Can I just replace my strut inserts?

[BISHOP901]

I removed my old strut inserts and clean out all of the fluid in the housing. I have ordered my new struts and I was wonder if I have to fill the housing with fluid or will the new struts be sealed and just drop in.

[Flieger]

You can put them in dry. The fluid helps to transfer heat to the outside of the strut housing and into the airflow. If you go without it, you have less chance for leaks and save a little weight.

[g rad]

If the old inserts had excess ware, like vertical grooving, etc along the sides.. then the bushes inside the strut housing need replacing, there are two in each side.. If they are worn (no Teflon) they should be replaced because they will score the new inserts quickly... I think the factory recommends just liberally oil coating with new bushes.and top seals... I just did my Bilsteins. Just tap up, with a drift around the rings and they will come off and expose the seals... hope this helps.... g rad

[Wil Ferch]

I think we're mixing apples and oranges here.....

I presume the first poster is talking about OEM black Boge housings. The original guts are exposed within the strut housing...and are not contained in a separate cylindrical tube insert as are the replacement shock inserts ( from Boge, Koni, Bilstein, others) that can be purchased to fit the Boge housing.

If THIS is what's being discussed then a SMALL amount of oil or such can act as a heat transmitting agent, as described. If too much, it will be quickly displaced as you drop in the new insert !!

The other text by other posters deal with ( I believe) the rebuild process of a Bilstein strut, which only takes Bilstein internals ( as individual parts....no insert).

[Zeke]

Wil, are you saying that the valving fluid (for lack of a better term) is contained within the strut housing and not the insert itself? I guess I've never removed a Boge shock insert from a Boge strut. If I have, I didn't notice where the fluid could enter and leave the shock and be resevoired in the outer housing.

I have always told people to place an once or two in the housing to transfer heat and that any fluid found in a Koni, Bilstein or other strut housing was NOT from the shock insert. I guess I was wrong in at least one application.

What is the procedure to fill the housing for Boge in Boge?

[Rot 911]

Originally Posted by milt

What is the procedure to fill the housing for Boge in Boge?

The same as with Koni and Bilstein. The struts are self contained. Any oil found in the housing is just for heat transfer.

[Zeke]

Thats not what he said, or I can't read.

[Rot 911]

Originally Posted by milt

Thats not what he said, or I can't read.

Yeah I read Wil's post again. I've changed out boge struts on several 911's and they were all self contained. I know the one's on my '86 were the original struts. Not sure on the other ones I changed out.

[4sd911]

The boge struts on my '74 were like the ones described by Wil, not the self contained type that are used now. The instructions with the new inserts do advise to add oil or coolant to the housing to help cool the new insert.

[Zeke]

Very interesting. My '77 Targa had Koni struts and inserts. My 914 race car had Koni struts and inserts. the Ragamuffin ('71 S) had Boge struts and Koni sport inserts. I know I changed over the '71 myself, removing the originals. I guess they could have been open at the bottom to suck in fluid. There was fluid in the struts, that I know. Now, the rears were Mulhollands, so maybe the fronts weren't original. It was a long time ago.

But, that must be a unique procedure to place an open ended shock in a strut housing and then know how much reserve to put in afterwards. It's got to be an off-the-car procedure. How in the world would the fluid stay up in the valve region while assembling? I can see how they would pump up and discharge any air once driving just like a remote reservoir shock does.

When I get more time later on today (I'm epoxy repairing those POS front light housings at the moment), I will dig out my factory manuals to see how this was done. Really. I wouldn't want to get caught stupid down the road. You never know what I might buy or work on next.

That's the fun of it. You learn something every day.

[Wil Ferch]

I come back to this thread and see I may have caused some confusion.

FWIW....on my 85 Carrera, when I changed out the shocks, the internals of the OEM, front Boges were NOT all self-contained in a drop-in cylinder. The "guts" as I recall, were somehow loosely all intertwined together, but no "one-piece" cylinder came out. Some large diameter seals on the very top and maybe bottom, IIRC, and a lot hardware stuff in between. There was therefore a lot of hydraulic fluid there originally (the shock fluid) that had to be removed in order to get the new "inserts".... well ... inserted.

After all this "junk" came out, I swabbed and soaked up all I could, and also added maybe a tablespoon of either oil or antifreeze ( can't recall) as a hydraulic cushion for the insert. You will immediately know if you put too much in, it will squirt out with a vengeance as you try to get the insert fully seated.

So...for BOGE housings, you can buy Boge, Koni, Tokico, KYB, Bilstein, etc ...cylindrical inserts. For the Bilstein struts, I believe they are built like the OEM Boges in that there are no separate cylindrical inserts, but have separate piece internals like guide ball bearings and such, that can be individually replaced and therefore rebuilt. I believe "upside down" too...with the shaft end running toward the bottom, and the hydraulic ( fat) end on top. Koni strut housings, (AFAIK, like Bilstein strut housings), only allow "like-brand" replacements.

Others can chime in more on the Bilstein or Koni specifics but that is how I understand them.

EDIT- with all due respect to our host, Jason Burkett of Paragon Products does a nice tech write up of front strut internals replacement ---> http://www.tech-session.com/kb/index.php?article=7

[signature65]

Not trying to hijack this thread. But......my 73T has Konis up front. Were these an option above standard equipment. I'm rather dissapointed I have Konis because they take the most expensive insert.....so annoying at times. Just courious to the order of strut quality.

[sig_a]

Replacing Boge inserts with Bilstein "Sport" last November first required disassembly of Boge strut, dumping out the oil and non-enclosed insert, cleaning inside diameter of strut , and finally sliding in the Bilstein's.

That's it.

I'm skeptical regarding the value of oil being very effective against excess heat in the Bilsteins.

The original oil within the Boge strut/insert is part of a much different design, and may provide a dampening and cooling function. I don't know.

[Nine9six]

Originally Posted by sig_a

Replacing Boge inserts with Bilstein "Sport" last November first required disassembly of Boge strut, dumping out the oil and non-enclosed insert, cleaning inside diameter of strut , and finally sliding in the Bilstein's.
That's it.
I'm skeptical regarding the value of oil being very effective against excess heat in the Bilsteins.
The original oil within the Boge strut/insert is part of a much different design, and may provide a dampening and cooling function. I don't know.

+1...Had the same experience.

[RJ911SC]

Having replaced my front struts with Koni sports (yellow) inserts the past week, rears already done, i did some past tread reading in here, and found that you can either clean out and install dry or fill with 1/3 fluid. I filled with 1/3 fluid, having said that, i also found out that the passenger side was Boge, and the drivers side was Blistein???
So i ordered a new Boge strut Assembly from Pelican got it yesterday for the drivers side. Anti freeze works as the fluid. The one side that is complete, took about 20 mins to take out and re install, and seeing as i now have to take the other side completely out to install the new Boge assembly and strut insert, i will probably post something as to how to remove the old assembly.
Good luck with the inserts, quite easy to do,,,,, well one of mine was ........

[Por_sha911]

The original Boge strut had the valving "swimming" in the hydraulic fluid. The outer case of the strut was the container. When you replace it, the new insert is self contained and no longer needs to be immersed in hydraulic fluid. Some folks will still put about 50 ml of antifreeze or oil in the strut when putting in the new insert. I believe that the benefit has more to do with keeping the cylinder from having condensation from the air which can cause problems with rust or freezing (if there is enough moisture). Some folks will put the insert in "dry". In that case it is a good idea to put a light film of oil on the inside of the cylinder and the insert for corrosion protection. Either way, be sure to get all the old hydraulic fluid out to clean and dry out the inside of the strut before putting in the new insert.