[Murphman]

My car has just returned to the road after a 3 year body restoration. Prior to the restoration, the convertible top worked well. No issues at all! Now the top does work, but it goes up and down slowly and sometimes I have to manually assist. I can hear the motor of the convertible top working, but I am careful not to burn it out.

Would you first replace the cylinders or the switch or look to the motor to increase the speed of the up and down function? Many thanks.

Murphman

[rohrt]

it not uncommon to loose some fluid in the system. I would check for air bubbles and try topping off the system first.

[Murphman]

Thanks, I will do that!

[Scott Thelander]

clean grounds and hot new battery helps too

[Peter Serio]

When those older hydraulic motors sit unused for years it is common for them to loose efficiency. First check and see what kind of fluid in in your system. It should be automatic transmission fluid.

Normally this type fluid does not cause trouble. In the fill plug keep in mind that you DO NOT fill the entire reservoir all the way full. It needs an air space in there because of fluid displacement.


The motor sometimes looses RPM from getting old or bushings loosing lubricant. Also common are "O" rings that shrink over time. There is an O ring around the drive shaft and that seal separates the fluid side of the pump from the electrical side. If fluid ever leaks into the electric side it causes all kinds of problems. Mainly the motor slows down and gets hot. You can burn one up trying to run it clogged with ATF. The pumps need torn down, cleaned and all the O rings replaced at least once per every 10 or 15 years. I would check all your hinges and pivot points on the folding top. Those get stiff over time and they will bind. The top itself is heavy and combined with all the joints that don't move freely, if you keep trying to move the top up & down eventually you will overheat the motor. The rams can get weak from non-use. They like to stick if left in one position for many years. Either up or down it does not matter. They do go bad or they sometimes leak. ATF is pretty easy to spot. Rams should ALWAYS be replaced in pairs!!!

[Murphman]

Thanks, Peter. I have a new switch which I will start with and then check as per your excellent recommendation. By "rams", I assume you mean the cylinders? Thanks.

[judger69]

Originally Posted by rohrt

it not uncommon to loose some fluid in the system. I would check for air bubbles and try topping off the system first.

You might already know this, but make sure you top it up with the top down ( rams in ). If you top it up to the fill hole with the top up ( rams out ) you will overfill the reservoir next time you put it down it as the displacement of the oil in the rams has to go in the reservoir. It could blow out the fill plug or worse blow out an oring in the pump and then make a big mess.

Check the voltage at the motor as the 49 yr old wiring can get old, brittle, corrode and crack and restrict current flow. a weak battery will cause low voltage too. I had 7.3 volts at the motor with it running and toasted it years ago. Try to operate it with the engine running to see if that helps.

There is a guy in South Carolina that repaired my top motor about 6 years ago. Its been perfect ever since.

[6869GTO]

[QUOTE=judger69;5892899]You might already know this, but make sure you top it up with the top down ( rams in ). If you top it up to the fill hole with the top up ( rams out ) you will overfill the reservoir next time you put it down it as the displacement of the oil in the rams has to go in the reservoir. It could blow out the fill plug or worse blow out an oring in the pump and then make a big mess.


There is fluid on both sides of the piston so whether it's going up or down the fluid level in the pump should remain the same. jmo

[judger69]

Nope. You have to account for the area of the ram as it goes in. It's in the convertible top manual to fill as I stated.

[Murphman]

Thanks to all. The convertible top motor was bled of fluid and partially refilled. Hose was also found to be crushed from quarter panel work, and fluid bled from the line. Used plastic line repair kit to repair hose and reilled with hydrolic oil. Top has never worked better.

Many thanks for your advice. Fortunately, did not have to replace the motor

Murphman