!967 DeVille Diagnosing and correcting a non operational Bench seat

[Larry Savino]

I recently purchased a new to me 1967 Deville Convertible, (thanks Mike) it has a six way bench seat .
front up and down works perfect with front switch
read up and down works perfect with rear switch
all up and down  work perfect from joy stick

But

When I try to go forward and back I just get the whirling of a motor no movement .
does any body have any suggestions one where to start looking to get this working . Could some one explain the series of events that need to take place under the seat to move the seat forward or back. and any failure paths I should avoid

Thank you in advance . I know I will have some other questions

[Michael Petti]

I suggest googling 60's GM 6-way power seat. I will describe a late 1960 set up but yours should be similar. You should have the single motor with transmission set up. Several good explanations with pictures should show up. The switch sends power to a relay which powers the motor and solenoids in the seat transmission which move gears to power the 6 cables that run the jacks on each end of your seat. Since 4 functions work, I would look at the transmission and cables. Are the cables connected to the jacks. If they are the most likely culprit, is the transmission. It is common for grease to dry out and get stiff hindering the gear movement and preventing one or all of the functions from happening. Open it, clean and regrease it. Be careful not to lose the thin washers on the gear shafts.

[Highwayman68]

More than likely it's a gear in the transmission mostly due to the lubrication has dried up and the gears are stripped. This is a tedious and awkward project that will strain your body trying to access the different parts of this system.

You are going to have to remove all of the bolts holding the front seat in. Allow the seat to tilt backwards to access the Transmission gearbox, motor and tracks under the seat.

You will need to ground the frame of the seat to be able to operate it in this position.

Each mounting track has a gear assembly on them to move the seat forward and backwards. Remove the cables to both of these at the track at the gear housing on the track. Try the switch and see if the cables are rotating at the ends of both cables. If they don't then your issue is in the transmission. If they do rotate then one of you mounting frames is probably jammed up, possibly from rust or lack of lubrication.

If the cables don't rotate then you will have to remove the transmission and open it up to inspect the condition of the gears.

At this point if all of the gears are good it is best to remove them after taking a picture of what they look like assembled so you will know how to put it back together. Thoroughly clean all gears and the inside of the housing of all old lubrication then reassemble with new fully packed lubrication then reassembled.

If you have a broken gear you will need to identify it with pictures to let us know. Some of us may have that gear in another broken unit for parts. Replace gear and thoroughly clean all gears and the inside of the housing of all old lubrication then reassemble with new fully packed lubrication.

If the cables did turn and the issue is in the tracks or the gearing unit. You will need to remove the gear unit from the frame, hook up the cable and try again. If the gearing doesn't move then it needs to be disassembled and inspected. If a broken piece is found then they parts or the whole unit should be replaced. Either way disassemble the units and thoroughly clean and lubricate them then reassemble them.

If it does turn then the issue is in the tracks of the frame which will need to be replaced.

[Larry Savino]

Thank you for the very descriptive, explanation ,  What tells the transmition to engage what gear, I know the switch is telling the motor to move but what tells the trans to engage what gear ?

Also what material to I grease the unit with 

[Michael Petti]

The switch buttons cause different a combination of contacts to activate different solenoids then gears, depending on the function you are activating. A helpful hint is to remove the bolts 4 holding the jacks to the floor (watch for the ground wire on the passenger side). You can lean  the seat back and prop it in place with a 2x4 between the floor and the passenger side leading seat edge. Removal of the transmission and motor is not brain surgery. It just takes some patience and a little creativity. I suggest detaching the cables with the unit in the car first. There is a great explanation of rebuilding the transmission on a Pontiac site. I have attached pictures of the unit in the car (a 60 Cad) yours is similar.

[Michael Petti]

I have attached a copy of the manual for the 61 seat which is very much like yours. if you don't have a manual for your car it would be worth it to get one. Hope all this helps.

["Cadillac Kid" Greg Surfas 15364]

Not to chime in here late,but I have found that the little driven "gear jacks" that are at the ends of the cables extending from the transmission are prone to pulling their bolts out of the frame rails and essentially loosing their marbles (ball bearings).
Greg Surfas

[www.eldorado-seville.com]

I had the same problem with my 67 Eldorado a while ago. Most of the time the grease in the transmission got hard and the solenoid can no longer engage. I took some pictures and documented the repair on my website: https://www.eldorado-seville.com/files/tag-seat-transmission.php

[Larry Savino]

Thank you all for the excellent advise , first chance I get I will dig in and get this correctd

[Matti R]

I had similar problem with 66 6- way seat. I did it without removing the seat as there are not that many screws to open. Not much space, I agree.