The standard hydraulic grease fitting, named after its inventor Oscar Zerk, with a spring-loaded check ball that lets grease in and keeps dirt out. Zerks come straight, 45 degree and 90 degree in several thread sizes. Experienced techs wipe every fitting before connecting, replace broken ones on the spot and fit colored caps that both identify the grease and keep dust off.
Zerk on the idler is busted and grease is squirting out the side, put a new one in before you pump.
If a fitting will not take grease, do not crank harder. A plugged passage or blind cavity will blow the seals out first.
Also heard as
- grease fitting
- grease nipple
- Alemite fitting
Related terms
Shot
One full stroke of a manual grease gun, the everyday unit for how much grease goes in.
Lube tag
Color- or shape-coded label at a fill point that tells techs exactly which lubricant goes in.
Grease
Semi-solid lubricant made of oil held in a thickener sponge, usually with additives.
Pack
To fill a bearing by hand, forcing grease between the rolling elements before assembly.