Car pulls quick while driving?

Tiny
LEVIAMILLER
  • MEMBER
  • 1997 CHEVROLET CAVALIER
  • 4 CYL
  • FWD
  • MANUAL
Hello again, I have a 1997 Chevrolet Cavalier, z24 2.4l 5speed. I have had a recent problem after an alignment. The car seems to pull quick to the right when accelerating and as soon as I let off it goes back left, it is very quick in action. As far as I can tell I cant hear any unusual noise. I have been chasing the problem for almost a month now, I took it back to make sure alignment was correct and they said that it was. In this time of chasing the problem I have replaced (this is on both sides)
tie rods, lower ball joints, struts, cv axles, routers, brake calipers, brakes, new tires all around (they were spin balanced), and just a couple months ago I put in a new clutch, flywheel, pressure plate, clutch mater cylinder, clutch slave cylinder. The only thing I can think of left is the torque mount, and engine mounts might be not working properly. Anyone have any suggestions?
Monday, August 29th, 2011 AT 1:10 AM

4 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Real common problem on GM front-wheel-drive vehicles. Your alignment mechanic needs to measure "steering axis inclination", (SAI). That's a secondary angle that is commonly overlooked. The exact values are not significant and there are no published specifications. All that is important is they must be within 0.2 degrees of each other. When they are not, the engine cradle must be loosened and pried to one side to make those numbers equal. This is often messed up after the transmission has been worked on because to get to it the cross member has to be lowered. If the bolt locations aren't marked with spray paint, there's little chance the cross member will be installed in the same orientation. Besides affecting "camber", which is the common adjustment, in effect, think of moving the upper strut mounts both to the right or both to the left. That will make both wheels tilt too, but that can be corrected with camber adjustments. Even though both tires will be standing up straight and equal, the steering upper and lower pivot points will not be in the same geometry.
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Monday, August 29th, 2011 AT 1:20 AM
Tiny
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Okay so I have called around to many garages, and it seems like nobody knows what "steering axis Inclination" even is. So I got looking more on the car and checked the engine mounts and A-frame bolts again just to be sure. I replaced inner tie rods while I was at it. I found the front left torque strut mount seemed to be a little loose so I tightened that and while doing so my hand slipped off the wrench smashed into the lower control arm, and to my surprise it moved. Turns out the bolt holding it to the frame was loose so I removed the torque strut mount and tightened it. Voila, problem solved. I appreciate all the help, probably will be back for help in the future. I'm sure of it with my beater!
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Monday, September 5th, 2011 AT 11:04 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Very happy to hear it's solved. When the lower control arm can move, two alignment angles, camber and caster change. Both have a real big affect on pulling to one side on rear-wheel-drive cars. Caster has very little affect on pull on front-wheel-drive cars, but camber will cause a pull, and a sloppy control arm bushing, (or loose bolt), will cause it to change when you're on or off the gas.

I should mention too that you most likely had the car jacked up when you tightened that bolt. If it's one of those I'm thinking of that goes through a control arm rubber bushing, that bolt should only be tightened when the car is at rest on the wheels. That means crawling underneath or driving it onto a drive-on hoist. The bolt will hold that bushing in the position it's in when it's tightened. If that's done when the suspension is drooping from the car being jacked up, that bushing will be held in a permanent twist when it is set back on the ground. Bouncing down bumpy roads will twist that bushing beyond its limits and lead to early failure.

Also, since the bolt was loose, the control arm would have been hammering it back and forth and would likely have stretched the hole in the frame. That would inadvertently put an adjustment into the car that needs to be set properly with an alignment. Because of the geometry of the steering system, anything that moves the position of the bottom of the wheel will also move the steering connection on the strut. That will cause the wheel to turn. Since that will make the car steer to one side, you have to correct that by turning the steering wheel. If you don't put the control arm back exactly where it was, (still assuming that mounting hole is hammered out), the steering wheel will be off-center.

You'll need an alignment anyhow due to the new tie rod ends. Be sure to mention the loose bolt so they adjust its position if necessary, and ask them to loosen and retighten it on the drive-on hoist if necessary. I had that problem with my car many years ago but there was not a single hint of a problem until right after I performed a maintenance alignment. When I finally found the cause, it was the mounting hole in the frame worn out making it twice as wide as it should have been. The fix was to remove the bolt so a washer could be installed on each end, the position of it was set on the alignment machine, then I tack-welded the washers in place to prevent the bolt from sliding in case I hit a big pothole.

As for SAI, it's measured automatically by every alignment computer when it measures caster. Those numbers should be on the printout. It's considered a secondary alignment angle so it isn't looked at unless someone is trying to solve an elusive problem. In the absence of any handling complaint, it isn't corrected as part of a normal maintenance alignment.

Here's a part of a Notes Page I produced for my students that shows what SAI is and how it can be off even though camber is in specs.
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Tuesday, September 6th, 2011 AT 8:50 AM
Tiny
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I had a hard time getting the bolt tightened on the lower control arm, so I put a jack on the control arm and jacked it up and tightened it as if it were sitting on the ground. I also noticed what you are talking about with it stretching the hole the bushing is all chewed up also. It also appeared to have bent the torque mount so I got a new one of those. I ordered a new control arm immediately. I am putting it up for alignment at the end of the week. I will make sure to let the know I replaced that control arm so they can align it properly

Thank you for the picture of the "SAI", it was hard to tell exactly what was meant from reading about it online. But the picture clears it all up.

Kind of grinds my gears it was only a bolt that was loose after replacing so many parts but at least I have a whole new front end, wont have to worry about it breaking for a while (hopefully).

Thank you again for all the help, it was greatly appreciated!
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Wednesday, September 7th, 2011 AT 2:35 AM

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