853, hydrostatic pump leaks on top, easy to fix??

[Muddin_Mavric]

i got a 853 and have not owned it that long and im trying to get everything ready to go and it looks like its leaking from the top of the right hand hydrostatic pump where the shaft goes into it to control the stearing. from looking at my service manual it looks like all you have to do is undo a couple bolts and pull the shaft out of the top and put in a new o-ring. but they all ready have the pump half way apart in the book when they show this step. is this somthing that can be done while the pump is still in the machine and is all that needs to be replaced is just the one o-ring?? if the answer to question number one is yes will i loose much hyd. fluid while doing this?? Justin

 

[thetool]

It's not difficult, but you probably won't agree until after you've done it once......=).
What they don't show in the manual is all the steering linkage and centering gear you've got to get out of the way first.
And yes, since your tank is above the pump behind the seat, you will loose some oil. I suggest clean-catching and re-using your oil first, since you've never done it, if your oil is good. If not, dump it and put in new, along with a filter....that can never hurt, and there's not a LOT of oil.
You need to mark and remove the linkage bars first, then remove the spring from the centering plate above your pump. Then you remove the lever from the leaking shaft. It has a squeeze-bolt. Remove the bolt then gently pry the lever off. Then you're ready to do it by the book.
You've got bolts holding a slide bracket and cover that carries a shaft seal, and there's a quad-ring under that. The shaft does not come out. Get a new seal and quad-ring. Punch out the old seal and seat the new one with an appropriatley-sized socket.
What I can't remember is if you have a tube coming down through the centering plate. If you do, instead of sliding the centering plate off and removing it, just slide it off and rotate it out of the way. Careful not to loose your slide bushings, they're just hanging in the plate and like to disappear when you slide the plate off the guide pins. You might have white platstic screwed-on guide bushings, which suck but stay put. They're easy to break, tho.
If your centering was okay when you started, you don't need to mess with the blocks bolted to the centering plate. Adjusting those blocks sets your neutral. If you leave them be, it will be alright when you put it back together.
Good Luck.

 

[Fishfiles]

It's not difficult, but you probably won't agree until after you've done it once......=).
What they don't show in the manual is all the steering linkage and centering gear you've got to get out of the way first.
And yes, since your tank is above the pump behind the seat, you will loose some oil. I suggest clean-catching and re-using your oil first, since you've never done it, if your oil is good. If not, dump it and put in new, along with a filter....that can never hurt, and there's not a LOT of oil.
You need to mark and remove the linkage bars first, then remove the spring from the centering plate above your pump. Then you remove the lever from the leaking shaft. It has a squeeze-bolt. Remove the bolt then gently pry the lever off. Then you're ready to do it by the book.
You've got bolts holding a slide bracket and cover that carries a shaft seal, and there's a quad-ring under that. The shaft does not come out. Get a new seal and quad-ring. Punch out the old seal and seat the new one with an appropriatley-sized socket.
What I can't remember is if you have a tube coming down through the centering plate. If you do, instead of sliding the centering plate off and removing it, just slide it off and rotate it out of the way. Careful not to loose your slide bushings, they're just hanging in the plate and like to disappear when you slide the plate off the guide pins. You might have white platstic screwed-on guide bushings, which suck but stay put. They're easy to break, tho.
If your centering was okay when you started, you don't need to mess with the blocks bolted to the centering plate. Adjusting those blocks sets your neutral. If you leave them be, it will be alright when you put it back together.
Good Luck.

I think what Muddin'Mavric is saying bout the shaft is on some sunstrands there a collar which slides over the shaft and holds a ring and back up under the plate which holds the seal , it can be hard prying it out sometimes , you would never know the rings were there if you didn't know , I think it's a good idea to change them while right there and always do

 

[Muddin_Mavric]

It's not difficult, but you probably won't agree until after you've done it once......=).
What they don't show in the manual is all the steering linkage and centering gear you've got to get out of the way first.
And yes, since your tank is above the pump behind the seat, you will loose some oil. I suggest clean-catching and re-using your oil first, since you've never done it, if your oil is good. If not, dump it and put in new, along with a filter....that can never hurt, and there's not a LOT of oil.
You need to mark and remove the linkage bars first, then remove the spring from the centering plate above your pump. Then you remove the lever from the leaking shaft. It has a squeeze-bolt. Remove the bolt then gently pry the lever off. Then you're ready to do it by the book.
You've got bolts holding a slide bracket and cover that carries a shaft seal, and there's a quad-ring under that. The shaft does not come out. Get a new seal and quad-ring. Punch out the old seal and seat the new one with an appropriatley-sized socket.
What I can't remember is if you have a tube coming down through the centering plate. If you do, instead of sliding the centering plate off and removing it, just slide it off and rotate it out of the way. Careful not to loose your slide bushings, they're just hanging in the plate and like to disappear when you slide the plate off the guide pins. You might have white platstic screwed-on guide bushings, which suck but stay put. They're easy to break, tho.
If your centering was okay when you started, you don't need to mess with the blocks bolted to the centering plate. Adjusting those blocks sets your neutral. If you leave them be, it will be alright when you put it back together.
Good Luck.

thanks for the advice. what you are discribing sound a little differnt than what mine looks like. just to make sure i will try and get some pics up tomarow so we both will know we are on the same page. thanks again.

 

[thetool]

thanks for the advice. what you are discribing sound a little differnt than what mine looks like. just to make sure i will try and get some pics up tomarow so we both will know we are on the same page. thanks again.

Yes, Fishfiles is right, I'm thinking wrong pump. But the linkage and centering plate stuff is the same. That's got to go away first.
And, since you're already in there, why not do both sections?.....=).

 

[thetool]

thanks for the advice. what you are discribing sound a little differnt than what mine looks like. just to make sure i will try and get some pics up tomarow so we both will know we are on the same page. thanks again.

Now I'm having brain cramps......does your machine by chance have control cables instead of steel bars going to the levers?

 

[Muddin_Mavric]

Now I'm having brain cramps......does your machine by chance have control cables instead of steel bars going to the levers?

yes, mine has cables running to the pumps. all i have to do is take out 2 bolts and the cables will be unhooked from the top of the saft that has the leak. 2 more bolts and the part with the spring will be loose and then the shaft with the centering deal/spring should just pull out right??

 

[Muddin_Mavric]

yes, mine has cables running to the pumps. all i have to do is take out 2 bolts and the cables will be unhooked from the top of the saft that has the leak. 2 more bolts and the part with the spring will be loose and then the shaft with the centering deal/spring should just pull out right??

here is the pic just to make sure we are all on the same page.
http://c3.ac-images.myspacecdn.com/images02/33/l_925a92b2bfcb4cf0a1c7111b8c1acf2a.jpg

 

[mllud]

here is the pic just to make sure we are all on the same page.
http://c3.ac-images.myspacecdn.com/images02/33/l_925a92b2bfcb4cf0a1c7111b8c1acf2a.jpg

myspacecdn.com/images02/33/l_925a92b2bfcb4cf0a1c7111b8c1acf2a.jpg
M

 

[mllud]

myspacecdn.com/images02/33/l_925a92b2bfcb4cf0a1c7111b8c1acf2a.jpg
M

Muddin Mavrick.
I tried to fix your link and accidentally hit post after I seen it wasnt going to work. I step down so the link has its own line. Works better for me.
When you post a link or a picture you need a space before and after the link. If the link is going to work it will highlight before you post.
Mike

 

[Muddin_Mavric]

Muddin Mavrick.
I tried to fix your link and accidentally hit post after I seen it wasnt going to work. I step down so the link has its own line. Works better for me.
When you post a link or a picture you need a space before and after the link. If the link is going to work it will highlight before you post.
Mike

how do you step down like that??? when i hit the "Enter" key it will step down a line and make another paragraph but when i hit post it smashes it all back tegether.

 

[Muddin_Mavric]

how do you step down like that??? when i hit the "Enter" key it will step down a line and make another paragraph but when i hit post it smashes it all back tegether.

a picture in my post!

holy cr#p look at that!

 

[thetool]

Muddin Mavrick.
I tried to fix your link and accidentally hit post after I seen it wasnt going to work. I step down so the link has its own line. Works better for me.
When you post a link or a picture you need a space before and after the link. If the link is going to work it will highlight before you post.
Mike

Woops------=)
All what I said before---------"never mind".........
This is a common leak, and you do have to pull the shafts, or rather sleeves and shafts. The sleeves have an o-ring and a back-up ring. Dirt gets in and wears the seals and bores, then you have a leak.
Ask your local Bobcat service guys for a Service Bulletin dealing with "pump servo sleeve replacement" or something like that. They can search it with those words and print it off for you, and you'll see what parts you MAY need to fix this, since it's older.
Yeah-it spews oil when you pull the shafts and sleeves, so I'd drain it.
This is a tricky repair for the guy who's never done it. I've done it a lot. If you're going to do it, I'll be happy to talk you through it.

 

[thetool]

Woops------=)
All what I said before---------"never mind".........
This is a common leak, and you do have to pull the shafts, or rather sleeves and shafts. The sleeves have an o-ring and a back-up ring. Dirt gets in and wears the seals and bores, then you have a leak.
Ask your local Bobcat service guys for a Service Bulletin dealing with "pump servo sleeve replacement" or something like that. They can search it with those words and print it off for you, and you'll see what parts you MAY need to fix this, since it's older.
Yeah-it spews oil when you pull the shafts and sleeves, so I'd drain it.
This is a tricky repair for the guy who's never done it. I've done it a lot. If you're going to do it, I'll be happy to talk you through it.

Guess I otta answer your question......=).
First, looking at your picture, you should have a little bolt on the sector of that bracket, and it looks to me lik the head on yours is snapped off. That's a problem.
Yes, if you undo the bolts on the lever bracket, and the cable bracket, you can just swing your cable out of the way. Then you mark the position of that sector bracket that's missing the bolt head, remove that bolt, and you pull it and the shaft straight out. This is when it will spew oil and drain your tank.
That shaft rides in a sleeve that also pulls out, and it has o-rings and back-up rings on it, and that is most likely what's leaking. That is what the service letter adresses. You have to be very careful when doing this repair or you can damage your pump. Let us know if you're going to go into that.
Good Luck.

 

[Muddin_Mavric]

Woops------=)
All what I said before---------"never mind".........
This is a common leak, and you do have to pull the shafts, or rather sleeves and shafts. The sleeves have an o-ring and a back-up ring. Dirt gets in and wears the seals and bores, then you have a leak.
Ask your local Bobcat service guys for a Service Bulletin dealing with "pump servo sleeve replacement" or something like that. They can search it with those words and print it off for you, and you'll see what parts you MAY need to fix this, since it's older.
Yeah-it spews oil when you pull the shafts and sleeves, so I'd drain it.
This is a tricky repair for the guy who's never done it. I've done it a lot. If you're going to do it, I'll be happy to talk you through it.

i would kinda like to get it fixed. the one pictured is not the side that leaks.
it dont leak enough for me to notice a loss of fluid but it sure makes one heck of a mess. a drop runs down the back side of the pump once about every 5 sec. when the fluid is cold. i dont wana see what it does when it gets good and warm.
the worst part is every place i park it leaves an oil spot on the floor. i think most of it comes from that shaft. if it wont take real long for somone who knows what there doing i could just take it in to get fixed. i just like to know how to fix my own stuff and only take it in if its gona be a real pain. like the head gasket in my dodge neon. yeah, i could have changed it but i really really did not want to so i took it to a guy i know named Bob. he also works on skid steer somtimes too. mostly he works on cars though.

 

[Muddin_Mavric]

i would kinda like to get it fixed. the one pictured is not the side that leaks.
it dont leak enough for me to notice a loss of fluid but it sure makes one heck of a mess. a drop runs down the back side of the pump once about every 5 sec. when the fluid is cold. i dont wana see what it does when it gets good and warm.
the worst part is every place i park it leaves an oil spot on the floor. i think most of it comes from that shaft. if it wont take real long for somone who knows what there doing i could just take it in to get fixed. i just like to know how to fix my own stuff and only take it in if its gona be a real pain. like the head gasket in my dodge neon. yeah, i could have changed it but i really really did not want to so i took it to a guy i know named Bob. he also works on skid steer somtimes too. mostly he works on cars though.

BTW the bolts for that bottom bracket are both hidden. i know it looks like its snaped off but its really hidding behind that top arm. in the pic you just cant see it.

 

[thetool]

BTW the bolts for that bottom bracket are both hidden. i know it looks like its snaped off but its really hidding behind that top arm. in the pic you just cant see it.

Oh okay I see now. I'm glad. If you remove that bolt after removing the cable, the shaft(it's actually a rotating valve spool) will pull straight out with the bracket and spring. If you see the little v-notch on the bracket, mark that on the pump body at the notch, so you get it back in the same place. That's for your servo neutral adjustment.
Did you understand what I wrote about the spool that the shaft slides into?

 

[Muddin_Mavric]

Oh okay I see now. I'm glad. If you remove that bolt after removing the cable, the shaft(it's actually a rotating valve spool) will pull straight out with the bracket and spring. If you see the little v-notch on the bracket, mark that on the pump body at the notch, so you get it back in the same place. That's for your servo neutral adjustment.
Did you understand what I wrote about the spool that the shaft slides into?

im not real sure what part exactly is the spool. as long as i know i can do it with out pulling the whole pump apart like it shows in the book and do it with the pump in the machine that was my biggest question. i should just be able to fallow what the book says plus your advice about removing that shaft and the sleave it slides in.

how easy is it to mess up the pump/what all can go wrong??

 

[thetool]

im not real sure what part exactly is the spool. as long as i know i can do it with out pulling the whole pump apart like it shows in the book and do it with the pump in the machine that was my biggest question. i should just be able to fallow what the book says plus your advice about removing that shaft and the sleave it slides in.

how easy is it to mess up the pump/what all can go wrong??

Okay-you don't have to pull your pump out and down to fix it.
If you remove the cable by removing the nuts and bolts at the lever, and the bracket bolts on the servo cover, you swing the cable out of the way, and you're ready to proceed.
You really need to dump the oil or it will drain the tank.
Clean off the top and mark the v-notch on the bracket, remove the sector adustment bolt and pull the assembly straight out. This will be the spool, the adjustment bracket, a clothespin-type spring and the lever all held together with a nut on top of the spool. There's an 0-ring and a white teflon back-up ring on the spool. If the spring is broken, as they commonly are, you have to disassemble this assembly to replace it, so you have to note the orientation of the spool to the bracket, because it has weird metering notches cut into it and it's not symmetrical.
Now your sleeve is still in the bore of the pump, and it's tough to pull out. It sticks up out of the pump about 1/4". Around this sleeve is where it commonly leaks. Dirt gets in the bore around the sleeve and takes out the o-ring and back-up ring(same as the spool, but larger diameter) AND puts a groove in the bore of the pump housing, which makes it almost impossible to repair by replacing the o-ring.
So for big bucks, but far less than the cost of a new pump, Bobcat offers replacement sleeves that have an o-ring groove further down on the sleeve from the top, so your new o-ring has a new, ungrooved contact surface, along with some protection washers to keep the dirt out in the future.
To pull the sleeve, I get a pair of vise grips, adjusted tight enough that it won't slip on the sleeve, but not so tight that it marks it. Clamp the vise-grip onto the sleeve, vise-grip horizontal, and use a pry-bar under the jaws of the vise-grip, between the jaws and the top of the pump, hold down with my hand on the vise grip handle and gently pry the sleeve straight up and out.
New sleeve or old, it has a notch cut out of the bottom of the sleeve. This notch indexes on a pin down inside the pump, and if you don't line it up squarely, it won't go in. The notch faces the servo when it goes in, and has to be exactly perpendicular to the long axis of the pump to catch the pin.
The sleeve will go down and stop short. This is where guys get impatient and tap it with a hammer and shear that little pin down in there. DON'T DOO DAT!.....=).
If everything's lined up, it will go down with hand pressure only. Both thumbs pushing down and it will pop in.
If you pay attention to your spool orientation, don't use a hammer or any other tapping or pounding device, don't mess with the cable lengths, line the notch on the bracket and get it back together in the same place, you shouldn't have any problems.
The parts breakdown list has all the parts you need, but there is more detail in the service letter I mentioned, more detail that in the service manual. Often the dust washers are neglected, I think they're important. Those sleeves are about $300 each and I think bobcat quotes the pump at $6K, 'cause it's no longer in production.
I also like to double o-ring instead of the back-up washer on the sleeve. Sometimes this will get you by without the updated sleeve, but get the dust washers regardless.
It sounds more complicated than it really is, and I'm sure you can do it.