Zierden 204 Boom seal "O" Rings

[Kevin James]

It’s not very often that my lead mechanic is stumped but this one has him perplexed. He is replacing the “O” rings in a Zierco 204 boom assembly seal Elbow. The Zierco parts breakdown shows a 2 “O” Rings #20410 and #20406. The Kleen-rite breakdown show them to be a #BO0092 O Ring (Yellow Mark) and a #BO0066 O Ring/Elbow Seal. The breakdown on the Zeirden web is also unclear as to which “O” Ring goes where. Does anyone know which “O” Ring goes where? The Yellow marked “O” Ring on the top or bottom?

 

[MEP001]

I don't remember which way is "top" or "bottom" but the "#BO0092 O Ring (Yellow Mark)" goes on the wet side of the seal.

 

[Randy]

This is the way it’s supposed to be done. install the #20406/KR #BO0066 O-ring first, it will fall into the first groove on the Seal Elbow.

Install the #20410/KR #BO0092 Yellow Mark/Dot O-ring second it will roll over the first O-ring. The #20410/KR #BO0092 Yellow Mark/Dot O-ring ends up closest to the floor.

Apply a silicone lubricant to both O-rings, do not use anything that contains a petroleum Distillate. Vaseline and WD-40 both contain petroleum distillates. Napa sells a product called Sil-Glyde, it works well.

When you reinstall the Seal Elbow leave 2 or 3 treads showing, Never Tighten the Seal Elbow

 

[Kevin James]

This is the way it’s supposed to be done. install the #20406/KR #BO0066 O-ring first, it will fall into the first groove on the Seal Elbow.

Install the #20410/KR #BO0092 Yellow Mark/Dot O-ring second it will roll over the first O-ring. The #20410/KR #BO0092 Yellow Mark/Dot O-ring ends up closest to the floor.

Apply a silicone lubricant to both O-rings, do not use anything that contains a petroleum Distillate. Vaseline and WD-40 both contain petroleum distillates. Napa sells a product called Sil-Glyde, it works well.

When you reinstall the Seal Elbow leave 2 or 3 treads showing, Never Tighten the Seal Elbow

Thank you Randy! With your excellent instructions we got the seals replace and no more leaks. Thanks again.

 

[Jet-Stream]

If you have an o-ring supply house with good selection, you can order these in bulk. The standard oring specification is:
For the upper (liquid side) 2-115 e70 in a EPDM
The lower (floor/outer side) 2-115 e70 in BUNA-N (aka Nitrile)
The size is the same for both, 2-115.
It is very important that the durometer be the same - e70 for even wear.
Very old Zeirden booms only have one groove, use the EPDM o-ring.
EPDM is chemical resistant, it holds up to tire cleaners and pre-soaks, the buna-n resist grease.

 

[Randy]

I wonder what the “AS568” number is. I wonder if it’s an AS568-115?