STUCK Koni: was...Rebuilding Rear Koni shocks

tencate · Postby **tencate** » 20 Feb 2011 21:45

Has anyone here rebuilt (by yourself) a Koni rear shock? I just googled and discovered that there are folks who have taken them apart and rebuilt them. I got a set of used rear shocks which worked fine when I got them but now one seems to have frozen (?!) :-(

Will take it off and see what I learn first.

But, just curious mostly. It's pretty easy to see where to send them away to have Koni do it... but I'm wondering if I can do it myself.

Jim

john 215 · Postby **john 215** » 20 Feb 2011 22:10

Hi Jim,

Would be intrested in what you find. Can you get hold of the parts to rebuild them ? If you can get hold of the parts i guess it would also be poss to uprate them.

Cheers John

LIVE LIFE A QUARTER OF A MILE AT A TIME!
1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6,ON THE ROAD NOW KICKING AR5E !!!!

tencate · Postby **tencate** » 20 Feb 2011 22:27

The Koni website I was just visiting also says it's possible to add external adjusters, or to make them adjustable on both compression and rebound (for some units). All for a price I'm sure. :-)

I will keep everyone in the loop as to what I find out.

On a related note, think we ALL could convince Koni to do another run of the ones for the TR7/8 series again?

Jim

Hasbeen · Postby **Hasbeen** » 20 Feb 2011 23:13

Jim, there is usually not that much to rebuilding shocks. Normally the main problem with simple oil shocks is that the oil is shot. A good clean up & new seals & oil usually does it.

You will need new oil, & it is a bit special. It has to be a non foaming hydraulic oil, with the right additives, or it will break down fairly quickly.

I had a company rebuilding the old BMC leaver arm type shocks, & the early struts for Fords & Triumphs. I had to have a number of grades of oil to suit different applications. WE got all the special oils from Shell back then.

With the MG A leaver arm shocks we got up to an SAE 15 oil for racing, but I have heard of some blokes using gear oil at times. The shocks don't last long that way, but they sure reduce body roll.

Hasbeen

tencate · Postby **tencate** » 21 Feb 2011 18:13

Took off the wheel to see WHY the rear Koni shock was frozen and saw this.

Seems the rubber bump stop inside the Koni (which you have to take out to adjust these) had somehow fallen/slid down and gotten jammed (tight!) and, of course, the shock wasn't working right. In fact, it was VERY jammed and was tough to get it apart again, even with the weight of the rear pulling it apart!

Anyone had this happen before? What's the solution? The little rubber spacer piece seems in pretty good shape yet and now that it's warm out, it seems to stick up there just fine. Hmmmm.

Marsu · Postby **Marsu** » 21 Feb 2011 18:19

I found similar problem with the std Koni TR7 rear shock (manufactured circa 1996). Simply, they have too much extension and either need to be shortened or have axle retaining straps (a la MGB) or lower spring retaining plates (Stag76 has fabricated this).

I had mine shortened during a rebuild and upgrade by the local importer.

I'm sure I have reported the measurement some time previously but will re-measure and post again if necessary.

[typo corrected]

Beans · Postby **Beans** » 21 Feb 2011 18:21

If this rubber bump stop is fitted correctly it won't fall or slide off.
But they do need a little bit of force to seat properly.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Beans · Postby **Beans** » 21 Feb 2011 18:24

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Marsu

... they have too much extension ... <hr height="1" noshade id="quote"></blockquote id="quote">
Don't agree there.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Marsu · Postby **Marsu** » 21 Feb 2011 18:28

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Beans

[quote]Originally posted by Marsu

... they have too much extension ... <hr height="1" noshade id="quote"></blockquote id="quote">
Don't agree there.
<hr height="1" noshade id="quote"></blockquote id="quote">

Perhaps yours are different.

In my case, the shock allows extension to a point where:
<ul><li>the top cover no longer overlaps the reservoir (tube bottom)</li><li>1" lowered springs come loose from their seats</li></ul>

tencate · Postby **tencate** » 21 Feb 2011 20:08

<blockquote id="quote">quote:<hr height="1" noshade id="quote">If this rubber bump stop is fitted correctly it won't fall or slide off.
But they do need a little bit of force to seat propely<hr height="1" noshade id="quote"></blockquote id="quote">

Can you elaborate a bit? I press them home and they seem to stay but can pretty easily still poke them out using the little access holes at the top, a little too easily for my tastes. When I got them (they were lightly used), the rubber bump stops inside were really nicely stuck in place. Maybe I need new ones? I'll take a photo and post it here later tonight (US Mountain time). Or maybe I put them in the wrong way around? Wouldn't be the first time I've done something silly like that.

Jim

Beans · Postby **Beans** » 21 Feb 2011 20:16

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Marsu

... Perhaps yours are different ... <hr height="1" noshade id="quote"></blockquote id="quote">
Don't think so ...

And that shouldn't be a problem as long as everything's fitted properly.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Beans · Postby **Beans** » 21 Feb 2011 20:25

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by tencate

[quote] ... Can you elaborate a bit? ... <hr height="1" noshade id="quote"></blockquote id="quote">
Will try [:D]

The original bump stop has a groove in it, that catches on the inside of the groove you see on top of the dirt cover in the picture of my previous post.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Beans · Postby **Beans** » 21 Feb 2011 20:35

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Marsu

... 1" lowered springs come loose from their seats ... <hr height="1" noshade id="quote"></blockquote id="quote">
The dangers of lowering a car [:p]

Always bear in mind that dampers (like the Koni's we're taling about here) are developed for the cars original set up / ride height, unless stated different.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Hasbeen · Postby **Hasbeen** » 21 Feb 2011 22:07

In all tubular shocks there is an internal bump stop, to ease the hit when they are stretched to full extension. One big advantage of repairable shocks it that this stop can be changed or modified.

Some shock manufacturers have a number of different lengths of this stop. Fitting a longer one will reduce the length of the shock, at full extension, to help retain shortened springs.

Fitting a second standard internal bump stop will have the same effect, but make sure it is a tight fit to the shaft, or is otherwise retained, so it doesn't flop around in there.

Hasbeen

tencate · Postby **tencate** » 22 Feb 2011 03:05

<blockquote id="quote">quote:<hr height="1" noshade id="quote">The original bump stop has a groove in it, that catches on the inside of the groove you see on top of the dirt cover in the picture of my previous post.
<hr height="1" noshade id="quote"></blockquote id="quote">

Thanks. That's what I thought so I've at least got the bump stops in the right way. It might be that I just didn't push them home when I first installed them. I've got another almost new set for the other car, can't wait to get them on. Hey, what setting are people using? These are paired with a set of almost new KYBs in front and I'm one full rotation from soft and that seems a bit harsh to me when I'm on bumpy washboard roads. But the control I have is fabulous!

Jim

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STUCK Koni: was...Rebuilding Rear Koni shocks

STUCK Koni: was...Rebuilding Rear Koni shocks

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