and at liest a dozen trips to town today and ultimatly i still got the wrong brake line for the right side.:fire::fire:. To d&*^ many 3/16 line choices . I have the tires mounted to stock f-150 aluminum wheels and maby I picked up 1-2" of tire sticking out on either side. I checked the aussie locker It locks and unlocks as described.

Some idea of the clearence now that the spider is installed.

 

[94 Crawler]

One more pic.

 

[94 Crawler]

Ok question time. Dose anyone have any 90 ish F-150 aluminum wheels (stock) they are willing to part with? Bullet hole style (I need one for my spare). And I asked this in a nother thead but I will ask again. What methouds are those of you who are wristing your radius arms using to weld the mild steel to the forged arm? Pre heat post heat?

 

[Kirby N.]

I actually didn't build mine so I can't say how mine were built. I did go over some of the main welds with some 7018 rod and I checked all the welds for cracks from different cooling rates.

From what I understand, the issue is with cooling. When you preheat cast then it will cool and contract at a more near rate to the mild steel. I have also heard of insulating the piece during cooling so that they both cool slowly. I made some extended Arms for a buddy and I did not preheat his either. There was a ton of welding on those, and nothing cracked, but they were hot for an extensive amount of time because of the entensive welding on them. When I hav welded center sections to axle tubes I have seen and heard the welds crack upon cooling. I usually just do 2 passes and that fixes it.

The best design I have seen for wristed arms is a guy drilled an extra hole through the main arm and the extension pieces for a dummy pin. Then he inserted a grade 8 bolt and welded it in, and ground it flush for insurance basically.

 

[IZwack]

x2 what KirbyN said -- post heat is very important. When I shaved the 14bolt and MIG-ed it, I kept the torch on the cast side for like 5 mins afterwards and then slowly moved the torch spot away from the weld area over a 25 min of torch on and torch off periods.

 

[94 Crawler]

Thanks guys. I'm not actuly wristing it. At this point I think I would have been better off to wrist the axle. There is a lot of fab stuff I need including a torch and plazma cutter, and Tig welder, and well you get the idea.

I had been doing some research on building a forge. If I can source the parts localy I can probably build one cheap out of a steel 5 gallon can. That should let it cool slowly. Other ideas I had was fire up enough charcoal to cover it and let it cool like that. Any other suggestions?

 

[james t]

The stock radius arms arent cast like an axle centersection, they are forged. Post heat is not as crucial with forged steel.

 

[94 Crawler]

The stock radius arms arent cast like an axle centersection, they are forged. Post heat is not as crucial with forged steel.

But they still need pre heat right. And maby some fire retardent insulation to slow the cooling. I will also bolt it as a precaution. Arent the outer c's forged also?

 

[Kirby N.]

The stock radius arms arent cast like an axle centersection, they are forged. Post heat is not as crucial with forged steel.

Thanks for chiming in. I too would be interested in the proper proceedure (not that I have already done a few!!)

 

[james t]

I have welded all over stock arms in various ways over the years... never pre-heated nor post-heated. Ive also never had a weld break on them. By all means pre/post heat if it adds peace of mind.

FWIW i asked a guy at our local do it all machine shop about this years ago and his advice was "forged steel welds just like any other mild steel- clean it white with yer grinder and git after it".

 

[Kirby N.]

Hmm, I guess I am better than I thought, thats what I did! :scratch:

I will echo that it welds just like mild steel. I have a steel wire wheel on my grinder and I have been using that like crazy lately. Before and after every weld. It cleans off slag completely in nothing flat and prepares the metal quickly and completely. Handy tool

 

[94 Crawler]

Thanks James and Kirby I'll just weld them then with a good cleaning. More updates soon.

 

[94 Crawler]

Ok first here are some pics. A little progress, I got the radius arms built and the crossmember finished. The front end is in the truck mostly. I m still missing the right spindle and the break lines need to be hooked up. I need to flex it to find out shock location and build shock mounts.

Now for my question. It seams awfully stiff. If I put a jack stand onder one side and drop the other it only flexes down a few inches . Is this normal? Or have i some how managed to make it stiffer than stock? I'm using the 7 degree bushings (urathane) with ballistic joints at the end of the arm. Which are mounted just outboard of the chassis. The radius arms should be no wider at the ends than on a full size. Or do I just need to flex it and break the bushings in? Thoughts? Suggestions?

 

[HahnsB2]

From what I understand RAs act like sway bars, a lot of the flex comes from the c bushings, get some good weight on there it should force it flex more.
On a side note I'm about to finally swap in your old D35 pig

 

[94 Crawler]

From what I understand RAs act like sway bars, a lot of the flex comes from the c bushings, get some good weight on there it should force it flex more.
On a side note I'm about to finally swap in your old D35 pig

I'll keep working to get it done and check the flex then. Thanks Hahns. Any more comments?

 

[james t]

I dont think i understand your problem. Its stiff but doesnt have springs under it yet? The C bushings have nothing to do with articulation... there is virtually no deflection at the C it all comes from the joint at the end of the arm.

 

[Kirby N.]

they actually do have a ton to do with articulation. Your C bushings will always be in conflict in a non wristed appication. Even with axtended arms. In articulation, one side is compressed, one side is extended. On the extended side, the radius arm, through the c bushing, is twisting the axle forward increasing caster angle. The compressed radius arm is doing the opposite through the cbushing. Decreasing caster twisting the axle back. Radius arms do act like sway bars becauser they are in conflict except when they are no articulted, therefore reducing body roll. I have a friend who actually builds all his uroc and rock race buggies with radius arms due to this.

Anyway, this is why it won't travel freely without weight on it like you see 3 or triagulated 4 links do. You can mount up one spring and then jack up the opposite side if you want to cycle the suspension so you can design steering, bump stops etc.

This is also why I like Wristed arms. Your extended arms essentially minimized the conflict. Shorter arms conflict much more. You also minimized the swaybar type of effect radius arms have on road. You should work great offroad. The thing I like about wristed arms is that you have the on road performance, then you can completely turn off the conflict offroad. Extended arms work great too though. When I have to get out and unpin mine, that is when I wish I would have extended them!

 

[Kirby N.]

Also, a ton of guys run rubber cbushings in a stock length (non wristed ) or extended arms because they are softer than poly bushings and allow the axle to articulate better.

 

[james t]

I agree, and i disagree. :

Most of the deflection in a Ford radius arm setup comes from the rear bushing, or the heim or whatever joint you are using depending on how you have them set up. This is why early Bronco guys run a stock length wristed arm and stock rubber bushings at the end instead of poly. Not only does it hinge at the bushing (or heim), but it also twists. If there was much deflection at the C bushing, the lower coil retainer plate would tear off since there is one bolt through the radius arm and another through the RA cap on the end of the axle.

Anyhoo, you are dead on with the idea that it wont flex with no weight on it. Get spings in and wheels/tires on and it will twist up really nice. Ford radius arm setups just wont flex on a jack with no weight/spring forcing articulation like a 3 or 4 link will.

 

[94 Crawler]

Thanks guys.Your help is always appreciated. My idea at this point is to finish and get all of the bugs out of the engine drivetrane and suspension. Get it on the road and put some miles on it. If the preformance off road is still not to my likeing then I have some options: 1 WAH which I like, but I dont like because all of the drive torque is still on the left arm. I'm shure it works well this is just a concern of mine. 2 find a high pinion housing that I can cut the c's off of, swap the guts from my axle, and link it. But first off I'm going to get it out and see what it will actuly flex.