782 leaking hydraulic fluid

skippy · #1 05-05-2010, 09:20 PM

I went to mow the lawn yesterday and found hydraulic oil under the 782. It made a mess of my storage shed nice concrete floor.
It did not lose so much as I was able to get the lawn mowed but do not wish to put it back in the shed until the leak is fixed.

Currently the deck is off and the 782 is on blocks. The leak appears to be coming from the front but am unsure where.

My question - is there a typical area of suspicion as what could be leaking?

If it means anything, I experienced rearward creeping while in neutral when parking it after the previous mow.

Thanks,
Skippy

#2 05-05-2010, 10:26 PM

Atleast one of you relief valve have gone by the wayside....leaking at weap hole at top....bet ya a dollar..

Scott

skippy · #3 05-05-2010, 10:46 PM

The leak seems to be near the top. Where are the relief valves located? Would it be difficult to replace? repair?

Thanks,
Skippy

CMA's129 · #4 05-05-2010, 11:42 PM

easy to replace. My local dealer just smears J.B.Weld over the holes, But never again will you be able to tow it without a dozer.
http://onlycubcadets.net/forum/showthread.php?t=3 Here is a short cut for new ones cheap!

CMA's129 · #5 05-06-2010, 12:05 AM

They will replace them if you want, but most old codggers are not up to sinking $300 into a 35 year old machine when the can buy a shiny new yard man out front for $875. And the fix does work. with out tools, on the automatic valves in half an hour. I myself only use OEM parts Unless I can build it better in my friends machine shop. I.E.grease fittings bronze bushings ect.

skippy · #6 05-06-2010, 12:15 AM

If I get the chance I will check it out tomorrow.

skippy

skippy · #7 05-06-2010, 01:30 PM

Well I checked it out and did find it was a check valve weep hole where the fluid was coming from. I removed it and cleaned? it with compressed air. When I re-installed it it leaked even worse.

I again removed it, drilled and tapped the weep hole to accept a grease fitting, and installed the grease fitting.

after putting it back together, there appears to be no more leaks.

Will there be any harm running it this way?

Thanks,
Skippy

Matt G. · #8 05-06-2010, 02:30 PM

Quote:

Originally Posted by skippy

I again removed it, drilled and tapped the weep hole to accept a grease fitting, and installed the grease fitting.

Why on earth did you do that? It's leaking because one of the internal O-rings is bad. You can't fix this unless you or someone you know is handy with a lathe and welder. You just destroyed that valve. I doubt it will function with the hole plugged. Click on the previously-posted link and get yourself two new ones.

aagitch · #9 05-06-2010, 04:08 PM

I agree with matt, I wouldn't use that valve. It was leaking out the hole to let you know it's no longer functioning as it should.

skippy · #10 05-06-2010, 05:58 PM

When I first took took the valve out everything looked good, the balls and springs all looked new, the action seemed OK. I assumed there must have been a one way valve in the top that would let air in through the weep hole if necessary but would not let fluid back out. That is what I would consider had failed - a ruptured diaphram or similar that allowed fluid through the weep hole. ( I would welcome to be set straight if my assumptions are way off).

I was not aware of any repair that could be made so I figured I would need a new valve anyway and had nothing to lose by messin' with this one.

I have a lathe and a welder(s) (as well as a plethera of other tools) but until I know what had to be done, I have no idea where I would begin. If there is a tutorial on valve re-building I would love to give it a try. I am sure I can formulate a plug with a weep hole.

I looked at the link provided and saw a manual and automatic version. Mine appears to be the automatic type. I do not know if the manual type could be substituted. Does the manual have to have linkage to activate the button?

I considered a grease fitting could work like a one way valve but am completely unknowledgable in the amount of vacuum necessary to unseat the ball in the grease fitting. My other thought was to put a screw in but knew that would totally plug the top.

Well after I put the grease fitting in, I got it all back together and ran it around the yard at various speeds - forward and reverse - with pto operating and not.

My impression is that it performed well forward and backward and even seemed better in reverse(stronger).

So far so good. However, I do not wish to do irreparable harm to the pump. So if this modification, even though it seems to work, would cause undue pressure or something else resulting in major damage, I will leave it parked until the replacement valve is acquired.

What I really need is a complete understanding of the hydraulic system.

Thanks,
Skippy

The valve in question is on the side away from the brake pedal.