The top in my 67 runs OK, just slowly. It takes too long to cycle the top either up or down, but no untoward noises or anything. Revving up the engine a little bit seems to help, probably because it boosts the voltage to the motor. High ambient temperatures also help to speed things up a little bit

No rust whatsoever anywhere

Could this be due to:

(a) worn pump
(b) low fluid
(c) something else?

Thanks!

From my experience with 2 different power top convertibles, I would think it's a fluid level problem. It might even be a little of both. If I were you, I'd definitely buy the Fisher Body Service Manual. There is a lot of very useful information in there including how to rebuild the pump motor.
You could always double check your electrical terminals & such. Thoroughly checking the fluid level for small leaks is a bigger hassle. You MIGHT whine up having to remove most of the back seat interior. But, to just check the fluid level of the motor it self wouldn't be nearly as difficult. Good luck.

The top in my 67 runs OK, just slowly. It takes too long to cycle the top either up or down, but no untoward noises or anything. Revving up the engine a little bit seems to help, probably because it boosts the voltage to the motor. High ambient temperatures also help to speed things up a little bit

No rust whatsoever anywhere

Could this be due to:

(a) worn pump
(b) low fluid
(c) something else?

Thanks!



If it works better with the motor at higher RPM's that would lead me to check for a wiring problem first!
Low fluid level and a bad/weak pump will make noise.

How long does it take for it to go down? I will time mine to give you a comparison.

I think there may be a weak charging system or old battery. Reving the engine spins the alt faster increasing it's output. A little of this is normal if it's excessive it's a good indication of an issue.

As for the fluid level if it's low the pump will sound like it's straining and reving the engine wouldn't really impact the performance of the top very much. It wouldn't hurt to go ahead and top off the system, doing the following, the system will purge itself of air and the fluid will not over fill the pump. It can be done with almost zero mess too.

To bleed and top-off the system I found a section of plastic tubing that fit in the pumps fill hole and wrapped one end with elect tape until it was the size of the stopper. Stuck one end in a qt of atf (brake fluid would work too) and the taped up end in the fill hole and seated it snugly. Run the top up and down several times and finally top down and replaced the plug. There has to be some fluid in the pump motor as a prime to start this off, since your top does go up and down you are already set to go...

If you find it's the pump motor and decide to replace it you can get one from almost any GM car that has a power top if you are not worried about correct parts.

Hey, i have the same problem :yes:
I think mine is the top motor not having run regularly for nearly 20 years by previous owners. The motor sounds like a blower motor on low instead of that hydraulic whine. I guess as I keep using it, it may start to loosen up.

If you replace your pump. I replaced my motor with a new one from http://www.hydroe.com $220. It fits and works great. They supply Rick's and NPD.

How long does it take for it to go down? I will time mine to give you a comparison.

I just timed it, and it must have been a good day, because it only took about thirty seconds each way, which I find acceptable. Sometimes it takes much longer (May be 45 sec to one minute, except I stop mid way to avoid overheating the motor)

Warm temperatures have a positive effect

I wonder if I should lightly oil the cilinder shafts?

PS 1: Following 327!275hp!Convt!'s suggestion, I have borrowed a copy of the Fisher manual, and yes indeed, it contains precious information, thanks for the tip!

PS 2: Removing the rear seat sounds like an uninviting job, but I think I will get around to checking the fluid level one of these days, and let you know. Thank you so much for all the valuable input!

Mine was slow because one of the brushes was worn out. Easy fix.

I think there may be a weak charging system or old battery. Reving the engine spins the alt faster increasing it's output. A little of this is normal if it's excessive it's a good indication of an issue.

As for the fluid level if it's low the pump will sound like it's straining and reving the engine wouldn't really impact the performance of the top very much. It wouldn't hurt to go ahead and top off the system, doing the following, the system will purge itself of air and the fluid will not over fill the pump. It can be done with almost zero mess too.

To bleed and top-off the system I found a section of plastic tubing that fit in the pumps fill hole and wrapped one end with elect tape until it was the size of the stopper. Stuck one end in a qt of atf (brake fluid would work too) and the taped up end in the fill hole and seated it snugly. Run the top up and down several times and finally top down and replaced the plug. There has to be some fluid in the pump motor as a prime to start this off, since your top does go up and down you are already set to go...

If you find it's the pump motor and decide to replace it you can get one from almost any GM car that has a power top if you are not worried about correct parts.

Where is fill hole on pump and how do you get to it??

there is a rubber plug on the passenger side of the pump. to access it remove the back seat. link to bleed procedure.... http://www.1stgencamaro.net/convertibletopbleed.html