I have SSM III's and one of the drives will not hold trim pressure. It goes up and down with no problem but will not hold in the up position. If I run it up within 10 to 20 minutes it will have dropped about 6 inches and will be all the way down within an hour or so. There are no visible leaks of fluid from the system. So I suppose there is an internal leak in either the pump or the cylinders. I'm thinking it must be the pump since both cylinders would have to be bad for it to drop that quickly. Is there a trick in figuring out which is the culpret. Or is this going to be a trail and error thing? If so which would you replace first?

the valving in the pumps start leaking internally when they get old,you have 2 options,one is a rebuild kit for the pump,the other is to find a different pump.

Thank's Mike. That's what I'll do.

I thought the pumps were non-rebuildable. I have the same problem. Could someone put up a link to a rebuild kit?

There are new trim pumps on Ebay for about $220 complete some with Q conecte lines worth a look .

Thanks I'll check them out.

Can the newer high volume/low pressure pumps be used with the older high pressure/low volume cylinders?