98 GMC SAS HPD60 steering issue

[Devillusion]

(suggested/informed to put this here instead of originally on the 88-98 threads so don't flame me for double post please....)


Ok...so here is my dilema.

I just finished up my 2 year build (more a less), and find now that I am running my 40's and so forth the truck does not steer like I would like it to. Might just be because I haven't driven her for so damn long I forget, but I'm pretty sure she didn't wonder like an old grain truck like this before. I was running crappy old military tires before (37's) and now am running some Toyo MT's in a 40. I realize she isn't going to drive like a cadillac, but I would expect some half decent response in the steering.

I have an ORU crossover steering kit (both arms are 7" in length), duall stabilizers, no track bar, 12" of lift, factory steering box, all front end parts and king pins are like brand new...including wheel bearingsand has 7 degrees of caster from what I can tell.

She seems to kind of be sloppy, with around a 1/4 turn of the wheel play from side to side before something happens. Just expected a bit tighter response is all with crossover steering. My alignment hasn't changed since I ripped her down so I don't figure that should be the issue.

I was told that I should look into a 454 or 350SS 2wd box with a closer ratio....anyone have any information on this or ideas as to what might be the issue?


Here are some pictures....





Thanks in advance....

[b454rat]

I know when I had my 89 that I SAS'd, sitting there turning the wheel back/forth the whole body would move. Track bar might help, but no factor solid axle GM ever came with one. Don't forget the tires are wider than stock, so will follow cracks and grooves in the pavement, making it go all over the place.

I noticed that with my old truck. Had some shot 37s, then some 315s, then 35x16" boggers, with the other two, pretty much stayed on track, but the boggers were all over.

[DirtyLarry]

Originally Posted by Devillusion

(suggested/informed to put this here instead of originally on the 88-98 threads so don't flame me for double post please....)


Ok...so here is my dilema.

I just finished up my 2 year build (more a less), and find now that I am running my 40's and so forth the truck does not steer like I would like it to. Might just be because I haven't driven her for so damn long I forget, but I'm pretty sure she didn't wonder like an old grain truck like this before. I was running crappy old military tires before (37's) and now am running some Toyo MT's in a 40. I realize she isn't going to drive like a cadillac, but I would expect some half decent response in the steering.

I have an ORU crossover steering kit (both arms are 7" in length), duall stabilizers, no track bar, 12" of lift, factory steering box, all front end parts and king pins are like brand new...including wheel bearingsand has 7 degrees of caster from what I can tell.

She seems to kind of be sloppy, with around a 1/4 turn of the wheel play from side to side before something happens. Just expected a bit tighter response is all with crossover steering. My alignment hasn't changed since I ripped her down so I don't figure that should be the issue.

I was told that I should look into a 454 or 350SS 2wd box with a closer ratio....anyone have any information on this or ideas as to what might be the issue?


Thanks in advance....

Hello Devillusion,

No flaming will be tolerated here. This isn’t Pirate4x4.

First, your project truck looks great. It looks like you have put a lot of hard work into you truck to fit your tastes and needs. Great work!

Without the luxury of driving your truck to see how it handles first hand and by just looking at your pictures (angle of the front diff cover) the axle looks like it needs more positive caster (bring the pinion up). Incorrect caster will definitely give you a wondering and disconnected feeling in the steering wheel, which could be misdiagnosed as a gearbox issue, etc.

What speed are you experiencing this issue? If dynamic rolling speed, I would recommend going with OEM caster setting that was recommended for the vehicle the axle was donated from in order to get the angle on the pivot points where the steering knuckles met the axle knuckles in line with what the angle the manufactures suggests. You mentioned 7 degrees but I don’t see what looks like a single positive degree in the pictures. Even OEM’s will throw much more caster over and above published specs to an alignment to correct wandering issues. When I worked on GM Tech Assist hotline for GM it was not uncommon for us to prescribe 4 degrees or higher positive caster (above what the OEM spec in the service manual listed) to correct issues with AWD Astro vans and K trucks (IFS rigs) and 3500-HD (which also had solid front axles like yours). Maybe more positive caster will work for you as well. I suspect more caster will get you where you need to be. Positive caster is your friend!

On the other hand, if you are experiencing the slop while static (not moving), I would look closer at the steering gear and all joints.

[Devillusion]

Well it is 7 degree's (laid back at the top)....that's positive no? I could be wrong though. I thought that is what you wanted for steering correcting etc. But feel free to correct me if I am (probably) wrong...lol.

I just measured again tonight with the alignment....my toe is dead on 0 degrees. Not what I want. I would assume I would want around a 1/4" of toe in? correct? Front end parts are all new including king pin kits top and bottom, and always get synthetic grease.

I'm thinking that I will for starters adjust that toe inward a few degrees, then try that. If that don't work I guess I'll have to think about a pan hard bar. I have my suspicions that there might be some slop in the box. Have to get the wife to help me out tomorrow night cranking on the wheel while I inspect everything.

thanks for the suggestions....much appreciated.

[DirtyLarry]

Well, heck…I got my bearings totally backwards somehow. Positive caster would be tilting the pinion down (upper balljoint/kingpin tilted towards the back which would mean the pinion would have to come down). Too many years away from alignments I guess. Sorry…

Hopefully correcting the toe corrects the issue. For some reason the axle position (diff-cover view) still seems off kilter to me but I could be wrong.

I just looked up the toe settings for a 1999 3500-HD with an I-beam front axle and it is 0.028 degrees-0.028 degrees while a late model GM 4500 4x4 with a SFA calls for the toe to be 0.02-0.08° and a caster setting of 3-5°.

It looks like you have a Ford Dana 60 so it would be worth checking the specs for a F-truck, which you probably already have done.

Sorry to confuse you with my previous backasswards post.

[Devillusion]

toe in fixed alot of the issues, nearly all actually. Thanks for the help.

[DirtyLarry]

Originally Posted by Devillusion

toe in fixed alot of the issues, nearly all actually. Thanks for the help.

Good deal!