Dorman 99977 Power Steering Reservoir Cap

Power Steering Reservoir Cap for Hummer H3

This Dorman power steering reservoir cap is a direct replacement for a cracked, worn, or missing original cap. It helps seal the reservoir to reduce fluid loss and limit contamination in the steering system. Dorman 99977 is built for a precise OE-style fit on select Hummer H3 and H3T applications.

Key Features

• Direct replacement power steering reservoir cap
• Plastic construction with black finish
• Twist-on attachment type for secure reservoir closure
• Includes an integrated dipstick for fluid level checking
• Measures 2.06 in diameter and 2.95 in height
• Fits 2007-2010 Hummer H3 and 2009-2010 Hummer H3T applications
• Dorman 99977 is a direct OE-style replacement for part number 15132766

Detailed Description

Built as a direct replacement, this Dorman power steering reservoir cap restores the sealing function of the original component on select Hummer H3 and H3T models. The twist-on design helps keep the cap seated properly, while the integrated dipstick supports routine fluid checks without removing additional parts. If the original cap is cracked, missing, or no longer sealing correctly, Dorman 99977 provides a straightforward replacement for the reservoir opening.

This part cross-references 15132766 for the same application.

What It Helps Solve

• Power steering fluid seepage from a damaged or loose reservoir cap
• Contamination entering the steering fluid reservoir
• Loss of reservoir sealing caused by a missing original cap
• Difficulty checking power steering fluid level with a worn dipstick cap
• Fitment issues on 2007-2010 Hummer H3 and 2009-2010 Hummer H3T steering reservoirs

Installation Notes and Tips

Verify reservoir opening diameter before installation. Align the twist-on cap with the reservoir neck and tighten until fully seated. Confirm the integrated dipstick is clean before checking fluid level, and inspect the reservoir sealing surface for cracks or debris before installing Dorman 99977.

Quality Assurance

Dorman manufactures replacement steering hardware to match original equipment dimensions and function for specific vehicle applications. This cap is intended as a direct replacement for the factory-style reservoir cap on listed Hummer models.