O-ring Lubrication

[George7941]

In my situation, the o-ring is being used as a gasket between two brass surfaces clamped together, with one surface flat and the other surface having a groove to retain the o-ring(Hansgrohe Shower Valve).

I do not know the composition of the o-ring, so I used Silicone grease (Sylglide) as a lubricant by applying a very thin coat on to the flat surface.

Now I have a small leak. The Hansgrohe instructions did not call for any lubricant. Did I err in using the Sylglide?

 

[oggb]

Do the two pieces move against one another? If not, there's no reason to use any kind of lube between them.

 

[mechtech2]

Maybe the used 'O' ring isn't seating/sealing well? Get a new one?
Also what Jred said.

 

[The_Eric]

The grease shouldn't have caused your leak. Look for a faulty install, damage or debris.

edit: this is assuming that this is the correct size o-ring for the application.

 

[Panzerman]

White grease probably would have been a better choice. I use that alot when dealing with rubber O rings and water. Its water resistant and wont harm the rubber.

 

[George7941]

Originally Posted By: JRed
Do the two pieces move against one another? If not, there's no reason to use any kind of lube between them.


There is no movement between the pieces but I am under the impression that, even for static applications, O-rings should be lubed because they deform and move a little under pressure.

The O-ring is new,it came with the new shower valve that I just installed. This is the actual shower valve base
http://www.hansgrohe-usa.com/us_en/120756_31353734315F32375F3736363130.htm
The white plastic centre piece gets discarded and the actual valve mechanism is screwed on to the base. The base has various ports and the o-ring seals around these ports.

I am calling it a o-ring because its cross-section is round but it has a complex shape because it is this one gasket that seals all the various ports.

There are automotive thermostat housings that use a o-ring instead of a flat gasket. The o-ring gets sandwiched and compressed between two flat surfaces, with one flat surface having a groove to contain the o-ring.