Rear Shock Assembly for 914-6 - Boge Options

[DennisV]

I hate to belabor the rear shock topic, but I am stuck. I didn't have the original setup to reference, and I'm not finding much in terms of Boge details for 914-6.

• #6 Bump stop: Taper up or down? In the drawings and videos I’ve seen, it goes down. When I trial assemble, it seats much better into #8 cap when taper goes up.
• #5 Rubber stop washer: Does the side with grooves go up or down?
• #4 Cap - boge: Does the beveled side (i.e., smaller OD side) go up or down? Why does it even have a bevel?
• #4 Cap - boge: I assume it is meant to rest on the beveled edge of the strut shaft? When I trial assemble (without the spring) I doesn’t seem like there is enough length to get the #10 threaded bushing to start without some serious compression on #6 bump stop. Is this correct?
• #17 Washer: What is OD and thickness?

Thanks for any assistance.

[Superhawk996]

Here’s a couple other pictures of rear dampers and where the jounce bumper goes (circled in red)

[davep]

Here’s a couple other pictures of rear dampers and where the jounce bumper goes (circled in red)

No, that is wrong! the bump stop (Jounce bumper) does not fit at the bottom of the shaft, but at the top and inside the spring cap.
The original bump stop had the stepped washer bonded into the top of the foam rubber. The bump stop only comes into play when the shaft is fully pushed into the shock and the spring is fully compressed. Its purpose is to keep the bottom of the shaft from slamming into the bottom of the shock body.

[Superhawk996]

The original bump stop had the stepped washer bonded into the top of the foam rubber.

Fair enough - may have been that way on OEM part in 1970. Good luck finding a OEM jounce bumper with a bonded washer in 2024.

What is going to happen is when the vehicle is driven, the jounce bumper will migrate up the damper rod. Due to tight fit to the damper rod it will end up staying at the top of the rod for a good while (maybe years). It will function exactly as intended.

Eventually years down the road as the jounce bumper gets pounded out, it will become loose and slide back down to the bottom of the damper rod and will still continue to function for years until it finally splits and falls out.

At that point you will be left with the stepped washer at the top of the damper rod - where they all have survived to this day.

Buy new jounce bumper. Rinse, lather, repeat.

Maybe someday Porsche will decide to offer the jounce bumper described.

I give the OP a (IMG:style_emoticons/default/first.gif) for ordering the jounce bumper. Many rear dampers are running around out in the wild on new dampers with no jounce bumper at all.