Steering Jerk on the freeway - Rack maybe?

[callys]

My 90 5.0 is my daily driver and I put a lot of miles on it. In the last month or so it has developed a strange steering jerk on the freeway. I don't know how else to describe it.

I got the car aligned, and if I take my hands off the wheel it drives straight but will kind of quickly rip to the right then straight again, then rip, then go. So it isn't the most confidence-inspiring machine on the freeway. This problem doesn't start until 75 mph.

All 4 tires are new, and balanced. The lug nuts are tight. The wheel bearings are tight. It has two new inner tie rods. I have a two post lift at my house, and if I put the car in the air and grab the wheel on each side and try to wiggle it I can't.

Is this most likely the steering rack going bad? Or maybe just bad wheel bearings? I need to get it sorted out, because I drive about 2k miles a month and I am worried about it going downhill fast.

Anyone ever have a similar problem?

Thanks

 

[93 LX]

sounds like inner and outter tie rods.

 

[wythors]

Was the problem present before the alignment? If not, it sounds like the caster setting is way off causing "tram lining", or your car following imperfections in the road surface.

 

[callys]

No the problem was not there before the alignment, but it wasn't there right after the alignment either...which has me stumped


How do you diagnose a bad rack?

It is hunting though as you said wythors

 

[Mustang5L5]

I've had certain tires do that. Right now the front two tires on my '03 do it badly. I swapped two other Mustang wheels on there just to see and it stopped completely. I put the other two wheels back on on and it would jerk me all around the road. Driving on the highway was fun because you had to hold the wheel when you changed lanes otherwise it would grab the ridge between the lanes and ride it.

I've gotten an alignment, and will be getting new tires shortly because it's annoying.

 

[795.0pacecar]

Try rotating the tires and see if it goes away, or if it shows up on the other side of the car, even if you have directional tires just do it temporarily to see if its a tire issue.

I would highly doubt that its a caster issue, there isn't enough caster adjustment even with caster camber plates in a stock fox front suspension.

My guess is bad bushings or a bad rack. Pry on the bushings with a pry bar, there should be very little play.

 

[Beasty306GT]

If you got 9" tires on ur front they find every crack and wave in the road...i found that out when i put my cobras on....i kinda wish i waited to do a 5 lug swap...now im stuck with my wheels

 

[callys]

The front tires are only 2 weeks old (same as stock 225/60R15s), it did it with both the old and new tires...

Will try to pry on the bushings tonight on the rack and see how much flex I get

 

[wythors]

Take it back to the shop that did the alignment and tell them to fix it. Your problem is obviously related to what they did.

 

[Mustang5L5]

If it did it with the old tires and new tires it might be more than just an alignment issue.

Put the front k-member on jackstands and get a prybar. Put the bar under the tire and lift up. See if you get any movement. Try for left to right movement as well