I picked these up on ebay for $80 many years ago knowing that they were rebuildable if they were no good but not knowing that rebuilding them costs as much as new Bilsteins.

My questions:
Is there any way to tell if they are any good other than running them and seeing how they feel?

In the second picture, I am guessing that the 8 70 might be a date code. If they are that old and haven't been rebuilt, is it even possible that they are still good?

I would like to run adjustable perches. Any recommendations on where to buy and what brand?

How do I adjust them?
Click to view attachment
Click to view attachment

Thanks,
Ken

Those winged logos are the old school logo style, so 8/70 is probably Aug 1970 mfgr date.

IIRC they weren't adjustable back then, but were top shocks around (I got some on my 73 in 1980-83 rolling resto/refurb with the later logo).

Go to the Koni website online & they have a link for their resto services, where they'll completely restore & rebuild them for you (including fresh paint & decals), then guaranty it for life for you (non-transferable IIRC).

After all this time the rubber seals & o-rings are probably a bit crispy, and those look to have some miles on them, so probably due.

Think of it as the "Eric Shea/PMB brake resto" for shocks!

Good Luck Ken!

Collapse them about 10 times back and forth. They are hydraulic so you will be charging the piston. See how hard it is to pull the rod to the top. This will give you and indication of how much pressure the valve is holding. These are adjustable so you can turn the rod in the piston from soft to hard. If there is no oil around the top they may be good. Rebuilding now cost the same or more than new ones.

I did the collapse test a few times. The first time, they went down easily, but after it was more difficult but consistent. However, it did not require as much force as I would have thought, although I have no way to measure or reference for comparison.

I also tried the adjustment procedures that I found in a few places, and they don't seem to apply to these. I also looked over all of the markings, and there is nothing that would indicate that they are adjustable, so I am guessing that Tom is correct.

"I also tried the adjustment procedures that I found in a few places, and they don't seem to apply to these. I also looked over all of the markings, and there is nothing that would indicate that they are adjustable, so I am guessing that Tom is correct."


Expect for the markings right on the shock with an arrow indicating "Heavy Turn" right above the part number.

It just may be the adjusters are stuck in one direction. I have some old ones that had sat for a while and who ever adjusted them last jammed them all the way to one end.

I should also add that after compressing and retracting them a few times, they smelled pretty bad. Not sure if this is gas escaping or old oil being awakened.

to adjust, collapse to rod all the way in . . It has a keyway inside on the bottom or the rod that fits into the adjuster body. . once it is engages, turn the shaft. . it should turn about 1 1/4 turn from full soft to full hard. . set it on full hard. . . stand the shock upright so all the fluid goes to the bottom. . . compress and pull out a few times to get the fluid on both sides of the adjuster body. . .
If it goes in and out with no resistance it's shot. . IIRC even when they are good one way goes easier than the other but I don't remember which [ rebound or compression].

Konis are rebound unless they are double adjustable.

PSI at sears point rebuild these. For $30 they can dyno both of them. Rebuilds are about $200 each. Ground Control makes the best adj perches.

Will try to describe as best I can what happens when I push the shaft all the way down and turn. The first time, it went down to what seemed to be the stop, and when I turned it, it just kept spinning, no stops in either direction, but I could feel what may have been a notch here and there. Then I found that it could be pushed down about another 1/8" if indexed in certain spot. In that bottom most position, it will not easily turn much more than a 8th or 16th turn without forcing, which Koni says on its site that should not be done. Not sure how easily these things are broken, so I wasn't about to put too much force into it. Both shock exhibited this.

Any ideas?

Ron, can you please expand upon this? These do not rebound at all when compressed.

Compression stroke is fairly easy unless they are set full hard. The rebound (extension) should be stiffer as it is meant to control the spring/torsion bar as it extends from compression or twist.

The racing shocks we used were adjustable in that we could set 70 rebound / 30 compression or 50/50 or 30 rebound/70 compression.

I remember looking at Konis' site at some point in the past and there was a statement that they were built for primarily rebound.

From a quick look at a website on Konis:

Like our Sport range, dampers in the Special range are of course adjustable, only these need to be removed from the vehicle first. The rebound forces can be adjusted by compressing and twisting the piston rod.

The shocks you have were called "Reds" Special Ds as I remember. They are oil filled, not gas filled. One you compress the rod, it is real stiff to pull back out at the heavy setting. They will not extend themselves unless they are gas or gas/hydraulic. The compression stroke is fairly easy but not overly so depending upon the setting.

Not adjustable back then? I had adjustable Konis on my 356 in the early 60s. That was ALWAYS the big selling point.

The Cap'n

This is good info. After looking at the markings, these are indeed Special D's, says so right on the shock. They are apparently set at 50/50, as the rebound and compression take about equal effort. I still have no idea how to change that, or even if I want to.

Interestingly, after messing with them tonight, I can hear the oil swashing around in them now, while I didn't notice it before.

I still have no idea whether I want to run these or aggressively market them to the guys building GTs who might be interested in an 8/70 date code.

They are "collapse to adjust" as described. The arrow on the shock body indicates the direction to go heavy or opposite direction to go light.

When the rod is pushed all the way in and rotated slowly it will engage a dog and then you can turn the adjusting mechanism. You must engage or nothing happens.

There was also info that if you lay a shock on its' side for an extended period of time they will go "bad" in that somehow the hydraulic fluid moves from where it is supposed to be and the shock will feel "bad". Positioning them in the upright position for a day or so allows the fluid to creep back where it is supposed to be and the shock may start working as it should.

Do you turn the shock body the direction of the arrow, or do you turn the shaft in the direction of the arrow? It's been so many years, that I don't recall which part you turn; it's an age thing you know!

Andys

Those are probably fine. Remember, there's a big spring there.



Spot on.

With the 8/70 date code, these should probably be sold to someone with an authentic GT conversion.

Already dun got some of those fancy double adjustable ones Ronnie was yak'n about on there...

Ground Control in CA has them. The kit with springs is priced very reasonably.

Andys

Thanks, all. Looks like I need to get these things pointing up for a couple of days.

Eric, thems is fancy new ones. You need to go retro (not metro).

Those are 70 models that TrueChoice restored.