[Cdover73]

I recently noticed my car has a drift effect that just started. It is very noticeable and is worse at slower speeds (45mph and less). I can feel it when I swerve the wheel left/right with quick inputs, when I shift 1,2 and 3 gears taking off from stop, if I give slightly aggressive throttle on and off, and sometimes when braking. The best way I can describe it is it seems like the rear of the car is trying to pass me or the rear axle is trying to steer in an opposite direction from the body. Almost like the frame is disconnected from the wheels and suspension and the rear of the body is swaying over the rear axles. It feels 'greasy' like when you have a low or flat tire in the rear. But it doesn't do it all the time...!!

I have checked all psi, wheel lugs, wheel bearing mounting bolts, a-arms upper and lower, differential mounting bolts, torque snubber bolts(that's what I call the anti-torque arms that bolt to the frame from the diff), CV axle joints, looked for leaks(shocks/suspension), steering rack for tightness where it mounts to the frame, steering column shaft flex dampener, Pittman arm connection, proper/adequate PS fluid, and tried to tell if any air is in the system. Everything appears normal. I followed all troubleshooting in the shop manuals and also tried prying on all the bushings, tie rod ends, ball joints, and suspension with a pry bar with the car both on the ground and also with the wheels off the ground with no load. I did find a very small amount of play in the lower a-arm bushings but I'm talking only thousandths of an inch. Why would it feel 'loose' in the rear like it has 4 wheel steering?

Recent work on the car:
-Changed all clutch components including slave cyl.
-New tires last summer (<2000 miles ago) mounted, balanced, and aligned by local reputable tire shop.
-changed PS/hyd fan lines to upgraded hoses after o-ring leak at pump
-attempted to change right rear wheel bearing but found e-brake to be where squealing was coming from, not wheel bearing so did not change.
-other engine/exhaust related repairs (spark plugs, oil change, O2 sensor, etc)

Problem started during a 100 mile interstate drive to Biloxi a couple weeks ago. Hasn't gotten any worse and doesn't feel unsafe to drive. Like I said, it's like the rear wheels are trying to steer themselves out from under the car.

Anybody else ever experience this or have an idea where to look next? Thanks in advance. Btw, car just turned 60,000 miles and has a fairly new set of PS2 Michelins all around.

Thanks,
Cdover73

 

[HughJass]

My Gen 3 has always felt like that. I assume it is the quick steering ratio.

 

[GTS Dean]

Most likely it is unequal toe-in L/R. One likely cause is that an alignment cam has loosened and shifted. This would affect caster, camber and toe on one corner. How many miles on the car? It could be rear toe link wear, but not expected under 40-50k miles.

 

[Cdover73]

Hopefully I can get it on a rack soon. I should be able to see witness marks if anything loosened and moved. I have a lot of oil under the car too that seems to be coming from the oil pan gasket. Although none of my fluids are low. And something going on with my evap system not purging properly. On top of the wet floorboard and running lean/rich issue....when it rains it pours.

 

[Motomaggot]

Maybe the belts in the tire have separated? (Just a wild guess based on everything you have checked/ eliminated.)

 

[Recluse]

Check your tires. I had a similar feeling when I replaced only the rear run flats with non run flat PS2s. Any kind of rutting in the road made the car want to jump into the ditch. Hard acceleration was the same. Once I replaced the fronts with non-run flats it handled great. I presume it is the difference in sidewall stiffness which could also occur if you are running two different tire makes on your car. And of course tire pressure should be checked as well.

 

[GTS Dean]

Maybe the belts in the tire have separated?

Belt separation most often leads to thumping in motion and you can almost always see a bulge or other obvious clues in the tread.

I still stand on my initial diagnosis. It's camber thrust, toe, or both.

 

[Plumcrazy68]

One of your rear tie rod ends is bad.

 

[GTS Dean]

See post #3.

 

[Cdover73]

Check your tires. I had a similar feeling when I replaced only the rear run flats with non run flat PS2s. Any kind of rutting in the road made the car want to jump into the ditch. Hard acceleration was the same. Once I replaced the fronts with non-run flats it handled great. I presume it is the difference in sidewall stiffness which could also occur if you are running two different tire makes on your car. And of course tire pressure should be checked as well.

PS2's all the way around with very few miles on them. Just put them on last summer. Running 29psi in all four and check often. I know these tires like to 'hunt' and dart with grooves or ruts in the road. That isn't what this is. It literally feels like the rear end is not attached under the body. It isn't very bad, but definitely noticeable.

Cdover73

 

[Cdover73]

I finally got another appointment to get it on a rack at a local tire shop. Gonna check all the connections. I'm leaning toward worn components as well. I jacked it up in the rear and tried to move both back wheels. There is very little play, but not from the wheel bearings. I can see it moving at the a-arm bushings. Not much but enough to see. The hub, bearing, rotor assembly all moves together and the slack is at the bushings.

Cdover73

 

[Cdover73]

Well hell....after getting it on the lift and taking all 4 tires off, checking the PS fluid level and output, checking all connection points for steering and suspension, checking torque on rear diff mounts, checking for broken welds, inspecting tires and wheels, and pretty much everything else we could think of....the problem is still there. The rack I used was at a local tire center and the guy helping me was a good friend and their front end alignment/exhaust guru. I just talked to him and he said he is at a loss. What the hell has my car going in whatever direction it wants to in the rear???!!!

We checked every possibility you guys mentioned and the only thing we could find was the little bit of play in the bushings. We put wrenches on it, had it on the alignment rack for 0/0 perfect alignment, tried binging the front tires in the c-channel track of the alignment rack and turning the steering to see if there was air or dead space in the steering or if anything moved....NOTHING!!!!

He rode with me and agreed something isn't right. He noticed it right away and said it feels like the car has front tire traction on the pavement but ice blocks for the rear. He even hung out the window to watch the passenger back tire to see if it was moving.

The only thing i have left that I can think of is taking the tires off the wheels to see if the sidewalls have broken down. That is actually what it feels like. Like the back tires are rolling off the wheels. But why only when braking or slow driving? Hit the gas and they plant and its on rails again like it should be.

Does anybody have any more suggestions???

 

[Brickhead]

Over-inflate tires & take it for a roll... whats to lose?

 

[GTS Dean]

I would confirm that they are mounted with proper directionality. If that checks, remove the rear wheels and swap sides of the car and retest. If still bad, dismount the rears and inspect them carefully.

 

[Cdover73]

And the win goes to....the guys that said rear toe link!! The flexible joint at the boot on both sides is where the slack is coming from, not the bushings. This small amount of slack is allowing the back tires to actually steer, hence the drifting I been feeling. I am surprised how both sides have about the same amount of slack. And how little slack makes that big a difference.

Now the question is, does this require an adjustment to correct or replacement of both tierods? I see adjustment nuts like any typical ball joint tie rod, but is the flex joint serviceable or adjustable? I haven't taken them off and have not tried getting the boots pulled back to inspect until I could ask what was under the boots.

 

[GTS Dean]

Under the boot it looks like a small ball joint with a very long stud. Instead of being pressed into a control arm, these usually come with either a male or female thread to screw into your inner toe link.

 

[Cdover73]

Thanks GTS Dean. So, does this mean any slack at this joint can be adjusted out, or do I need to get two on order? The manuals don't say much about inspection and replacement criteria.

 

[GTS Dean]

Order a pair. No matter how much you adjust, the slack is still there.

 

[Cdover73]

And finally just to be totally clear...you think this is actually my problem? I mean is the looseness i describe a known direct result of wear to the tie rods? Even though the amount of slack is minimal? Just wanna make sure I am changing the right parts. But this is the ONLY place that has slack. I thought it was bushing play in the a-arms but after looking closer it is for sure coming from these flex knuckles. If they wouldn't cause the slipping in the rear then I haven't gained by changing them.

 

[GTS Dean]

The geometry of the outer steering knuckle toe link attachment magnifies the looseness in terms of toe per wheel. How ever many thousandths the ball joint moves is multiplied by about 3x at the tire OD. If both sides are worn, multiply that by 2x.