Davis Backhoe Brackets And Lantex Seals

[bremery]

I picked up a Davis D100 that seemed to be retrofitted to a Bobcat. It utilized the trailer style coupling method, but it was all beat up so I made my own. It was hacked together when I got it and someone branded it with Bobcat logos.
I took the pushbeam from an old Fisher snow plow and cut the framework on the backhoe so that when the bucket cylinder curled all the way back the backhoe seat would be level. I had to lengthen the push beam so the ears lined up where I wanted them.

I then took the brackets that came with my backhoe and cut the ball off and welded 1/4” plate that I drilled with a 1” hole that would line up with the 1” hole on the push beam.

To beef everything up I used a piece of 1/4” diamond plate and covered the top surface of the framework. This provides for a small platform where I might put a spill kit or a cooler.

This setup needs a little tweaking but its better than the trailer coupler method. Many here suggest using tractor 3pt links, but I had all this material around and its the same concept minus the adjustability aspect.
The backhoe works well and will dig down at least 6 feet.

That rock is about a 1/3 of a yard and picked it right out.
My main problem now is the seals on the boom and bucket cylinders leak after I take it off my Bobcat and let it sit. They do not leak while connected to the Bobcat. I believe the boom cylinder leaks about 8oz everytime. I have a local guy that will install the seals, but I need to get the seals before he will do the work. The pistons are Lantex brand and the bucket cylinder is marked 847C. JD8875 has replaced the seals on his backhoe and I am waiting to hear back from him in regards to the part numbers he purchased. The boom cylinder has a different packing nut that the bucket cylinder.
I understand how to disassemble the bucket cylinder to measure the seals if I have to, but I don't know how to disassemble the boom cylinder. I tried tightening the nut, but it just spun. After I tightened the cap it didn't leak as bad, but it still leaks. Any ideas would be greatly appreciated.
The bucket piston cap looks like this.

Where the boom cylinder cap looks like this:

 

[jerry]

That bucket cyl has od threads, remove the two allen socket screws that you can see in the picture on the side of the gland nut and use a large chain wrench or something similar to unscrew it. It should be right hand thread, may be one of several different threads on it. It may be a job for a cyl shop if you do not have big tools. The boom cyl has id threads and you remove the gland with a spanner wrench, across the two holes in the face. You can make a spanner wrench if you have a little time. It looks as though you may be able to get some grip on the od of that face also. Once it is apart seals should not be hard to get by the dimensions or even take the old seal in and they will figure it out.

 

[bremery]

That bucket cyl has od threads, remove the two allen socket screws that you can see in the picture on the side of the gland nut and use a large chain wrench or something similar to unscrew it. It should be right hand thread, may be one of several different threads on it. It may be a job for a cyl shop if you do not have big tools. The boom cyl has id threads and you remove the gland with a spanner wrench, across the two holes in the face. You can make a spanner wrench if you have a little time. It looks as though you may be able to get some grip on the od of that face also. Once it is apart seals should not be hard to get by the dimensions or even take the old seal in and they will figure it out.

I finally rebuilt my cylinders. Above is a picture of how I pulled the rod out of the bore. It was fairly difficult to pull the rod out. After putting some tension with a come a long, and a few hits with a dead blow hammer the rod and piston came out.

Here is a shot of the external seals for one of the cylinders. Once I got the seals out, I took them to the hydraulic shop where they matched them up with new ones. This nut is an 1-11/16“. The other cylinder I did had a 1.5“ nut.

Once the new seals were in, I torqued the rod nut with a large 3/4” drive torque wrench. I also used some Loctite 277 on the rod nut. After oiling everything the piston and rod slid back into the bore with little resistance. After hooking up the hoses everything worked, with no leaks. It wasn't a bad job, but it was very messy.

 

[Tazza]

I finally rebuilt my cylinders. Above is a picture of how I pulled the rod out of the bore. It was fairly difficult to pull the rod out. After putting some tension with a come a long, and a few hits with a dead blow hammer the rod and piston came out.

Here is a shot of the external seals for one of the cylinders. Once I got the seals out, I took them to the hydraulic shop where they matched them up with new ones. This nut is an 1-11/16“. The other cylinder I did had a 1.5“ nut.

Once the new seals were in, I torqued the rod nut with a large 3/4” drive torque wrench. I also used some Loctite 277 on the rod nut. After oiling everything the piston and rod slid back into the bore with little resistance. After hooking up the hoses everything worked, with no leaks. It wasn't a bad job, but it was very messy.

Changing any ram seals is a messy job. Its pretty easy to do, it just takes time and a bit of force to get them apart some times. You had the rite idea with how you held the rod! many many people don't think of doing it that way, myself included. I have torn a vice off a bench removing a nut before i thought about it and pushed a bar through the eye of the rod for leverage (i do them all this way now). Using loctite is exactly what you should have done, you don't want it to wiggle loose.
Glad you got it all fixed up and its now leak free.