Alpine951

My car was in my garage for the previous two years. I finally got it back on the road. Its been shaking in the front end and through the steering wheel on the highway. I got the wheels rebalnced and still shakes. I took a look underneath and everything looks tight. I popped open the hood and looked at the top of the strut mounts. I noticed there is about 3/8" of space between the top metal plate and the rubber beneath it on one of the strut mounts. I jacked up the car and the gap disappeared. I replaced the stock boge or sachs shocks about four years ago with the paragon koni inserts and 300# springs with the lowering kit. i don't think i replaced the mounts at that time. Should there be a space in between the top metal part of the mount or is this a sign of a bad mount that would be causing all the shaking?

asoduk

i'd look at the tires first... many times, when a car sits that long the tires develop flat spots and you get shaking.
usually a bad strut mount makes a popping noise when its loaded under cornering.

Alpine951

The car was up on jacks the whole time.

knfeparty

^ smart man, that saves the springs, too.

I've had strut mounts go bad and the car still felt solid, but would pop when you would be driving back and forth in a parking lot (especially backing up, turning, and braking at the same time). I don't know, I mean alignment, wheel bearing tightness, tire balance is about it, unless a control arm bushing or caster block went sour.

Potomac-Greg

The gap between the hockey puck and the metal plate is not an issue as far as I can tell.

Lizard944

Wheel bearings are too loose?

968rz

My money is still on tires, try to swap tires with another 944(if you can) that is driven and see how it feels.

Van

How do the brakes feel? Pedal soft? Pulsating?

Also check your tie-rod ends.

Alpine951

I put the track wheels and tires on and it still shakes in the front between 50 to 90mph. Sometimes the shaking is not as bad. I jacked up the car and started tyanking on a few things. I didn't get the chance to devote much time to looking under there. The castor rubber looked solid. I yanked on the tierods and they didn't move. I put a bar under the tire and pulled up on it to see if it might be ball joints. I didn't notice ant play but did notice that the wheel moved up about 1/2 inch meaning the shock compressed. I have the the paragon koni inserts with shorter springs that are only under tension when the car is on the ground. I tried moving the wheel side to side and it turned the steering wheel an inch until the steering wheel locked but there was no more play beyond that. Hopefully the weather is good this weekend. I will crawl under and see how tight the rack, cross member, and control arm bolts are. I am still wondering about the strut mounts though? They are original and I wonder if the car being up on jacks for a few years made them compress. What actually fails on the strut mount? I don't remember what it looked like but isn't it that there is a bearing that the strut rod goes through? Does the bearing fail and is the failure diagnosed by side to side play of the strut. I tried shaking the car from the side to see if the strut cap would move but it didn't move side to side. I will probably take the wheels off and check the bearings also. Brakes seem fine, no pulsating.

Alpine951

The right side wheel bearing was a bit loose. I could shake the wheel a bit by hand so I snugged the nut and it didn't shake by hand anymore. I couldn't see any play in the ball joints. I took it for a ride after doing the wheel bearing and it was still shaking. I crawled back under and noticed the rubber was cracked on the drivers side castor block. Here is a pic. I am wondering if this is the problem. The xar was up on ramps when i noticed this. I put a jack under
the control arm right where it attaches to the castor block and jacked it up just a little and I could see the rubber compress a bit upwards. My finger is holding back the piece of the rubber that I can pull away.

KuHL 951

Yep, you need new caster blocks. Use the 968 style and it will tighten the entire front end up. By any chance did the car ever run 17" or larger wheels? Not saying this will solve everything but that one in the pic is toast.

jstand22

alpine, where in MA are you?

Will Feather

im here in MA to lend a hand!

xsboost90

make sure you adjust the wheel bearings so that you can barely move the thrust washer once the nut is tight with the tip of a screwdriver. If you go too tight the aluminum will expand and lock up the hub.

check to make sure that the nut on top of that strut is tight all the way.

951Tom

It would be good to get a 4-wheel alignment done afterwards.