What Can I Use to Replace the Hydrastar 303 Oil Cap?

Updated 05/14/2026 | Published 05/13/2026

Products Featured in This Question

Valcrum Universal Threaded Aluminum Oil Bath or Grease Cap for 6K to 9K Axles - Black

(42)

$39.95

Oil Cap and Plug for 7,000-lb to 8,000-lb HydraStar Disc Brake Kits - Qty 1

(8)

$12.71

Question:

I want to replace the existing caps on my oil bath bearings. The existing plastic cap is marked Hydrastar 303. Will this Vlacrum Part No. VA45JR work as a replacement?

asked by: Phil

Expert Reply:

Hi Phil,

We do carry the Hydrastar Oil Cap and Plug for 7K and 8K axles that work for Hydrastar disc brake kits. If your Hydrastar disc brakes are rated for 7K, 7.2K, or 8K and have 2.25" spindles then this will work perfectly for you!

The Valcrum Universal Threaded Aluminum Oil Bath Cap for 6K to 9K axles part # VA45JR has the same thread outer diameter of 2.875" as the Hydrastar and is rated for similar capacities. As long as your current cap's thread outer diameter matches and the axle's weight capacity falls into it's range you can use either the Hydrastar or Valcrum oil cap as a replacement.

What is your axle capacity and the outer diameter of your current cap?

expert reply by: Claire H