I recently picked up and installed a new top motor and fluid lines. When I ran it for the first time, the motor was straining and I saw lots of air in the lines. I went through the instructions on the motor, adding ATF and not exceeding 75% capacity, then running the top with the hydraulic cylinders disconnected from the top. I'm not sure how a person can tell if it or over 75% capacity. The fill plug is about 3/4 of the way up from the bottom, so I added fluid until it barely started to drip out of the fill plug.

After going through this cycle a few times, air in the lines was gone. Grabbed a bite to eat and came back to the car to reassemble. Connected the cylinders back to the top, and the very first time I ran the top, fluid shot out of the top of the cylinder on the passenger side only. Fluid escaped the cylinder toward the top where the rubber seal is.

Do I have a bad cylinder if it's just the one that had this issue? Or did I overfill the pump motor? I'm not sure of a testing procedure for this. My bet is that the cylinders are original. Maybe it's time to replace both after 71 years, but I don't want to do that if overfilling the pump motor was the issue all along. If that is the case, I'll just destroy the new ones.

 

I recall reading where someone else had a similar issue related to overfilling the system.

That math doesn't seem right.

 

LOL the 5 and 7 key are close and my fingers are fat!

 

I recall reading one or more cylinder top threads/posts, as well. I'm keen to recall those threads/posts since I have a '71 CS convertible and I try to keep up on things when I read of items pertinent to my car. Here is a list of "top cylinder" threads/posts. It may change. If it does, perform a search with the keywords "top cylinder" (quotes must be included). You'll need to read and decipher if any of these threads/posts are pertinent to your issue - I can't assist there. Good Luck!

https://classicoldsmobile.com/forums...archid=6717674

 

Guys, forgive me, I just don't see how "an overfilled pump reservoir" would cause leaking out of the top of the hydraulic cylinder. Say the OP missed the mark at 75 % and hit at 90% how would the cylinder now leak. At leak at the pump seems more feasible if it is overfilled.

 

Yeah that makes more sense. I think the issue in the post I was remembering is the pump reservoir was topped off when the pistons were extended so it overflowed when they were retracted.

 

I always filled pumps til it dribbled out the hole and never had a problem. Causing a cylinder leak? Can’t imagine it.

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