I'm having issues with the pump that runs the windows, seat, and top. The pump and motor have been rebuilt, all lines replaced, all cylinders replaced, and I refilled the system using dex/merc trans fluid. I know originally they used brake fluid which eats the paint if a leak develops. However, the pump runs very slowly doesn't put out much oil and generates a lot of heat in the motor very quickly. The windows also work very slowly. I've read that most people have switched to trans fluid but I don't know if they saw a resulting drop in efficiency or increase in heat. I hit it with 12v and it shot oil about 4 feet across my shop floor. The part number on the motor of 4557871 seems to be correct for this application. I also increased the size of the cable from the starter to the pump solenoid.
Any insight is appreciated

 

Hydraulic fluid was originally used, not purpose made brake fluid. Jeez a new one every day, I never heard or read anyone is using ATF in that system, including me.. What did your rebuilder suggest?

R&O hydraulic oil is what I bet most rebuilders like Apple would suggest, and would closely match original GM hydraulic fluid.

GOOGLE R&O hydraulic oil:

https://www.google.com/search?q=R%26...hrome&ie=UTF-8

Man you have a mess now with the need to flush the ATF from the system. Best of luck~

I checked the Hydro-E-Lectric website and am shocked at what they are now suggesting for fluid in systems with original parts. Factory GM manuals and paperwork on this topic are easy to find. I will let these speak for themselves. It would seem cruise night and chat forum ideas are once again replacing long settled knowledge.

From H-E-L website: "....

How to Install Top Cylinders & Pumps

Tools & Supplies - 3 quarts of fluid. Cars older than 1953 use DOT-3 brake fluid. Cars 1953 and up use brake fluid or automatic transmission fluid. Cars prior to 1953 may use ATF if all new hoses have been installed. CAUTION - brake fluid destroys paint. A turkey baster is a great tool to fill pumps with a filler plug. You may also use an oil can or bleeder system...."

 

Hmm, I have used ATF on a number of top cylinders and related hydraulics, never a problem, never noticed a slowing down of the systems. Have you put a pressure gauge to see what pressure is actually being put to the system.... Tedd

 

I rebuilt my pump and installed new hydraulic rams and hoses. Filled it with dexron atf and it works great.

 

Is your car a 6v system? Does the motor seem to run freely while raising the windows? My motor seems to be in a bind while pumping even with the discharge open to atmosphere.

 

12 volt. 57 Olds convert. Runs the top only. Does not run the windows

 

@Mark Desing The part number on the motor of 4557871 seems to be correct for this application



1950 master body parts book for Body style #483867X : Group #14.481 Motor & Pump assembly part #4557871

Motor assembly part #4165786.

Bob