Can Koni shocks be rebuilt

David,

Over here, beer would be probably more in the spirit of the day...spring time at last! Pleasantly warm and sunny; provided it holds until the week-end, a good time to have the top off on the GTS and go for a long drive.
Back to the topic: I have two '89, a GTB and a GTS, separated by five weeks on the production line, and by about 500 c/n. Both are ABS cars.
At the drop of the hat, the "S" is on Konis, the "B" on Bilsteins...
A guy met a few weeks ago has a "B", twin sister of mine by a few production numbers; ABS also: it is on Konis.
Go figure!

Best

 

I wanted to piggyback on this old thread and ask if anyone (or Peter!) can tell me how to remove this one piece(blue highlight arrow)?

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From Peter's photo, it looks like the piece should thread right off. I tried to put the cylinder into the vise to grab hold - it would not rotate and I started to scratch the surface, which kinda upset me. I will soak it with penetrating oil tonight and maybe try some heat on the piece tomorrow. The shock looks to be in good condition for a "1990" date. I wanted to get all the pieces off the shaft so I could finish powder-coating(400F heat) the upper shock tower.

 

I made a jig to hold the part in the vise, these photos are from 20 years ago and since I don't remember what I had for breakfast much less specifics of rebuilding shocks 20 years ago I can only offer some old photos.

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Thank you! You have saved me from staring at the Absyss while trying to formulate a jig in my head.

You should see the redneck jig I made to grab the top gland nut that would not turn without some persuasion.

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Fun Fact that I learned.....the 4 digit on the shock is the "year/month". I can see with my four shocks that they were replaced in 1989/1990

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Put the shock in a vice, put a piece of old timing belt around the foot valve and grab some vice grips to rotate it. No special jig needed, just be careful not to mark the face, it doesn’t take much force to loosen it.

 

I had the proper wrench for the gland nut but as you found out they are really tight. I secured the lower shock mount in the 3 point hitch's upper mount on my tractor and used a 3 ft pipe over the spanner wrench to break it loose. I have progressed since then as I now have a trackloader to attach stuff to. It doesn't move even when unscrewing a many decades old large hydraulic bottle jack with a 6' pipe on the wrench handle.

As a side note back in the 1990's I had a co-worker who left the company for an engineering position at the Koni rebuild facility which is local to us near the Cincinnati International Airport. A few months later he took me on a tour of the shop and I watched the put shocks in a lathe and cut them apart with a parting tool. They welded them back together later in the process. I'd rather disassemble them in the "normal" way.

My shocks were clogged with rubber crumbs from the rod seal(s) in the gland. My shocks were 1977 vintage which just used a stack of plumbing washers compressed by the gland nut, I modified my gland nut to accept a regular oil seal like Koni went to sometime after my shocks were made. I replaced the oil with motorcycle fork oil, there are a multitude of viscosity's available at any motorcycle shop.
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I will look into the motorcycle fork oil.....I was researching the "AW32 hydraulic" oil and which quality one to use.

The front shock shows needing 8 ounces, and the larger rear shocks needing 10 ounces.....

 

Put the shock in a vice, put a piece of old timing belt around the foot valve and grab some vice grips to rotate it. I spent a week with Jeff Leblond in Phoenix rebuilding a few sets of Konis. You can replace the internal components and lubricant but setting the travel and rebound needs to be calibrated to specification.

 

someone in the vintage section posted that Koni USA changes the orig design somehow.

 

Before disassembling, I counted 2.5 turns for the rotating bottom piece (with the ears)....I know there is another post that explains how to set the adjustable soft to hard setting by rotating the collapsed shock.

 

Good that you took note of that but my point was you will have no way to determine if the shock is operating at the proper compression or rebound specifications after you replace the guts and oil. After spending a week in Jeff’s shop I can honestly say you cannot DIY rebuild the shocks “properly”, I did two sets and all 8 needed to be opened up and “tweaked” after putting it on the dyno to observe its compression and rebound characteristics! Once it’s in spec you can make them a bit softer or firm by the adjustment you noted.
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Thank you, Jeff, for that info and guidance. I will change the oil, clean the orifices, and powder-coat the bodies. I will probably send them to Koni for a dyno test. I wish there was a local dyno service!

 

Send me a private message and I will share the correct paint code with you.

 

I started my hand at powder-coating the suspension parts and the shocks/springs. It's been a fun learning process. From my research, the Koni shock color is RAL2002...it seems to match well with the original paint on my shock. I have some new Koni stickers from eBay to apply later.

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Believe Chevrolet engine orange is also a pretty close match to the Koni shock color.

 

If anyone is interested in a set of front and rear shocks to rebuild I have them in boxes. I replaced mine rather than rebuilding them.