Movement in front wheel - bad strut?
08-01-2002, 06:25 AM
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Movement in front wheel - bad strut?
Had movement in right front wheel when grabbing top of wheel & pulling.
So I just got done replacing both side front wheel bearings on my '93 968 due to what I tought was a right front wheel bearing going bad. Turns out that wasn't the problem. Old bearings looked original (looks like neither hub had ever been off the car) and car has 80k+, so might has well have.
I pulled on coil spring and got the movement. So it wasn't in the hub or bearings. Next place to look, ball joint and/or eccentric. Pulled on the coil spring got movement, the entire suspension assembly pivoted on ball joint (ball joint OK), upright to strut mount assembly didn't move. So the next place to check, upper shock mount. Everything was tight.
So could the strut be bad? They are Koni yellows. Has anyone ever had a failure mode like this on their struts? The shock is still damping well enought to feel right, even in an Auto-X situation (I heard a clunk at the beginning of the last run of the day, finished the run and was slow, but within reason - a few tenths).
Any help is greatly appreciated. I have a track day coming up with some folks at work on the 19th and really hope to get this fixed by then.
So I just got done replacing both side front wheel bearings on my '93 968 due to what I tought was a right front wheel bearing going bad. Turns out that wasn't the problem. Old bearings looked original (looks like neither hub had ever been off the car) and car has 80k+, so might has well have.
I pulled on coil spring and got the movement. So it wasn't in the hub or bearings. Next place to look, ball joint and/or eccentric. Pulled on the coil spring got movement, the entire suspension assembly pivoted on ball joint (ball joint OK), upright to strut mount assembly didn't move. So the next place to check, upper shock mount. Everything was tight.
So could the strut be bad? They are Koni yellows. Has anyone ever had a failure mode like this on their struts? The shock is still damping well enought to feel right, even in an Auto-X situation (I heard a clunk at the beginning of the last run of the day, finished the run and was slow, but within reason - a few tenths).
Any help is greatly appreciated. I have a track day coming up with some folks at work on the 19th and really hope to get this fixed by then.
08-01-2002, 06:40 AM
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If you're certain the ball-joint is okay - it's got to the be either the upper strut mount or the strut itself. Not common for the strut shaft to move so freely as to cause concern, but certainly possible. More common to the strut insert cars to have a loose retaining cap... this will not happen with your sealed Koni.
Assuming you have a dust boot, you're going to need to move it up so you can see the strut shaft as it enters the case... check for movement. The upper strut mount has a bearing within that can wear out. You won't see any movement from the top unless you remove the plastic dust cover from the strut washer. If neither of these show any movement, I'm stumped.
You don't happen to have the Koni insert conversion (8641-1414S)?
Good Luck!
Assuming you have a dust boot, you're going to need to move it up so you can see the strut shaft as it enters the case... check for movement. The upper strut mount has a bearing within that can wear out. You won't see any movement from the top unless you remove the plastic dust cover from the strut washer. If neither of these show any movement, I'm stumped.
You don't happen to have the Koni insert conversion (8641-1414S)?
Good Luck!
08-01-2002, 10:51 AM
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I have this same problem. it started with a bad ball joint. Bought it that way. so I have no idea how long it was driven previously. but I can actually see the wear and movement on the strut insert. I just got a new insert today and have bought new bearings and swaybar bushings in the last few weeks.. will assemble this weekend. As near as I can tell this all started with a leak in the power steering unit and it just ate away all the rubber to the point that the strut shaft was bearing all the wieght of the corner and enventually wore into the strut shaft? I will learn more after I tear it all apart.. Not sure if this helps at all. just letting you know that It has happened.. 
08-01-2002, 10:55 AM
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How long ago did your replace your bearings? It takes a little time for them to seat themselves, and afterwards, you may need to tighten them a little.
That's what happened to me after replacing the driver's side bearing and doing a track event. Had to tighten it less than a 1/4 turn.
-Zoltan.
That's what happened to me after replacing the driver's side bearing and doing a track event. Had to tighten it less than a 1/4 turn.
-Zoltan.
08-01-2002, 12:58 PM
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Assuming that the car is jacked up when you feel the movement -
With the shock at full extension, it is not unusual for there to be a little side-to-side play in the shaft, in other words, for the assembly to "bend in the middle" where the shaft enters the shock tube. It will produce just the effect you describe. With the car on its wheels, the movement goes away because of the longer distance between the shock piston and the upper bushing.
It does not necessarily indicate that the shock is shot. I confirmed this with Koni a while back, and with the guys at Auto Associates (Jim Newton's noted Porsche shop). I drove my car in lots of track events and for several thousand street miles after discovering it with no problems. It did eventually get worse, though, to the point where is was really loose. Last winter, after some persuasion, Koni sent me a new set of strut inserts under warranty.
Matt
With the shock at full extension, it is not unusual for there to be a little side-to-side play in the shaft, in other words, for the assembly to "bend in the middle" where the shaft enters the shock tube. It will produce just the effect you describe. With the car on its wheels, the movement goes away because of the longer distance between the shock piston and the upper bushing.
It does not necessarily indicate that the shock is shot. I confirmed this with Koni a while back, and with the guys at Auto Associates (Jim Newton's noted Porsche shop). I drove my car in lots of track events and for several thousand street miles after discovering it with no problems. It did eventually get worse, though, to the point where is was really loose. Last winter, after some persuasion, Koni sent me a new set of strut inserts under warranty.
Matt
08-02-2002, 07:04 AM
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Strange, but true...
Was at the shop today having my car inspected for this weekend's DE, and Ryan says "Hey, thanks for the note on Rennlist". Huh? What'd I miss? Durned user names - I noticed he was from my tip of the country, but had no idea who it was - small world <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Anywho, it turns out that "Megatron's" problem was indeed a loose strut banging around inside the housing. Yet another - "Strange, but true"... the 968 normally uses sealed struts - even in the Koni variety... seems the shop had modified his struts with threaded tops welded over the cap area, and gland nuts to hold down the 1038S insert. Yet another reason troubleshooting cars over the Internet is a huge risk... solution was easy, free, and caused no damage. Congrats, Ryan - case closed
Skip
Was at the shop today having my car inspected for this weekend's DE, and Ryan says "Hey, thanks for the note on Rennlist". Huh? What'd I miss? Durned user names - I noticed he was from my tip of the country, but had no idea who it was - small world <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Anywho, it turns out that "Megatron's" problem was indeed a loose strut banging around inside the housing. Yet another - "Strange, but true"... the 968 normally uses sealed struts - even in the Koni variety... seems the shop had modified his struts with threaded tops welded over the cap area, and gland nuts to hold down the 1038S insert. Yet another reason troubleshooting cars over the Internet is a huge risk... solution was easy, free, and caused no damage. Congrats, Ryan - case closed
Skip
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08-02-2002, 02:34 PM
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Sorry if I misled anyone here. I bought bushings and bearings. They are not yet instaled. My refference to movement are with the wheels on the ground. I get a nice wiggle on anything other than flat road. On just the passenger side. Operator side is tight. 130,000 miles I figured a set of bearings would not hurt.. Thanks for the tip on retightening though. The procedure for front rotors bothers me. It sounds like leaving them somewhat loose.
