ABB AHMA & HMB Hydraulic Mechanism Rebuild
Full shop rebuild of ABB AHMA and Hitachi Energy HMB hydraulic operating mechanisms, the breaker drives that run the pump nonstop or trip to lockout once the seals stop holding pressure. We strip the mechanism, replace every seal, rebuild it, refill it with new hydraulic fluid, and pressure-test the system for 24 hours before it ships. AHMA-4, AHMA-8, and HMB-1, we rebuild them all.
We have rebuilt a number of these. See a documented ABB AHMA mechanism rebuild, resealed and pressure-tested for 24 hours, and the technical background on the AHMA and HMB hydraulic drive.
Mechanisms
we rebuild.
Full teardown, every hydraulic seal replaced, rebuilt and refilled with new fluid, then pressure-tested for 24 hours.
The HMB replaced the AHMA and shares the same hydraulic architecture. The HMBs leak down the same way, and we rebuild both.
Pump motor running continuously, mechanism that will not hold pressure, a breaker drifting toward lockout. Replacing the one seal you can see never fixes it. We replace them all.
After the rebuild we pressure-test the system for 24 hours and return the unit with the documentation.
Why they
fail.
The hydraulic seals degrade with age and can no longer hold pressure. The pump motor runs continuously trying to keep up, and left unaddressed the mechanism can drive the breaker into a lockout condition. Chasing the one visibly leaking seal does not solve it, because the rest are on the same clock.
How we
rebuild it.
We strip the mechanism down, replace every hydraulic seal, rebuild it, and refill it with new hydraulic fluid. Then we pressure-test the system for 24 hours to confirm it holds before it goes back to your breaker. The same machine shop that makes utility contacts and hardware backs the work.
Quote within
one business day.
Send the mechanism model and what it is doing, running the pump nonstop, dropping pressure, or in lockout. We respond with a clear scope, price, and timeline, fast.