1968 912 Spring Plate Cover Misalignment..

[robert crouse]

Hi, I'm in the process of replacing the spring plate bushings on my 912. This is the first time I've done this, so I may be missing something, so any help would be much appreciated. Here's what I did so far:

I disassembled both the right and the left without any real issues. During re-assembly, I put the spring plate (with the new interior bushing installed) into the body and set the correct angle. Then I installed the exterior bushing into the cover and slid the cover with the bushing onto the spring plate.

Problem: one of the holes in the spring plate cover (lower left in the photo) is not aligning with the corresponding hole in the body (see photo). It's close but I just can't get the bolt into the hole. I've tried pushing, twisting, etc. the cover around (with two of the other bolts installed) but I haven't been able to make it happen. Note that the two upper bolts shown in the photo are not tightened

As shown in the second photo, I also clamped the spring plate to the trailing arm to help align the holes, which was very helpful, but

Note: one thing I haven't done yet is put a screwdriver, for example, through the hole in the cover into the hole in the body and tried to align the holes that way (I was a little concerned that it could damage the threads in the body so I wanted to ask here first.

As a sanity check, I also disassembled everything and removed the torsion bar and re-installed the spring plate with both bushings, and was able to align everything.

Any advice or ideas?

Thanks
Bob

[WFBowen]

Robert:
The last time I did mine I found it helpful to use a few longer all threaded bolts put in one at a time to get all four aligned and started with just a few turns on each to engage the threads then with a nut on each, start to tighten each in a rotating pattern. Once the plate is just starting to snug up the original bolts can be installed.
That lower right one in your photo should be put in and aligned first since it also serves as a stop for the spring plate. I’ve also found it helpful to put a light coat of silicon grease on the outer bushing (the rubber safe kind.) You can also try bolting up the spring plate to the arm then taking some weight off of the spring plate and see if that helps to get that lower bolt started.
Bill

[robert crouse]

Hi Bill, thanks for your help.

I actually have some longer bolts that I purchased for this, but I didn't align the installation using the lower right hole to align the cover. I'll try that.

One question: did you completely install the outer bushing on the spring plate before trying to bolt on the cover? I installed the outer bushing in the cover and then tried to install the cover/bushing together.

Thanks again.

[WFBowen]

Originally Posted by robert crouse

One question: did you completely install the outer bushing on the spring plate before trying to bolt on the cover? I installed the outer bushing in the cover and then tried to install the cover/bushing together.

Robert: Yes, I first installed the bushing on the spring plate, then mounted the cover.
Also are you certain you have the correct bushings for your car (i.e., same as you removed?)
Bill

[robert crouse]

Bill, I believe I have the correct bushings. I purchased them from Pelican Parts after talking to one of the Porsche parts specialists using my VIN. They seem to fit perfectly. I don't really know about the original bushings because they were completely degraded and misshaped.

I also tried installing the spring plate (from the left side) on the opposite side of the car (right side) as a test, but the misalignment also occurs on the right side too. This is why I think I'm doing something wrong during assembly.

[robert crouse]

Well, that seemed to work, but it does seem to deform the bushing more than I thought (see photos). Does that seem ok?

My mistake was that I installed the bushing into the cover first and was then pushing that bushing/cover combination onto the spring plate before trying to insert the bolts. Now, per your advice, I first installed the bushing onto the spring plate then placed the cover barely over the bushing, and then used the long bolts to align the bushing/cover combination to all four holes in the body.

Thanks again Bill!

[WFBowen]

You might be closer than you think. See if you can pull the top of the cover away from the car while snugging uo the lower part of the cover. The idea is to start and keep the cover parallel to the spring plate while gradually tightening the bolts and eventually replacing the long ones with the factory bolts. Once you can get at least two opposing factory length bolts started the cover can be tightened up. Just make sure the cover is kept as close to parallel as you progress.
If you haven’t seen it, here’s a good video (starting around the 29:00 mark.)

https://m.youtube.com/watch?v=MaqwQRMpndI

Bill

[robert crouse]

Hi Bill, thanks again for your help with my problem, which has been resolved! However, I found that after driving in the long bolts, I needed to wait a time before replacing them with the short bolts. Otherwise, the bushing had a tendency to shift again so that the one I was replacing became misaligned (at least that's what it looked like).

[WFBowen]

Robert:
If you’re near a “real” hardware store see if you can come up with four all-thread long bolts and four nuts and washers. With the nuts and washers on each one tightened as close to the head as possible, insert each one and get a few turns started.
Then, using an open end wrench, begin tightening each nut in a shoe string pattern. The all thread method allows you to tighten up all four studs until the cover plate is cinched up very close to a final position. At this point substitution for the original bolts should be easy. I’ve found that a light coat of silicon grease (rubber compatible type) applied between the bushing and cover makes the job a little easier.
Bill

[robert crouse]

Hi Bill, yep that's what I did and it worked. Thanks again for your help.

The video you pointed to was very helpful. Actually, when I ordered the long fully threaded bolts I considered ordering carbon steel alloy bolts and just leaving those in place. The heads of the original hex bolts are marked "8.8," which I think indicates carbon alloy steel. In the end, I ordered stainless steel bolts and swapped-in the original bolts to keep it simple. Do you know if using 8.8 long bolts instead of the original short bolts would cause any issues?

[WFBowen]

Glad to hear it worked. As for using non-stock bolts, I think it would not cause problems however it’s always better to stay with stock parts. The Porsche engineers really paid attention to all specs and details, including bolt tensile strength and shoulder vs threaded properties.
Good luck,
Bill