SERIOUS PROBLEM: Bobcat 843

[aaron187]

I just purchased an 843 yesterday (knowing it was broken) and have found out the problem. The U-Joint connecting the engine to the hydraulic pump is destroyed as well as the input shaft is snapped going into the hydraulic pump. The engine is almost ready to pull out and be inspected better. How to I take apart the pump or how much of it do I need to take apart, to replace the shaft? Where do I get the u-joints and if anything else is destroyed beyond recognition, how can I know what to get? any help is greatly appreciated. And sorry if these questions are in another thread, I'm new here.

 

[HanSolo]

I think the 843 has the Vicars pump. Check some of the sponsor links on this site and also a eBay search will help determine replacement cost. Not sure how available individual parts for that pump will be. Did you purchase that machine in Nolensville TN? I was looking at a Craigslist ad that would match that description.

 

[jav]

the individual pumps are available (LPS has them).. but how do you know the pump shaft is snapped if the engine isn't out yet? If the coupler splines are toast- I think you'll need to contact bobcat direct for that one. I don't think the U-joint is special. you should be able to source that. Once it's fully apart, you should be able to tell what you need. I think 843 pumps were Cessna. Depending on the serial #, there was a used early pump here: http://discountbarnshop.ecrater.com/p/14706065/bobcat-843-hydrostatic-and-hydraulic-pumps don't know if it's still available. I have the same machine and blew the gear pump (i think) this weekend so I've been looking too. Mine is the newer one though so i can't use this one.

 

[Tazza]

the individual pumps are available (LPS has them).. but how do you know the pump shaft is snapped if the engine isn't out yet? If the coupler splines are toast- I think you'll need to contact bobcat direct for that one. I don't think the U-joint is special. you should be able to source that. Once it's fully apart, you should be able to tell what you need. I think 843 pumps were Cessna. Depending on the serial #, there was a used early pump here: http://discountbarnshop.ecrater.com/p/14706065/bobcat-843-hydrostatic-and-hydraulic-pumps don't know if it's still available. I have the same machine and blew the gear pump (i think) this weekend so I've been looking too. Mine is the newer one though so i can't use this one.

Talk to loaderpartssource.com for that. They are an older pump and harder to get parts for, but last time i spoke to them about 843 pump parts, they still had some.
The real money is the valve plate, if it is scored up, they need to get it ground, hard faced and re-ground to bring it back to spec.
You will need to pull the pump and pull it down to inspect the damage and clean out any metal particles that are in there.
It does sound a lot like the machine HanSolo was looking at......

 

[HanSolo]

Talk to loaderpartssource.com for that. They are an older pump and harder to get parts for, but last time i spoke to them about 843 pump parts, they still had some.
The real money is the valve plate, if it is scored up, they need to get it ground, hard faced and re-ground to bring it back to spec.
You will need to pull the pump and pull it down to inspect the damage and clean out any metal particles that are in there.
It does sound a lot like the machine HanSolo was looking at......

Sure does, doesn't it Tazza? Anyway, he's a new forum member and Bobcat owner so we're here to help!

 

[Tazza]

Sure does, doesn't it Tazza? Anyway, he's a new forum member and Bobcat owner so we're here to help!

Indeed, if it is, you may have dodged a bullet
Yet, anything can be repaired, it just depends on how much it costs and how long it takes.
New U-Joints won't be too expensive, the problem is the input shaft to the pump. I don't know if this pump is still made. Absolute worst case, i believe a machine shop could re-weld it and grind it back down to the right size.
Hopefully there is no other damage inside the pump. Here is a link to a remanufactured rear pump: http://www.loaderpartssource.com/bo...obcat-843-rear-hydraulic-drive-pump-4477.html

 

[aaron187]

Indeed, if it is, you may have dodged a bullet
Yet, anything can be repaired, it just depends on how much it costs and how long it takes.
New U-Joints won't be too expensive, the problem is the input shaft to the pump. I don't know if this pump is still made. Absolute worst case, i believe a machine shop could re-weld it and grind it back down to the right size.
Hopefully there is no other damage inside the pump. Here is a link to a remanufactured rear pump: http://www.loaderpartssource.com/bobcat-parts/bobcat-hydraulic-pumps/reman-bobcat-843-rear-hydraulic-drive-pump-4477.html

Thanks for the response. I know the shaft is broken because I have the cog with the tip of the input shaft in my hands. Also I can feel it with my finger by fishing my arm behind the pump. The u joint assembly is out (mostly destroyed) so therefore I can feel around a bit. I checked with a general engineering company who may be able to replace or build that back part of the pump that is damaged so ill be alright there. And no it wasnt the CL add I bought it from a contractor. Its going in my shop for complete dissasembly so ill keep you all posted and maybe throw some pics up here.

 

[aaron187]

Thanks for the response. I know the shaft is broken because I have the cog with the tip of the input shaft in my hands. Also I can feel it with my finger by fishing my arm behind the pump. The u joint assembly is out (mostly destroyed) so therefore I can feel around a bit. I checked with a general engineering company who may be able to replace or build that back part of the pump that is damaged so ill be alright there. And no it wasnt the CL add I bought it from a contractor. Its going in my shop for complete dissasembly so ill keep you all posted and maybe throw some pics up here.

Also how the heck do you get this thing to free roll. Is the parking brake on? Or do these cats not roll unless the pump is turning

 

[reaperman]

Also how the heck do you get this thing to free roll. Is the parking brake on? Or do these cats not roll unless the pump is turning

You wont be able to get the machine to free roll. So your going to have to either push really hard, drag it, or get some kind of casters under the wheels then pull it.

 

[HanSolo]

Also how the heck do you get this thing to free roll. Is the parking brake on? Or do these cats not roll unless the pump is turning

There should be a hydraulic pressure relief that's somewhat accessible. Do a quick search on the site for that and some threads should pop up. You're going to need a service manual so I would search for threads on that subject as well. Some of our top posters have links to downloadable docs.

 

[aaron187]

There should be a hydraulic pressure relief that's somewhat accessible. Do a quick search on the site for that and some threads should pop up. You're going to need a service manual so I would search for threads on that subject as well. Some of our top posters have links to downloadable docs.

I called the bobcat dealer this morning he said they will not and do not free roll when off. Took us 2 hrs and a big ass truck to push it in my shop. Ill be ripping the engine and rear drive pump out this evening. I may post some pics later. Pics in threads make it so much more interesting

 

[Tazza]

I called the bobcat dealer this morning he said they will not and do not free roll when off. Took us 2 hrs and a big ass truck to push it in my shop. Ill be ripping the engine and rear drive pump out this evening. I may post some pics later. Pics in threads make it so much more interesting

Yeah, when the drive motors are full of oil, it will really fight against rolling.
If you need it to roll, make sure the brake is off and you can remove the two big hoses to each drive motor. Roll it slowly and make sure no grud gets in the drive motor when the lines are open.
Pics would be great.

 

[aaron187]

Yeah, when the drive motors are full of oil, it will really fight against rolling.
If you need it to roll, make sure the brake is off and you can remove the two big hoses to each drive motor. Roll it slowly and make sure no grud gets in the drive motor when the lines are open.
Pics would be great.

Here is a pic of the U-Joint assembly ( whats left of it ) https://photos-2.dropbox.com/t/0/AABOa-lAqWYgLPiQMai2xo8toM8-re2FkaSVJoB8_DCpsA/10/49078623/jpeg/32x32/6/_/1/2/20130213_203251.jpg/607yBjkBHSX5r_jz55CT_m92jzbXnliKyzlWXSsMk38?size=1024x768&size_mode=2 You can see the input shaft broken here. no other visible damage so far. https://photos-3.dropbox.com/t/0/AAAcpSgAMaJZd0vBQTlwU2a41TgCowF1dgJ3_6IOB6RRFw/10/49078623/jpeg/32x32/6/_/1/2/20130213_203219.jpg/iIELHhWwhL9pjetiNQ5k5ElosB6GpsM4t9R4MN4538E?size=1024x768&size_mode=2 Sorry I can only get it to post links and not the pic. There a trick to this?

 

[Tazza]

Here is a pic of the U-Joint assembly ( whats left of it ) https://photos-2.dropbox.com/t/0/AABOa-lAqWYgLPiQMai2xo8toM8-re2FkaSVJoB8_DCpsA/10/49078623/jpeg/32x32/6/_/1/2/20130213_203251.jpg/607yBjkBHSX5r_jz55CT_m92jzbXnliKyzlWXSsMk38?size=1024x768&size_mode=2 You can see the input shaft broken here. no other visible damage so far. https://photos-3.dropbox.com/t/0/AAAcpSgAMaJZd0vBQTlwU2a41TgCowF1dgJ3_6IOB6RRFw/10/49078623/jpeg/32x32/6/_/1/2/20130213_203219.jpg/iIELHhWwhL9pjetiNQ5k5ElosB6GpsM4t9R4MN4538E?size=1024x768&size_mode=2 Sorry I can only get it to post links and not the pic. There a trick to this?

The way i do it is to open the image in a new window, right click/copy come back to the message right click/paste.
I can't seem to get those links to work either

 

[aaron187]

The way i do it is to open the image in a new window, right click/copy come back to the message right click/paste.
I can't seem to get those links to work either

Ok I fixed my dropbox to share now. try this link https://www.dropbox.com/sh/j8ee9xzyt751y6e/5gLkTlqrpt

 

[reaperman]

Ok I fixed my dropbox to share now. try this link https://www.dropbox.com/sh/j8ee9xzyt751y6e/5gLkTlqrpt

Thats quite a project you have going there.

 

[Cyclone Ranger]

U-joints are available here:
www.drivetrainamerica.com
Neapco 1-2186, $48.09
Neapco 1-2185, $40.84

 

[Tazza]

U-joints are available here:
www.drivetrainamerica.com
Neapco 1-2186, $48.09
Neapco 1-2185, $40.84

That doesn't look too nasty. If you can get the shaft welded and possibly replace the rear bearing, the pump may be just fine.
The flywheel may need to be balanced though, i got a price locally for a machine i'm working on for a friend, it wasn't much at all.

 

[Ken743B]

That doesn't look too nasty. If you can get the shaft welded and possibly replace the rear bearing, the pump may be just fine.
The flywheel may need to be balanced though, i got a price locally for a machine i'm working on for a friend, it wasn't much at all.

I've seen much much worse.