89 S-10 Front end problem

I have an 89 S10 blazer 4x4 the other night i was driving and i got a thumping in my front end that jerks the steering wheel....imediatly i thought tie rod but i checked the tie rods today and there is a small amount of play but nothing that would cause the wheel to jerk like it is and the bearings seem to be in good shape as well...Also it happens while driving in a straight line could this be caused by a worn steering box? Anyone ever have a similar problom or any ideas of what may be causing this????

Thanks
Steve

Jerking while driving on a straight level road would be more indicative of the tie rod than the steering box, but don't rule that out just yet. Am I correct in assuming there's no constant wobble or vibration to indicate a wheel bearing? It doesn't take much play in a tie rod to cause your vehicle to jerk. 3 degrees, which doesn't feel like much when you're pulling on the tie rod, equates to about 3/16" on the outer edge of the wheel, enough to case a jerk when it shifts from one side to the other. The steering box can also cause a jerk if there's play, but you're more likely to feel the problem more in the steering wheel. Try this. Lock your steering column and jack your front wheel up (only one wheel off the ground at a time). Be sure to block your wheels and use a safe support. Push and pull on the outer edge of your tire - straight out to the front from your hub. Any movevement would indicate a tie rod, since the tire still on the ground would stop any play in the steering box. The tie rod is a better problem to have than a steerig box. It's cheaper and easier to fix. If you don't get any play on either front wheel, then try lifting both tires off the ground - be sure it's supported safely. Pull on the edge of either front wheel and watch the other. If both wheels move in the same direction at the same time, then you might have a problem in your steering box. Have someone watch the steering wheel to make sure it's not moving at the same time. If the steering wheel does not move while the wheels do, have your steering box serviced. The steering box is a primary system. If you're not familiar with this system, I'd recommended having it services by a professional.

you might also check the idler arm too those go out quite a bit. on an odd shot and not 100% on what they used but it could be a u-joint at the wheel for the front diff axle too.

RahX, you're right. I forgot about the CV and front differential factor.

They don't usually go to jerking without giving some other symptom first, but that could be. Have you noticed any thumping noise when you turn in one particular direction? And how about now, if you turn sharp in one direction or the other do you get a thumping or the feeling that the wheel is pulling back from you in surges?

RahX, you're right. I forgot about the CV and front differential factor.

They don't usually go to jerking without giving some other symptom first, but that could be. Have you noticed any thumping noise when you turn in one particular direction? And how about now, if you turn sharp in one direction or the other do you get a thumping or the feeling that the wheel is pulling back from you in surges?No there was no thumping, but im starting to lean twords the tie rod because there is a slight amount of play in the tire....But the steering wheel is jerking with the thump

It's good to rule the tie rod out first. That's the easiest and least expensive problem to fix of the listed possibilities. Do you hit all your greese ports every other time you change your oil (assuming you're changing oil at 3 to 4k miles)? If so, have you noticed any leaking from your tie rod end?

It's good to rule the tie rod out first. That's the easiest and least expensive problem to fix of the listed possibilities. Do you hit all your greese ports every other time you change your oil (assuming you're changing oil at 3 to 4k miles)? If so, have you noticed any leaking from your tie rod end? Ya i grease the front end every other oil change, everything looked ok the last time i did it. I will be able to get a better look tomorrow at my buds garage when i get the truck up in th air....I really hope its not the steelring box but i have to fix it no matter what it is

hi you might also look at the front tires. it sounds like a broken belt or two
on one wheel.

I would stuff grease in 1 component, then go for a test drive. If it's a little better you've found the problem, if not try the next grease nipple, ect
The front end will tighten up to a point when it's got lots of grease

This may sound completely retarded, but check to see if your lug nuts are on tight. I had the same problem after i got a new set of tires from a shop up here in yooper country. every so often i would have a jerk in the front end. You may have already checked this, but I thought I'ld just run one more idea at ya. Like i said, it sounds like something stupid, but it can happen...