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Slurry or mortar leaking at a shaft end seal

Manual section
Book 1 · § 4 · 11.5
Level
OPERATOR + TECHNICIAN
M

Symptom

Grey slurry mixed in the grease at a seal, or mortar dripping at a shaft end. Later, one bearing housing runs hotter or rumbles.

Likely causes

  1. Seal running without enough grease (blocked line, empty pump, distributor fault).
  2. Seal worn out at the end of its life.
  3. Concrete build-up at the end wall pushing into the seal area (worn end scrapers).
  4. Non-drive end seal damaged by shaft expansion movement.

Most likely and cheapest to check first.

Checks

  1. Look for fresh grease at all four seals. Wipe the old grease so you can see new grease tomorrow.
  2. Check the grease flow and pressure to the leaking seal.
  3. Compare the temperature of all four bearing housings after one hour of production.
  4. Check the non-drive (stub) ends first and most carefully.

Fix

  1. Grey slurry in grease — restore full grease flow and plan the seal change within days.
  2. Mortar dripping — stop at the end of the shift and replace the complete seal kit.
  3. Hot or rumbling housing — stop and replace the bearing together with the seal kit.

Stop the equipment if

Mortar is dripping from a seal, or one bearing housing is clearly hotter than the others.

Parts you may need

ATP-TS-08Shaft end seal kitATP-TS-09Shaft bearingATP-TS-14.1Progressive distributor
Request a part for this fault Get the full chapter as PDF

The most critical point of the mixer

Where each shaft passes through the end wall, a seal keeps the concrete inside. Fresh concrete is a liquid full of sand and finds any gap. The seal works by keeping grease at a higher pressure than the concrete, pushed continuously from outside toward the tank.

A seal that runs without grease lets slurry in. The slurry destroys the seal, then the bearing, and finally the shaft. Fresh grease visible at every seal is the daily sign that all is well.

SignWhat it meansUrgency
No fresh grease at a sealLine blocked, pump empty or distributor faultSame day
Grey slurry or water in greaseSeal starting to leakWithin days
Mortar dripping from the seal areaSeal failedStop at end of shift
One bearing housing much hotterBearing damage or no lubricationStop and inspect
New grinding or rumbling at one endBearing damageStop and inspect
FIELD TIPPut a gloved hand on all four bearing housings after an hour of production, or use an infrared thermometer. They should all feel about the same. Investigate if one is more than 15 °C hotter than the others, or above 80 °C.
COST OF NEGLECTA seal kit is a small part. A destroyed bearing means lifting the drive and often repairing the shaft journal. A worn shaft means removing the whole shaft with all its arms.
CAUTIONAlways replace the shaft seal kit when you replace a bearing. A new bearing behind a worn seal fails again within months.

⚠ Every check inside a machine starts with full lockout. Safety disclaimer

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