New to me 753 hydraulic leak

[Dave the Ozzie]

I've got the seals, will check the sintered filters tomorrow, after pumping out the excess oil from the case. I guess while I have the motors out, I'll run it for long enough to see if there's excessive leakage. And I'll block it up so all four wheels are off the ground.

As I stated earlier, when I purchased my machine a couple of years ago it had been sitting out in the weather for four years as apparently the last guy that had the covers off the chain case hadn’t sealed them well enough as water had entered in to it turning the oil to a coffee coloured milk.
I wouldn’t be in a rush to change out the motor seals as it’s a pretty big job to remove them. Oil can not leak from them if they’re not driven as the pumps that operate them are variable displacement piston pumps and when the swash plate is in the neutral position (wheels don’t turn when machine is on stands) the pumps do not stroke therefore displace no fluid.

 

[icecheez]

Update: i went to work on it today, fully expecting the chain case to be full, but nope! oil is at proper level. So i put about 1/2 gallon in and started it, pulled up the cab, saw fresh oil again. I thought i saw something drip down by the valve body. Add i was squeezing down to look for the source of the leak, one of my feet stepped on a peddle and i heard bubbling. I think the house from the pump to the valve body got worn through rubbing against the bottom of the case. Any easy way of getting to it? Or do i need to take all the hoses off and the valve body out like i think? At least I'm closer to figuring it out. I want to get this thing home, it would be much easier to work on it, don't really want to winch it on to a trailer the winch it back off. I want to wash it before taking it apart, but his well has very little water, it has run dry at least three times in the last 2 weeks.

 

[icecheez]

I think it is this hard line that changes to hose. In any case there is a hose that goes down to the bottom and comes back up to the control valve. I think whatever oil i saw on the chain case was either a spill or drip. And it's the only hose that was emerged in oil.

 

[Dave the Ozzie]

I think it is this hard line that changes to hose. In any case there is a hose that goes down to the bottom and comes back up to the control valve. I think whatever oil i saw on the chain case was either a spill or drip. And it's the only hose that was emerged in oil.

Hopefully you’re on the right track, it looks like the fitting will take a 1” open ender, but confirm first and check that it’s the same size at both ends. Take an angle grinder with you and couple of the right size spanners and be prepared to chop one if need be to gain access. Also take a couple of different size jemmy bars as you may need them for leverage on a chopped/stubby spanner. Good luck.

 

[icecheez]

Thanks!

 

[icecheez]

Yup, found the problem. That hose from the pump to the control valve thing went down to the bottom and rubbed through. I don't know why it was so long, no reason not to have it just hang in the air. I was worried I was going to have to remove all the hoses but instead, I removed to drive motor and was able to reach over and disconnect it. I discovered the little access plate to stick a wrench through(1 1/4") wish it was a little bigger, but i managed. Then got the other end, pulled it out and found the abrasion and hole. I might make the new one a little shorter or wrap it in rubber to prevent it from happening again. unfortunately, being Saturday, all the local hydraulic places are closed, so Monday i should have a working skid steer!

 

[Dave the Ozzie]

Yup, found the problem. That hose from the pump to the control valve thing went down to the bottom and rubbed through. I don't know why it was so long, no reason not to have it just hang in the air. I was worried I was going to have to remove all the hoses but instead, I removed to drive motor and was able to reach over and disconnect it. I discovered the little access plate to stick a wrench through(1 1/4") wish it was a little bigger, but i managed. Then got the other end, pulled it out and found the abrasion and hole. I might make the new one a little shorter or wrap it in rubber to prevent it from happening again. unfortunately, being Saturday, all the local hydraulic places are closed, so Monday i should have a working skid steer!

Happy days.