Shaking steering wheel... what to start checking

[cchase]

My Chevy C1500 has had a steering wheel shake most noticeable around 40-45 mph recently. The truck was recently aligned and the tires balanced.

Since I can only assume the alignment is correct and that the tires are properly balanced, where can I start going to isolate the problem? I'm assuming I am going to be looking at various suspension components.

Yes, all the joints and bushings are original at almost 370,000 miles but when the truck was aligned they did not mention anything beind worn (which I thought was a pre-requisite for doing an alignment... that is, if something is worn out they can't even properly align the vehicle and would have told me). In any case, I asked them if everything was in good shape and they gave me the good-to-go.

 

[sbergman27]

If you've ruled out balance and excessive play in the steering components, you could have an out of round wheel, or wheels. Or you could have a tire defect, like a separated tread. The latter could be quite dangerous. Jack the front of the car up and spin the tires, watching for any lumps, ridges, or out of roundness. If you see anything, determine if it is in the wheel or the tire. If it is in the tire, replace with the spare *immediately* and then figure out where you want to go from there.

 

[Scott_Tucker]

I would recommend having the tires balanced again. It would suck to start replacing parts if it just turned out to be a balance problem.

 

[rshunter]

Swap the wheels front-to-back. If the shake goes away, it's tire/wheel related. If it doesn't, then it's the truck.

 

[1 FMF]

you need to see if when the alignment procedure was done they actually made adjustments. If they did, then it's probably uneven wear on your front tires. Try rotating tires, and vary tire pressure might help. if you have them near max inflation, 40psi or higher depending on the tire, try dropping them down around 30 psi or if they are around 30 then put them up near max, and see if that has an affect.

 

[willix]

Swapping frt to rr is a good Idea. a tread separation may not be visible without centrifugal force pulling the tread away from the carcass.

 

[sbergman27]

Originally Posted By: rshunter
Swap the wheels front-to-back. If the shake goes away, it's tire/wheel related. If it doesn't, then it's the truck.

I've been dealing with this issue on my 1988 Chevy Sprint Metro (really a rebadged Suzuki.) After 350,000 miles of service, I have more than one slightly bent rim. Swapping front to back doesn't help. ;-) I picked out the 2 best ones and put them on the front. One of these days I'll get around to having them straightened.

 

[cchase]

I swapped the front tires to the back and back tires to the front this morning as a matter of fact, with no change.

I can safely rule out the tires and wheels through this. In addition, the same thing was happening with the snow tires which are mounted on separate wheels.

 

[Pop_Rivit]

Originally Posted By: cchase


Since I can only assume the alignment is correct and that the tires are properly balanced, where can I start going to isolate the problem? I'm assuming I am going to be looking at various suspension components.



Don't assume your tires are properly balanced. It could have been incorrectly balanced when the tires were replaced, or it could have thrown a weight.

 

[sbergman27]

When do you notice the shake? Low speeds? High speeds? Only certain speeds?

 

[cchase]

Originally Posted By: Pop_Rivit
Originally Posted By: cchase


Since I can only assume the alignment is correct and that the tires are properly balanced, where can I start going to isolate the problem? I'm assuming I am going to be looking at various suspension components.



Don't assume your tires are properly balanced. It could have been incorrectly balanced when the tires were replaced, or it could have thrown a weight.


Normally, I'd be inclined to agree with you, but this is 6 separate tires (all of which have been balanced within the past 6 months) that don't exhibit any strange wear patterns or imbalance in the back.

Originally Posted By: sbergman27
When do you notice the shake? Low speeds? High speeds? Only certain speeds?


I suspect it is doing it at most speeds, but when I really feel it is about 40-45 mph and then occasionally around 50 mph. The shimmy is fast enough by 65-70 that it's just a very light, almost un-noticeable vibration by that point.

 

[1 FMF]

at this point if you're sure its not tires and wheel balance,
I would start looking into ball joint play, if it were a ford I would definitely say ball joints, typically they can tell ball joints are shot when doing an alignment because they can't get a good alignment that holds. do you trust who did the alignment, is it possible they did it, collected your money, and sent you on your way? reading back, you say 370,000 miles? it's most likely ball joints and possibly wheel bearings/hubs with that mileage.

 

[cchase]

This is not one of my automotive strong points, admittedly.

I just went outside and lifted the front wheels, one at a time, by the bottom of the shock. I then took a lever under each tire and pried to see if there was slack anywhere. I then took the wheel and bear hugged it and tried seeing if there was any slack in the steering components.

None of this resulted in any feeling of slack.

 

[hardcore302]

That's not the steering wheel. Haven't had a drink in a while?

Joking, lol. Driveshaft or tire balance.

 

[cchase]

Originally Posted By: hardcore302
That's not the steering wheel. Haven't had a drink in a while?

Joking, lol. Driveshaft or tire balance.


I doubt it is the driveshaft as this isn't something you can particularly feel in the vehicle. Only the steering wheel sits there wiggling back and forth.

 

[daves66nova]

Originally Posted By: sbergman27
Jack the front of the car up and spin the tires, watching for any lumps, ridges, or out of roundness.
I had a vibration at about 65mph.Turned out it was a bulging split on the inner side of the rear tire.

 

[cchase]

I am beginning to think I need to bring this somewhere and have them check the alignment as nothing else seems to be coming up as a likely culprit.

 

[Papa Bear]

Take it back to where the alignment and balance was done and get it done right.

 

[cchase]

I just spent 45 minutes out in the truck trying to narrow things down and determine what exactly is going on.

I think all I've done is confused the issue further. I performed many informal tests.

1) I tried determining if there was a specific speed that it started shaking at. I have determined that it can occur at just about any speed but does not at all some times.

2) I tried determining if it was related to a specific steering input. I could not make a connection between the two.

3) I tried isolating the power steering pump itself as a cause by shifting into neutral and revving the engine, letting it idle to change the speed of the power steering pump. No difference.

4) I tried an emergency stop from about 35 mph with my hands off the steering wheel to see if there was any noticeable pulling. There is none.

5) The truck tracks straight. Tire wear is even.

6) Turning the steering wheel even minutely results in corresponding movement at the wheel, there is no slack in the system.

7) I tried seeing if it happened during acceleration, deceleration, or steady state speed. It can occur under any of these conditions.

8) I tried seeing if hitting a bump would set it off when it was not currently shaking. Sometimes hitting a bump would result in it starting to shake, other times it would not. I tried this on identical bumps at identical speeds.

9) I tried driving on a variety of pavement surfaces and road conditions. It happened on rough roads and then did not happen on rough roads other times, the same result on smooth roads.



Any more thoughts or ideas? At this point I feel somewhat confident ruling out the alignment and I am completely confident in ruling out the tires and wheels. It almost feels like there is some underdamped steering component, if that's possible. FWIW the shocks are only about a year old and are Bilsteins which I have had excellent luck with for a long time.

 

[eljefino]

I think some bushing looks good visually but is giving you some sort of "death wobble" like affects Jeep cherokees. Tracking it down is going to be painful. Control arms would be a good place to start.