Undertray attachment on '88 S4
04-21-2013, 07:18 PM
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Undertray attachment on '88 S4
After some late night roadside disassembly (during which I discovered that removal of the undertrays requires lifting the front right of the car) the two undertrays are now no longer attached to my car.
There are 14 fasteners in all (not that this differs from what is shown in the 87-91 PET PDFs from the Porsche website):
* Five at the front of the plastic tray that attach the undertrays to the front splitter.
* Three in the middle joining the two trays together.
* Two in the "ears" at the front of the aluminium tray that stops the middle of the trays dragging along the ground.
* Four at the back of the aluminium tray that attach to the two pairs of arms hanging down.
The two fasteners in the aluminium tray ears have disappeared. What are they supposed to be?
There are 14 fasteners in all (not that this differs from what is shown in the 87-91 PET PDFs from the Porsche website):
* Five at the front of the plastic tray that attach the undertrays to the front splitter.
* Three in the middle joining the two trays together.
* Two in the "ears" at the front of the aluminium tray that stops the middle of the trays dragging along the ground.
* Four at the back of the aluminium tray that attach to the two pairs of arms hanging down.
The two fasteners in the aluminium tray ears have disappeared. What are they supposed to be?
04-21-2013, 07:39 PM
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The ears on the rear aluminium tray screw directly into the frame rail too - One of my cars came with one 10mm-headed screw (14G?) on one side. I'm not sure it was factory, but the holes tend to strip and the fasteners fall out. I just drilled them out and stuck in M6 riv-nuts, so I can use regular M6 bolts (I actually did this to various locations).
From memory, it sounds like you're missing a few:
The ears on the front tray - two screws with 8mm head which screw into the underside of the body's frame rail
Two screws with 10mm heads in the middle of the front tray, which screw into speednuts on loops on the crossmember (through tabs on the vents IIRC)
(I vaguely recall one other 10mm headed screw in a round depression too - possibly into steering rack plate?)
I need to do the riv-nut modification to my 87, so I'll take pics when I do it (hopefully next weekend - once done modifying the X-pipe to add another O2 bung).
From memory, it sounds like you're missing a few:
The ears on the front tray - two screws with 8mm head which screw into the underside of the body's frame rail
Two screws with 10mm heads in the middle of the front tray, which screw into speednuts on loops on the crossmember (through tabs on the vents IIRC)
(I vaguely recall one other 10mm headed screw in a round depression too - possibly into steering rack plate?)
I need to do the riv-nut modification to my 87, so I'll take pics when I do it (hopefully next weekend - once done modifying the X-pipe to add another O2 bung).
04-22-2013, 08:31 AM
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2 front 'ear' screws
5 front 'lip' screws
2 'up the duct' screws (to speed nuts on engine carrier)
2 bolts through steering rack cover plate
3 screws fastening the two trays
2 'ear' screws on aluminum tray
6 screws for the brackets on the AL tray (4 to-tray, 2 to-body)
I'm not sure if there was a real standard for what fasteners were used. Based upon what I've seen, I think that the 8mm captive-washer hex-head machines screws (NLA IIRC) were used on all(*) positions unless Hans or Franz was careless drilling the holes in the chassis in which case the 10mm variants were used in one or more of the 'ear' positions.
(*) except the 'through-rack' positions; those are always 6mm bolts. (IIRC 1.0 thread pitch.)
5 front 'lip' screws
2 'up the duct' screws (to speed nuts on engine carrier)
2 bolts through steering rack cover plate
3 screws fastening the two trays
2 'ear' screws on aluminum tray
6 screws for the brackets on the AL tray (4 to-tray, 2 to-body)
I'm not sure if there was a real standard for what fasteners were used. Based upon what I've seen, I think that the 8mm captive-washer hex-head machines screws (NLA IIRC) were used on all(*) positions unless Hans or Franz was careless drilling the holes in the chassis in which case the 10mm variants were used in one or more of the 'ear' positions.
(*) except the 'through-rack' positions; those are always 6mm bolts. (IIRC 1.0 thread pitch.)
