Can these struts be refilled and used

[DavidSwedem]

I got hold of some early 911 struts, when i took them apart I discovered that there was no cartridge insert, instead the whole strut was filled with oil and there was an internal damper piston/cylinder insert in the oil bath.
The strut casing acts as the oil reservoir for the damper
I am not sure what make of strut they the only number I found was on the steering arm L655.01 with a small logo that I couldn't read. They were very rusty so I have media blasted them and painted them black so this is not the original color.

Question: Can I refill with oil or do I need to get a damper insert?

If any one has come across this before or can identify the stut it would be appreciated

[Ian Comerford]

I found the same on my car when I did a suspension refresh about 3 years ago. I described the open oil bath damper system to a few people who doubted I knew what I was talking about, both on this forum and also one other. Only useful piece of advice I got was to try motorbike fork oil, which i did. I bought the wrong weight initially and found the strut barely moved when pressed, so change it for one weight lighter and it seemed fine. Sorry I can't remember if it was 10 or 15 weight I used. When if took the car for alignment the garage owner drive it afterwards and asked what front dampers I had on because they felt so nice! One in the eye for the people who didn't believe I had that type of damper in the car.

Long way of saying try 10 or 15 weight fork oil

Good luck

Ian

[DavidSwedem]

Ian,

Thanks for taking the time, yes I have had the same response a lot of doubting

Anyway a few questions if you have the time:

Is there a procedure to follow when filling or is it just to pour in the oil?
How much oil, fill to top?
Did you replace O rings if so what material.


Thanks again

[Ian Comerford]

No problem, happy to help. There is no procedure for filling, just pour in the oil and slowly insert the damper. Only thing I did once the damper was in was to exercise it slowly to tease any air out. When I stripped mine for some reason I kept the old oil and so knew roughly how much to put back in, although I had no way of knowing it was the right amount. All I did was put the same amount of new oil back in. Sorry, but you are going to have to guess. I would go for a little too much rather than not enough for obvious reasons.
I didn't replace the seal as it doesn't do too much and seemed in ok condition, it just keeps muck out really.

Hope this helps

Ian

[DavidSwedem]

Thanks Ian,

Appreciate your help

[HarryD]

Was the internal piston insert sealed?

My 73 had I've struts that had an insert like the one pictured. When I removed the strut, a very nasty oil spilled out.

Sounds like a Boge strut and the oil is used to cool the strut by helping conduct the heat to the housing.

[Chris_chch]

Not sure if this helps... But I just pulled out the exact inserts from my 1980 RoW SC. I Replaced them with a Koni insert. After getting the old oil out first.

My guess is they are the original open bath style? I was keen to try adding fresh oil to see if it would bring them back to life, but already had the Koni's on hand...

[Ian Comerford]

Originally Posted by HarryD

Was the internal piston insert sealed?

My 73 had I've struts that had an insert like the one pictured. When I removed the strut, a very nasty oil spilled out.

Sounds like a Boge strut and the oil is used to cool the strut by helping conduct the heat to the housing.

The main function of the oil in this type of damper (open bath) is to provide the damping effect as it is forced through and ever-decreasing set of holes as the suspension compresses. The sealed inserts use the oil for the function you describe, but the type in question here is not sealed.

Hope this clears it up

Ian