Our 7-Step Vacuum Pump Rebuild Process

The pump is completely disassembled, down to the last bearing and port plate. Before anything is cleaned, we photograph and measure the pump as it came in, because scale deposits, wear patterns and witness marks tell us how the pump was running and why it failed. Then every component is cleaned and measured.

The goal of this step is to identify the cause of failure, not just the failed part. A pitted cone tells us cavitation; cavitation tells us seal water was too hot or too scarce; that tells us the rebuild should include a look at the seal water system, or the same pump will be back with the same damage. This is where 40 years of teardowns matter: we know what fails, why it fails, and how to make it better.

What you receive: a teardown inspection report with photographs, measurements against OEM specifications, the identified cause of failure, and a repair scope and quotation before any further work begins.

This is the machine shop step. Cracked or eroded cast iron heads and bodies are welded and machined; cast iron repair is considered by many to be a lost art, and Precise Mechanical performs these operations on a daily basis. Worn cones, heads, port plates and bodies are clad in 304L or 316L stainless steel and machined back to original dimensions. Shafts are straightened, sleeved, or made new. Rotors are repaired or remanufactured and rebalanced.

Parts the manufacturer no longer supports are reverse engineered from the originals and machined in-house: milling, turning and grinding on equipment sized for the largest pumps in the world, including a 120-inch vertical boring mill and lathes to 240 inches between centers. Every remanufactured part meets original manufacturer specifications.

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What you receive: remanufactured components documented in the job file, with material certifications where the material was supplied new.

The pump is assembled by the same people who measured it. New bearings, seals, packing and gaskets are installed. Rotor position is set, and every clearance is double-checked with the pump assembled, because a clearance that is correct on individual parts can stack the wrong way once the shaft, rotor, cones and heads come together.

Coupling hubs, sleeves and any customer-supplied components are fitted at this stage. If the pump is going into a packaged unit, the motor, gearbox or belt drive, manifold and instrumentation are mounted and aligned now.

Packaged units

What you receive: an assembly checklist with final clearances recorded.

Before crating, the finished pump is inspected against the job file: rotation, clearances, fasteners, seal and bearing installation, paint and tagging. It is turned by hand and checked for free rotation. Nothing ships until the person who inspects it is satisfied it matches what the customer ordered.

What you receive: a final inspection sign-off and, shipping documentation, and installation and startup recommendations, including seal water flow and temperature guidance to protect the rebuild.