The Stovebolt Site Forums The Shop Area Driveline All new but still handles bad

Ok Guys, Here's the deal. I've replaced:

Front leaf springs with a good set with good arch.

Front and rear spring shackles, pins, bushings, etc.

King pins.

Front wheel bearings and races.

New modern style tie rod and drag link

Adjusted the steering box according to the shop manual and had the truck aligned.

Now the truck handles as good as I would expect a sixty year old truck to handle, which isn't too bad. On good paved roads I can cruise along without hardly touching the wheel. Problem is on black top roads that start to get slightly rutted, the truck wants to run near the center line or next to the shoulder. If I try to keep it in the center of the lane I'm swerving back and forth. Bumps and bad spots in the road tend to cause me to swerve a bit too. In fact a good bump seems to toss the rear end to one side or the other. I'm running 265/70/17s, so I've got a tire hight of about 31.5" and the tread width is about 9". Is it the wide front tire that causes the wander? Is there something I'm overlooking?

I plan to install an anti sway bar as soon as I can make some brackets to fit the GMC front crossmember, but I don't expect that's going to have any effect on strait highway driving.

I'd like to get it fixed because it scares my wife to ride in the truck.

What is your tire pressure? Maybe try decreasing the tire pressure by a few psi?

I have the same question as Tim on tire pressure, plus, what width wheel are you using? If the wheel is too narrow for the tire, it will do exactly as the problem you're describing. For that size tire, you should have at least a 7" wheel, preferably an 8".

On my late model truck I run a 295 tire and when I get on the black topped roads that the semi's travel it gets really hairy. My truck is a late model suspension 2001 with really low miles and so I think you hit it correctly with the wide tire you are using, it is railroad tracking in the grooves-coupled with the ancient steering and suspension = scary ride. I'd be willing to bet you get a narrow tire/wheel radial on there, it will be much better, but it will still be there, not a lot you can do about it IMHO.

Tires call for 80 psi max. I acually have 35 psi now. I don't think it was near that low before it went to the alignment shop. Guess I should increase psi? Wheel width is 9", same as tread width.

I need to see if I can find a couple narrower wheel/tires I can run on the front for a test run.

Are the front springs arched too high? The drag like should be near parallel with the frame. An angle can cause bump-steer.
I believe the big tires are causeing most of the problem.

I agree the drag link that isn't horizontal can cause a lot of bump steer.

But, you told us everything you did to the front. What about the back?
You said at times the back jumps sideways. Bad shackles and spring bushings, missing spring clamps, loose or broken leaves or broken center bolt can cause the rear axle to track badly.

Might also have the castor double checked.

The front springs were a good set off a doner truck and not over arched. The drag link looks perfectly horizontal, but I havn't measured it.

I also replaced front and rear shocks

Rear leaf spring shackles and bushings were replaced the same time the front was done. The front and rear springs look great with no breaks or broken center bolts. Some of my spring clamps are spread open tho.

I appreciate all the help on this.

Is there a way I can check the caster myself? In fact, I'd like to double check the whole alignment myself. The guy that did the alignment is top notch, but I'd like to 'see it myself' if you know what I mean.

Do you have the castor wedges installed?

Also recheck the toe in.

I would take it back to your alignment shop!

Yep, castor wedges are installed and properly oriented.

With your description, it sounds like the toe-in is not in spec. I think 1/8" toe-in is what the shop manual calls for.

I had this trouble with my Nova when I had belted bias ply tires on it. On the roads where trucks have worn the road in two slight depressions, the car was back and forth, fighting it all the time...... radials fixed it right up.
Wide tires and rims don't get along with ball bearing front hubs.
John

John, please explain why "Wide tires and rims don't get along
with ball bearing front hubs".
I can't see any reason why the ball bearings, in good condition
and properly adjusted would have anything to do with what tires
or rims your running. I've been running '70 3/4-ton Chevy rims
and radial tires on my 3600 for nearly 15,000 miles now, with
the stock ball bearing hubs and it handles just fine.
I would say there is an alignment problem.
Denny Graham
Sandwich, IL

I have a few comments/suggestions from my experience.

1. I would get a steering stabilizer (look at a place like So-Cal speed shop), they're an easy install and will help the bump steer a lot with a straight axle.

2. As you mentioned, try getting a set of narrower tires to try going for a drive. The wider tires will tend to track more and cause issues like you mentioned. My 2004 Avalanche has the same size tires, and they tend to track ruts, even with modern suspension. I can't imagine how scary this could be on your 53 at times.

3. I wouldn't expect the sway bar to make a change in the tracking. Has the ride height of the truck been modified at all, or is the only modification the wheels and tires?

I disagree about the steering stabilizer helping with bump steer. As mentioned I would recheck the front end settings. Make sure the caster shims are in place between the axle and spring as mentioned.

I don't usually chime in. I read all these posts. I always feel I don't want to give the wrong info. But, here goes.
I too have/had this condition. I have 8inch wheels, tires about 26inch top to bottom. Bought new shocks, actually removed a leaf to lower slightly. New rear shocks.
Felt like every time I was on rough roads, or ruts, I thought I would be sent off into the shoulder. VERY SCARY!
Now in my instance, shocks were way to firm, but also, I checked my front toe after reading a lot here.
I used a tape measurer to measure tread to tread front, then behind front tires. I was tow out by about 3/4-1 inch!
I set mine as per specs listed on here, about 1/8 in. I did slight more because of the force when driving forward, so I did like 3/16-1/4 in. What a difference! I can drive truck much better. Its actually my daily ride with a 216. I can go on smooth highway and let go for about 1/4 mile with no drift.
NOW, there are some roads, highways near me that have roadwork, and I know what you mean about those ruts, and on that type of road, I white knuckle it still a little.
I just think after sooo much reading here, these trucks aren't/weren't made to go on these roads at these speeds.
I will be changing mine to mustang front end soon and coilovers in rear with 4link. I will have to because like I said, its my daily ride, and I will need to do 65 safely.
Top speed for me now is 53 comfortably, and that's with a t5.
So, I agree with those that said toe issue.
I also work for a major auto dealer in the serv dept. High end car. I cant tell you how many times I see customers who went to alignment shop and they are way off!
The equipment nowadays is awesome, but you need trained techs to set it up, and perform it. Local shops and chains aren't gonna cut it. Use the tape measure, it will tell you in 2 minutes.
Good luck and let us know.

PS??? One of the biggest problems with these sites is that when the initial problem is asked about, no one EVER responds with the fix. We all nee to improve on this, myself included.

The only thing thats not stock under this truck besides the wheels and tires is the modern style tie rod and adjustable drag link. otherwise the suspension etc. is all stock.

Is there a way I can check toe in and castor at home? The more I think about it, the more I think the toe in is not correct. On the drive home from work today (20 miles) I was paying close attention to the way the truck handled. It seems like it's always pulling, very slightly, so that it is easier to let the truck wander to one or the other side of the lane and then keep it there by turning the wheel toward the center of the lane just enough to maintain my position. It's so minor that it's hardly noticeable. Then of course, a bump or irregularity in the road causes me to swerve to the other side of the lane.

So again, can I check my alignment at home?

Phil, thanks. I will do some measuring. If it's as simple as adjusting the toe in a bit, I'll be tickled. And I'll let you know.

That is an incorrect statement. Many mechanics in the alignment business us the exact same equipment that the "high end dealerships" use, in some cases, even better equipment. I've lost track of the number of times I've had a car on the rack after a dealership "aligned" the car and had to completely reset it.
Back on topic, you should set the toe at 1/8", with radials, you can set it a bit tighter at 1/16". Caster should be 1.5-2 degrees positive. To check, you'll need an magnetic angle finder. Simply place it on a flat spot on the axle or spindle, get the reading. If it leans to the back, that's positive caster, if it leans to the front, that's negative. Positive caster is more stable, and will aid in proper tracking. Negative is less stable, but much easier to steer. Not many vehicles use negative caster, the only one I can think of off the top of my head are mid '60 Thunderbirds.
Toe is relatively easy, scribe the tires with a chalk line so you have a good reference point, then measure the front side and back side, then compare them.
On your tires, the 9" wheel should be ok with that tire, but with the high load range you're running, you may consider bumping the tire pressure up. running 35, you're not getting enough sidewall support. Try running 40-45 psi, should help the problem.

Longbox, thanks for the info. I plan to check toe in tomorrow after work. Maybe stop by my local FLAPS and get an angle finder. I was running about 50 psi before it went in for the alignment. I'll probably bump it back up to 45-50 tomorrow as well.

The castor angle really helps in the stability of steering on those bumps and ruts.

I have radial on my 58 with original ball bearings and no problems.

I think we should mention the modern drag link. If it is not exactly the same length as the old one, your steering box will not work correctly. There is only one center spot in the box where the lash is at minimum and this must be with the wheels pointed straight forward.

Why? I've personally experienced it helping on different vehicles. I'm curious why you are so adamant it doesn't work.

Just as a test; try putting 4- 50 pound bags of sand in the bed against the tailgate and test drive. That may stop the rear bounce. Also, was the steering box rebuilt or just adjusted the 50+ year old gears? Might still be play in the box. There is a steering stabilizer made for these trucks. It will dampen the front end jerking. streetperformance.com look for MOOG steering stabilizer SSD42. Might help.

truckernix makes a point. If your drag link (or any other part of the front end) doesn't allow for the wheels to be pointing forward at the same time as you feel that sweet spot of the middle of travel inside the steering box , you will likely be fighting the steering wheel to go down the road.

Ok, here's an update;

I guess in this neck of the woods toe in and toe out mean the same thing. I was toed out 1/8 inch. Corrected that and it made a big difference on a short drive. It tracks better but still wild on those bumps because........

I checked the castor and I've got about 1 degree positive. And yes it does have castor shims in place. Looks like I'm in the market for new shims.

Truckernix, good point on the modern drag link but I'm way ahead of you. After adjusting the steering box I found dead center on the box according to the shop manual(with the drag link removed). Then I pointed the wheels straight ahead and adjusted the drag link to fit from the pitman arm to the steering arm without moving either.

Classic One, first off, welcome to the Bolt. Second, I've considered throwing some weight in the back to see what effect it might have. It does seem that my springs are too stiff. Maybe some spring liners front and back would help.

Steering stabilizers. . . for every 'heck yes' there's a 'heck no'. Makes it hard to decide.

As I progress I'll ad more. I'm anxious to see what more castor angle will do for me.

Try the steering stabilizer. It won't hurt.

Toe in made a huge difference to my truck. How did you measure the caster angle? No shims under my axle but would be good to know what it is. Steering stabilizer? Can't hurt as long as it is mounted correctly. Might not help much, maybe. But it can not hurt so try if you like. Any thoughts on sway bars? That should get some ideas out there.

Steve H, I picked up an angle finder at Napa for $7-$8. I checked several places on the axle; on the front and rear of the I-beam at both ends, on the flat area on the front of the axle as close to the spindle as I could get, and then on the flat area on top of the axle right next to the prings. Of course it took a while to find a place to park the truck that was flat and level.

Back to steering stabilizers again. As this is my daily driver, I might look into getting one, but only after I've fine tuned all steering components. I need to do some more reading on them too.

As for sway bars I've heared they are the second best improvement you can make to the handling of these old trucks next to radial tires. I've got one but I'll have to fab up some mounting brackets to run it on my GMC cross member.

Are there caster shims of different degrees? Since my caster is only 1 degree do I get a 1 degree shim and stack it with the old shim or do I get a shim that's 1 degree 'steeper' than mine?

Yes, caster shims are available in different sizes, with 1/2 degree increments.

Bill,

You have probably posted a source for those shims in another post, but would you please post the company and part number(s) again?

Thank,

Moog has them, should be able to get them at any Moog dealer like Advance Auto or O'Reilly. I'll see what I can get for numbers, seems that most of what is listed are 2 1/2" wide or wider.

Alright, here's what i have in numbers from Moog for a 2 1/2" wide wedge;
K8878 1/2 degree
K8882 1 degree
K8886 1 1/2 degrees
k8890 2 degrees
K8894 2 1/2 degrees
K8898 3 degrees
K8902 3 1/2 degree
K8906 4 degrees
I did come across an Amazon listing for AC Delco wedges, but they did not come up as fitting older trucks. I'm going to check for a different source to verify weather Amazon is correct on that. The AC Delco shims were listed at being 2 inches wide, and seem to be available in 1/4 degree increments.

I have bought many fabrication parts from WFO concepts. They have degree wedges in stock, fair priced, and usually ship the same day.


FYI-make sure that the degree wedges you end up going with are steel and NOT aluminum. The aluminum will destort under load and time while the steel will hold firm.

http://www.wfoconcepts.com/cr/Axle-Shims/3225

Thanks for the info on the angle finder. $8? Even I can get a new toy for $8! Placing on top of the axle, sounds like a good spot to me. Front of the I beam might be a good place as well. Thanks!

install some stock wheels on it

What is the NAPA part number for the "angle finder?

Longbox55, Thanks for the info.
Joker, I do have the original set of wheels. The tires are probably as old as the truck and have paint on them from every repaint the truck has had. They also have flat spots that never did go away.
Tclederman, the angle finder part # is SER2968 by Central Tools inc. in a Napa package. It's made in Taiwan so you know it's accurate
Is there a way to tell what angle shim I'm currently running?
I did some driving around town today and I'm amazed that I never noticed it takes almost as much to steer out of a turn as it takes to steer into one. I'd like to see about 2 degrees positive.
On the drive to and from work, the difference in the toe in was obvious! Everything felt nice and tight.
It's hard to tell just how well the truck handles when you're sitting on a bench seat made of coil springs and you're bouncing all over the inside of that cab