Home > Q&A > Midmark 75 Evolution
Thu Jul 20 2017

Midmark 75 Evolution

I have a Midmark 75 Evolution that spills hydraulic oil over and out the oil inlet port. I've changed out the entire pump, including the valves, and it worked for five minutes before doing the same thing. Any suggestions.
Report Post
Fri Jul 21 2017Reply from JohnJones
avatar placemark
This would be a good time for other members to chime in with thoughts or ideas!

Report Post
Thu Jul 20 2017Reply from GDMEADE
avatar placemark
It does sound strained.

Report Post
Thu Jul 20 2017Reply from JohnJones
avatar placemark
That is all good information, rules out some things I was thinking. Ok, if the oil level is correct, then it swells and overflows I can only assume that air is being introduced somewhere and forming bubbles. There is an anti-cavitation solenoid on the pump, maybe that would be something to check next. Obviously there is a flow problem, maybe a collapsed hose lining, something causing it to bubble up. Does the motor sound like it's straining when it did work?

Report Post
Thu Jul 20 2017Reply from GDMEADE
avatar placemark

The mIneral oil base that come with the replacement pump. The pistons were all working, but everything stopped.  I can hear the solenoids engaging, but nothing happening.  All the electrical connections are tight and receiving electricity when solenoids are engaged.  Again, everything worked for five minutes after the pump replacement.  I thought I had the problem solved, till the oil bubbled over and everything quit, again.


Report Post
Thu Jul 20 2017Reply from JohnJones
avatar placemark
Ok then...couple more questions, what type of oil are you putting in it, don't say "hydraulic, be specific. And again, once the spilling out stops, do all the pistons still work?

Report Post
Thu Jul 20 2017Reply from GDMEADE
avatar placemark
No pistons sink by themselves and the motor is running. The oil cap is tight. After the pump replacement, it seemed to run fine as I was putting the chair through its paces up and down. Then, it started to flow out the top of the new pump motor. Very frustrating.

Report Post
Thu Jul 20 2017Reply from JohnJones
avatar placemark
When it "spills out" is the pump motor running when it happens? Do any of the pistons sink by themselves? Once it stops spilling out, do the pistons still go up and down?

Report Post

For questions about using the MedWrench web site:

(866) 989-7057TOLL FREE  •  (770) 692-8371INTERNATIONAL

support@medwrench.com

MedWrench is in association with:

TechNationMedical DealerOR TodayMD Expo


Testimonials  •  Advertising  •  Privacy Policy  •  Terms and Conditions

© 2017 MedWrench, LLC. All Rights Reserved