- Incomplete surface prep. To have a successful formed-in-place gasket, you need to prep both surfaces so that you’re working with clean, bare metal. Failure to clean off old gasket or gasket maker materials may result in the mating surfaces coming together in an uneven alignment. This can compromise the seal and the operation of the assembly. Never scrape off old gaskets with a razor blade or anything that can scratch the metal surfaces and create a leak path. Use a plastic scraper or nylon brush. You may want to also use a chemical gasket remover.
|Only fill large gaps, larger than 20 thousandths of an inch, with an RTV gasket maker.||Use a plastic scraper or nylon brush to fully remove any old gasketing material.|
Incorrect reassembly. A common gasketing error occurs when the reassembly process is rushed. Many mechanics believe that four hours of cure time is sufficient to return a vehicle back to service when using silicone gasketing products. There are gasketing formulas that allow an immediate return to service, such as Permatex The Right Stuff®. However, most gasketing products require 24 hours of cure time.
For proper assembly when using RTV gasketing, please take the following steps to ensure a quality seal:
- Apply a continuous bead of silicone to the mating surface.
- Assemble parts with bolts finger tight ensuring contact is established while the silicone is still wet.
- Let set for 1 hour, then torque all fasteners to proper values dictated by the vehicle service manual.
- After 24 hours of cure time, fill all necessary fluids and return the vehicle to service.
Using a gasket maker as a dressing on a conventional gasket. This might be the most common gasketing error of all. Many mechanics will use an RTV gasket maker to hold a conventional or cut gasket in place during assembly. Some mechanics will even use the RTV gasket maker as a dressing, coating both sides of the gasket.
Gasket makers are the wrong product for these applications - their formulations are too thick for use as a dressing. If you’re installing a conventional gasket, use a solvent-based gasket dressing - they’re available in sprays, liquids, and tubes, with specialized formulas for a variety of applications.
Whether you’re a full-time auto repair pro or dedicated Do-it-yourselfer, gasket makers and flange sealants are products you’ll want to keep on hand to save time and money. Keep clear of these common errors and your assemblies (and your customers) will thank you.