Sloppy steering

My blue Sportvan has sloppy steering. I have tightened up the steering lash and replaced the tie rod ends (I have not had the front end aligned yet, however). This tightened it up some but not enough.

I read this in the Chevy Van suppliment manual:

STEERING GEAR TROUBLES AND REMEDIES

Loose Steering
a. Improper adjustments.
b. Worn steering linkage components
c. Worn sector shaft bushings.

I'm surprised it said nothing about the lash adjustmennt (high point pre-load adjustment) or the worm bearing pre-load adjustment. They seem to have more to do with tension in the steering wheel.

In the expoded view it shows that the sector shaft bushing is where the main shaft rides, the shaft that the Pitman arm attaches to. I could see that causing some slop. I'll see if I can detect any slop on the one on my bench.

Also, one big thing I notice with the steering on the blue van is that it won't straighten itself out from a turn. The manual attributes this to Caster. Look on
page 3-3.

"The purpose of caster is to provide steering stability by keeping the front wheels in a straight ahead position and assist in bringing the wheels out of a turn. A truck with no caster or negative caster would lack steering stability, tend to wander, and be difficult to straighten out at the end of a curve or turn."

That's EXACTLY that van's problem! I want to fix this before I sell the van. BUT, there is no real adjustment for caster, as far as I can see, except altering the angle of the leaf spring. Look at the illustration. The angle of the turning axis of the king pins is supposed to have a "backward tilt" when viewed from the side. My front leaf springs are not sagging, if anything they are riding a bit higher than normal. The front of the van seems too high. I'm wondering if the front leafs have altered the caster angle. This could happen if they are too curved in front of the axle. I have another set of leafs I could install on the front...

Any ideas? Is there a caster adjustment? I don't see how, other than changing the angle of the axle, which means changing the angle of the leaf spring.

I don't know anything about the chevys, but in regards to the Dodges I kinda recall someone saying that you can shim between the axle and the spring to give it some adgjustment.

Yea what Itruns said. I think all my Early Chevy vans got a shim plate between the axle and springs??? Paging Dr Don

Don is right (of course) that I need to check all the other likely suspects in the front end. But this got me interested caster. Here is the info from the Chevy manual:



I did some Internet searching. Caster is what allows a bicycle to go straight when riding no-handed, also a car when towed by a tow bar.

Here are some links:
http://en.wikipedia.org/wiki/Caster_angle

Here is a video that explains caster very well:
https://www.youtube.com/watch?v=TrWkqJzYfQ4
Video on how to measure caster:
https://www.youtube.com/watch?v=R_qV4lbe8hk
second test after measurement:
https://www.youtube.com/watch?v=9HbkslChoBY
Hard to measure without a special tool. And our vans don't have a handy adjustment for this.

I think our manual calls it positive caster because they are measuring from the top. The videos call it negative caster. Maybe they're measuring from the bottom.

Thanks for the feedback about shims, Itruns and Savage. I found a "degree shim" that is inserted between leaf springs and the axle for a Jeep. And they make upper ball joint sleeves that are off-center to change the angle.

Don, have you ever found shims in any of the front ends you've dismanteled?

Listen to Donivan65 put the front axle on jack stands and basically grab the driver's wheel and look for play then check out the passenger side. After what you done already I would suspect the bearings and king pin bushings.
This last van I bought the guy was trying to fix the steering slop. From what he said he replace the drag link; tie rods; and kingpins and was dumbfounded so he bought what he thought was OEM front leaf springs that he gave me with the van which they turned out to be for 1st gen not 2nd. And when I did check I found the large bolts that attach the steering knuckles(?) were loose, especially the passenger side which must of just wandered around. After tightening them up and replacing the missing cotter pins in the castle nuts it's been my best steering van I've had. I can't tell you how long I kept looking at it shaking my head.
Good luck!

In the drawing above, the caster is positive because degrees are read counter-clockwise. Thus, a backward tilt to the driver's side front wheel axle/kingpin, when viewed from the center of the vehicle, would be a positive caster. The same adjustment would be viewed as a negative amount of degrees if viewed from outside the vehicle... but it's probably best just to think of normal caster as being a backward tilt of the axle/kingpin. I find it helpful to think of a shopping cart's front wheels. These have a lot of positive caster - that is how they track straight ahead with nothing else to control their direction. Remember that the axle/kingpin on the van is connected below the center of the wheel... so putting the axle slightly ahead of the center of the wheel results in a backward tilt to the kingpin and positive caster.

In the '67 service manual, it says that the tapered shims between the spring and the axle can be flipped around to change the caster angle.

However I'd be reluctant to do that unless there was real instability and flipping the shims around resulted in more positive caster. I agree that going through and checking for slop in the linkage is the best bet, and then adjusting or replacing the various fasteners/links as needed to correct the slop. Be careful tightening up on the worm bearing in the steering box. If you do that with the steering off dead center, then it might be impossible to return the steering wheel to center without damaging in the internal mechanism. Always make any such lash adjustments with the wheels straight ahead, and check for free movement from steering lock to steering lock before attempting to drive the vehicle.

Thanks for all the advice, guys! I'll give it a good lookin' at on Saturday and give you a report.

Today I checked the caster on my van. This would have been impossible for me to do at home but Don actually owns an alignment testing device! He lent it to me and I hooked up this crazy-looking thing this morning.



The procedure is to turn the wheel inward 15 degrees and zero out the Caster bubble. Then turn the wheel to 15 degrees outward and read the bubble. Both sides of my van read positive 3.5 degrees. That's good! But what now...?

Don arrived just in time to come up with Plan B. We turned the steering wheel and looked at all the linkages. Nothing looked loose. We jacked it up so both wheels were off the ground. Don grabbed each wheel and worked it vertically, but we felt and saw no slop in the kingpins. We brainstormed.

While turning the steering wheel, Don thought it felt too hard to turn. We jacked up my green van and Don was able to turn the steering wheel easily with just one finger! Now we were getting somewhere!

Don topped off the steering box with lube (it was low) and I pumped grease into the four kingpin fittings. One of them would not accept grease but as we worked the wheels back and forth, we could tell it was getting easier! (Later we will try a bigger grease gun or Don's air powered one.)

After Don left, I went out for dinner and drove the van. I'd been on the freeway for a while when I started hearing a knocking sound. As it got louder I realized what it was and pulled over immediately. Sure enough, I had forgotten to do the final tightening of the lug nuts on the front left!!! And since I had rotated the tires that morning, I checked the others and found one more with loose nuts!! D'oh!

But the good news is, believe it or not, it drove real nice! Straightened out of turns much better and cruised straight. On my way back home I found I was steering with just a couple fingers of one hand!! There's a tiny amount of slop, probably the same amount as all our vans have. Nothing you'd take note of.

I figure the caster effect was trying to do its job but wasn't strong enough to turn those stiff kingpins!

I have a guy interested in buying my van but he didn't like how it drifted on the freeway. I told him I would fix it because I didn't like it either! I'd say it's time for my buyer to take another test drive!!

I had one on my van that wouldn't take grease either. It's probably a stuck grease fitting. Double ought (OO) grease that's meant for riding mower transmissions is the right viscosity for manual steering boxes. If you put regular chassis grease in there, it's going to make the steering stiff during cold weather.