Clean surfaces & the use of gaskets & sealants

[rx4ur7]

This was in response to an (well done) o ring modification to the Mazda oil pump. It brings out one of my pet peeves, clean surfaces and the use of the proper sealing materials. ( if any of you enjoy or learn from it please post and let me know if you want to see any more stories from a crusty ol’ rotor. )

I have been privileged to be able to go to a few factory training schools. First was General Motors Chevrolet. One of the first things that our instructor railed on us about was the proper cleaning and use of gaskets. I believe it was his peeve too.

He told us that in a perfect world, gaskets would not be necessary in that if you have two properly (ie perfectly) machined surfaces you do not need to use a gasket. Formula 1 motors do not use any.

“Never use sandpaper, files, grinders to clean these surfaces!” If it is damaged or out of spec and can not be machined to spec, replace it.

Chemical removal of gasket material was his preferred method. Careful hand cleaning was second, making sure you use an implement that was made of a softer material than what you were cleaning. Over the years though I have become pretty proficient with razor blades.

It can be a pain in the butt and time consuming to clean a couple of surfaces properly but it is well worth it over the long run. Out of the thousands of sealing surfaces done I have never had one comeback for a leak from a replaced gasket. Granted also, I have used only factory gaskets be it Chevy, Porsche or Mazda.

The only ones that leaked were a few that were rushed jobs where a small piece of old gasket was involved, if I used RTV they probably would have been sealed for a while. I know though that I would have seen them down the road for a leak. (the above few leaked straight away so they did not leave the shop, proof to me not to do flat rate or rush work on client vehicles.)

I have saved a lot of money over the years too not buying a lot of permatex or 3M.

So my procedure is clean both surfaces, inspect, clean again, inspect, clean again, inspect assemble.

Sealants I do use where recommended by the factory, MazdaBond, HondaBond, YamaBond, or ThreeBond.



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