Hydraulics 101

[jax65]

I am a recent first time tractor owner (older grey market 30hp kubota - with a one year old generic front end loader. In this short time I have had two hydraulic cylinders, one on bucket and one on the lift, fail due to internal seal failures. Two questions - Could seal failure (they shred) be caused by exceeding weight limits? Is it possible/advisable to install a after-market hydraulic filter? Thanks for any advice. /forums/images/graemlins/confused.gif

 

[Soundguy]

Are your pistons smooth and true?

Soundguy

 

[john_bud]

Hi,

Interesting post. I am repacking cylinders (If I can get them open!). One was shredded. The piston nut was loose, spec is 550 ft-lb and it was probably only 150 ft-lb. It could be that the cylinders were not correctly assembled. Exceeding weight limits should not cause packing damage, it should cause the relief valve to open IF you really exceeded.

Not only is it possible, but it is a smart idea to install a filter on the return line to the tank. I like to get a filter that is 50% more flow than the rated pump output. Make sure the filter housing has a pressure relief bypass. Fancy ones have ports for pressure gages.

jb

 

[jax65]

Thanks for the information john, interestingly after the first cylinder failure i bought an extra set of seals in case of another failure, but I was unable to get the cylinder apart to replace them and had to visit the hydraulic shop again - $105 versus $28 - oh well! After asking what i realized was a fairly lame question about the filter, I ordered one form Northern Tool. Soundguy, the folks at the hyd shop said everything internal checked out and no damage or flaws - the only thing they offered was that it was just bad seals??? Hopefully this will be the last one for awhile.