763 tilt cylinder leak

[kmills]

I have a Bobcat 763 and the tilt cylinder started leaking fluid while I was using it this weekend. I want to try to put new seals in myself. Tazza did a wonderful post in 2005 about repairing a tilt cylinder on a 743. Is the repair for a 763 about the same as the 743? I live in a small town and the closest place to get it worked on is over an hour away and I was going to attempt to do it on my own. I already got a seal kit from Bobcat on its way. Any help would be greatly appreciated. Thanks Kyle

 

[Tazza]

The seal setup is the same. The hardest part is removing the gland nut, sometimes they are really tight and you need heat to get them free.
All rams use the same basic seal setup. the main difference is how the gland nut is secured. Yours should simply un-screw.

 

[kmills]

The seal setup is the same. The hardest part is removing the gland nut, sometimes they are really tight and you need heat to get them free.
All rams use the same basic seal setup. the main difference is how the gland nut is secured. Yours should simply un-screw.

Thanks for the info. I'll be getting into it tomorrow so I'll let you know how it all goes.

 

[Tazza]

Thanks for the info. I'll be getting into it tomorrow so I'll let you know how it all goes.

Excellent.
One thing, when you install the new piston seal, you will have to stretch it to get it over the piston then into the groove. It helps if you get a piston ring compressor and some paper. Wrap the paper or thin card board around the piston then clamp the piston ring compressor around it. This will make the seal contract to close to its original size and will fit in the bore of the cylinder easier. I have cut a seal in half once when i didn't do this, it was too loose in the groove and got pinched and sheared off when i installed it.
A hose clamp would probably work too but the ring compressor is better as its smooth and the only spot you need to protect the seal from is where it overlaps.
Remember use heaps of oil when assembling and give it a good clean. Watch the direction of the seals, the lip on the pressure seal MUST face the pressure side , so toward the piston. The wiper seal faces outward.

 

[latrobe]

Excellent.
One thing, when you install the new piston seal, you will have to stretch it to get it over the piston then into the groove. It helps if you get a piston ring compressor and some paper. Wrap the paper or thin card board around the piston then clamp the piston ring compressor around it. This will make the seal contract to close to its original size and will fit in the bore of the cylinder easier. I have cut a seal in half once when i didn't do this, it was too loose in the groove and got pinched and sheared off when i installed it.
A hose clamp would probably work too but the ring compressor is better as its smooth and the only spot you need to protect the seal from is where it overlaps.
Remember use heaps of oil when assembling and give it a good clean. Watch the direction of the seals, the lip on the pressure seal MUST face the pressure side , so toward the piston. The wiper seal faces outward.

Just another thought on the seal replacement, I feel its easier to loosing the gland nut before you remove the cylinder, if you don't have a good place to hold the cylinder. Also run the rod all the way in or protect the rod with something so you don't nick the rod if the wrench slips off. Don't forget a bucket and lots of rags to catch all the oil, I always make a big mess out of it. All in all its not a bad job to do. Good luck.

 

[Tazza]

Just another thought on the seal replacement, I feel its easier to loosing the gland nut before you remove the cylinder, if you don't have a good place to hold the cylinder. Also run the rod all the way in or protect the rod with something so you don't nick the rod if the wrench slips off. Don't forget a bucket and lots of rags to catch all the oil, I always make a big mess out of it. All in all its not a bad job to do. Good luck.

Thats a good point with cracking the gland nut on the machine. If you have a length of bar you can remove the cylinder and put it through the top pivot point, get someone to stand on it while you crack the gland nut. I worked this out AFTER i pulled a 6" vice off the bench..... This was me hauling on it with a 6' length of water pipe mind you.

 

[kmills]

Thats a good point with cracking the gland nut on the machine. If you have a length of bar you can remove the cylinder and put it through the top pivot point, get someone to stand on it while you crack the gland nut. I worked this out AFTER i pulled a 6" vice off the bench..... This was me hauling on it with a 6' length of water pipe mind you.

Thanks for all the info. The rebuild went smooth as could be. It was much easier than I thought it would be. The gland nut came off much easier than I was anticipating. That was about the hardest part of the whole re-seal. The step by step that Tazza wrote for the 743 guided me right thru and we were done in no time. This morning I'm putting the cylinder back on and looking forward to getting back to work. Anyone that needs to re-seal a tilt cylinder should think about trying it yourself. It saved me a lot of time and money. Thanks again Kyle