No grease at the shaft seals — central lubrication fault
Symptom
No fresh grease at one or all seals, the distributor indicator pin does not move, grease escapes at the pump relief valve, or a lubrication alarm is active.
Likely causes
- Reservoir empty, or the pump motor runs but does not pump.
- One blocked outlet stops a whole progressive distributor, so all four seals starve together.
- On multi-outlet pumps, one blocked line starves a single seal and nobody notices.
- Dirt in the grease from opening the reservoir lid, or two incompatible greases mixed.
Most likely and cheapest to check first.
Checks
- Reservoir level above the minimum mark. Mark today's level with paint and the date.
- Watch the distributor indicator pin while the pump runs. A pin that does not move means a blockage.
- Look at the pump relief valve. Grease escaping there means a line or outlet is blocked.
- Disconnect the outlet lines one at a time and run the pump. If the distributor cycles with one line off, that line or seal is blocked.
Fix
- Refill only through the filling connector with its filter, never by spooning grease in.
- Clear the blocked line by pumping fresh grease through it with a hand gun until clean grease reaches the seal.
- If the distributor itself is blocked, dismantle and clean it, pushing the pistons out with a brass rod by hand only.
- If the pump fails during production, grease the distributor inlet by hand until grease appears at all four seals, every 2 hours of production.
Stop the equipment if
The reservoir is empty, or no grease appears at any seal.
Parts you may need
The life insurance of the seals
If the central lubrication pump stops, nothing looks wrong for days. Then four seals fail one after another. Check the reservoir level and the grease at each seal every day, and treat any lubrication alarm as urgent.
| System | How it works | Key weakness |
|---|---|---|
| Progressive distributor | One pump feeds a block that delivers grease to each outlet in sequence | One blocked outlet stops the whole block |
| Multi-outlet pump | One pump element and one line per shaft end | A blocked line starves one seal unnoticed |
CAUTIONUse only the grease type on the pump label. Many seal systems use a soft or semi-fluid grade. Never mix two greases with different thickeners: they can separate and block the lines.
FIELD TIPIf the paint-marked reservoir level has not dropped after a week of production, the pump is not pumping, even if its motor runs.
COST OF NEGLECTSeal kits, bearings and shaft repairs are the largest maintenance cost after wear parts. Almost all of them start with a lubrication failure.
FIELD TIPEach shaft end usually has a spare grease nipple. Press its ball with a fingernail: grease coming out means the line is working. Before a long shutdown, purge old grease from the system so it does not harden in the lines.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer