SO.... is there really no way to fix the steering rack issue on the H3?

[backcountryislife]

Would it be of any benefit to have the stock rubber bushings made out of delrin?

My guy that works on my stuff machines bushings out of delrin for sleds... the problem with delrin though, it's slippery. it would be solid for up & down motion, but would allow for in & out movement. He's the one who will be putting my rack in, so I'll talk to him about it. I know he makes his sled bushings for about $2 a piece, they're easy. I bet he could make these for a little more than that.

Perhaps the delrin one against the hydro fitting where it would absorb some energy & not allow the unit to move, but then put the hunner sleeve at the end where IT will avoid in & out motion?

 

[atvspeed4]

I was thinking delrin bushings for the driverside to replace the stock rubber bushings and a solid mount at the passenger end.

 

[backcountryislife]

I can talk to him about it.

He's a one man deal, he makes delrin stuff by hand... this wouldn't be some "let me talk to some guy & he'd need to make 50 of them" kind of thing... Bill would make me a one off I'd bet if we wanted to see if it would work. Heck, he's made me parts as I've been standing there so we can put them on my sled!!:thumbs:

 

[atvspeed4]

Nice! Might be worth doing while you are waiting to put a new rack in.

 

[backcountryislife]

It JUST showed up a second ago, I'll see what he can do!

So, just so I'm clear, which one are you thinking? making a bushing to imitate the stock rubber one on the mount, or making on where the rack bolts on?

Only limitation I see is that his delrin stock is pretty small in diameter, so he might need to buy a bigger chunk of it.

 

[bebe]

You guys don't think that delrin is too hard of a material and would cause feedback in the steering wheel?

 

[backcountryislife]

You guys don't think that delrin is too hard of a material and would cause feedback in the steering wheel?

Compared to

??

With that mounting the end of the rack 100% solid to the crossmember I don't think some delrin will make much difference.

Myself I'm not concerned with a little "feel" difference as long as I get some durability increase, it would be a minor tradeoff imo. In a sled though, the delrin absorbs more of a hit than steel, and smooths out impact more than you'd think.

We use these:

in our suspensions & they keep things from breaking as much, they absorb more than steel, but let things flex SOME to keep from snapping.
I could see some of those qualities working in this application.

 

[atvspeed4]

I agree with what you said above^ and delrin is more resistant to breaking down. I was referring to pressing out the stock bushings on the driverside and replacing with delrin ones.

 

[backcountryislife]

Don't have it in front of me, so not sure what is on the driver's side. (oh yeah... steering input would be on driver's side... derr...)


do you mean the one that's in this pic?

Just looked at it in the box, I THINK he's got delrin that large, I'll check when I get it down there. I'm still waiting for my T-case & diff housing from Zach, so it'll be a few days as I want to bring it all down at once.

 

[atvspeed4]

Yeh these two...

 

[Hunner]

That Delrin might be one way to secure the pass side of the rack.
I think the two drivers side mounts are absorbing some of the forces transmitted that could go up the steering shaft to the wheel.

 

[Mr_Rich]

It was a day to change the oil in my truck. I decided since I had all the shields removed I'd jack the truck up and check for any play/ looseness in the steering or suspension. I didn't detect any noticeable play in the suspension or bearings. I was able to rock the front wheels laterally a small amount, but too much for my liking. How much looseness is allowable with the steering rack. I think that is an important question. When I had lateral play in the steering of my '89 K1500 like this, the idler arm was worn and I replaced it with a Moog Problem Solver. My K1500 has 235K miles on the chassis and my 3T has 60K. I would estimate at least 1/8" play side-to-side in the steering rack when I rock the front wheels at the three and nine o'clock position.

 

[bebe]

That Delrin might be one way to secure the pass side of the rack.
I think the two drivers side mounts are absorbing some of the forces transmitted that could go up the steering shaft to the wheel.

I can't remember right now Hunner, but didn't you put a good size poly bushing under your clamp? Somehow I remember it was cushioned somehow.

 

[Hunner]

I first wrapped it in that thin red fiber reinforced rubber gasket stuff but later found that got squished around and loosened up. So 40,000 miles ago I just went for it and installed it metal on metal but I got the bracket to fit tight.

 

[backcountryislife]

The one thing that makes me wonder, you've got a solid mount on one side, and a rubber mount on the other... I'd think if you put delrin in the one that was in line with the other mounts but left the other one (90 deg to that one) rubber, you'd get some slight front/ back movement but no side to side movement.

 

[06 H3]

I've always wondered if the rack is really a weak pile of **** or if it's just the mounting that makes it a pile...even the biggest baddest parts will fail with too much movement it would probably just take longer.

 

[4speedfunk]

Yeah...I feel the same way about the front axle. It might hold up better if it was attached to the truck better. All of that "stuff" under there is floppin around way too much.

 

[atvspeed4]

Yesterday I took apart the passenger side steering clamp and could see that the rubber was not worn but the rack had been moving side to side about 3/16". I took all of the measurements yesterday and am 90% drawing up a final design for a metal two piece clamp. As soon as thats done I am going to send the files off to two of the shops I deal with for pricing. Also the top bolt was not that bad at all with the right combination of tools. Short 15mm socket, 3/4" long extension, 3/8 ratchet, 19mm socket over the handle of the ratchet and 1/2" drive long extension into that socket to give plenty of leverage. Came right out!

 

[4speedfunk]

You're totally correct atv...I've seen this several times. The rubber bushing actually wears down the O.D. of the steel rack tube. The constant slipping back & forth wears on it so badly that even when you install a new bushing...you can't get it tight enough. The reason for this is that the mounting bolt runs out of threads and bottoms-out before the bushing gets tight. Many people mistakenly replace the bushing, only to have the same issue re-appear within 5000 miles. Its not the fault of the bushing...but rather the reduced O.D. of the rack. In some cases...the bushing can become worn and it will "squish" out the side of the clamp, but most of the time, the problem is the rack itself and not the bushing. Ironically...the rubber out-lasts the steel.

As redneck as it sounds...wrap a few turns of duct-tape around the tube, and add a large 1/8"-thick washer to the backside of the bushing (between the frame and the bushing). The tape will restore the O.D. back to the correct diameter, and the washer will allow you the extra threads needed to tighten the clamp all the way. It will be tighter than it was when it left the factory.

I assume GM designed the tolerance on this assembly so that when you tighten the clamp to a specified torque...it is supposed to pre-load the bushing and gently "cradle" the rack against the frame. Well...this might give the H3 a nice Cadillac-ish road feel but, this pre-load is not enough. Dirt, sand, mud, and water getting in between the bushing and the rack accelerates the wear, and once its starts to slip just a tiny bit...it will quickly grind the OD down to the point where the slippage becomes more and more drastic. However, once you stop the movement completely...it will hold for a very long time. Try the duct-tape/washer trick...you shouldn't have to touch it again. Unfortunately, this won't make the rack any stronger but, at least you know its properly bolted to the truck and it makes the steering much more precise.

 

[atvspeed4]

Thanks! That's what I was thinking ^ Glad this is heading in the right direction. This is the design I have so far based on the measurements I have taken.

 

[backcountryislife]

That looks sweet!


I think that, coupled with Hunner's sleeve on an extra mount will help a ton.

 

[jakesz28]

I bet this drawing is sized to work without the sleeve or bushing. I would make them that way.

 

[atvspeed4]

I bet this drawing is sized to work without the sleeve or bushing. I would make them that way.

Yes the drawing is without a sleeve or bushings as it would clamp the steering rack tight.

BackCountry was referring to adding another factory clamp/ bushing to the middle of the rack where there originally was none on top of this new clamp.

 

[backcountryislife]

Tonight while tearing down reaper's t case, we got under and watched the rack move when you turn the wheels... unfrigginreal that these things stay together at all, that was so sketchy.

Dan took a video of it moving in his bushing, I'm sure he'll post it up soon.

Now I really understand just how critical better mounting is to the survival of these things.

Sent from my A200 using Tapatalk 2

 

[4speedfunk]

unfrigginreal that these things stay together at all

So true. If you think the rack movement is scary....don't dare look at the axle housing!

There has never been an axle in more need of a truss than the AAM that comes in the H3. If you could stiffen-up the housing and how it mounts to the truck...I'm sure it would stay together longer. The soft, rubber bushings and 3-point mounting system...basically allows the "bolt-together" AAM housing to pull itself apart under load. There is no way this design can absorb the external forces of being jerked, yanked, and pulled around (by spinning tires grabbing on rocks)...while still maintaining accurate internal alignment between ring and pinion. It either needs to be one solid, rigid housing...or it needs to be attached to the frame, in a such a way that it cannot move around. It actually needs both! I began work on a truss system a couple years ago. However, I shelved it because it became apparent that even with beefing...the AAM is (A) too small of a ring-gear for a 5500lb truck, and (B) it cannot be re-geared to anything lower. This realization ultimately lead me to do a SAS but, the idea is still relevant for guys that want to 33"-ish tires and a stock IFS. It basically worked like this:

Cut-off the (2) rubber outboard mounts, leaving the end plates (which hold the half-shaft seals in place). Also remove the troublesome biscuit from under the snout of the pumpkin. Then fabricate a 3/16" steel truss that bolts to the end plates, and also the center mount. This would be a fully welded "girdle" that would reinforce and connect the three individual pieces that make-up the AAM housing, into one rigid structure. After you get this figured-out and bolted to the axle...you then need to attach the new truss (and not the 3-piece housing!) to the frame with some real (urethane) bushings. You might be able to re-use the stock mounting points but, you would now be using them to attach the truss. I would seriously consider abandoning the stock mounting points if you can find room for something else. The basic idea is that you are removing all external forces (pulling, yanking, twisting) from the axle housing...and applying them to the truss. This will free-up the wimpy AAM housing to do its real job, which is to control the internal forces of spinning the diff.

Somewhere I got some pics of a cardboard mock-up of this thing, and I've been trying to find them. I'll post em if I can figure out where they went.