Loose Steering/Poor lane tracking 91 Caprice

[red88jeep]

Hi, What is going on and what to fix? I have a 1991 caprice wagon with 138K miles, 5.0 TBI motor. It has 17 x9 inch Emki RT6 wheels, 255/50r17 Goodrich TA KDW tires. Wheel offset is '0' as shown for the SS with the same size tires and wheels. Stock wagon suspension with factory autoride fully functional. (rear air shocks with auto ride height control) shocks and bushings in good shape. It has front sway bar. no rear. (rear track is over 2 inches wider on wagon and bar from sedans will not fit. I tried) I have a problem with the car not tracking straight. Car weighs 4420 lbs and has almost perfect 50/50 weight distribution on scales. It requires constant wheel corrections going down the road. It is getting worse. I run 40 lbs in tires. It seems to be best for response and wear. 35 lbs wears outside of tires more than center. I have had suspension aligned to both factory specs and the recomended specs from the Impala SS owners web page to no avail. I do not find any overtly worn components when I inspect the front end and nothing at the rear end either. Front end shops often want to replace the rt idler arm but its replacement makes no difference. (done that too, no improvement) What do I need to do to fix the hound dog hunting back and forth steering? (the car runs straight, front and rear lined up properly. just keeps wanting to bump steer side to side following ruts and uneven surfaces. no solid 'centering tracking') It has gotten worse over the last couple of months. Thanks Ron (Did not find theread on this, but if you know of one, point me at it.) PS. when using full left or right turn lock when backing out of parking stalls tires scrub enough to shake the front end when they slip I have been told that this is a common GM trait by more than one shop.

[silicon212]

Check:

Center link, tie rod ends, idler arm, steering gear, control arm bushings, and 'rag joint' (the rubber fabric donut shaped gizmo the steering column interfaces with at the gearbox).

[bobss396]

My Caprice does the tire scrub thing when I back out of a parking spot. I agree with checking the rag joint first, since competent (I hope) shops have shaken down the front end already.

The thing with the tires grabbing the lines in the road can go with the toe being out, or something that controls the toe. I would get another front end check, have the steering box tightened up (if it needs it) and double check the toe.

The 40 lbs of air pressure can contribute to the tendency to wander, so will too little caster. I would drop the air down to 34 until you sort out your mystery and see about increasing the positive caster angle (top ball joint needs to be kicked back). The existing positive caster angle also promotes the tire scrub, so that won't get any better.

You can do the caster yourself in the driveway if you're sharp. You have to jockey the shims from the rear of the arm to the front. Pick a big shim on both sides, it has to be done equally.

Bob

[PeteA216]

My Caprice does the tire scrub thing when I back out of a parking spot.

Is that when turning sharp and very slowly the tire kind of slips and makes the fron jump a little bit?

[j cAT]

Originally Posted by silicon212

Check:

Center link, tie rod ends, idler arm, steering gear, control arm bushings, and 'rag joint' (the rubber fabric donut shaped gizmo the steering column interfaces with at the gearbox).

i think that the steering box is worn, i would have that checked out . if the alignment was done at 2 different shops! otherwise bring it to another shop for hardware issues,and check alignment. if toe is insufficent you will get wandering. also 40 psi is too high 35psi in front is good.
I had this problem in 72 impala the factory did not torque idler arm to frame and the front end wandered. also if any of the parts silicon212 mentioned can be the cause of this wandering. wearing on the outer edges can be aggressive driving............

[red88jeep]

Hi again. Thank you for your replies.
The scrubbing I am talking about is when you are backing up with a full lock turn. The tread loads up then skips. The inside tire has the top tipped to the outside and the bottom turned in in a positive camber mode, the outside tire is in a negative camber mode. Does it get more pronounced when the tires get more worn down? I wore out the 1st set after about 60K. Have about 45K on this set. I rotate on a fairly regular basis. Have had to replace a couple over the years due to road hazard punctures by bolts and nails that were not repairable.

I took a look at the front end again. Still did not find any issues. However, I did not get to inspect the rag joint. Will have to make an extra effort to get to it. There is a plastic collar over the lower end of the steering column shaft. Checked the steering box bolts to the frame to see if anything was cracked or loose. all tight. Steering seems tight. no slop when motor running and I cannot detect any noticable amount with the motor off. I had boosted the tire pressure based on what the discount tire store said was the book recomended pressure for these tires. They said that performance would improve with the higher pressure. The cornering got better and the gas mileage went up when I bumped them up. I was running them at 35 front and 33 rear for a long time. It rides smoother and quieter at the lower pressure, but corners better at the higher pressure.

below are the alignment specs I asked for it to be aligned to. The alignment guy said that those were his recomended specs as well. I got them from an impala SS web site.

Description

Specification (deg)Tolerance (deg) Front Left Camber-0.250.25 Front Right Camber-0.250.25 Front Cross CamberN/A0.25 Front Caster4.000.50 Front Cross CasterN/A0.50 Front Total Toe0.000.06 Rear Camber0.000.50 Rear Total Toe0.000.12 Thrust Angle0.000.25

Thanks, Ron

[j cAT]

[quote=red88jeep]Hi again. Thank you for your replies.
The scrubbing I am talking about is when you are backing up with a full lock turn. The tread loads up then skips.

this will occur when the steering box gears/teeth are worn. also excessive hunting ........

[PeteA216]

My car does that... it has since I've owned it (5 years). Maybe I should look into a new gear box if that's the case... oh and what do you mean by "hunting"?

[silicon212]

It's not necessarily the gearbox. It could be the caster setting, causing too much camber near the locks. It could also be the toe (which is also affected by caster) going too far out-of-spec near the locks. My car does this as well, as has every RWD GM car I've ever owned (and a Ford I've driven, as well). It's a part of the design of the system.

[j cAT]

Originally Posted by PeteA216

My car does that... it has since I've owned it (5 years). Maybe I should look into a new gear box if that's the case... oh and what do you mean by "hunting"?

hunting is a term that means vehicle is constantly changing from left to right whenever tires ride over small grooves in pavement. loose /worn steering componets will cause this and it appears that many alignment shops are unable to see this, because of these types of questions , after the vehicles have been aligned......an alignment tech on an alignment machine computer guided should quickly determine if this is gonna occur and why. do these tech's know what there doing?

[bobss396]

[quote=j....an alignment tech on an alignment machine computer guided should quickly determine if this is gonna occur and why. do these tech's know what there doing?[/QUOTE]

I did front end alignments every day for about 6 years, the old timer that I was "learning" from had been setting the toe wrong on cars for 22 years! I had learned the right way in automotive school, no wonder he had so many complaints for crooked steering wheels, etc.

I find that many alignment techs are ok with "going by the book" and don't know what to do when an odd problem comes up. Also some of the new alignment systems won't "let" you align a car out of spec and they spit out a ticket with all the "as adjusted" angles against the specs in the system computer. I've also seen these "smart racks" being used when they're out of calibration and producing bad alignments. We proved a few out in one shop using the good old Snap On camber/caster gages.

Bob

[PeteA216]

Any recommendations for how to make sure you're getting a good, accurate alignment? Here in rochester Sears seems to be pretty good, but seeming and being are two different things. The do ask you prior if you have any compaints about steering wheel alignment.

[bobss396]

Originally Posted by PeteA216

Any recommendations for how to make sure you're getting a good, accurate alignment? Here in rochester Sears seems to be pretty good, but seeming and being are two different things. The do ask you prior if you have any compaints about steering wheel alignment.

I had worked for a Sears auto center for a while doing alignments. We had one other guy doing them on days who was not that good and a couple of guys on evenings that did a very good alignment. The first thing I asked the customer was if he had any complaints like the steering wheel being straight, which could be a slight pull condition. I'd take my time getting the car straight on the rack, centering the steering wheel and locking it in position, we also used a foot brake lock. On some cars we would do a quick steering box adjustment if it was not a time eating ordeal.

I also worked for some independent shops doing front end work and alignments. The totally independent shops were the best to work for, they had the least amount of employee turnover and wanted to protect their reputation.

Some of the chain shops by me were out to make a buck and often ripped off customers and gave out a crappy alignment. One shop I worked at, we used to get all of one chain's dissatisfied customers.

You'd be best by looking for an independent shop with a good reputation and be leery of those who can align a car in 10 minutes.

Bob

[PeteA216]

Thats what I'll do then when I need it... go to a smaller, non-chain shop with a good rep for doing quality work.

[j cAT]

Originally Posted by PeteA216

Thats what I'll do then when I need it... go to a smaller, non-chain shop with a good rep for doing quality work.

the problem i believe is simply they do not inspect vehicle proir to alignment for suspension/steering componet wear. they will align vehicles with worn componets and then you get these type of problems..........