Really loose feeling when hitting bumps?

[Chris_North]

A while ago I noticed that when hitting bumps in the road at speed (anything greater than 30MPH) I would have a hard time controlling my truck when making turns. To an extent I know this is normal, but it almost feels like the bottom of the truck (mostly in the back) is being kicked out from underneath the body a good few inches and it feels like I'm about to lose control. I especially notice this at a particular exit from the freeway, where I'll probably be slowing from about 55 while turning, then there's a fairly massive buckle in the pavement that almost causes me to launch off the road.

This really started to occur only slightly at first. Then I had an issue with my rear wheel bearings and diff. It was much more cost effective to replace the entire rear axle assembly. During replacement, I found one of the shocks was completely destroyed. The other seemed okay, as did the fronts, but I replaced all four with Monroe Gasmatics. This actually seemed to make the problem worse. I also replaced the front sway bar support bushings with no difference. As far as I can see everything is intact as far as suspension components, but I have a front clunk noise occasionally when turning the wheel. I plan on replacing the rear sway bushings as well (they don't look horrid, but could be replaced).

I've tried rocking the truck from the outside and seeing what moves, but the only thing I see flexing is the tires. They are Cooper Discoverer HT, about a year and a half old, with 40% wear on them. They were inflated 35/35 but I dropped the front down to 30 PSI as per the door tag recommendation. I remember when I first bought my ranger it had really worn Wranglers on it and handled somewhat similarly before I put the Coopers on. After that I had a lot less sway.

So where should I be looking to fix this? Is it possible that this is all caused by worn tires? I'd like to get this sorted out because especially in the rain I could see losing my truck after hitting an unseen bump on the highway. I'd also like to make sure this isn't indicative of a more dangerous underlying problem.

 

[straycat]

That issue is caused by suspension wear. If you don't know anything about rebuilding the front end you need to get it to a shop...NOW. You could cause an accident or a death. Ball joints or another part worn or loose, but you don't need to wait from a response to see what the matter could be...get to a shop.

 

[gjm4l]

HUGE x2^. If your unknowledgable get it to a shop before it comes apart or you do lose control PLEASE! It could be anything from a blown front wheel bearing to tierod ends to ball joints to all of the above.

All trucks will "feel" a little tail light while hitting a bump with the rear unloaded (under braking) in a corner but if it truly is about to get away then there is something WRONG!

It seems in your post you did your new axle and new shocks yourself so I assume your mechanically inclined. So get the front end on jackstands. Look at both front tires see if they have excessive or choppy wear if so somethings gone bad.. Then grab each tire top and bottom and push/pull and see if there is any play. Any more than just a "fraction" (as in you can feel it but not see it) means something is worn out. In/out movement is an indicator of bad/loose bearing and/or bad balljoints. Even if it's just a fraction of movement I'd still check my wheel bearings.

Then grab tire on left and right to check for side to side movement. You can "feel" looseness and play without moving the tire more than an inch back and forth. Usually you can feel a rod end clicking back and forth if it's bad and hear a box slapping around (I don't remember for sure but your 98 may have a rack by now, a rack or pump going bad will usually show itself with stiffer steering/noise)

If none of those checks work it's time to put hands on every last part to check for slop. Visually inspect all bolts and mounts and for ball joints and rod ends if you don't put hands on it to check for play you didn't check them.

There is something or everything badly worn out or broken in there and it needs to be fixed YESTERDAY!

 

[Chris_North]

Definitely don't want to kill anybody. There's a shop I trust so I may take it in to him or take to sears for an alignment because in the past they have found things wrong and warrantee their work for 6 months so after I fix I will be able to take it back and get everything redone for free. I've had the front end up and pulled on the wheels but I don't have any real play in the front. I'll double check tomorrow.

I forgot to mention the upper ball joints are new. IIRC last time I had it in for an alignment they said the lowers were getting worn and could be replaced. For replacing the entire lower A arm how do you take the tension off the torsion bar? After jacking it up and backing the adjustment screw off is it pretty much under no tension or do you need special equipment? I'm not real experienced with automotive, but I am mechanically savvy. I just got done replacing the heads a few weeks ago. There's only one shop I trust around here, but I don't like to spend money I don't have to.

Forgot to say it really doesn't feel like bump steer, it feels almost entirely in the back. I was driving today over the stellar PA roads and I noticed really the whole truck drives like crap. It corners fine, but any kind of bump you feel like the cab is on a waterbed, then on the frame.