Bilstein Strut Housing: Internal Bushing Replacement

[franklinstower]

I have the dreaded wobble of my new strut insert in the strut housing. I would like to have the old bushings pulled and new bushings installed. I read the bushings that Bilstein are suppling during their rebuilds are shorter (20 or 40mm?) and others have sourced longer bushings (50+mm) which seem to last longer.

Question, who is rebuilding the struts these days? And who supplies the best bushings so I don't have to do this again?

Is there a tool to purchase, borrow, rent, etc so I can pull the old bushings myself? Or should I leave this to the pro's?

This seems to be a relatively common problem, but not a lot of info about it here on the Pelican for the DIY'r. Other than send them to Bilstein for a rebuild.

Thanks,
Paul

[Bill Douglas]

Paul I had that too. It turned out to be the ball joints.

[David Inc.]

It's not something that's really worth a DIY. When I did it it was $300 to have them re-bushed, and at that price having it done properly in factory is totally worth it.

Doing a quick search I found this--no idea if this guy is still active, though. http://forums.pelicanparts.com/porsche-911-technical-forum/562566-bilstein-strut-play-safty-issue.html#post5544544

[jpnovak]

There are 2 bushings in the struts - an upper and lower. They are difficult to replace even with the correct tools. Many years of being stuck in place doesn't help.

The bushings are available.

I now have the tools from Craig. If you want to ship the stripped struts to TX I can replace the bushings for you. PM or email for details.

[stownsen914]

I had mine done at a local-ish machine shop who I've worked with. Porsche suspension parts vendors/rebuilders like Elephant should be able to either do it, or tell you who can. Or you have an offer here in this thread!

[franklinstower]

Originally Posted by jpnovak

There are 2 bushings in the struts - an upper and lower. They are difficult to replace even with the correct tools. Many years of being stuck in place doesn't help.

The bushings are available.

I now have the tools from Craig. If you want to ship the stripped struts to TX I can replace the bushings for you. PM or email for details.

Thanks, Craig mentioned you had the tools now. What can you tell me about the bushing size? Have you sourced the longer DU brand bushings?
I did find a guy locally that has replaced these, but it's been a long time and he has no idea of what happened to the tool he made. He's a machinist and mentioned using a reamer in his mill as an option for removal.
I am doing a full front refresh with rebel racing bushings. I still need to take it all apart, so it'll be a while.
I'll send you a message JP when I'm ready.

[jpnovak]

Thought it would be a good idea to update this thread with more information on how to remove the strut tube bushing.

First, you have to remove the struts from the car. Next, pull the strut insert. I use a drift to remove the roll pin from the bottom.



Here is the roll pin removed.



Once the roll pin is removed you can pull the damper insert from the housing.



Next, you have to remove the dust cap seal from the top of the strut. I found a drift works well to use a drift to walk it off. A drop through press could also work but I find this is faster and doesn't require any setup.



Here is the dust cap removed. BTW, i have come across at least 3 different styles of dust caps. They all function the same.



Now its time to get the special tools out. First is the bushing extractor tool. This is a long rod with a stop at one end. What you can not see clearly is a disc object that is in the palm of my hand. Sorry, these are all the pics of the process that I have.



The rod slips through the strut from the top and will exit the center hole of the strut at the bottom.



Once the rod is inserted the disc shape object drops down inside the strut. The disc has two relief cuts in the outer circumference. This allows it to drop past the ID of the bushing. once inside, it rotates and the center hole of the disc sits on the center pin of the rod. You can see this assembly when looking down the strut tube.



Next, get out your BFH and "press gently" the bushing from the tube. Hah. Actually you will beat the crap out of it. I was not able to fixture the strut tube in a way that allowed me to press them out. So, BFH it is.



Eventually the bushing will succumb and come out. The top one is easy. the bottom one, well. you can guess. It takes more effort.



Once the bushing is out you can check for play. Here is a quick video. These bushings had about 1mm gap to the side (0.5mm circumferential play). The new bushing is nice and tight.





the bushings do compress slightly when installed and the insert fits nice and tight.

[jpnovak]

Now that you have the new bushings its time to put the new ones back in.

The second part of the toolset is a stepped drift. The bushing actually fits on the lower step and is support fully. the larger step matches the strut tube ID.

So,. Gently get the new bushing started. I use a block of wood and a mallet.



Then insert the step tool into the bushing. I use some light taps off angle to square up the bushing.



Then, drive the bushing into place. A press also works.




I have the measurements written down for the depth of the bushings but do not have them for this post. The lower one goes to the bottom of the damper OD. the top one I install 5mm below the top edge of the strut tube. I have reference marks for the depth on the tool itself.

Once finished installing both bushings, you can install the top cap seal.




Don't forget to reinstall the dampers. Fresh grease is needed on the new bushings.

Voila! finished.




I hope this clears up the process for those interested in doing this or having it done. It has cured many a speedwobble, unexplained clunk, tire wear and other issues that were not fixed by wheel bearings, control arm bushings, new dampers, new alignment, etc.

[franklinstower]

Excellent write-up. Your process and tools are pretty much as I imagined.
Thanks for posting!

[wjdunham]

I take it this is specific to the Bilstein front struts? My '85 era Boge struts don't appear to have any replaceable bushing, or am I incorrect there?

Bill

[jpnovak]

Bill, that is correct. These are for Bilstein only. And 911 specific with the inverted damper. The boge and Koni struts do not have any bushings.

[tsuter]

I have my front struts completely out and am replacing 44 year old struts and inserts with the complete brand new Bilstein strut assemblies. Left and right.
However I notice that the old strut coming out has a large top washer/bushing 2 1/2" or so and the new ones have a small rubber bushing about 3/4".
See next pic.
The top dirty one is the old one with the big washer bushing. The lower one is new and small.

Here is pic up into the strut tower at the bottom of the camber plate mount which I am not replacing.
It seems I need to switch the new struts to the larger washer/bushing. Having that small one up there does not seem correct at te bottom of the camber plate.
See next pic.

[Cory M]

Great info Jamie. Decades later, my Fox mountain bike forks use the same bushing design. It's rare that they wear out but it does happen.

[rywats]

Does anyone have a current Part Number and source for these 2 internal Bushings.

Seals I found from Summit, E4-B36-800A.

Thanks-

[gled49]

Get rid of the big washer, it was for higher ride height. The rubber piece is for shipping the parts, get rid of it also.

[ertech]

Great write up . I got these parts
M4040tu from motion industries for 3$ each
The seals from summit
Roll pins from our host

Instead of removing the bottom bushing can we install a bushing on top of it so there would be from the bottom
Old bushing —new bushing — top new bushing ?
We would leave the bottom one there

[rywats]

Where did u confirm thats th correct P/N?

I thought it was supposed to be E4-B36-473A3, also from summit - but way more expensive.

This was stamped on mine that was removed however, so I think you're found correct ones:

[chrisbalich]

If this is the fix for my occasional, completely untraceable front right clunk, I would be so excited.

I'm looking forward to confirmation on the pn for the bushings. I should be able to make a tool to remove/install.

[rywats]

I just ordered those M4040TU Bushings from Motion, they are acutally down the street so will see tomorrow when they arrive. I'm thinking they are just re-stamped with BILSTEIN Part number but same product.

I just went through the removal process, see my post here: https://forums.pelicanparts.com/12120098-post86.html

[rywats]

Here is a comparison between the 1982 bushing on the left and motion replacement on the right. I can’t tell any differences.

I now need to conclude what grease to use.