Solving a leak issue on General Motors Automobiles

When an automotive tier one supplier came to CGR Products with a leak issue around an injection molded module for gas pedals, we jumped to action by providing multiple prototypes to ultimately find the ideal solution.

automotive injection molded plastic assembly

The Challenge:

Our Initial meeting with the tier supplier gave us the history to their issues. Their customer, General Motors (GM) was experiencing a leak issue with water seeping inside some cabins of GM vehicles.

GM had sent the plastic injection molded piece to one of their independent test labs to run submersion tests along with other water saturation tests.  It was determined there was a potential for leaks around the area where the gas pedal coupling was installed in and around the injection molded part. GM required the tier supplier to come up with a solution.


As a long-time supplier to the chassis division, the engineers from the tier supplier asked the CGR Products team to assist. The engineers initially came up with their own design that included “tabs” to help hold the part in place.  Our first samples proved unsuccessful due to the lack of “initial tack” from the adhesive.  The tabs began “popping up” and ultimately separated from the plastic injection molded part.

The Solution:

The CGR team met and came up with two possible solutions.

  1. Create slits around the tabs that would relieve the stress created when pressing the tabs down onto the molded plastic part.
  2. Change adhesives to a more aggressive, high tack adhesive.

Subsequent samples were made using both options.  After testing, it was determined only the adhesive change would be needed.

The next phase consisted of sending samples of the entire injection molded component to GM for humidity testing.  During these tests, the newly designed gasket was drawn into a hole on the injection molded part.  The engineers along with CGR Products determined that a “vacuum” was being created by the heating and cooling exposure during the test.  Further design changes were made to create “weeping holes” along the outer perimeter of the gasket to release pressure on the part during any future humidity challenges.


sponge gasket after vacuum testing for leak issue

The gasket result after vacuum exposure

sponge gasket redesign with weeping holes

The gasket after “weeping hole” redesign











The Result:

The final approved solution was a gasket made from Armacell 8002 EPDM closed cell sponge rubber with 3M 9775 adhesive.   The gaskets are kiss cut on a roll allowing easy assembly for the tier supplier.    Parts were approved by GM in mid –June 2018.  Production began by the end of June 2018.


The CGR team was involved from the very beginning, and through quick response with a knowledgeable group of associates from CGR, the tier one, and GM, we were able to develop a great solution to the leaking problem.  Based on our long-term relationship with the tier supplier, we were trusted to assist in their solution process.


“Great things in business are never done by one person. They are done by a team of people” – Steven Jobs

CGR thrives on these types of challenges and is always ready to collaborate with customers to develop ideal solutions to their problems.  Contact us today to see how we can assist your business with a similar challenge.