1971 911E front hydropneumatic conversion -- what have I got here?

[ZombieBranz]

I've decided to replace all my front rubbers (control arms, drop links, etc) with new Elephant OEM rubbers...along with turbo tie rods and new struts.

Here is where I am lost. Obviously being an E my car came with the hydro-pneumatic struts. I've read that the original hydro struts cannot take standard strut inserts without either being replaced with non-hydro struts or some people back in the day were able to rework them to take regular inserts.

So here is what I have currently;

Struts are Boge #901 341 083 01

I believe these are original hydro struts, correct? if so looks like my car was reconfigured back in the day to include sway bar and drop links and to use these struts.

I would appreciate some input into what I have here; does it look like these struts were re-configured to take regular inserts? I was hoping to just throw some Bilstein inserts in. Should I keep these struts or source non-hydro struts? anything else look funky or wrong here?

I don't know the size of the sway bar...didn't find any number on the end of it. Thank you.

[gled49]

I see a torsion bar ride height adjusting screw, so conversion is done. So you got that going for you.

[ZombieBranz]

I see a torsion bar ride height adjusting screw, so conversion is done. So you got that going for you.

Yes conversion is done...happy for that...however based on part# struts seem to be original hydro struts that were customized for inserts? Or are these non hydro Boge struts that will take inserts? Thats mainly my question.

[Frank Beck]

...however based on part# struts seem to be original hydro struts that were customized for inserts?

Yes.

Back in the day we made spacers and bushings to accommodate stock Boge inserts. Pull the inserts out and dollars to donuts that's what you'll find.

[ZombieBranz]

Yes.

Back in the day we made spacers and bushings to accommodate stock Boge inserts. Pull the inserts out and dollars to donuts that's what you'll find.

Thanks Frank...will update once I get things ripped apart.

[Jim Breazeale]

You can usually tell the brand of insert by looking at the threaded end of the strut. Take a good picture of the strut end in the trunk and chances are that it can be positively IDd. Many of those strut conversions utilized Koni inserts. 70 and later 911s had to change the cross member and lower control arms, in order to add torsion bars. 69s only had to add torsion bars and the adjusters. A arms on 70 and later 911s with Hydropneumatic front suspension were hollow.

RegaRDS

jIM

[ZombieBranz]

You can usually tell the brand of insert by looking at the threaded end of the strut. Take a good picture of the strut end in the trunk and chances are that it can be positively IDd. Many of those strut conversions utilized Koni inserts. 70 and later 911s had to change the cross member and lower control arms, in order to add torsion bars. 69s only had to add torsion bars and the adjusters. A arms on 70 and later 911s with Hydropneumatic front suspension were hollow.

RegaRDS

jIM

Thanks Jim, sort of lost b/c I thought Boge struts could take a Koni or Bilstein insert but maybe that is only for the non hydro Boge? I actually already had Bilstein Boge inserts on order so your input is timely.

here are add’l pics of strut thread....also just noticed pass. side control arm has a nice ding in it. By hollow I assume you donkt mean boxed? This are boxed but Yes these look to be hollow....in fact drv side, on the flat side of a arm, (facing driver) has a hole in it....pass side does not.

Do you have solid control arms and non hydro Boge struts? Might just be easier to deal with non hydro struts if I am taking the time to redo it all. Appreciate the info.

[Harvey Weidman]

When we modified the hydropneumatic cars for torsion bar suspension, we had the struts reworked at a machine shop to accept the Koni inserts (we were a distributor or we would have used Boge) and then used stock torsion bars...if there were no torsion bar splines like Jim was referring to, we put in 914 arms because they were more available and costs less.....(the spline count is different)....If you ever find any with that set up, they were probably from us.
We did dozens of them ...mail order and in house.
H

[ZombieBranz]

Called Jim at EASY this am and he gave me enough advice for me to get the driver side control arm out. Thanks Jim...sorry our phone call disconnected...but thanks for the help!

Got the strut off and the control arm off. Don’t have a big enough pipe wrench to get the strut cover off.

Control arm required a little persuasion to free itself. You can see that hole...looks rough and ugly like someone did that for some reason? Any ideas?

So far struts look servicesble so plan to follow Jim’s advice and just replace inserts.

Will pull off other side tomorrow. Thanks for all the help/info/advice

[Jon B]

So here is what I have currently; Struts are Boge #901 341 083 01... I believe these are original hydro struts, correct?

...based on part# struts seem to be original hydro struts that were customized for inserts? Or are these non hydro Boge struts that will take inserts? Thats mainly my question.

If it wasn't already clear, the number 901.341.083.01 is for a left front BOGE Hydropneumatic strut.
The number for the right front Hydropneumatic strut is 901.341.084.01.
You can confirm that the strut housings are Hydropneumatic by measuring the tubes, which were larger than the tubes for shock absorber struts: 64mm (2.52").
Notice too that the strut in your photo doesn't have a metal dust cover; it didn't come with one when new.

Jon B.
Vista, CA