that black GT looks just like the one in my garage ! I have a hitch on both my 928,s . The GT has just a reciver bolted to the alum bumper beam , with a flip down plate holder .Only capable of towing very light trailers . My 81 has a frame mounted hitch that I made and has towed 3500 # + . As a major trailer manufacturer, 50,000 and counting , making and developing a hitch for the 928 would not too hard . I would have to check to make sure our product liability insurance covered it . Anyone else building a hitch should do the same .

Hitch Info
 

Here is some info on the hitch. The one I have is just like the one in Porken's Pic. What are these things worth? I see where the PO paid $207 just for the ball neck. I also have the wiring harness.

On the car
 

Here is the pic on the car

Sorry
 

The pics won't upload:banghead:

If you have the harness and all the mounting hardware, I'll open the bidding at $400 plus actual-cost shipping to the PRK.

Dumb question-

Per PET, it looks like there are 2 flavors of factory tow hitch:

928 722 031 02, for 78-86

928 722 003 00, with wiring harness, for 87-91. 'cept the wiring harness (928 612 905 01) is separately listed for '85 and up.

I wonder what the difference is?

FWIW, I need the hitch for a 78-86 car.

First time I've seen all of the parts for the install.

What does (42) do?
Where does (40) attach?
(55) attaches to the battery box?


http://members.rennlist.org/porken/HitchParts.jpg

I have a factory hitch on my 85. When the draw bar isn't installed it is fairly inconspicuous, not as much so as, the ones with the receiver in front of the license plate, but still fairly concealed. I’ve tried numerous times in the past put have been unable to get any reasonable pictures of the mount points until recently. I had the fuel tank out the other week which allow for me to snap a few pic’s of the installed hitch (cell phone camera so not great). I will try to post them here in in the near future.
To mount the factory hitch the rear bumper cover does have to be removed, as the side mounts attach at the bumper shock mounting points. If you notice on the pic that PorKen posted the side mounts are “C” shaped to reach both the upper and lower mount bolts. With the “C”s both facing the center you cannot get the hitch in place without removing the rear bumper shocks, necessitating the removal of the rear cover. If someone were to replicate the OEM hitch and face both the “C”s in the same direction I believe it would greatly simplify installation. I personally like the factory style hitch mount as it does not rely on the bumper shocks to carry any load. Also the torque applied to the hitch it handles by the long forward arm of the hitch. In a bumper mounted hitch all the tongue weigh and torque of the pulling and stopping force (if the ball isn’t perfectly in line with the center of the bumper shocks) is carried by the bumper shock mounting bolts which are only a couple inches apart. If you are only carrying a very light load this is probably acceptable, but I wouldn’t want to rely on it.
I think the ideal setup would be one which picks up the factory mount poits but incorporated a standard 2” receiver. For mine I currently have the 50mm ball which allows me to tow any trailer with a standard 2” ball hitch. I however also have a trailer with a 1 7/8 hitch, and I would like to have the ability to use hitch mounted bike racks and other standard hitch accessories, but of course none of it interfaces with the factory mount. When time permits I figure I will make an adaptor to go between the OEM hitch and whatever accessory want, just haven’t had time yet.

Intresting hitch drawing Ken . If I had a original hitch , I could copy it and do a run of them , with a 2" reciver style hitch .And some mounting updates.

That would be sweet. I'd be in.

Dan
'91 928GT S/C :eek: 475hp/460lb.ft

+1

Unfortunate that we don't live closer. I would be more than happy to let someone take any measurements and attachment details (though it looks as though I'm missing a couple parts in the sketch above, I don't have 40 or 41) from mine. I'll admit it would be really convenient to have the 2" receiver incorporated.

Parts from drawing above

#51 Vertical link attaches through right rear of spare tire well with bolts #46. (Pic 1 below)

Left and right ends of hitch #19 attach at “C” shaped brackets to bumper shock mounting points with bumper shock mounting bolts #44 and #45. (Pic 2 below)

Forward end of hitch #19 attach through forward side of spare tire well with bolts #44 and #46, and vertically through rear deck with bolt #46, and forward through body with bolt #46. (Pic 3 and 4 below)


I believe #40 is designed to capture as much body material as possible to distribute the load at the forward end of the hitch. I do not have this piece, and didn’t know it existed until the above drawing was posted, so during my install I used oversized fender washers. I also the rearward hole on the forward arm of my hitch was not a through hole it only penetrated one layer of the overlapping welded arm so I did not install a bolt at that location. I also did not see how to gain access to the forward side of the body sheet where the forward facing bolt would be located so I omitted that bolt not knowing how to get a nut on it. Looking at the drawing all locations where #42 interface with bolts there are no nuts present, so I assume #42 are tapped nut plates which may explain how the forward bolt would be installed. I’ll have to go back and look at that area again and see if there is access to install them, if I can still see the area since I have reinstalled my tank.

Awesome. Makes sense, now.


(40) and (41) mount inside the cabin, as backing plates.

yes 41 and 42 are backing plates. they also provied additional fore/aft bolt locations to further distribute the load.

I posted info on where to buy these in Germany many months ago. The company is Oris. They may still be in business.