GM axle swap

[scouter77]

Ok I am getting into the nitty gritty of my axle swap but TSM1MT I have a quick question and figured it would be better posted here rather than private e-mail so others who want to do this can see. I am wondering on the spring perch on the pass side (on the housing) did you grind off the bottom of the housing where the tube is pressed in or get a different sized u-bolt to go around it? As it sits the u-bolt sits flush up next to the housing and I would have to grind it off to fit. Any suggestions? I can take pics if necessary...

[Scout Dude]

If the axle came from a GM, then it should be a 44, a 10 bolt, or a 60. All of these were spring-over already. Why not use the stock size u-bolts? Maybe I need to see a pic, cause I think I'm missing something

[tsm1mt]

Originally posted by YDB:
<STRONG>Ok I am getting into the nitty gritty of my axle swap but TSM1MT I have a quick question and figured it would be better posted here rather than private e-mail so others who want to do this can see. I am wondering on the spring perch on the pass side (on the housing) did you grind off the bottom of the housing where the tube is pressed in or get a different sized u-bolt to go around it? As it sits the u-bolt sits flush up next to the housing and I would have to grind it off to fit. Any suggestions? I can take pics if necessary...</STRONG>

Originally, I did it like this:


I ground a new "channel" into the housing just to the outside of the original Chevy U-bolt channel (on the diff). On the outboard edge I ground it down enough to get the U-bolt to fit. Both U-bolts were different from the standard SII parts. They were "wider" to go around the thicker casting portion.

I did all of this so the U-bolts would sit flush against the 2" wide Scout springs (vs. 2.5" Chebby ones)

HOWEVER.. after I taco'd the front axle, I noticed..



that the "outboard" U-bolt had popped off the thick cast perch and onto the steel tubing. I've popped this U-bolt at least once before and had to pound it back into place. Originally I welded a small tab to the tubing to try and keep the U-bolt in place.

When I put the new front end under it (should be here Saturday!) I think I'm going to do it differently.

I'm going to keep the perch stock-GM.

Instead, I'll fab a new U-bolt plate (you can re-use SII plates the way I did it originally, but it's a real bear to get the U-bolts into the slots).

I'll build the plate for a wider U-bolt pattern. I'll then add a piece of 2"x1/4" strap to the assembly.

When I'm done, I'll have, from side to side at the spring pack.. U-bolt, 1/4" strap, 2" springs, 1/4" strap, U-bolt.

Weld the 1/4" strap to the top U-bolt plate and/or weld tabs onto the straps so instead of a flat bar they're a "C" shape - end result, keep the straps from falling out.

As long as the 1/4" strap stays put the spring won't be able to pivot on the center pin. But without the straps, it would.

Pat Decker did something similar, but used his "recessed U-bolt plates" from his SUA instead. In that case, the top plate is shaped like a "U" and the spring sits in a 2" channel that is the U-bolt plate.

I think in the end one of these two setups would be stronger than the way I did it originally. I won't have to worry about popping the U-bolt off the housing like I've done, and it will mean NO grinding on the housing (that took a while!) to make a new U-bolt groove on the inboard side, either. Just bolt it in.

It'll take a little longer to fab the U-bolt plate.. but I think it'll be stronger.

That help? <IMG SRC="smilies/smile.gif" border="0">

-Tom

[HooperSSII]

You can see my recessed u-bolt plates in these two pictures. Notice the size of the nut on the top of the ubolts on the left side. In order to get a ubolt that was long enough to go in the groove on the pumpkin, then up through my leaf pack to the plate on top, I had to move up two sizes in u-bolts. These things are massive, but they still fit just fine into the groove in the pumpkin.



On the passenger side, there is not room to drop the spring plate back down to wrap the springs. So, it ends up looking like this. You can see the 1/2" strap I use to clamp the pack together. You can also see the massive ubolt I used.


This is the driver side


I pulled the ubolts tight enought to bend my spring plates a little, but they can only bend so much before they press against the sides of the springs. So, I have effectively encapsulated my springs with this setup.

I was not happy with the front to rear splay I had for a while, so I pulled my spring plates and redrilled everything straight.

Also, it is hard to describe, but I added a brace across the back of the spring perch that bolts to the spring plate. In essence, it is bolted to the bottom of the spring plate, and extends down below the axle housing perch. What this does is make sure that the axle, even if it shears the center pin, cannot slide to the rear. I have recently read a lot of stories of center pins shearing and allowing the axle to go caddywhumpus. This angle iron, dropped down that way, transmits any rearward force against the axle, back up to the spring plate. Should help keep the center pin from getting tweaked. That is the theory, anyway.

Patrick

[Scout Dude]

Sorry, I forgot that SII's used 2" springs...I see what you are talking about now.

[RustoleumWhite]

IMO, having helped Patty with his SO, Tommy's idea (which was my plan as well with mine, *great* minds think alike :rolleyes <IMG SRC="smilies/smile.gif" border="0"> is the best/easiest. Even better becasue then you can just order up a front u-bolt kit for a Chev Front axle and get all the proper u-bolts. Beafy bastards as well, the Rancho RS705 (for 3" axle tubes) kits I got are extra stout 9/16" U-bolts. Standard parts are always good. Then build yourself a new set of plates, or modify a set of stock GM plates, and your set.

Course, I'm fixing the whole spcer thing with 2-1/2" D-1100 springs <IMG SRC="smilies/biggrin.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">.

FYI, we found with Patty's housing that, with stock shackles and "stock" springs, a 7º shim was required on top of the perch to angle the pinion to the t-case. Patty is currently NOT running a CV shaft, and reports little/no vibration at (his, I tend to go faster on the boring parts <IMG SRC="smilies/biggrin.gif" border="0">) trail speeds, over 15MPH on the other hand......

With my RS it will require grinding the pearch as well as the shim.

later
-mark

[ 10-02-2001: Message edited by: RustoleumWhite ]

[HooperSSII]

I would be inclined to go with an 8 degree shim if I did it again. I am *almost* pointed at the t-case, but not quite. On the other hand, as the springs settle a little, or as I work them on the trail so they warm up, I think it will work out to be just about perfect.

[scouter77]

Originally posted by tsm1mt:
<STRONG>
That help? <IMG SRC="smilies/smile.gif" border="0">

-Tom</STRONG>

ABSOLUTELY! I need to go buy more steel <IMG SRC="smilies/rolleyes.gif" border="0"> But I will have the comfort of a solid mount. I was looking at that yesterday and was hoping you didnt grind into the cast part too far. Then I thought that was the side that taco'd and got really scared! Then I saw the pics and got unscared but its better off this way. I like hooper's spring perch setup I think I am going to do that. ughh I got the front pretty much all figured out and the rear will be cake walk. I just need to get my brakes squared away <IMG SRC="smilies/crybaby2.gif" border="0"> Thanks for all the replies they all helped a LOT <IMG SRC="smilies/idea.gif" border="0">

[REDDMANIAC]

Tom or Hooper, did you actually have to round out the center pin hole in the gm44 perch farther inboard or what. Or just reuse the hole & gring the perch casting to 2in. <IMG SRC="smilies/usa.gif" border="0">

[Hayraker]

Originally posted by tsm1mt


When I put the new front end under it (should be here Saturday!) I think I'm going to do it differently.

I'm going to keep the perch stock-GM.

Instead, I'll fab a new U-bolt plate (you can re-use SII plates the way I did it originally, but it's a real bear to get the U-bolts into the slots).

I'll build the plate for a wider U-bolt pattern. I'll then add a piece of 2"x1/4" strap to the assembly.


-Tom[/QB]

Tom you can get spring plates that will work at a trailer supply place, just get the ones for a 6000 lb axle and they should work fine for what you are going to do.

My scout and skeetshooters samurai have about as many trailer parts as our trailers do

<IMG SRC="smilies/biggrin.gif" border="0">

[ScoutsHonor]

Hey fellers, I'm right in the middle of putting my Cheby Dana 60 in the front of my Scout. I've got an '80, with the Dana 300, and after the springover and reverse shackle is said and done, and we've sat the front axle in, the angle on it is pretty steep, I'm gonna say probably between 25-30 degrees.
How much of a shim do you guys suggest, or do you suggest just turning the pinion up towards the TC, and then cutting & turning the knuckles? Please someone gimme all the input you can! Thanks in advance!

Matt "Taz" Green

[Hayraker]

Originally posted by Matt Green:
<STRONG>Hey fellers, I'm right in the middle of putting my Cheby Dana 60 in the front of my Scout. I've got an '80, with the Dana 300, and after the springover and reverse shackle is said and done, and we've sat the front axle in, the angle on it is pretty steep, I'm gonna say probably between 25-30 degrees.
How much of a shim do you guys suggest, or do you suggest just turning the pinion up towards the TC, and then cutting & turning the knuckles? Please someone gimme all the input you can! Thanks in advance!

Matt "Taz" Green</STRONG>

I used shims, but I wish I had (and I will soon) turned the knuckles because I still have about 2 degrees negative caster and when you get in a bind in the rocks it puts a lot of pressure on the steering linkage, not to mention being a bitch to drive on the highway.

[ 10-02-2001: Message edited by: Hayraker* ]

[tsm1mt]

Originally posted by REDMANIAC:
<STRONG>Tom or Hooper, did you actually have to round out the center pin hole in the gm44 perch farther inboard or what. Or just reuse the hole & gring the perch casting to 2in. <IMG SRC="smilies/usa.gif" border="0"></STRONG>

I think the center pin spacing is the same as the SII, and if it's off, it's 1/2" or so.. I couldn't notice.

It's just that SII springs are 2" wide vs. 2.5" wide Chevy. I notched the corners of the driver's perch to make the U-bolts sit flush.