How to test KYB strut out of the car?

Yves

True Classic
I have a pair of grey KYB front strut just sleeping in garage for 6 years.
Before I removed I had used for about 3 years with no issue.

Question ... how can I check the condition when not installed on the car.
I can full compress with hands with constant pressure.
But they return by themself only about 1.5 inch then I need to pull with a constant pull pressure to fully extend.

Any trick to confirm the strut is in good shape and can be reused.
 
I have a pair of grey KYB front strut just sleeping in garage for 6 years.
Before I removed I had used for about 3 years with no issue.

Question ... how can I check the condition when not installed on the car.
I can full compress with hands with constant pressure.
But they return by themself only about 1.5 inch then I need to pull with a constant pull pressure to fully extend.

Any trick to confirm the strut is in good shape and can be reused.
Its blown. Get new ones
 
I asked the same question not too long ago..

 
Its blown. Get new ones

When I read the thread from "fastfiat81" "KYB struts bad" I observed the same behavior of him ... I have significant resistance in BOTH directions but they not extent by themself ... only 1.5 inch.

I just want to be sure not to throw away for nothing. The answer of JimD and Myronx from thread KYB struts bad?, I understand the strut is usable. I'm wrong?.
 
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When I read the thread from "fastfiat81" "KYB struts bad" I observed the same behavior of him ... I have significant resistance in BOTH directions but they not extent by themself ... only 1.5 inch.

I just want to be sure not to throw away for nothing. The answer of JimD and Myronx from thread KYB struts bad?, I understand the strut is usable. I'm wrong?.
Throw em on, and see 🤷‍♂
I'm just of the school of thought, that if a strut doesn't rebound, its either bad or failing 🤷‍♂️
 
The newer KYB units are NOT the high pressure gas "monotube" (Dr.DeCarbon) design that the older ones were. The old style would be extremely difficult to compress (even with your full body weight) and they quickly pop back up to full extension by themselves. The newer ones do not; they can be compressed (slowly) by hand without too much difficulty and they do not return back up much by themselves - but can be extended (slowly) by hand with resistance.

However it gets confusing which ones are which due to a lot of inaccurate/misleading information. For one thing both are often referred to as "gas" filled. It's true both are, but one is a very high pressure gas with a floating divider piston between the gas and fluid (i.e. monotube), while the other is a low pressure (or possibly non-pressured) gas in separate bags or chambers around the outside of the fluid chamber (hince the double or twin wall). Second I'm seeing the names intermixed; "GR-2" vs "Excel-G" vs "Gas-A-Just" vs "MonoMax" ,etc, etc. So the listings are not always accurate. The color was once a decent indicator (grey vs black), but that seems to have changed a few times over the years, not necessarily following the different types like it once did.

Therefore it depends on which type you actually have. You should be able to tell by looking at the shape of the tube. Typically the older monotube is very straight all the way along the body, while the newer twin-tube has a bulge toward one end. Unfortunately I don't have good pictures to show this for the X applications, hopefully someone else does. But if they are the newer design then the degree of difficulty to compress and extend them (particularly extension) will help tell their condition - the more resistance you feel the better. And it should be consistent all the way through the travel, not easy - hard - easy or such. If you had both types side by side the difference is extremely obvious - the monotube is MUCH harder to move.

Sadly KYB's have lost some of their quality compared to the old days. I recall when the brand first came to the US market. The US distributor was located in the Santa Ana, CA area and I was helping to build rally cars for Hendric Block (no relation to Ken Block). He managed to get a sponsorship from KYB so we had access to anything they offered (I put them on all of my cars at the time). The old "Gas-A-Just" monotube high pressure units were extremely good - somewhat comparable to Bilsteins for a fraction of the price. And the warranty was amazing as well. Now they seem to be poor overall quality and will degrade even sitting on the shelf.
 
I should also add that which type of KYB's you have it does not necessarily depend upon on when they were purchased. I seem to recall that both types were offered at one time, with the price depending on the choice.
 
I should also add that which type of KYB's you have it does not necessarily depend upon on when they were purchased. I seem to recall that both types were offered at one time, with the price depending on the choice.
I bought my high pressure gas units in 1983 and they were also selling the standard model as well. The attached photo of the end of a gas strut cartridge box indicates that they were marketed as KYB GAS:

KYB Gas Strut Cartridge Instructions.jpg


I don't know how pressurized they still are after 37 years but they seem to damp OK with about 38K on them. When new, they had enough pressure to slightly lift the car.
 
I bought my high pressure gas units in 1983 and they were also selling the standard model as well. The attached photo of the end of a gas strut cartridge box indicates that they were marketed as KYB GAS:

View attachment 39303

I don't know how pressurized they still are after 37 years but they seem to damp OK with about 38K on them. When new, they had enough pressure to slightly lift the car.
The fact they could actually lift the car up slightly is indicative of the high pressure monotube ones. I'll bet when you first got them they came in the box with a heavy nylon band holding them compressed? And when you cut that band they quickly shot up to full extension?

The difficult part is these days they also refer to the non-high pressure, twin-tube, standard units as "gas". Because there is a gas chamber in them, just a completely different design altogether.
 
Bon jour Yves. You have been getting some conflicting - and wrong - advice here.

Those KYBs you have are a typical twin tube "gas" shock. They are just like a normal (and like the stock OE Fiat ) struts ...except.....they were filled at the factory with a low pressure nitrogen gas charge sealed inside the strut tube. The supposed advantage of this "gas charge" was that - under extreme conditions - the oil inside moving quickly from chamber to chamber would not froth and fade in the presence of nitrogen - like it would tend to if exposed to atmospheric air.

This nitrogen gas charge - at a higher pressure than atmosphere so it would also extend the shock on its own if unloaded ( like you are trying it now ) - had a tendency to slowly leak out over the years - which basically reverted the shock to a normal twin-tube shock. When this happens.....the shock would still retain its normal damping characteristics.... that doesn't change if the oil has not leaked out.

So no real big deal if the nitrogen has leaked out. The shock would still dampen the same as it always did . Only if you drove the car really hard over bumpy roads would it then have a tendency to fade or weaken as the oil began frothing....

So...as long as the shock has firm and even resistance when you compress and extend it...and over the whole travel.....the shock is still perfectly usable. Ideal ? No. As good as new? No. As good as a normal twin-tube shock ? Yup.

The loss of some gas pressure - like on yours - is quite normal as the shock ages. Many here have found that.

My opinion....dont throw them out !!!!

Others here talked about high pressure monotube gas shocks. And yeah....that it a totally different animal....and yeah...loss of gas pressure in that type of shock is critical. But NO..KYB NEVER made a high pressure gas shock - or gas insert - for the X1/9. Those 363017 were a low pressure gas twin tube strut insert.

By the way, Yves, what are you running for shocks now ? And ...a very merry Xmas to you and Lucie and Kermit !!!

Doug
 
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Hello Doug,
That a pleasure to read your explanation you're so precise and clear, now I fully understand my situation.

For the last 6 years 2014 to fall 2020 I'm running the KYB Excel black (MWB KYB coilover kit).
The strut on the shelving in the garage have been install on Kermit on 2012 with new Vick Auto performance spring.
Then on february 2014 I decided to go with 15 inches rim wheels (No availability of 13 inches tires).
To be sure to don't have issue space between coil spring and the 15 inches wheels I bought from MWB the KYB coilover kit.

Last week I decided to verify if my old GR-2 with Vick Auto spring can fit with the 15 inches wheels, to my surprise Yes they fit!

I just want to come back to the Vick Auto coil spring with the KYB GR-2 and my 15 inches wheels.

When I removed the black KYB Excel from the MWB coilover kit I compared with the GR-2 on shelving
and both have behave similar when I compress or pull... same issue!

That the long story...
For the next season I will give a try to that setup for Kermit.

Thanks for the good wishes, also Merry Xmas to you Doug and your family.

Great projects for the next years to keep you busy as usual.

Best Regards
Yves
 
Exactly what Doug said - my GR2s had that same effect after only 3 years of service and 7000km... they still dampen perfectly fine :)
 
KYB 76015 adjustable shock
Actually I recently did quite a bit of research on that exact KYB part number.
It is for a Toyota MR2 or Celica Turbo. Unfortunately it is too large diameter to fit any X strut housing. Shame because the overall length (body, rod, stroke) is about an inch shorter than typical inserts for the X, which would be perfect for a lowered X.

While they are less costly than say Koni or Bilstein, they are not cheap for a KYB item. However they are adjustable as you say. And that would be a big plus to tune the desired effect.
 
Actually I recently did quite a bit of research on that exact KYB part number.
It is for a Toyota MR2 or Celica Turbo. Unfortunately it is too large diameter to fit any X strut housing. Shame because the overall length (body, rod, stroke) is about an inch shorter than typical inserts for the X, which would be perfect for a lowered X.

While they are less costly than say Koni or Bilstein, they are not cheap for a KYB item. However they are adjustable as you say. And that would be a big plus to tune the desired effect.
Has anyone heard of these guys in Australia?
 
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