Matt Romanowski

I thought people might find this interesting. This is the guts of a Bilstein front shock insert for an 70-87 911. I bought these inserts and were told they came out of an SC with 187k miles. By looking at things, these may have been the original shocks.

Here is what you are looking at. The first photos is the shaft with everything on it. Starting on the left is the top rod guide, seal, droop limiting bump stop, steel washer, rubber washer, then the piston assembly. To the far right is the gas separating piston that separates the oil and nitrogen charge.

The next shot is just a close up of the parts that go with the shock shaft, followed by a photo of the piston assembly together. You can see the steel piston seal around the middle of the piston. Note the heavy staking of the nut on the shaft!

The next photo is of the piston assembly apart. The piston is in the middle. Surrounding it are shims (precision thickness and diameter spring steel washers) followed by regular shock washers and the nut to hold it all together on the right.

The close up photo is a shot of the compression side of the piston. It was originally completely smooth. The pitting is a result of cavitation which is caused by not enough nitrogen pressure or too fast shock movements.

Next photo is just a shot of the divider piston and the o ring on it. You're looking at the oil side of it in the photo.

Final shot is the old oil. It is nasty! This oil originally had the color of engine oil - mostly clear tan colored. It is broken down, has lost it's viscosity, and doesn't lubricate the way it should anymore.

harveyf

Cool! Thanks.

analogmike

That's why I love Bilsteins. A Koni would have been in the dumpster in pieces decades ago.

Matt Romanowski

I figured a couple of things out to get them apart and to get them back together. For all intents and purposes, both regular Bilsteins and Koni's are not user rebuildable.

GuyIncognito

huh, I thought they were filled with nougat.

mrbill_fl

What kind of oil did you put back?

Matt Romanowski

Haven't reassembled yet. I'm working on a couple of different valve options. With all the data I have, I think I can come up with something significantly better than people have.

For oil, there are a lot of options out there. I will probably use oil from Bilstein.