Bobcat 843 servo

[donald73d]

The servo for the left drive is leaking at a good clip. (Its more of a valve, but Bobcat calls it a servo). Are they rebuildable? Kits available? Or replace? If I get a used one is it likely to have a leak shortly also. I believe we replaced the bushing either in the servo or the part that attaches to it as it was very worn. It cannot stay like it is.

 

[Tazza]

They are basically a hydraulic cylinder, if you get it apart, take it to a hdraulic seal shop and get them to match the parts for you. The dealer may even be able to supply them.
I don't think you will need another one, they are pretty easy to re-seal. I have replaced a rod on one before without any issues.

 

[donald73d]

They are basically a hydraulic cylinder, if you get it apart, take it to a hdraulic seal shop and get them to match the parts for you. The dealer may even be able to supply them.
I don't think you will need another one, they are pretty easy to re-seal. I have replaced a rod on one before without any issues.

The hydraulic fluid is leaking around the bushing so my mechanic thinks there is a crack in the casting around where the bushing is pressed in.

 

[donald73d]

The hydraulic fluid is leaking around the bushing so my mechanic thinks there is a crack in the casting around where the bushing is pressed in.

Is it possible there is suppose to be a small hole in the casting to let some hydraulic fluid lubricate the bushing? (long shot)

 

[Tazza]

Is it possible there is suppose to be a small hole in the casting to let some hydraulic fluid lubricate the bushing? (long shot)

Can you get a picture of it?
I don't think there is a hole to lubricate the bushing unless there is a seal to hold the oil back.

 

[donald73d]

Can you get a picture of it?
I don't think there is a hole to lubricate the bushing unless there is a seal to hold the oil back.

I brought the servo to a hydraulic repair place and they seem to think there is a crack where the bushing is pressed in. I am hoping they can weld it?

 

[Tazza]

I brought the servo to a hydraulic repair place and they seem to think there is a crack where the bushing is pressed in. I am hoping they can weld it?

With the right gear, they could weld and re-bore the bushing.

 

[donald73d]

With the right gear, they could weld and re-bore the bushing.

They pressed the bushing out and it was covering a metal plug and o-ring that was not in properly. Its odd in that I do not see that in the parts diagram for the servo. I have not looked at the servo yet with the bushing out. Need to get them another bushing to press in. What would this metal plug and o-ring be for? Unless it had to do with machining the servo. Perplexed.

 

[Tazza]

They pressed the bushing out and it was covering a metal plug and o-ring that was not in properly. Its odd in that I do not see that in the parts diagram for the servo. I have not looked at the servo yet with the bushing out. Need to get them another bushing to press in. What would this metal plug and o-ring be for? Unless it had to do with machining the servo. Perplexed.

Not sure... Unless the previous owner thought a modification was in order, on ethat made sense to only him?
If it was not in the parts break down, i guess it shouldn't be in there.
They can't turn a bushing to press in?

 

[donald73d]

Not sure... Unless the previous owner thought a modification was in order, on ethat made sense to only him?
If it was not in the parts break down, i guess it shouldn't be in there.
They can't turn a bushing to press in?

They appear to have smushed the existing bushing pressing it out. I should have a new bushing from Bobcat today for them to push in

 

[7LBSSMALLIE]

They appear to have smushed the existing bushing pressing it out. I should have a new bushing from Bobcat today for them to push in

its quite possible that previous owner came up with better idea? cause straight off the line . this was a faiulerure. always herky jerky. never beena fix. don't what to say . I cringe when they show up. can get back to factory spec . but it sucked to start. SO youre question is how do I fix this. you don't. bad desighn . can be brought back to factory specs. but wasn't much to begin with. GOT NO ANSWERS. live with or dump it. you aint gonna fix it. that being said the fix was. replace spools (they have furthining feather glands) reseal cyls. but it don't work. been there done it. gets it better but not to its happy place. .if you want I can get detailed proucdure. but ive tried it don't work. and about 2 grand worth o parts.

 

[donald73d]

its quite possible that previous owner came up with better idea? cause straight off the line . this was a faiulerure. always herky jerky. never beena fix. don't what to say . I cringe when they show up. can get back to factory spec . but it sucked to start. SO youre question is how do I fix this. you don't. bad desighn . can be brought back to factory specs. but wasn't much to begin with. GOT NO ANSWERS. live with or dump it. you aint gonna fix it. that being said the fix was. replace spools (they have furthining feather glands) reseal cyls. but it don't work. been there done it. gets it better but not to its happy place. .if you want I can get detailed proucdure. but ive tried it don't work. and about 2 grand worth o parts.

I would lean toward this being the way the servo value was made and it may have had something to do with the way the servo valve was machined. Even though its not in the parts diagram. The servo valve it ready to be installed now, lets hope it no longer leaks.

 

[donald73d]

I would lean toward this being the way the servo value was made and it may have had something to do with the way the servo valve was machined. Even though its not in the parts diagram. The servo valve it ready to be installed now, lets hope it no longer leaks.

Well its installed, working properly and no leak from where it had been leaking before. With over 4500 hours I guess I can expect lots of areas of worn linkages.

 

[Tazza]

Well its installed, working properly and no leak from where it had been leaking before. With over 4500 hours I guess I can expect lots of areas of worn linkages.

Glad it's back in and leak free, hopefully it will stay that way.