How long does a vacuum pump cylinder housing last?

With routine vane changes and clean duty, the cylinder housing typically lasts the full life of the pump (decades). Cylinder wear ("washboarding") usually only occurs if vanes are run too long after wear sets in — the worn vanes scrape the housing rather than sliding cleanly.

Can a cracked cylinder housing be welded or repaired?

Generally no — cast iron is difficult to weld reliably, and even small cracks compromise the vacuum boundary. A cracked housing typically means pump replacement, although some specialist rebuilders may attempt cast-iron repair on legacy heavy-industrial pumps where replacements are unavailable.

Ironware & Castingsfor Vacuum Pumps

Cylinder bodies, end covers, rotors, pistons, hinge bars, and structural castings for major-overhaul rebuilds. Stokes Microvac hinge bars, Kinney piston rings, Edwards rotor assemblies, plus replacement parts for legacy heavy-industrial pumps. Next-day UK delivery on continuous-stock items.

What are ironware & castings?

Vacuum pump ironware and castings refers to the heavy mechanical components — cylinder bodies, end covers, rotors, pistons, hinge bars, and exhaust manifolds — that form the structural and pressure-bearing parts of the pump.

What this category covers

What's included in ironware & castings

Cylinder housings — cast iron or aluminium pressure-bearing bodies
End covers — cast components sealing the front and rear of the cylinder
Rotors — the central rotating element with vane slots
Pistons (rotary piston pumps) — the piston that travels eccentrically inside the cylinder on a Stokes Microvac or Kinney KT/KC
Hinge bars (rotary piston pumps) — the floating guide bar that registers the piston position; #1 wear part on Microvac/Kinney pumps
Exhaust manifolds — exhaust port castings, often with integral oil drain

When to replace

When should ironware & castings be replaced?

Major rebuild scheduled

On rotary piston pumps (Stokes, Kinney), the piston rings, hinge bars, and crank components are typically replaced as part of every major overhaul cycle (5–10 years).

Cylinder housing wear ('washboarding')

If vanes are run too long after wear sets in, the cylinder bore can be scored — visible as washboard pattern on inspection. Cylinder + vane replacement required.

Pump dropped or impacted

Cast iron components can crack on impact. Inspect carefully on any pump that has been dropped or jolted.

Signs of wear

How to spot a problem

Severely reduced ultimate vacuum that doesn't recover after a vane change
Audible knocking on rotary piston pumps — hinge bar wear
Visible scoring on the cylinder bore or rotor (on inspection)
External oil weep that doesn't track to a gasket joint — possible cylinder crack

By Brand

Ironware & Castings by manufacturer

Stokes (Edwards)

Microvac hinge bars (the #1 wear part), pistons, piston ring sets, and cylinder kits for 212, 412, 612 series.

Tuthill / Kinney

KT and KC piston rings, hinge bars, and rotor service for triplex and two-stage rotary piston pumps.

Edwards

Rotor assemblies and cylinder housings for E2M, RV, and legacy 1-stage pumps.

Leybold / Pfeiffer / Busch

Rotors, end covers, and exhaust manifolds for rotary vane pumps — typically only replaced on major overhauls or after upset events.

Need ironware & castings?

Tell us your pump model, part number, or just describe the symptom — we aim to come back within 24 hours with a quote and confirmed lead time.

Request a Quote 0121 544 4385

Frequently Asked Questions

Common questions about ironware & castings

On Stokes Microvac and Kinney KT/KC rotary piston pumps, the hinge bar is a floating guide that registers the piston's position relative to the cylinder. It's the #1 wear part on these pumps because it sees full piston-side load every revolution. Hinge bar replacement is part of every major rebuild.