scmack

I have enjoyed reading thru the many forums that are available on the internet and thought that the time had come to join one.

I have a 72 olds convertible with a power top issue. The top has been sluggish the past couple of years but never let me down. When I awoke the beast from its winter hibernation this spring, the top was of course up and no noticeable difference from earlier behaviour when I lowered it. However when I went to raise it again, there was no movement. The switch did not appear to be working so I removed the switch, carefully opened it up to reveal a very simplistic mechanism. Regardless of the simplicity it did not work. I ended up ordering a new switch and tried to operate the top again. Nothing. The motor can be heard working but no top movement. I decided to dive right in and removed the back seat and side panels. I detached the cylinders from the roof and hit the switch again with no load on the cylinders. Lo and behold they started to move. They did not travel their full length however as the motor stopped on its own. Several minutes later I tried the switch again and the cylinders would move again. I did notice that the back of the switch was getting warm to the touch. I decided to remove the whole system do a little clean up work, as I have had the vehicle for 6 yrs and never attempted any work on the hydraulics. I drained the systems, cleaned up as best as I could and reassembled with fresh ATF. A partial re-install of the system back in the vehicle yielded no better results. The motor and switch get very warm after cycling several times. I was curious about the condition of the new switch so I carefully disassembled and saw that there is some serious heat happening as there was some melted plastic around one of the contacts.

My question is, what is causing this excessive heat? Is the motor/pump on its last legs and working to hard and therefore drawing too much current? If so would a pressure test on the motor/pump pinpoint this as the problem? Could the motor/pump be all gummed up and in need of cleaning/rebuild?. Sorry for the long winded post, but I want to paint a clear picture of the problem.

Your words of wisdow are greatly appreciated.

3 Deuce 64

I know the 66 olds has a thermal relay that will shut the system down replaced one on my friends last year . his top would start up and shut off let it sit hit the switch again and would move again .His was located on the firewall drivers side close to the fuse block connections
your top motor pump could need a cleaning . they can get build up sludge in them condensation . it is a very simple motor pump . put down a cookie sheet tray when you take it apart the only real part you have to be careful about loosing is the ball at the end of the shaft that is used for a bearing GM pumps are pretty much the same 64 - 72 switched from 4 legs to 3 legs in 67

we use clear power steering fluid in our systems . we currently have 4 verts two 64 GTOs a 67 GTO and a 91 cutlass

scmack

I have read elsewhere about a relay under the hood attached to firewall on drivers side. Any idea how to troubleshoot for proper operation?

I plan on pressure testing the pump to rule it out/confirm if it is the culprit.

3 Deuce 64

you can actually bypass it or jumper it for testing . it is an in line thermal breaker .

justa note when filling the pump with fluid i found a pump that you would use to fill the lower unit on the out drive on you boat works well you can use an quart motor oil jug put power steering fluid in it screw on the pump the end fits nicely in the fill hole of the pump .remember the system is a closed system and the oil flows both ways the rams will always have the same amount of fluid in them just on the opposite side of the piston sow as you fill it you will need to put the plug back in and run the air out of the lines . run it both ways a couple times then fill it back up until the fluid is level with the fill hole do that a couple times until the air is purged and your level is full the line are self bleeding to the pump . Don

scmack

I just picked up the motor from a Starter/Alternator shop and they have indicated that the armature is shorted and needs to be replaced. Cost to replace quoted at $125.00. New motor costs about $200.00. I'm going to see if a motor can be found at a wreckers, but I have at least identified the motor as the problem.

Thanks to 3 Duece 64 for your suggestions.