In the oilfield, a mud pump failure doesn't just slow you down — it stops the drill. Every hour your rig sits waiting on a fluid end or power end repair is money walking out the door. Kelsey Machine Services has been rebuilding mud pump fluid ends, power ends, and oilfield tools for over 40 years, with the in-house machining capability to restore your equipment to OEM performance fast. Every rebuild is backed by a written 24-month warranty, and our 24/7 emergency service is answered every day of the year.
We serve drilling operations, oilfield service companies, and industrial facilities across all 50 states, Canada, and Mexico. Our structured repair process gives you full transparency: written failure analysis, itemized quote before work begins, and complete documentation on delivery. Free national pickup is available for critical situations.
Types of Equipment We Repair
Fluid End Repair & Rebuild
The fluid end is the high-pressure, high-wear component of any mud pump. KMS rebuilds fluid ends to OEM specifications, replacing valves, seats, pistons, liners, and packing. We restore bore geometry and surface finish for proper seal and extended component life.
Power End Repair & Rebuild
The power end converts rotary motion to the reciprocating action that drives the fluid end. KMS rebuilds power ends including crankshafts, connecting rods, crossheads, crosshead guides, main bearings, and pinion shafts.
Oil-Filled Tool Repair & Recertification
Downhole tools, pipe handling tools, and hydraulic tools used in oilfield operations require specialized repair and recertification. KMS repairs to API and manufacturer specifications, with complete documentation.
Mud Pump Valve & Seat Replacement
Mud pump valves and seats are high-cycle wear items requiring regular replacement. KMS stocks a wide range of configurations for rapid replacement.
Liner & Piston Replacement
Liners and pistons are the primary wear surfaces in the fluid end. We replace with quality components and ensure proper fit and alignment for maximum service life.
Hydraulic Tool Repair
Hydraulic cylinders, actuators, and tool assemblies — repaired with full pressure testing before return.
Common Failure Modes We See
Valve & Seat Wear
The most common fluid end failure — valves and seats wear from abrasive drilling fluid and pressure cycling. Worn valves cause pressure loss and accelerated liner wear.
Liner Wash & Erosion
Abrasive drilling fluid erodes liner bores over time. Worn liners reduce pump efficiency and cause piston seal failure.
Packing Failure
Piston packing seals the liner bore and prevents fluid bypass. Worn packing causes fluid leakage and contamination of the power end.
Fluid End Cracking
High-cycle fatigue and pressure spikes can cause fluid end body cracking. A cracked fluid end is a safety issue and must be replaced.
Power End Bearing Failure
Power end bearings carry significant loads at high cycle rates. Contamination, overloading, and improper lubrication are the leading causes.
Crosshead & Guide Wear
Crossheads and crosshead guides wear from the side loading of the reciprocating motion, causing misalignment between the power end and fluid end.
Our Repair Process
- 01
Intake & Inspection
Disassembly, documented as-found measurements, written failure analysis before authorization.
- 02
Component Assessment
Every component measured against OEM specs — valves, seats, liners, pistons, packing, bearings.
- 03
Precision Machining
Liner bore restoration, crankshaft work, crosshead guide restoration — done in-house.
- 04
Component Replacement
Quality valves, seats, liners, packing, bearings, and seals from inventory or sourced quickly.
- 05
Assembly & Test
Reassembled to OEM tolerances. Pressure tested where applicable. Full documentation.
- 06
Warranty & Return
24-month written warranty. Coordinated return shipping — minimize your rig downtime.