The principle "driver" behind the 1974 re-design were US bumper laws. The cars had to be able to take a 5mph hit with no damage. So we got impact bumpers. Both front and rear bumpers actually sit on a pair of hydraulic rams that are bolted to the unibody. These allow the bumpers to get pushed inwards without causing damage. To account for that motion on the outside, Porsche used hard rubber "bellows" that bolt between the car and the bumper.
A side effect is that if our cars get a love tap when parked out somewhere, these bellows can get pushed out of position.
I found lots of articles on line about pulling off the bumpers, but nothing detailed about these little rascals. So it's not complicated but fixing them has some interesting wrinkles. .
I did try heating them with a heat gun while on the car to see if I could soften them up in place but did not have much luck. They are very stiff. Putting them in boiling water for a few minutes might do the trick? But hard to do with them on the car...
* Note: I did have to go back and order the support wire that is supposed to go in the middle of them to help them keep their shape. I didn't know there was one until after I had already worked on these. It is part 911 505 375 00 and called a "clamp" in the parts list. (#7 below)
Materials and Tools:
8mm socket for sheet metal screws and nuts for bellows
Parts:
Front L Bellows: 911 799 505 63
Front R Bellows: 911 799 505 64
Front left (DS) "The Easy Side"
Jack up the car and remove the front DS front wheel
You can get to the nuts on the back of the bellows via the wheel well.
How we received the car. <sad bumper noises>
I had picked up a new part just in case I couldn't save the old one. You can see where the wire goes in this pic as well. Near in the center there is a groove for it.
Support the car and remove the front LH wheel and look up into the front fender. The near bolts are for the back of the bellows. I did not pull the little trim panel off initially.
Once you have the rear off, you can pull out the bellows and carefully tuck it back into its slot.
This is where we wound up in the end. We'll need some paint work eventually and the bellows still a little out of shape on the bottom, but a lot better. The wire should help as well or I may just install the new piece.
* Update: So... when I went back in I found that the old one actually did have the wire in it and was still pretty misshapen from spending so much time bent. It was never going to fit properly.
So I went back and removed the trim panel and replaced the bellows here on the driver's side. The good news is they are around $25 from the usual suspects.
Trim panel is off, (4 sheet metal screws, 2 nuts. All 8mm) bellows just has the two forward bolts holding it. I took the opportunity to clean the area in here. It was pretty nasty.
I shot them both with penetrating oil, and while the upper is pretty easy, the bottom is tricky because the marker light housing bracket is in the way. There isn't room for an extension, and a regular socket isn't long enough. It's an 8mm and I don't have an deep 8mm socket. I got it off with the old trick of putting the socket on first and then getting a little bit of the ratchet in place.
Here is the old bellows, and you can see the support "clamp" in place under the dirt.
I put the new clamp into the new bellows. It's a very tight fit. I got it in by putting it in upside down to locate the ends, and then rotating it into position while I pressed down with a blunt screwdriver, moving along its length until it popped into place. If I had it to do again I might soften it up in hot water first and see how that goes.
Close up of the end result. Much more even on the bottom.
Good as new from a few feet away!
Front right (PS)
To get to the RH front bellows the easiest path seems to be to remove the trim panel behind it.
Remove the 4 sheet metal screws that hold the panel in
Remove the 2 locknuts that attach the bellows to the trim panel
Now you should be able to access the nuts at the front of the bellows by pulling the rear of the bellows out a bit. In my case I just needed to tuck in back in where it had been popped out, so I pushed the lower valence down just enough to allow the bellows to go back in place.
Where we started on the passenger side. This one is a bit trickier in some ways due to a very cramped space behind it.
Here is the view from the fender well with the wheel off. Oil cooler, bumper support, and out of sight are the horns. The bumper support presents a particular challenge.
Here is the view from beneath the passenger side fender so you can see the tire (bottom), oil cooler and horns. It's tight.
I removed the 4 sheet metal screws that hold the metal trim panel behind the bellows here (held in by clip nuts) and am pulling the panel and bellows away from the body to help with access
The gaskets that go above and below the metal trim and the sheet metal screws that hold it on.
A different view. The rear bellows bolts are loose but not off. No reason to remove.
I pushed down a little on the front valence and tucked the bellows back in and then screwed it back together. Not a big deal but replacing the bellows would have been hard due to the location of the front nuts. If you have a car buddy you can always pull off the front bumper together and replacing the bellows would be a lot easier.
Again, we'll need paintwork eventually, but the bellows is a lot better, when I get my deeper 8mm socket I will probably replace this one to get rid of that little 'bunch' on the low side. *
Not perfect, but a big improvement until we're ready to touch up the paint.
I tried once more this this past w/e to replace that bellows but it does not seem possible without some more disassembly. I think the bumper probably does need to come off for this one.
Here I have removed the trim panel and pulled the bellows outwards to give me more room to see where the front nuts are. The upper is too close to the bumper support to get a socket (or any normal wrench) on, and the lower is a lost cause. The upper would take a long time, lots of tiny movements and turning the wrench over. Once it is off I am not sure it gets you anywhere worthwhile.
Comments