Bronze bushings for pumps, valves and hydraulic cylinders
Pump, valve and cylinder bushes have in common that the medium or the hydraulic oil does the lubricating, the alloy must resist that medium, and the shaft is stainless steel or hard chrome. Industrial pumps and valves – for automotive transmission pump bushings see your vehicle parts supplier. Machined from cast gunmetal, tin bronze and aluminium bronze stock to the pump maker's drawing or the worn part.
A pump bush keeps the shaft centred and takes the radial load of the impeller while the pumped liquid – or a grease or oil supply – lubricates it. The alloy is chosen for the liquid: gunmetal LG2 for fresh water and general service, aluminium bronze for seawater, slurry and hot water, C93200 for oil-lubricated positions; the clearance is larger for water than for oil because water films are thin and the bush must not bind when it warms.
- Centrifugal pump shaft bushes, stuffing-box and throat bushes, wear rings: LG2, aluminium bronze
- Reciprocating pump crosshead and guide bushes: C93200, CuSn12
- Valve stem guides, gate nuts, butterfly shaft bushes: LG2, C93200, aluminium bronze
- Hydraulic cylinder rod guides, gland bushes, eye bushes: C93200, C86300
- Water-lubricated bushes: larger clearance, plain or straight-grooved bore
Pumps: shaft bushings, wear rings and stuffing-box bushings
| Pump type · position | Medium | Lubrication | Alloy | Clearance and form |
|---|---|---|---|---|
| Centrifugal pump shaft sleeve bushes, throat / stuffing-box bushes | water, process liquids | by the medium | LG2 · aluminium bronze · C93200 | clearance above oil practice; plain bore or G2 |
| Centrifugal pump wear rings (casing / impeller rings) | water, slurry | by the medium | LG2 · C95400 · C95500 | thin large-diameter rings to drawing, running clearance per pump maker |
| Vertical / submersible pump line-shaft bushes | water, sea water | water lubricated | aluminium bronze · LG2 | long sleeves, G2 straight grooves for water flow |
| Reciprocating pump crosshead pins and guides | oil | oil bath / splash | C93200 · CuSn12 | G4 / G6, close clearance |
| Gear and screw pump side plates and shaft bushes | oil, viscous liquids | by the medium | C93200 · CuSn12 | thrust faces G7, to drawing |
| Slurry and dredge pumps | abrasive slurry | flushed / grease | C95500 · C86300 | thick wall, sealed, G3 flushing groove |
Valves: stem bushings and gate nuts
Valve stem guide bushes and yoke bushes see slow rotation or sliding under moderate load, often in a wet or steam-heated bonnet. LG2 gunmetal is the standard for water, steam and general fluids (it is the classic valve alloy); C93200 for oil and dry gas; aluminium bronze for seawater, brine and higher temperature. Gate-valve stem nuts and butterfly-valve shaft bushes are machined from the same stock to the valve drawing; threads and keyways as drawn. Hydraulic and irrigation gate guide bushes in LG2 and aluminium bronze run in silt-laden water with generous clearance.
Hydraulic cylinders: rod guides, eye bushings and gland bushings
The rod guide bush in the cylinder head runs on a hard-chromed rod (Ra ≤ 0.4 µm) in hydraulic oil – C93200 or CuSn12 with a plain or spiral-grooved bore and the clearance the seal maker specifies. Gland bushes and piston guide rings are made in the same alloys. The eye bushes at rod and cap ends are pin joints on a mobile machine: heavy oscillating load, shock and dirt – C86300 or C93200 with figure-eight grooves, greased through the eye.
Clearance and lubrication for water-lubricated bushings
Can bronze bushings run in water without grease? Yes – a bronze bush lubricated by clean water is standard in vertical pumps and hydro equipment – provided the clearance is larger than with oil and the shaft is stainless or chrome-plated. Water films are thin and carry away less heat than they seem, so an oil-practice clearance binds when the bush warms; start-up before the pump is flooded is a short dry run that the bronze must survive. Take the pump maker's clearance where it exists; otherwise work from the design guide with the larger shaft tolerance (e8) and confirm with us for the medium and temperature. For particle-laden water prefer aluminium bronze and straight grooves that flush.
Sizes and forms
Shaft bushes are typically thin-walled and long, wear rings large-diameter and thin, guide bushes short with or without grooves; all are machined to drawing from Ø10 to Ø1000 mm, metric or inch, with the material certificate that pump and valve makers require (ASTM B505 / B271 or EN 1982). Sleeves in stainless steel are not our product; the bronze parts that run against them are.
Alloy by medium
| Medium | Alloy | Notes |
|---|---|---|
| Fresh water, potable water | LG2 / C83600 · C93200 | gunmetal is the classic pump and valve alloy; lead-free tin bronze where regulations require |
| Sea water, brackish water | C95500 · C95400 · LG2 (low load) | nickel aluminium bronze first choice; stainless shaft |
| Slurry, sand-laden water | C95500 · C86300 · C95400 | hard alloys, flushing grooves, seals |
| Hydraulic oil, lubricating oil | C93200 · CuSn12 | close clearance, spiral grooves |
| Hot water, steam, condensate | aluminium bronze · LG2 | aluminium bronze keeps strength hot; check thermal clearance |
| Mild chemicals, brine | aluminium bronze | confirm compatibility for the specific medium |
Qualitative guide; the pump or valve maker's material specification governs where one exists.
Parts we machine for this sector
Typical parts:
- Shaft sleeve and stuffing-box bushes for centrifugal pumps, LG2 and aluminium bronze
- Casing and impeller wear rings to drawing, LG2 / C95400
- Line-shaft bushes for vertical pumps, grooved, aluminium bronze
- Valve stem guide bushes and gate nuts, LG2
- Cylinder rod guide and gland bushes, C93200 / CuSn12; eye bushes, C86300
What to send for a quote
Drawing preferred; otherwise:
- Bore, outside diameter, length (and flange / ring dimensions) with tolerances
- Medium, temperature and pressure; shaft material and finish
- Alloy or the maker's specification; certificate standard (ASTM / EN)
- Groove pattern if any; quantity; sample first?
Frequently asked questions
Which bronze for a seawater pump bushing?
Nickel aluminium bronze C95500 (or C95400) against a stainless or chrome-plated shaft; LG2 gunmetal for lightly loaded seawater positions. Not leaded tin bronze – it dezincifies and pits in seawater under load.
Can bronze bushings run in water without grease?
Yes, with a clearance larger than oil practice, a stainless or hard-chrome shaft, and the right alloy (LG2, aluminium bronze). Dry start-ups must be short. See the water-lubricated clearance section.
LG2 or SAE 660 for pump bushings?
LG2 for water, steam and general fluids – it is the classic pump and valve alloy. SAE 660 for oil-lubricated positions and higher radial load. Both machine and cast to the same dimensions.
Do you make pump wear rings?
Yes – casing and impeller wear rings in gunmetal and aluminium bronze, machined to the pump drawing with the running clearance the maker specifies, from Ø50 to Ø1000 mm.
What clearance for a bronze pump bushing?
More than for oil: the pump maker's figure where it exists; otherwise work from the design-guide table with an e8 shaft and confirm the medium and temperature with us. Water-lubricated bushes that are too tight bind when warm.
Send the drawing and the medium
We confirm the alloy, the certificate standard and the clearance for the medium, and quote in 12 hours.