Well the seal has blown out two times within a month on my FAE mulcher. The first time I had to pay $1200.00 to fix (seal and new belts). The second time was under warranty. My concern is they say they found nothing else wrong that would have caused the seal to blow again. There has to be something causing it to blow out. I checked out everything on my Bobcat s-330, even blew out the case drain line to make sure it wasn't clogged. The coupler seems fine. Anyone ever had this problem?
FAE blown seal
- Thread starter satxcedar
- Start date
Robbie Hegwood
Platinum Member
If you have exhausted all other factors then do this. Take the case drain line loose and let it dump into a clean bucket (so you can re-use the oil), run the head for 1 minute and tell us how much oil you get. The small pistons in a motor are like those found in car. Something could have happened and one or more of those rings have been damaged, this would allow excessive blow by pressurizing the case leading to too much oil causing the seal to blow.
yellowdogsvc
Veteran Member
While I don't really know how my FAE motor works internally, that makes sense.
I've also lost a seal due to a case drain popping off the machine (my fault for not making sure it was locked) on the same motor satxcedar uses. It's always a concern since the case drain seems to be the weak link. His machine should have a case drain filter that needs to be serviced occasionally. I would check that, too, if the rest of it is working fine.
It's very frustrating to have this happen. Literally cuts off income and usually costs a lot to do. Even though FAE has more room to work than some of the other heads, it's still tough to get to things. I hope I never have to change the hoses on a 2 speed skid steer FAE head. Almost impossible to reach the one on the back side of the motor. I imagine the seal isn't much easier.
tonyoz
Platinum Member
Changing the seal is a job you can do yourself. If it's a Rexroth motor the you will need a ratchet type sir clip plier but this doesn't solve the problem of why.
I got my mulcher back this week and used it yesterday,ran normal. Before running it I changed the case drain coupler and filter. The filter had a broken (what looked to be) white plastic o-ring and some black stuff, probably torn up o-ring. I was glad to see the filter had junk in it thinking this is why the seal is blowing. My question now is where did the broken o-rings come from? I am hoping it came from the coupler or originally part of the case drain filter and just broke up. I am hoping its not from the mulcher motor.
tonyoz
Platinum Member
Gees I hate being a gloom merchant, but the junk in the filter could have come from anywhere in the hydraulic system. Have you checked all the other filters?
I have not checked the other hydraulic filters yet. The white o-ring I found I think would be to small to be part of any other hydraulic filter on the bobcat,the other filters are fairly large. I am just hoping its not from the mulcher motor.
SSdoxie
Elite Member
The white pieces are more likely a backup ring used to help hold an O-ring in place that has pressure against it. It could have come from a coupler or one of the relief valves or solenoid stem in the diverter valve block on the cutter. A missing, worn seal on one of these stems could allow extra case drain flow and increase back pressure at motor seal. With a new case drain filter, will probably work for awhile until more debris gets plugged in the filter.
Take out each of the relief valves and solenoid stem to check for missing seal. Look for a groove with nothing in it, or a chaffed) O-ring in too wide of a groove.
Take out each of the relief valves and solenoid stem to check for missing seal. Look for a groove with nothing in it, or a chaffed) O-ring in too wide of a groove.
Thanks for the input. It is one piece of white o-ring and not a bunch of pieces. The o-ring when I put the broken end back together is about the size of a dime. After looking at the case drain coupler, I don't see how it could have passed through it. The small black fragments could have though.
yellowdogsvc
Veteran Member
They could have been lodged in there and when you used compressed air, got pushed further. The white pieces doxie is talking about are fairly rigid. Try posting a pic. I have had those sticking out of my couplers when they fail. I am generally alerted to a failure when they start to leak. I carry extra couplers for attachments, machine aux and case drain. The case drain filter on machine or attachment should be replaced as a precaution.
As far as the mulcher motor having a failure, they should have checked that when they were replacing seal.. Hopefully they did but I would check with them on that.
Maybe run the mulcher for awhile and change the case drain filter again. I think on the M series like I have, everything goes through the main filter and there is no separate case-drain. Yours, i think, had a 700 or 800 change interval but in our conditions here, I'd change it more often to be safe especially since you opened that system a few times.
Good luck and pray for rain!
