Description

Everything you need to rebuilt your pump except a new shaft.

Impeller               C-E-5-1
Spacer Bush       C-E-5-2
Slip Ring Seal      C-E-5-3
Shaft Seal            C-E-5-4
O-Ring                 C-E-5-5
Pump O-Ring      C-E-5-6
O-Ring                 C-E-5-10
Impeller Bolt        C-G-3-11
Crush Washer     C-E-6-7
Crush Washer     C-E-6-8

• Rebuilding the oil/water pump on a BMW K is important for several key reasons:

  1.

  Prevent Coolant and Oil Leaks

  The oil/water pump on the K100 is a combined unit that manages both engine oil circulation and coolant flow. Over time, the internal seals—especially the shaft seal between the oil and water sections—can wear out. If the seal fails, coolant can mix with oil, or oil can leak into the cooling system, leading to serious engine issues.

  2.

  Avoid Cross-Contamination

  The K100 has a weep hole between the oil and water sides to let you know if one of the seals is failing. If you see oil or coolant coming from the weep hole, it’s a clear sign the pump needs attention. Letting it go too long could result in cross-contamination, which can ruin bearings or lead to overheating.

  3.

  Improve Reliability

  This is a 1980s/1990s bike, and many K100s still on the road are running with original or aged components. Rebuilding the pump refreshes critical seals, bearings, and impellers, restoring performance and reliability, especially if you’re planning long rides or touring.

  4.

  Prevent Overheating or Oil Pressure Issues

  A worn or damaged pump can cause cooling inefficiency or reduced oil pressure, both of which can lead to overheating or even engine failure.

  5.

  Cost-Effective Maintenance

  Rebuilding the pump is usually cheaper than waiting for a catastrophic failure that damages the engine. Kits are available, and many DIY riders handle the rebuild themselves.

  If you’re noticing leaks, odd oil/coolant behavior, or it’s just been decades since it was touched, it’s smart preventive maintenance to rebuild