power top problems

[Adam]

My power top motor stopped turning, when I flip the switch I hear some relay clicking but nothing from the motor. Any thoughts, I haven't taken a close look at the motor or anything yet, just wondering if this is a common problem in these cars, and where I should start looking. Thanks.

[centurion 455 ragtop]

Adam

First before doing anything check the fuse. The motor for the power top is behind the top of the rear seat just to the right of the relay. I would first remove your rear seat top and bottom. I am pretty sure the bottom comes out first. Next with the motor, relay and the two cables in plain view, visibly inspect the cables (They are two blue ones that resemble a speedometer cable each goes to a gear box on either side of the car.) Also check the wire conections to the relay and motor. Then have someone hit the switch while you are in the back seat area. Listen and watch.

Nothing happens or clicking noise from the relay or motor can either be the relay or motor or maybe something is binding. I would then disconnect the two convertible top cables from the the motor. Just unscrew them and pull them out from the motor and leave them alone.

I would use a test light to make sure you are getting juice to the relay when the switch is hit. If so, then see if you are getting juice to the motor when the switch is hit. If the motor starts spinning then you have some sort of cable binding which may be either one or both cables binding. It would not be the motor or relay.

No juice to the relay, your problem is the wiring or switch, but you say you hear clicking noise from the relay. So I would figure the switch and fuse and wiring are good. Problem is either the relay or motor. If juice is flowing to the motor from the relay, and the motor is not running, then it's shot. No juice from the relay to the motor, then the realy is shot.

Oh and while you have the seat removed take a peak on the underside, you just may find the build sheet of the car.

One last advise: Get yourself an extra motor, relay and cables. E-bay or from any full size GM 71-76 convertible. With these cars being over 30 years old, nothing is uncommon when it comes to breakage. The worse being far from home with the top down and having a cable break....and it starts raining:Dou: You will definitely get wet unless you have a spare cable tucked away in the trunk.

[Adam]

Thanks. I pulled the seat, found the build sheet:), but also some rust :( nothing so bad that I'm worried about the seat going through the floor, but enough that I will eventually have to replace a portion of floor under the right side of the rear seat. I also had to pull up a bunch of rotten insulation out from under the seat.
The right cable turns easily by hand, the left cable would not turn when I tried to twist it by hand. But I tried to turn on the motor with both cables disconnected, and while I heard the relay, the motor did not turn, but it did heat up. So I pulled it out, and I'll take it apart and have a look at it later.
I took a pic of the build sheet, I'm going to have to put it in a plastic sleeve or something to keep it from comming apart.

[centurion 455 ragtop]

Wow! Glad you found the Build Sheet. That is an unexpected treat! Your Buick is very well optioned out. When I first pulled my rear seat I had some small rust holes on the corners and passenger rear floor pan. It wasn't enough to do major surgery, so we cut out the rust and welded in some fresh metal to patch it up. Under the car I undercoated it and on the inside I ended up using an eastwood epoxy rust paint and then fiberglassed the entire floor sealing it all in.

Anyway it does sound like the motor is shot. The cables may not be able to spin by hand as they attached to the gear boxes on the other sides. If the motor is heating up at least you know its getting juice, there must be a short of some sort inside it. New replacement motors run around $150 or so (I think) but they can be obtained. Also a good used one can be gotten fairly easy if you have no luck on fixing it.

[Adam]

I opened up the motor, it was siezed with rust. I sanded off the rust, cleaned everything up, lubed it where it needed lubing, put it back together, but I probably won't have time to take the seat out again and try it till the end of the week.

[73 Centurion]

For some reason these cars rust under the rear seat. Just about everyone ends up finding rust here, no matter how solid the rest of the body is.

Water collects here when it is kicked up by the rear tires. I think there are holes intended to let water drain out, but they end up doing the reverse. The pan under the rear seat has cardboard sound insulation that soaks up the water and keeps the metal wet.

I've never seen evidence of paint in this area, I don't think it got any coating from Buick, so you get bare metal with wet cardboard. I don't know if the presence of the muffler is a cause, but it's definetely worse on the passenger side.

If you haven't checked you should take a look.

John.

[Bob Alberini]

Hi Adam,
Just in case you didn't notice it, I sent you a p/m last night regarding your car's build sheet. It appears your car had a very interesting beginning and I hope you may know more about it.

[centurion 455 ragtop]

Hi Adam,
Just in case you didn't notice it, I sent you a p/m last night regarding your car's build sheet. It appears your car had a very interesting beginning and I hope you may know more about it.

OK Bob you got me hooked:shocked: I saw the hand writing on the Buildsheet must mean somethng. Come let us know....

[Adam]

I really don't know what the "show job" means. I bought the car from a retired air force pilot who said he bought the car from a guy in Florida in the late 70s. It has been around alot, there's still a 1979 Onizuka air force base parking sticker on the windshield. But it hasn't been driven much since the early 80's, the 1982 tires that were on it when I got it still had some tread on them. The guy I bought it from said he had it repainted when he bought it, and you can tell by the bad bodywork on the right door. Other than that the dual pipes I put on, a right side mirror added at some point (which is larger than the other one and looks awful, I'll probably eventually just remove it), and the side trim which is now sitting about a foot higher than it should be (probably changed when they repainted it) it's basically still original. If I ever get myself a garage to work on it in my plans are basically to restore it to stock in appearance, with the exception of the 455 which I'd like to hop up a bit. And if I ever come across an early-70s Buick 8-track stereo I'd like to add that. I took another pic of the build sheet, flattened out a bit, I'd be interested to hear any information you all might have.

[Bob Alberini]

Adam, Rick and fellow site members, I am by no means an expert in any of this but I can tell you that your build sheet is not typical, Adam. I've seen a number of convertible build sheets and for whatever the reason, there is ALWAYS a handwritten CONV somewhere on the bottom of the sheet. I've seen two build sheets with special order paint and in those cases, the Dupont paint code itself is also handwritten on the bottom of the sheet. But your build sheet is the first one I have ever seen with "Show Job" hand written on it. The other thing which causes certain suspicions about your car is that the "Charged To" block is blank (this was used for the ordering dealer) and the "Shipped To" block is listed as the GM Assembly Division in Kansas City where your car was built. Based on the VIN number and body number, your car was a VERY early build and that causes me to wonder if it was assembled for some Buick or GM auto show. That fact that it is so loaded would also make one think that that would have been very appropriate. It looks highly unlikely that we will ever know more since you don't have the early history, Adam, but I wonder if the Sloan might possibly have any additional information. Your car is definitely unique though.

[Phil Genario]

Hi Adam,
Just in case you didn't notice it, I sent you a p/m last night regarding your car's build sheet. It appears your car had a very interesting beginning and I hope you may know more about it.hey bob, what can that mean? auto show? have you ever encountered that before? phil

[Bob Alberini]

Hi Phil,
There is nothing else I can add other than my post directly ahead of yours, Phil. (I think you may have missed it.) Adam doesn't have any knowledge of the car's beginnings so we will probably never know but the "show job" hand written note is very atypical as is the lack of a "charge to" dealership with delivery going to the assembly plant itself. My best guess is that it was built for some Buick, GM or perhaps major city auto show or event. We probably will never know but it isn't your usual build sheet. (The car was also a very early build which might lend some credence to its use for some special purpose.)

[Phil Genario]

hi bob, please e mail me at pgcarsport@yahoo.com , please let me know how keith is,phil

[dewbers]

Cool read guys. Thanks for sharing this Adam, Rick, Phil and especially Bob... that's facinating. I think my build sheet is gone as the car was done in 93, but I will be looking this weekend or early next week. I am just way too curious to see if it's there......
Good luck Adam !!

Bob - Pls pass along our hello's to Keith as well. Miss him around here.