Dash Removal Procedure
I have done R&R on dash and pod. Unlike 911, the windshield does NOT have to be removed first.
The procedure is not difficult, just take it slow and easy. The dash is only held in by four bolts, but you have to remove a lot of stuff to get to them. Steering wheel, Pod & instrument cluster, knee shelves, glove box, a/c center vent, a/c control head, radio and clock, console and seats all should be removed for easier access. Be very careful and look for hidden bolts if things don't move easily or seem to hang. I had wonderful advice from an experienced Porsche 928 mechanic who had done this many times and the benefit of the 9 vol. factory manual set. The friendly mechanic was more useful. I had to fabricate replacements for some broken plastic tabs on the console that the PO broke while installing a radio and I stripped the 5mm hex-cap-head bolts that hold the steering column brackets.
Rather than a full description, which I'm not sure I remember, I'll just give a few hints.
You should remove the seats for better access. You will spend a lot of time on your back with head under dash.
A fluorescent worklight will keep you cooler and less burnt.
A 1/4" drive swivel-head socket drive bar is VERY useful. This is not the same thing as the 360 degree swivel adapter found in every socket set, but is a straight 1/4" drive non-ratcheting socket handle whose head swivels 180 degrees. 3" and 5" extensions in 1/4" drive size will prove useful. A yellow paint pen (available from art supply houses) is useful in marking parts and positions and easier to see than nail polish.
The five knobs on the pod just pull off the pod switches. The switches can be pulled forward by using two small screwdrivers to push the 'ears' together and pry the switches out through the front. Then the switches can be unplugged from their connectors. Mark everything. When you reassemble the pod, you will never be able to get the plugs onto the switches from the rear. You will need to pull the cables and plug ends through the holes in the pod, then attach and seat the switches.
The instrument cluster has three edge-card connectors. Mark polarity before removing.
The cluster and pod is held in place by two long (about 3" & 5") 5mm hex-cap-head bolts. The shorter of these goes into an eccentric offset bolt that holds and centers the cluster in the pod and the pod in its dash opening. If you elect to separate pod and cluster (i.e to replace or recover a cracked cluster cover), mark the position of this offset bolt.
If something doesn't come out easily or hangs, look for a hidden bolt. I remember one inside the center a/c vent (pry out vent with spatula), one inside the glovebox, and two at each rear edge of the console (broken tabs).
FWIW, I paid $150 to a local auto upholstery shop (King Kover, Oakland, CA) to have my dash and glovebox lid recovered in vinyl. The shop that did my work had to use a stretchy vinyl but even matched the Porsche style of stitchery on the seams. My only regret was in not insisting on and getting an exact color and texture match between vinyl and leather. This could have been done by dying the vinyl to match the leather. I was more worried about eventual cracking or flaking of the dye (essentially an acrylic paint) than the mismatch in color.
DASH REMOVAL II
The tricky part of dash removal is removing the instrument cluster/pod. The six switch-knobs in the pod pull right off. The switches can be carefully levered forward by squeezing the 'ears' together with a couple of small screwdrivers and pulled through the front of the pod without removing the pod and then the switches themselves are pulled off their plugs. Replace any of the small switch illumination lights that are bad. I mention this, because when you go to reassemble the cluster/pod, you must pull the switch plugs and cable bundles through the front of the cluster cover (pod), install instrument cluster, cover, align steering column, then plug in the switches and push into the holes in the pod. You will never be able to plug the plugs from the rear.
You will want to pull seats, steering wheel, pod, knee shelves, glovebox door and liner, front roof pillar post trim & center console before pulling the dash. The good news -- you don't have to remove the windshield as on a 911. The dash is only held by a few bolts (four, I seem to remember) but you will need to get the other stuff out of the way for access.
It is not difficult work, just tedious. The best advice I received was to proceed slowly, mark and label everything. If you tug on something, and it doesn't move freely, look around for a hidden bolt - e.g., there is a bolt inside the glovebox on the left side. Another bolt is behind the a/c vent (lever out with putty knife) in the center console. Look in the manuals about removal of instrument cluster and a/c blower. You don't have to actually remove the blower, just the other stuff.
Second best bit of advice was to get a 1/4" drive swivel bar. This is not just a universal socket, but a bar with 1/4" head that swivels through a 180 degree arc.
You may need to replace the three 5mm socket-head bolts that position the steering column. I stripped two of mine in removal, but replaced them with grade eight metric bolts - not socket-head.
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