NAA Hydraulic Cylinder Gasket Blows

CAC63

Member
NAA has a gasket between the lift cylinder and the
lift cover. I keep blowing out this gasket (#16 in
attached picture) usually after some heavy use like
plowing. Does this happen because the safety relief
valve (#21) on the hydraulic cylinder is not
functioning properly? I have blown this gasket four
times in two years.
a94163.jpg
 
Which of the three holes in gasket is blowing out?
NAA_cyl_valvebody_1.jpg
The two round holes are cylinder pressure.
The bathtub hole is pump pressure, which will be cylinder pressure during lifting, backpressure valve pressure during hold & lower, and will have upper limit set by overpressure relief valve located in bottom of hydraulic cavity (#638B)....this is not he ram cylinder relief valve that you mentioned (#984F)
 
I'll take an educated guess at this since I can not be 100% sure on something like this. #1 do you any gasket goo?? If you do you should not be. #2 yes the relief valve maybe going bad. #3 you maybe over loading the system depending on what and how your doing things. #4 is the two parts 100% flat because if either is bent or warped it will blow a gasket like yours is doing. #5 do you torque the hold down bolt/nuts even and to spec if it has spec that is
 
It may not be your problem here, but a common reason these guys blow out is that people forget to install the two "donut" spacers (#15 in the parts diagram, usually included in gasket kits). Without those in place, the surfaces on either side of the gasket don't sit totally parallel when torqued down and eventually the gasket springs a leak under pressure.
 
I rebuilt my hydraulics one summer for a blown piston seal ring. I replaced all the gaskets in there thinking it would be a good idea. Worked good for a while then I blew out the gasket like you did the next spring while disking. I think the bouncing weight on the three point over rough ground is tough on the hydraulics.

I pulled it all apart again and found that the studs were loose. I had put the nuts on tight but the studs in the houseing were loose. Fluid pressure then blew out the gasket.

I removed the studs, tapped out the holes till they were good and clean, degreased everything, and then re-installed a new gasket using Permatex gasket sealer (#1 I think, the real sticky stuff in the can.) I then used [u:d3a8a88b7a]new[/u:d3a8a88b7a] studs and torqued and loctited them into the housing. I then used [u:d3a8a88b7a]new[/u:d3a8a88b7a] nuts and torqued them down to the max torque specified for the stud size. I have not had a problem in several years now. Also, make sure mounting surfaces are spotless and de-greased before re-assembly.

Good luck, not a hard job but frustrating when you have to do it repeatedly.
 

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