Bobcat Hydraulic Case Drain Filter Element Replaces 6661807 (Includes O-Rings)

A case drain filter is a small hydraulic filter element used in certain systems to filter oil returning through a case drain/return circuit. Its job is to catch fine debris before oil returns to the hydraulic tank or system, helping reduce contamination and wear. Not every Bobcat uses the same style, so part-number matching is the most reliable way to confirm the correct filter.

Location varies by model. On many Bobcat machines it’s in the hydraulic compartment near the reservoir/return plumbing or in a small filter housing used for the case drain/return circuit. Because placement differs, the best method is to check your Bobcat service/parts manual for the exact location and replacement procedure for your model.

Symptoms can include slower hydraulic response, increased hydraulic noise, heat buildup, or warning indicators (if equipped). A clogged filter can restrict return flow and cause extra stress on the hydraulic system. If you suspect restriction, replace the filter at the recommended interval and verify correct hydraulic oil level and condition.

Some Bobcat 753 configurations use 6661807, but not all—fitment can depend on serial number and hydraulic setup. The safest confirmation is checking your parts manual for the filter part number or matching the number on your existing filter/housing.

You receive the case drain filter element and O-rings as shown in the product photo.

Clean around the housing before opening it so dirt doesn’t fall in. Replace O-rings if they’re flattened or damaged, lightly oil the new O-rings before install, and confirm there are no leaks after startup. Always follow your manual for the correct bleed/check steps and fluid level.