1970 power seat repair

Started by Rob Leonard, July 21, 2017, 02:27:12 AM

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Rob Leonard

I've recently acquired a '70 FWB with 78K miles. Not a show car, but a nice driver.
The first issue to deal with is the driver's power seat. The seat motor runs but there is no movement when activating any of the three control switches. The car has the 40/60 split - the passenger-side 6-way PS works perfectly.

Is there a "usual" failure mode to these? My mechanic says the "track" is bad. He wants to acquire a seat from another '70 and piece together a working mechanism with parts from the two seats. I'm afraid of what this will cost. I've not worked with this particular mechanic before and am not sure I trust him. Any advise would be much appreciated. Thanks, Rob Leonard

The Tassie Devil(le)

It could be that the transmission is burnt out.   It could also be that the transmission cables are not connected.

The below picture is of a '69 SDV 40 seat transmission, which should be the same as yours, and it looked good on the outside, but the inside was a sorry sight.   

I had to strip it down and use the guts of another transmission, as I couldn't find one the same.   I told the supplier what I wanted, but what came was totally different.

I managed to reconfigure the solenoid coils, and reassemble the replacement parts into the original housing.   Required a bit of reconfiguring of the wiring plug, but everything worked perfectly.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Jeff Rose CLC #28373

#2
Don't do the track just yet. That isnt your problem.
The motor running does not move the seat. It goes thru the transmission then out to the tracks thru speedo cables.  Take the seat transmission out and clean it. It is probably all gunked up. The pictures above show it well. It just splits in 2 and you can disassemble it for cleaning. Take pix so that it all goes back the same. Fairly simple, just clean it well and be sure all goes back the same way.
There are 3 solonoids if I remember correctly. They engage/disengage with a plunger action. Take it out, disassemble and clean it. If the plungers move freely then the seat should work.
Easier to get it out if you can get the seat in the highest position. Clean the tracks too but that should not be your problem.
Cost for my fix was $0.
Jeff
Jeff Rose
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

67_Eldo

I second Jeff's response above.

I have a 1967 Eldorado with the same mechanism -- I think the same seat-adjustment pieces were used from 1965(?) to 1978(?) -- and it exhibited exactly your symptoms.

The transmission was disassembled, degreased, de-corrosioned, the solenoid cylinders were honed, and the solenoids were scrubbed. Then it was reassembled using lithium grease.

While it was out, the cables were lubricated too, but that was strictly optional because the cables were OK.

It works fine now.

Chas

I had the problem where the seat would go back and forth, but the rear would not go up and down. Ended up that the cable had snapped. They're EZ to find and relatively cheap.
1967 Coupe DeVille
1970 Coupe DeVille
1976 Coupe DeVille
1983 Coupe DeVille
1977 Harley Cafe Racer
1991 Harley Fat Boy
1957 Harley Hardtail
1949 Lusse Bumper Car
If you're 25 years old and not a liberal, you have no heart. If you're 45 years old and not a conservative, you have no money!

Rob Leonard

Thanks guys. You put me on the right track!
I now feel that I can do this project myself.
I'll post progress once I've started.
Rob

The Tassie Devil(le)

Don't forget to get a friend to assist in removing the seat, as it is HEAVY, and awkward to move around without damaging anything.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Bob Hoffmann CLC#96

Rob,
No need to remove the seat. Just unbolt it & let it tilt back.
HTH, Bob
1968 Eldorado slick top ,white/red interior
2015 Holden Ute HSV Maloo red/black interior.
             
Too much fun is more than you can have.