Is your convertible top not moving at all, and the pump motor is not running, although you hear the relays clicking next to the pump? This is the most common convertible top pump failure symptom for your Maserati.

If you or your mechanic have diagnosed a bad pump motor, or your dealer told you that you need a new pump motor, we can rebuild and upgrade your pump to exceed factory specs for a fraction of the price of a new replacement.

The pump ships back to you filled with fluid. Please be sure to drain the old fluid from your pump before you send it to us.

Top Hydraulics fully rebuilds and tests your pump before sending it back to you. This includes service and repairs to the electric motor, upgrade of some motor components, resealing of the pump unit, inspection of all pump components such as pistons and impellers (replacement if they are not to spec), and extensive testing for output pressure, output flow, long term performance, and thermal behavior. We keep the tolerances so tight that no pump will ship without at least exceeding factory pressure specs by 5%.

Top Hydraulics gives you a three-year warranty on the pump rebuild. It is highly advisable to flush your hydraulic system at this point. Simply cycle your top and the storage cover manually while either the reservoir is empty (that way you expel old fluid into the reservoir and suck air into the cylinders), or while the pump is disconnected from the valve block (put a waste container under the valve block). One manual cycle without fluid in the reservoir will expel about 95% of the fluid remaining in the system, which is good enough. Your Maserati 4200 hydraulics are self-venting. As soon as you have a proper fluid level in the pump's reservoir, the pump can operate again. Air from the cylinders will be expelled back into the reservoir - you will have to top off the reservoir once or twice. While there is air in your cylinders, the top and the storage cover will move down faster than usual. Try to catch them by hand a little the first few times, or simply let go of the convertible top button once they start picking up speed. Almost all air will be out of the system after five cycles. Allow the electric motor to cool down between cycles - it is not made to operate continuously for extended periods.

Cleanliness is very important while dealing with your hydraulic system. Do not allow any dirt to enter the system, and use the proper fluid. For hydraulic fluid, either use Maserati fluid, or Mercedes fluid p/n A0009899103, or FeBi 02615, or Pentosin CHF-11S (or Aral Vitamol in Europe). All these fluids will mix. FeBi 02615 is your least expensive alternative, without any compromise in quality.