Replacing O-rings

[Randy Cook]

Group,
I have an L5740 HST, s/n prior to 2010 with a deck. I have a significant hydraulic oil leak which appears to be behind or as a part of the controller valve. My intention is to remove the controller valve and replace all of the O-rings I can get access to easily. I have an assortment of Hydrogenated Nitrile Butadiene Rubber (HNBR) O-rings. Assuming the size is correct can I use these to replace the OEM O-rings?

2nd Question - How critical is the o-ring's thickness? Said another way "What would be an acceptable margin of difference between OEM O-rings and my O-rings regarding thickness?

Thanks in advance.
Randy

 

[steveInMaryland]

Question 1 I have no idea but suspect they are totally fine. I have and use a NAPA o-ring kit and have never had on fail. I replace it as often as I use them up.

Question 2, there is no way to tell because the old compressed one will be only measurable in the fact of thickness now and not what they were. That being said, if you put a micrometer or caliper on them and its less than your new rings you should be just fine. Puffed up, new o-rings under pressure for years really compress down into their available space and harden.

Semper Fi

 

[Randy Cook]

Steve, Thanks. What a great help.
Randy

 

[D2Cat]

When I'm replacing a metric 0-ring I only replace with metric. I don't try to find something "close".

I've driven 35 miles one way to Coleman's to get the correct 0-ring, and it cost less then a dollar! I just didn't want to put something together and have to repeat my work to get it right.