Oil & Fuel JD 750 How to bleed hydraulic system

[GaryDG]

I didn't notice a leak in a line which allowed my hydraulic level to drop below any dipstick measurement. I added hydraulic fluid to an appropriate level but the hydraulics still do not work. They worked before I shut the tractor down but two days later they didn't work.

I believe I need to bleed the system. What is the correct approach for doing so?

Thanks!

 

[moship]

I never had to bleed my 750 hydraulic system after complete fluid changes and such. Perhaps check to make certain the knob under the seat is open to allow hydraulic flow. Have you checked the hydraulic filter screen lately? If you have power steering you'll also have a hydraulic filter.

There was a post several months ago about a 750 having similar symptoms and it ended up being contaminated fluid and a clogged screen. It's behind on of the rear wheels.

 

[GaryDG]

Thanks moship!

Yes I saw that post which included a diagram of the filtering mechanism.

I don't have an owners manual - so thanks for letting me know what that knob is for. I have never moved it from its position.

I have not checked that screen.

So I have a couple things to check, then. But a couple questions, if I may.

Where would be the drain plug for the hydraulics?

Do you know of a source for online part diagrams for this tractor?

txs again

 

[moship]

Check out JD web site they have exploded views of the various parts. Don't have the link handy to included it in this post.

Search the other 750 posts. I think I included a parts drawing in one of them.

 

[moship]

I think this is the thread I was thinking of.

http://www.tractorbynet.com/forums/john-deere-owning-operating/272306-alternator-bearing-hydraulic-noise-jd.html#post3207051

 

[arrow]

Thanks moship!

Yes I saw that post which included a diagram of the filtering mechanism.

I don't have an owners manual - so thanks for letting me know what that knob is for. I have never moved it from its position.

I have not checked that screen.

So I have a couple things to check, then. But a couple questions, if I may.

Where would be the drain plug for the hydraulics?

Do you know of a source for online part diagrams for this tractor?

txs again

Gary the drain plug is under the tractor about inline with the seat back. I have drained out my 750 when I had it several times and never confronted that which you are dealing with. Hydraulics were always operational after fluid change. Hope your pump didn't let go.

 

[moship]

Gary,

At one time JD had the owners manual available on line, but now they just have the part number listing for them. I've included the links below in the event they are of any value to you.

Tractor: John Deere Ag - New Equipment: Technical Publications - Publications Search

Attachments: John Deere Ag - New Equipment: Technical Publications - Publications Search

You might be able to find unauthorized downloads on the net. Follow these at your own risk. Example: John Deere 650/750 Utility Tractor Technical Manual (TM1242)

Back when I owned my 750 I had the Service Manual and it was well worth the cost and came in handy. If you plan on having your tractor any length of time and you do your own work, I would highly recommend it.

Good luck with your issue and please update with your findings so we can all learn.

 

[kuboman]

You may have introduced air into the system. Try jacking the front wheels off the ground and then cycle the steering from stop to stop.
For parts go to jdparts.com.

 

[satellite]

It sounds like the filter screen is clogged. If you haven't changed your hydraulic fluid in a while, now is the time. Pull the screen out and clean it. They still sell new screens if yours is damaged.