Hydraulic Rod Seal

[lukin1977]

Hello
What is the difference between a rod seal and a buffer seal?
Also, what is a wiper seal?

 

[HPost]

The rod seal keeps the oil in the rod end of cylinder by sealing the gap between the top gland and the rod.

A buffer seal does the same, but also offers some insurance against side load on the rod.

The wiper does what it says, it wipes the crap off the rod to stop the crap from getting into the rods seals.

 

[lukin1977]

ok, so if my piston has a rod guide ring a buffer seal will be redundant?

 

[HPost]

Need to clarify here, as some people know buffer seals as different things.

A buffer seal is not a suitable replacement for wear strip or guide ring, the contact area is not as big. They are described as being meant for heavy duty applications.

Some have a PTFE ring set into them, some are made of a harder polymer.

Either way, for high pressure or aggressive applications, some folks like to fit buffer seals.

Google it, there are lots of videos and images about

 

[lukin1977]

thanks HPost

It is a low pressure application. Just 200 psi
I am having trouble with an oil leak at the rod seal. That the rod is wear beyond the seal`s ability to close the gap

 

[HPost]

You'll need to get the rod re-chromed. It is possible to install seals with a smaller bore, but the excess load will wear the seal quickly and you'll end up with a leak and less money. If the surface of the is damaged, well...it's just pointless.

Lots of people will tell you to pack it out, but the only long term solution is to replace the rod or get it re-chromed.