scupper

Went to pick up the C2 last evening after having new Bilsteins and H&Rs installed. While driving the car off the alignment rack and around to the front of the shop, the mechanic was horrorfied to hear a clunk clunk sound in the rear when going over bumps, etc. Brought the car back into the shop and could find nothing loose. He suspects it is the shocks bottoming out against the bumper stops he reinstalled on the Bilsteins. He believes there is less travel and that bumper stops are not necessary. Not sure this sounds correct.

Any thoughts? For those of you who have made this change on a C2, did you retain the bumper stops on the rear shocks?

As always, thanks in advance

Chuck
93 C2

scupper

Just received a call from the shop - seems that the 93 C2 model has a different take up point for the rear shock mount - and thus requires a different shock. The 91 and 92 use Bilstein F4B46-1735-HO, while the 93s (and presumably 94s) use F4B46-1547. Shop is waiting for the new parts to arrive. (sigh).

Chuck

johnfm

Yep, the rear shock mount changed completely for the later MY 964s

scupper

Well, Rats! Shop just called to say that the correct Bilsteins are not available locally so I won't have the car until Monday evening. On the plus side, however, the shop owner is letting me keep his Mini S - which is a fun car - not a P-car, but still fun. But man oh man, I sure do miss the Pcar seats. The Mini's are not near as comfortable nor supportive as the C2's seats.

Chuck
93 C2

Michael Delaney

I thought the rear shock mount changed after 1990.

Adrian

Dear Roy,
I am also not aware of rear suspension changes in 1993 which required a different shock absorber. In fact I did not know of any changes in the suspension for model year 1993. The only change in Porsche documentation was introduced in Nov 1990. I would love to see the documentation for this.
Ciao,
Adrian
911C4

scupper

Hmmmmmm . . . . er . . . . ah . . . . why do I suddenly have a queasy feeling.

Chuck

Michael Delaney

Adrian, From my service information book ('91). It states the bodies are being modified to improve cabriolet roof opening. The spring strut domes are now lower by 22mm. I am getting ready to order Bilsteins for my car and did not see any other struts than the change at 1991.

scupper

Just looked on the Bilstein web site - appears the suspension point changed in 91 - - - the 89 and 90 model years use 1735 rear shock and the 91 and later years use the 1547. Appears my shop did not want to tell me they ordered the 89/90 shock -- <grin> Thanks, Adrian and Roy, for the heads-up and correct information.

Chuck

Michael Delaney

Scupper, You have my curiosity aroused now. Went to the Bilstein site. 89-90 require B46-1735,91-93 require B46-1547. This is for C2/C4. I think this should include '94 but that is what it says. I read all this that the later shocks would have to be shorter by 22mm. Hope this helps.

Jeff Curtis

Scupper, I was just about to say they apparently ordered shocks for a '90/early '91. <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />

You knocking sound may also be attributed to the fact that they apparently didn't trim .75 inches off the bump stops like the H&R directions state. <img border="0" title="" alt="[Eek!]" src="eek.gif" />

Man, to think that you're just 3hrs away and I couldn've hooked you up on this installation...vice the "goofy" shop you're using. <img border="0" title="" alt="[Wink]" src="wink.gif" />

scupper

Jeff - this shop enjoys a reputation for having good mechanics and being honest. They sponsor a water pumper race car (can't remember if it's a 944 or a 968); they also race Bimmers. Although they work on 911s, these cars are not their long suit. I have to wonder if the mistake wasn't made by their parts supplier in California shipping the incorrect shocks. In any event, my shop is being up front and I am driving their Mini Cooper S all weekend, a fun car, but certainly no Pcar!

That said, I did give them a print out of your step-by-step instructions posted over on the 964 board. Bright and early tomorrow morning, I will call to their attention your step 11 in which you discuss the bump stops.

Anxious to get the baby back - need to take the snow shoes off for a Drivers Ed event next weekend at Summit Point.

Chuck