86 928 seat removal - 2d post
 

In a previous post, I asked for suggestions on how to remove the seats from a wrecked 1986 928 which had all the relays and fuses removed and did not have levers under the seats to allow manually moving them backward and forward to get at the allen screws holding the seats to the frame. Two replies were helpful. One told me of the allen screw connected to plastic gearing which, when turned, would do the job. Unfortunately, the plastic gears were broken - that method was out. The other told me to simply apply 12 volts to the wiring in the front and that would do the job. I've attached photos of the front underside of both seats. Could someone tell me where I connect the positive and negative wiring from the battery? I assume, once the connection is made, the controls on the side of the seats will function. Thanks for any help offered.

This will be a trial and error process. I believe the wires go in to the back side of each motor. As soon as you connect the battery directly to the two posts per motor the motor will engage. The trial and error part involves which post is positive and which post is negative. If the seat moves in the direction that you were wanting, just continue. If the seat moves in the opposite direction that you desire then you should switch the wires on the battery and reverse polarity. The seat should then move the desired direction. I suggest attaching the leads to the motor first and then it will just be a matter of making contact with your battery.

If the plastic gears are fubar then you are SOL.

If you're connecting directly to the motors (bypassing the controller) you will find the motors are bidirectional. Reversing polarity switches the spin of the motor -- and therefore the direction of travel.

MUCH Easier--

The two cables that connect to the motor assembly at the front are retained with wire bails that pop off. Then the cables can be extracted from the gear drive. Inside each cable sheath is a flex cable with a formed square end. You can use a small wrench to turn each cable in the housing to slowly move the seat. It's one side at a atime, so do one a little then the other until you can access the mounting bolts.

A lot slower but +1 Dr. Bob

Well the two plugs that power the center motor are very clearly visible in the second pic.

If you choose to go the "take off the cables" route, the spring clip for the left side (right in pic) is visible in the first pic, seems to be removed in the second.
The right side cable has the plastic gear/manual screw thing that has a plate that bolts in. The bolt is the one facing down. Visible in both pics, the little 2 pin plug is pointing almost directly to it.

You say the car is wrecked? Is this an opportunity to hone your Sawzall and/or cold chisel skills?

That would let you finish the job on the bench, standing up straight or seated rather than pretzeled.

ww

Actually looks more like it was used as a chicken coup...

I had a dead controller relay on mine, as a result the seat would only go backwards. Not being aware of Dr Bob's approach, I removed the wire from the front motor and connected alligator clip test leads. By switching polarity of the 12v supply to the test leads I could move the sea forward and back at will, which allowed access to fasteners.

Pretty easy actually, for that one motor.

By the way, I believe the manual adjustment gear intentionally has a tooth or two missing so the normal cycling of the motor doesn't continuously spin the little nylon gear. When you use the Allen wrench method to move the seat, you will come across that blank spot periodically as you spin the wrench.

Being unaware of that until I had disassembled my seat, I thought my gear was broken as well. Turns out it worked fine, considering the above behavior.

I didn't try to "jump" the motor.

I used the manual allen wrench, and yes, there's a missing tooth. It's very disconcerting to have it jump. But it's normal.

I had to use the "unhook the cables" method on one seat. The jackscrews were out of snych, and the switch only worked for "back". So one screw had bottomed out and every time someone (including me) tried to move the seat, they pressed "back" as well as "forward" and tightened it a bit more.

The last time I put that up, someone (Australian Dave maybe?) warned about being too aggressive turning the cable CCW. It's just a spun cable and it can be "unspun" and damaged. I had to turn pretty hard on the stuck one and had no problems, but I don't remember if the one I had to crank on was the CW or the CCW one.

My passenger seat came to me "stuck" on one side in the rear-most position. It took a combination of turning cables and serious pushing from the rear on the frame to get it "straightened" on the rails so it wouldn't get stuck at the rear again.

928 seat removal
 

My 88' 928 driver's seat is frozen in the back position. Removing drive cables and using a square drive will not turn the shaft, right or left. Therefore, I cannot access the rear anchor bolts. Is there another way to remove the seat? Unlike the other suggestions here, nothing will rotate the shafts. The seat must come out to repair. Suggestions?

get some deoxit 100 and spray it into all of the seat switches,
work the switches and do it again,
then let it sit you may have to wait a day then try the seat switch

My issue is mechanical, not electrical. I have removed the flex drive cables from the seat motor and the seat motor works fine. The horizontal threaded shafts have build up and rust on the threads, they will not rotate. I am looking for advice on how to remove the seat when you cannot access the rear anchor bolts. Thanks.

Hmmmmmm, that's a tough one. Short of destroying stuff, I'd work at getting the seat to shift so you can get to them...