Wading in on a 7710 II

dieselpup · Jan 18, 2013

I recently picked up a 7710 II. The DP will slip as the tractor warms up. The mechanic where I purchased the tractor says it needs pto clutch seals based on the hyd pressures on the dp and fwd circuits. I've talked to the service manager at the local dealer - he mentioned putting a shim in to block off one of the hyd lines as a double check, one thing i haven't done. But after spending a couple hours with the manual an think I'm about ready to start. Anything to watch out for or check before starting in on it?

RodinNS · Jan 18, 2013

I don't know what you'd shim... other than the PTO pressure regulating valve. Even that will not gain you anything other than a day's work you don't want.
Basically... what you normally do is tee into the DP line or the pump manifold for that line and test with the DP in high and low, the PTO engaged and disengaged and the FWD engaged and disengaged. That will usually tell you where the leak is. If not, isolate the PTO from the front lines and test that separate... then add the DP to the mix... If that doesn't find it for certain, remove the DP and isolate the FWD clutch with the PTO.
I suspect if the first guy tested it and said the PTO needs seals... it needs seals.
Also... when you get it all back together, make sure you retest the pressure because I've found a couple of them now that don't and probably never did make the stated pressures in the manual of 160-180 psi in that circuit. Also beware that a PTO clutch reseal REQUIRES a rear split to get at the PTO. Tractors without a load monitor could have the PTO removed out the top... but 7710's generally all had load monitors.

Rod

lfc · Jan 18, 2013

Remember that the FWA uses hydraulic pressure to hold it out of FWA (clutch is spring loaded), so you should get higher pressure readings with it in FWA.

jbirnsch · Jan 18, 2013

A trick the dealer told me is to put the 3 DP teflon seals compressed inside of a spray paint cap for a day or 2. They will take on a tighter dia and hold tight to the DP clutch pack housing and have less of a chance of getting nicked or damaged when putting it back into the DP housing. When the oil reaches on the first start they will be pushed out to seal. Seemed to work for me when I rebuilt the 9000 DP. My DP pressure when hot disking would be 155 to 160 PSI hot and about 220 cold at startup after the rebuild.

dieselpup · Jan 19, 2013

Thanks all, have everything apart, hoping to borrow some stands tomorrow or Monday since I have the day off work. so far everything has gone well. Except for one fuel tank backet. As long as it can stay with the splitting stands I"ll be ok. If not it may come down to the blue-tip wrench.

edhOH · Jan 24, 2013

Take good care of that machine....I hear there"s a lucky guy somewhere getting a heckuva deal!!

Wading in on a 7710 II

dieselpup

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RodinNS

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lfc

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jbirnsch

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dieselpup

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edhOH

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