Replacing boom hydraulics in 934d-9 gradall?

[Dex]

Hello Everyone,
I own a 1999 Gradall 934D-9. The hydraulic lines are leaking inside the boom. Could someone give me some advice on how to access them? Any help would be very appreciated.
Thank you very much,
Dexter

 

[CM1995]

Welcome to the Forums Dex.

I've got a 1998 534D6 Gradall that fortunately have not had to go into the boom but I've thought about how to go about it.

It looks like you would have to pull the main cylinder out the rear and replace the lines. While you're that deep in the boom it would probably be a good idea to repack the cylinder.

There are real mechanics on the forums that can tell you exactly how to do it. Maybe one will come along.

Good luck!

 

[skata]

Haven't done a gradal. But disconnect the lines, tie a rope to them and pull them out . Use rope to pull new lines in.
Take old lines to a hose shop to match length.

 

[BigWrench55]

Can't give you any real good advice except for this. If you take the hoses to get matched you will want to make them shorter by a 1"-1-1/2". The hoses that you take out have stretched. And if you put the same length hose back in, they will stretch and wad up. Then all that work and money will be for nothing but practice. Good luck. As someone whose done this job a few times. I can tell it isn't fun and not all that easy.

 

[Dex]

Thanks for the help.

Could you give me some advice on how to access the ends of the lines? Obviously I can access the ones at the end (front) of the boom but where do I access the other end of the lines? Are they inside the boom?

 

[BigWrench55]

My experience is with genie and terex. I can't be of much help there. Probably at the back of the boom. Hopefully someone who has done this job for your model will come along and give better advice.

 

[skata]

Can't give you any real good advice except for this. If you take the hoses to get matched you will want to make them shorter by a 1"-1-1/2". The hoses that you take out have stretched. And if you put the same length hose back in, they will stretch and wad up. Then all that work and money will be for nothing but practice. Good luck. As someone whose done this job a few times. I can tell it isn't fun and not all that easy.

Any slack can be left by the tilt cylinder or in the inner boom section. . I wouldn't go shorter.

 

[skata]

Thanks for the help.

Could you give me some advice on how to access the ends of the lines? Obviously I can access the ones at the end (front) of the boom but where do I access the other end of the lines? Are they inside the boom?

Other end goes to tilt cylinder. Also remove cover on back of boom.

 

[Dex]

Thanks Skata.

Where do I access it on the other end? That is where I'm struggling. Thanks again for helping me on this.

 

[Knepptune]

The lines go into the boom on the bottom side about where the cab is. Its been awhile but Heres how did it, take the lines loose from the tilt cylinder, hook your tie wire up to that end. disconnect the spring tensioner from the bottom of the boom, pull some slack so you get to the fittings at the bottom, disconnect that end. Fasten your tie wire there. Go to back of the boom, pull your hoses out the back. Repeat process on the new hoses. I never just changed out one. I don’t remember if bracket at the end of the boom that holds the tele had to come out or not. I think on some models it did and others you get around it.

You can go to a hydraulic shop and have the new hoses made but I’ve never had much luck with them lasting. The hoses from a hydraulic shop will stretch to much and eventually get caught on something. The ones you buy from jlg are prestretched and the exact length you need. They’re well worth the extra money. If your gonna go the hydraulic shop route buy them 1-2 ft short and use a come along or ratchet to get them hooked up.


If I remember correctly it was about a 2 hr job.

 

[skata]

Thanks Skata.

Where do I access it on the other end? That is where I'm struggling. Thanks again for helping me on this.

The tilt cylinder end? Not sure if you can access them without removing the cylinder on the gradal. You'll have to look up in where the tilt cylinder is

 

[Knepptune]

It’s been a while but I know I never removed any cylinders when I did it. Is there not an access hole right at the end of the boom.

I haven’t been around any of those for a few years. Do you have a picture of the end of the boom.

 

[CM1995]

The tilt cylinder end? Not sure if you can access them without removing the cylinder on the gradal. You'll have to look up in where the tilt cylinder is

I thought the OP was taking about the cylinder inside the boom that extends the boom in and out.

 

[Dex]

The lines go into the boom on the bottom side about where the cab is. Its been awhile but Heres how did it, take the lines loose from the tilt cylinder, hook your tie wire up to that end. disconnect the spring tensioner from the bottom of the boom, pull some slack so you get to the fittings at the bottom, disconnect that end. Fasten your tie wire there. Go to back of the boom, pull your hoses out the back. Repeat process on the new hoses. I never just changed out one. I don’t remember if bracket at the end of the boom that holds the tele had to come out or not. I think on some models it did and others you get around it.

You can go to a hydraulic shop and have the new hoses made but I’ve never had much luck with them lasting. The hoses from a hydraulic shop will stretch to much and eventually get caught on something. The ones you buy from jlg are prestretched and the exact length you need. They’re well worth the extra money. If your gonna go the hydraulic shop route buy them 1-2 ft short and use a come along or ratchet to get them hooked up.


If I remember correctly it was about a 2 hr job.

Thanks for the help I will give this a try!