testing hydraulics and rams seals for leaks.

Rob

Member
Lifetime Member

Equipment
B6000DT / B7100DP /B8200DT/L225/Globe PTO Chipper/Lewis Backhoe/huxley TR66
Nov 22, 2009
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Leafy England....
hi all

A question for those in the know on the title subject of hydraulics.
I'm still rebuilding my K450B FEL for my B6000, I've fabricated a complete new subframe to the same spec etc as the original Kubota item, rebuilt the two spool valves etc but now i'm on the rams.
The two B7100 bucket rams need completly rebuilding as both rods are bent,seals are shot and pistons not much better, i've sorced new rods but they need matching piston and seals ,so i'll change all the bits together.

anyway the two main lift rams were looking less than servicable, i've totally cleaned down the cylinders to bare metal, cleaned off the light surface corrosion at the top of the rods , not a big prob as its not on the working chrome area.
The problem that has come to light now is that i suspected that the seals etc were shot on these rams also, and to make things worse the cylinder top cap (has what looks like a circlip holding it on)is damaged and cannot be removed without wrecking the cap.
now I've though that if i connect the rams to my air compressor and wind it upto 100psi any leaks would become clear as air is lighter then oil, so if they hold air then the seals must be ok.
So i did, and they have lost very little air if any at all, can i therefore asume its safe to reuse them without further diasembly and refitt to the hydraulic system.
thansk
rob

just a footnote: on a safety note. the ram was securely fixed in a work bench vise, no cylinder caps had been removed and the rams were 1 way only with no pilot check valves etc fitted.
 
Last edited:

Theekillerbee

New member
Jun 28, 2009
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0
Pleasant View UT, USA
Rob, sounds like you know your stuff. Testing with air is a pretty good solution, but changes in air temperature will affect your psi, not much, but it will. I would suggest finding a buddy with a MIG welder and testing with an inert gas like argon, or CO2. You can test at a higher psi, and air temp will not have a noticeable change in your meter readings. Your hydraulic pump will be pushing over 1000 psi, so testing to only 100 may not yield the results you are looking for.