Loose Steering/Poor lane tracking 91 Caprice


red88jeep
02-02-2008, 01:37 AM
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
02-02-2008, 01:54 AM
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
02-02-2008, 07:33 AM
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
02-02-2008, 01:19 PM
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
02-02-2008, 09:06 PM
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
02-03-2008, 03:33 AM
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
02-03-2008, 09:41 AM
[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
02-03-2008, 07:12 PM
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
02-03-2008, 08:29 PM
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
02-04-2008, 12:46 AM
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
02-04-2008, 06:59 AM
[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
02-04-2008, 12:21 PM
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
02-04-2008, 12:35 PM
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
02-04-2008, 03:51 PM
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
02-04-2008, 11:27 PM
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..........

PeteA216
02-04-2008, 11:56 PM
Yeah, I see what you mean. I do actually check all steering a suspension components everytime I happen to be under the car.

red88jeep
02-29-2008, 04:40 PM
Hi Again. I got the loose steering/poor lane tracking problem resolved. After sniffing around the front end, rear suspension and steering column and not finding anything wrong for the 6th time, I took the car back to the tire store (Discount Tire /Americas Tire) and talked to them again about the problem. They took it in and did something they called a "Tire Road Load check" or some such thing. I have no idea of exactly what it really is or what they do. Never heard of it before. Anyway, they took it off, did something with it and remounted it. They basically turned it around on the rim and aligned it with the wheel rim for lateral and radial runout. They rebalanced it and put it back on. Guess what? problem is gone. The car is steering straight (back to the Chevy steering on novocain. Its as numb with lack of road feel and feed back as almost every big Chevy made.) The wheel is centered again and it goes down the road more or less directly like it should. Rides smoother too. (wish it had a good quick ratio rack and pinion system though.) I guess the lesson from this is that tires can cause symptoms that simulate major mechanical flaws and it takes folks who know what they are doing to solve them properly without spending a lot of money. (my cost, $0.00 as I have a life time balance, rotation and flat repair with my tires.) Thanks, Ron

bobss396
03-01-2008, 11:39 AM
That happens sometimes, but usually the tip off is the tire takes an excessive amount of weight upon the first balancing. Normally tires should require a reasonable amount of weight, the ones with problems require something like 3 ounces and up.

If it wasn't the initial balance, I would say that your tire didn't have one of the beads fully seated when it was first mounted. Every tire needs a visual inspection after it is mounted, most of the tires you can eyeball pretty accurately and see if the bead is uniform.

That would easily cause your problem. If you don't know to look for it on a mechanic level it can drive you nuts. But they did the right thing and broke the tire down (used lots of soapy water) and remounted it. All's well that ends.

Bob

j cAT
03-01-2008, 12:57 PM
If it wasn't the initial balance, I would say that your tire didn't have one of the beads fully seated when it was first mounted. Every tire needs a visual inspection after it is mounted, most of the tires you can eyeball pretty accurately and see if the bead is uniform.

That would easily cause your problem. If you don't know to look for it on a mechanic level it can drive you nuts. But they did the right thing and broke the tire down (used lots of soapy water) and remounted it. All's well that ends.

Bob

If the rim bead area was not cleaned properly and they added too much water to the bead sealant/lurbricant to save a few $$$ this could have caused the bead not to seat properly, but the tire will be balanced...basicly an out of round tire causing a shifting effect.....going down the road...

red88jeep
03-03-2008, 04:29 PM
Hello, Just to further my education on tire behavior issues. I guess we are now moving in the more advanced area of tire/chassis setup knowledge. Just to clarify, the tire did not have a lot of weight installed. I think the total weight was less than 2 oz. The wheels are in excellent condition and the bead area is not damaged or corroded. After they remounted the tire this last time, there is now 1 tiny weight on the inside (the flat stick on type mounted to the centerline of the rim). Am I to understand this is not uncommon for a tire to not mount properly on the bead/rim interface? When it happens it will change the way the tire rolls down the road big time? An otherwise perfectly serviceable tire not properly mounted can cause the side to side pull, be thumpy and vibrate just because of a problem with the bead seating? It does makes sense, but I thought that the sidewall flex would mitigate the issue. Thanks Ron

GreyGoose006
03-03-2008, 04:42 PM
hoping that since his problem is solved, you can help me with mine...
my caprice, (84, 4dr) seems to drive straight at lower speeds but on the highway, i feel like a drunk trying to drive it...
it wont stay in the middle of the lane and seems especially prone to wandering when the rear of the car is loaded down with luggage.

example.
the other weekend, i had a total of 7 people in my car, including me, and the trunk was full of their stuff, and the car simply would not stay straight.

is this normal, or what?
anyway, i am having many of the same problems as red88.

silicon212
03-03-2008, 06:23 PM
GG, in your case, check the performance of your shocks. A new set can do wonders.

GreyGoose006
03-04-2008, 10:05 AM
the shocks are pretty recently new.
i got them ~2 years ago
they are the super heavy duty 9c1 spec shocks

silicon212
03-04-2008, 11:50 AM
Yes, but that doesn't mean they're in great shape. I bought a set of monroe Sensa-Trac shocks for my 9C1 back in late '06 - by mid '07 one of them had to be replaced due to tracking issues - it had leaked out.

bobss396
03-04-2008, 03:14 PM
Hello, Just to further my education on tire behavior issues. I guess we are now moving in the more advanced area of tire/chassis setup knowledge. Just to clarify, the tire did not have a lot of weight installed. I think the total weight was less than 2 oz. The wheels are in excellent condition and the bead area is not damaged or corroded. After they remounted the tire this last time, there is now 1 tiny weight on the inside (the flat stick on type mounted to the centerline of the rim). Am I to understand this is not uncommon for a tire to not mount properly on the bead/rim interface? When it happens it will change the way the tire rolls down the road big time? An otherwise perfectly serviceable tire not properly mounted can cause the side to side pull, be thumpy and vibrate just because of a problem with the bead seating? It does makes sense, but I thought that the sidewall flex would mitigate the issue. Thanks Ron

I've seen tires that had a un-seated bead that caused weird ride problems, just like yours. Balancing the tire only showed that a 2 ounce weight got it to balance, which is not a tremendous amount of weight.

The fact is that the course of action the tire shop took was the right one. They broke it down, rotated it on the rim perhaps and made sure the bead was fully seated. Some radials take more oomph to seat the beads than others, lubrication is crucial too.

Bob

red88jeep
03-04-2008, 03:18 PM
GreyGoose, My suggestion: Start with the simple things. If you already have not done so is to start over with a ground (tire up) inspection of everything. Front AND rear. Toss out any previous thinking of what might be wrong. It can cloud the process. As you verify the function and condition of each component, then move to the next one. Take time to inspect your tires and wheels for matching size, type, condition and fit. Use an accurate Tire Gauge to check the air pressure in the tires and make sure they are to spec. (7 people and gear can add between 1000 and 2000 pounds of payload. Most cars and their tires only are rated for about 900 to 1100 lbs of people and gear. See car capacity plate on door jam.) If your tires are not rated for the car weight and payload, they can get mushy on performance (See side wall of tire for weight capacity at what pressure.) Just because a tire looks OK, does not mean its properly inflated. Often you do not see any visible change in the tire shape until the pressure drops to around 15 to 22 lbs. From that point, closely look at every thing from tires to lug nuts, Wheel Barings to springs, frame to bushings, steering components and so on. If you are using aftermarket wheels and or tires, make sure the offset is within proper factory parameters. If you go to far out of range, it can cause the geometry to get way out of whack and the suspension cannot function properly. the result is poor steering and possibly tire and component wear. If everything checks out then you might try moving tires around to see if it changes anything. If you have a tire doing goofy things, then you might discover it by moving it to a different position. After all that, then an alignment check is probably in order with attention to toe.
My last piece of advice is not to just throw money at replacing things. If it seems not quite right, make sure it is verified against spec. A common problem is to replace perfectly good parts because they were not properly inspected using the right process. Shocks, ball joints and steering linkage components are common items replaced without proper verification to specification for replacement condition. Just because its old and dirty does not mean its broken. Ron

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