Strut replacement problem

[rallysam]

Hey guys, I replaced my struts with KYB AGX's this weekend, and they feel great but I have serious issues on the fronts. The backs are great, but I need help.

The problem is the ball bearing joint in the front strut top mounts. This is the bearing that allows the struts to steer along with the wheels. The bearing is binding up whenever I tighten the top nut (the nut that connects the damper rod to the top mount). I'm not talking about cranking it down, I'm saying if I finger tighten that nut, then it binds up the steering (the symptoms are that it's slightly harder to turn the wheel and I hearing creaking/binding noises while I steer). The only other option seems to be actually leaving the nuts loose enough that when I go over cracks/potholes the whole mount actually rattles loudly because the damper rod is loosened from the top mount. Are there supposed to be washers under that nut? The rear AGX's came with washers but not the fronts. (I am using the new nuts that came with the AGX's)

Here's how I assembled that strut and diagnosed:
1) Everything is disassembled, spring is compressed
2) Top strut mount still spins freely
3) Put old spring onto AGX along with old top mount, bumpers, dust boots, spring seats, etc
4) Used impact wrench (on lightest possible setting) to tighten top nut because any other method would be inaffective due to the damper rod rotating
5) Noticed that the top mount could no longer spin
6) Cursed
7) Impact wrench to unscrew: then it rotates freely again
Impact wrench to rescrew: then it's bound up
7) Loosened top nut with hand wrench (that's why I don't think I overtorqued it) until top mount can spin again
Uncompressed spring
9) Installed in car
10) Now that car weight is on it, top nut is now clearly unscrewed far from it's resting postiion
10) Upon driving, loud rattling going over potholes due to loose top nut
11) Tighten nut with fingers (while strut is installed in car) until it just barely starts to bottom on the top mount
12) Rattling stops completely, but steering is bound up (harder to turn wheel, creaking noises as wheel is turned)

What's wrong here?
Thanks for any help
Sam
90 Legacy L Wagon AWD

[Legacy777]

something is obviously wrong.......Did you have washers on there before?

I don't remember if mine had washers or not.....I could go and look this afternoon.

It's possible that the strut top mount is old, and the bearings are messed up.

If putting a washer on doesn't fix the problem, I'd say get new top mounts......

[DLC]

There's supposed to be a washer that goes from the stock setup to the new setup. It's not a flat washer, but is tapered in towards the top and i think it only makes contact with the center part of the bearing so that when you put the nut on, the pressure is on the inside.


It sounds like you're binding is happening on the bottom side, where the top hat is being pushed into the bearing.

Look over your stock setup and you should be able to find this piece.

Dave

[rallysam]

I suspect that you are right and those washers in the picture are the problem. I thought I was careful to reinstall them in the exact same place, but I must have been wrong.

It looks like I have them below the upper spring seat (sitting on the shoulder of the damper shaft) and they are visible from underneath in the wheel well. I must have put them there because the taper of the washer matched the conical shape of the spring seat. The diagram says they should be above that spring seat... between it and the rotatable upper mount. Darnit, I guess I'll have to get those struts off of there while I miss a rally cross this weekend.

I'll let you know what I find once I get them off the car and can actually look at them up close. Thanks a lot for the help!

[rallysam]

Problem fixed!

For reference: Without those conical washers, the spring seat was pushing and dragging on both the inside and outside races of the ball bearing - preventing it from spinning. This made the steering sorta hard .

Now, those conical washers are in place to take all the force from the spring seat and funnel it to the inside race of the bearing - leaving the outer race free to spin without drag.

Miraculously, nothing broke and the AGX shocks feel great.