shortening shock absorbers

[kent olsen]

Has anyone tried cutting the shock shaft and rethreading it on a lowered car?

[911pcars]

I''d be interested to know. The shaft is pretty tough material. Cut the shaft off of a used shock and use as a nice, chrome-plated drift punch.

Sherwood

[Flieger]

I know Clint at Rebel Racing sells shortend Bilstein dampers. I think he has them custom made at Bilstein, though. The "can" is at least shorter, and I think the rod must be too.

[Walt Fricke]

One nice thing about Konis for older 911s is that they have a steel peg on the bottom. Cut that off, and you have a shorter shock just like that. You can either section out an equal amount from the strut, leaving the threaded part useable.

Or you could have a spacer machined so the cap would essentially reach way down by the amount you cut off inside the housing, and hold the insert tight as designed. But I am not sure just what ould be gained by doing this with a stock length strut.

[175K911]

Bilstein will shorten the shaft of any shock or strut to your specs. Don't recall the price but it's relatively inexpensive.

[stownsen914]

I had some Koni strut inserts revalved by Truechoice a couple years ago. Apparently in order to seal them up again they had to shorten the body of the shock a little. This wasn't by my request, but worked out fine for me. In an unmodified strut I had to put a small spacer under the insert to get it long enough to make it tight in the strut. I didn't bother to have the shaft shortened.

Now that I'm building some new struts, I'm taking advantage of this to shorten the strut. I also cut off the nubs on the bottom of the inserts as Walt mentions above to shorten the inserts (and the struts) another 3/4".

Scott

[kent olsen]

I've been chasing a metalic clunk in the front end ever since I had the car lowered, corner balanced , 4 wheel aligned and camber plates added. Any chuck hole causes a metalic clunck. I put new Sachs schocks in the front but still to no avail. I also added Koni Race Rubber Snubbers to the top of the shaft.

I'm 23" at the front fender lip with 205X50X15 tires. I just installed new ball joints and turbo tie rods. Still no change. On my last visit to Sebring, I have since moved to Oregon, one of the respected members of the Tampa Club, thought the schock was bottoming out.

With the relativily low ride height that seems to be the only other possiblity. I'm going to bring my shocks to a local machinist today and see what he thinks.

[kent olsen]

During an Autox

[Flieger]

I bet you it is the A-arm hitting the chassis seam between the suspension pan and inner wheel well. I was searching for a clunk on my car on large bumps but the lowest part of the car is scrape free (rear anti-sway bar). There is a little denting on that seam, though. There is probably less than 1/4 clearance there since I do not have raised spindles. Clint at Rebel Racing clued me into that. On side of his car has that seam all buggered up from before he started raising spindles and putting stiffer springs in.

You can cut that seam for clearance. The 930 Turbo has that seam cut from the factory from where they spliced in the raised crossmember mount.

[Flieger]

Take a look at this. Look familiar?


Front Suspension Geometry_ 018 by Max_911_fahrer, on Flickr

[kent olsen]

I saw that as well. I took my grinder and opened it up and also glued a thin piece of foam on top of the A arm. I see no imprint that would indcate contact.

Driving over large chuck holes or dips it seems to make the noise as the suspension contracts ( tire moves up) not on the way down.

Frustratingly watching the weekend go by!!!

[Walt Fricke]

I damaged a set of Koni Sport front shocks because I had the car too low despite the 23mm torsion bars. Bottoming out caused the adjustment feature of one (that nice plastic knob you can put on and turn to adjust rebound) somewhere down in the bottom of the insert where it all works. This despite installing the rubber shock bump piece, and then shortening it as well.

Explained some occasionally evil handling on the track. Installed Bilstein HDs.

Much better after I just raised the ride height up a bit.

[kent olsen]

Raised the ride height up to 26" and went down the road to my "bump". Clunk is still there so that throws out the shock absorber theory. Next will be the sway bar and inspection of the old bump steer I installed years ago.

[kent olsen]

Disconnected both sides of the front sway bar and drove down the road to my bump. Seemed to be marginally better? Next step today is to add some oil to the strut housing, just found out from Steve Weiner, there's supposed to be a little oil in there.

Then it's make sure to get as much torque as possible on the big screw that holds the shock in the strut housing.

[kent olsen]

With a friends help we jumped up and down on the front and tried to find the contact. I don't think that is the noise.

Now today I loosened the nut on the top of the shock and drove down the road. Hmmm, I think that could be where the noise is coming from.

New Boge shocks and camber plates on top. I'm wondering what torque to use. I used my air wrench with 110lbs of air pressure. I'm not sure if that is enough or if I have the right hardware. There is a taper to the shock shaft that looks like it fits into the bottom of the camber plate. The threaded part of the shock shaft looks like I have plenty of thread to pull it up tight. There is just one thin washer between the nut and top of the camber plate housing.

Anyone have any ideas?

[Trackrash]

I would check the a-arm bushings and the ball joints. A loose shock insert can clunk. A bottoming shock will BANG.

From my experience you will have to raise the spindles to have a low front end that has adequate wheel travel. Be careful with that modification, max is 19 mm with 15 inch wheels. You will then need modified tie rod ends to reset the bump steer.

[175K911]

Originally Posted by kent olsen

With a friends help we jumped up and down on the front and tried to find the contact. I don't think that is the noise.

Now today I loosened the nut on the top of the shock and drove down the road. Hmmm, I think that could be where the noise is coming from.

New Boge shocks and camber plates on top. I'm wondering what torque to use. I used my air wrench with 110lbs of air pressure. I'm not sure if that is enough or if I have the right hardware. There is a taper to the shock shaft that looks like it fits into the bottom of the camber plate. The threaded part of the shock shaft looks like I have plenty of thread to pull it up tight. There is just one thin washer between the nut and top of the camber plate housing.

Anyone have any ideas?

Kent- what upper camber plate are you using? I had a clunking/ clanking sound driving through the pits at any event, and during occasional street driving. I chased everything in the front end and finally just pulled the upper strut mounts out and put the stock ones back in. Voila, no noise. Turns out that Ira at Tarett had gotten some bad upper bearings that he'd used in his offset upper mounts. They wore out very fast. He was kind enough to send me two new bearings which were easy to replace in the offset mounts, and that was after more than a year of service. New bearings were perfect, and quiet.

[kent olsen]

The camber plates where installed in Orlando not quite a year ago at a shop there. I don't know what kind they are. I tried to look yesterday but their just red, no ID that I can see.

The clunk started then and the first thing I did was change to the Boge shocks. New ball joints, and turbo tie rods. I already had the bump steer kit. Looking in the camber plate I can see three little abrasion marks on the top so maybe there is something bad with both left and right units.

[175K911]

My Tarett's are red. I'd had stock upper mounts prior to that with the Elephant Racing Monoball cartridge. They had always worked great but I needed more negative camber thus the Tarett offset parts.

When I removed the Tarett upper mounts and took the bearings out they were stamped made in China. The replacements Ira sent me were stamped made in USA. If you have the Tarett pieces and pull one of the camber plates out, you can remove the bearing with the removable plate on the underside of the camber plate, and the bearing will pop out. Small allen bolts, don't remember what size though. Makes replacing the bearings themselves pretty easy. Of course your alignment will be shot when you do. Might be able to pull the strut rod out of the upper mount and access the small bolts that hold the bearing retainer plate while the mount is still in place.

Just a thought for you since it seems like you've tried so many other things.

[Chuck Moreland]

Originally Posted by kent olsen

With a friends help we jumped up and down on the front and tried to find the contact. I don't think that is the noise.

Now today I loosened the nut on the top of the shock and drove down the road. Hmmm, I think that could be where the noise is coming from.

New Boge shocks and camber plates on top. I'm wondering what torque to use. I used my air wrench with 110lbs of air pressure. I'm not sure if that is enough or if I have the right hardware. There is a taper to the shock shaft that looks like it fits into the bottom of the camber plate. The threaded part of the shock shaft looks like I have plenty of thread to pull it up tight. There is just one thin washer between the nut and top of the camber plate housing.

Anyone have any ideas?

Kent

Confirm that the strut-top nuts are bottoming out against the camber plate, and not bottoming out by running out of threads. If you are running out of threads, put a washer beneath the nut to space it up.