How A Simple Sealing Problem Evolved Into A Groundbreaking Feature For Heavy Truck Engines.


This project began when our customer in the heavy truck industry identified a sealing problem with a metal oil fill tube assembly. Since RL Hudson has a long history of sealing expertise, they asked us to look at it.


We suggested a fairly simple design change that would solve the leaking problem. In addition to sealing expertise, our design team is also known for their knowledge of metal-to-plastic conversions. Soon the customer was interested in replacing the metal tube assembly with a plastic one.

The Bubba Test One major challenge was something the customer called “the Bubba test.” The fill tube would have to withstand a three-hundred pound person standing on the end without breaking. It took some work, but we overcame that hurdle.

To Cap it Off Next, it was determined that the new plastic fill tube should have a cap that can’t be easily lost. So, we integrated a tether into the design.

An Extension Finally, marketing weighed in and said that the customers complain about the difficulty of filling the engines with five-gallon containers of oil because the fill point is so close to the side of the engine.  We were not able to increase the space envelope, but  after a little head scratching, we came up with the unique extending inner tube.

When the new fill tube had its debut at the Louisville truck show, we were told the extension was one of the most popular features. This flexible product development approach and the speed with which we were able to make changes and prototype, both with physical prototypes and virtually within FEA and Pro/Engineer, became the standard by which we approach every project. And the cap and tube have become standard on this customer’s engines. The design has also been imitated across the industry.



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