SERIOUS PROBLEM: Bobcat 843

[aaron187]

Has anyone seen an electric fan conversion? It seems like there would be enough room to mount a fan on top of the radiator and draw air up and out.

the estimate was 273 for the shaft and 73 dollars for the seals. That did not include any labor on machining.there is a machinist here who has a metal lathes and he cuts down flywheels to the same length like that pretty often. He said that's the best way to do it.also he sends his hydraulic pumps to a guy and they can do that prepare for a lot cheaper. So I will see about a new and better estimate soon

 

[HanSolo]

the estimate was 273 for the shaft and 73 dollars for the seals. That did not include any labor on machining.there is a machinist here who has a metal lathes and he cuts down flywheels to the same length like that pretty often. He said that's the best way to do it.also he sends his hydraulic pumps to a guy and they can do that prepare for a lot cheaper. So I will see about a new and better estimate soon

That quote is not too bad. I figure about 5 hours labor for the rebuild. Even at $100 an hour, that would put you under $1000 parts & labor. Electric fan? That's not a bad idea at all. Have the flywheel blades cut down to the same size. Reinstall everything and work the machine hard on a hot day to see where temps end up. If things are running a bit hot, add the electric fan. That would probably mean loosing the screen but my 843 is missing that anyway!

 

[Tazza]

That quote is not too bad. I figure about 5 hours labor for the rebuild. Even at $100 an hour, that would put you under $1000 parts & labor. Electric fan? That's not a bad idea at all. Have the flywheel blades cut down to the same size. Reinstall everything and work the machine hard on a hot day to see where temps end up. If things are running a bit hot, add the electric fan. That would probably mean loosing the screen but my 843 is missing that anyway!

There was a member on here a few years that converted i think a 743 to have thermo fans as the blower housing was toasted. The problem was, it never got cool enough. He even made a shroud to pull all the air possible out, but i don't know if he ever actually got it right.
If you do go this route, use powerful high displacement fans. They work on cars, not sure why it didn't work so well on a skid steer....

 

[HanSolo]

the estimate was 273 for the shaft and 73 dollars for the seals. That did not include any labor on machining.there is a machinist here who has a metal lathes and he cuts down flywheels to the same length like that pretty often. He said that's the best way to do it.also he sends his hydraulic pumps to a guy and they can do that prepare for a lot cheaper. So I will see about a new and better estimate soon

Finally pulled the motor on my 843. Very much the same damage as your Aaron.

I'm going to find a machine shop that will trim all the blades down to match the shortest. Then check the balance. I found some of the weights they used to balance the flywheel. The shroud is in fairly good shape. Now I can see why no one greases the u-joint. How can you get to it with the shroud and those blades?

 

[Tazza]

Finally pulled the motor on my 843. Very much the same damage as your Aaron.

I'm going to find a machine shop that will trim all the blades down to match the shortest. Then check the balance. I found some of the weights they used to balance the flywheel. The shroud is in fairly good shape. Now I can see why no one greases the u-joint. How can you get to it with the shroud and those blades?

Not as much damage as i have soon on others.
How is the pump shaft?
I kno on the 743 there was a little room to get a grease gun in there, just not much.....

 

[HanSolo]

Not as much damage as i have soon on others.
How is the pump shaft?
I kno on the 743 there was a little room to get a grease gun in there, just not much.....

Excuse me Aaron if I've high jacked your thread... The input shaft on the pump is broke in half. I've tried several salvage yards but they all say this is a common problem on the 843 and as soon as they get one with a good pump, that part sells immediately. Looks like I'll send it off for rebuild. Minimum cost will be $900 plus shipping. I figured it would take a couple thousand to get this one back up running. I got the flywheel off tonight and I'm taking it to a machine shop tomorrow.

 

[aaron187]

Excuse me Aaron if I've high jacked your thread... The input shaft on the pump is broke in half. I've tried several salvage yards but they all say this is a common problem on the 843 and as soon as they get one with a good pump, that part sells immediately. Looks like I'll send it off for rebuild. Minimum cost will be $900 plus shipping. I figured it would take a couple thousand to get this one back up running. I got the flywheel off tonight and I'm taking it to a machine shop tomorrow.

Well it looks like we are in the same boat. I took my stuff to another shop Tuesday to get an estimate and most likely I'll get them to fix it. They are the best and cheapest alternative to the Dealer. I'll have the estimate when they find the parts and assess the damage. I'll keep you all posted. As for the flywheel yea they told me that the welds will break and balancing it will be impossible. looks like they will cut it on a lathe to the shortest one. Not a huge deal.

 

[HanSolo]

Well it looks like we are in the same boat. I took my stuff to another shop Tuesday to get an estimate and most likely I'll get them to fix it. They are the best and cheapest alternative to the Dealer. I'll have the estimate when they find the parts and assess the damage. I'll keep you all posted. As for the flywheel yea they told me that the welds will break and balancing it will be impossible. looks like they will cut it on a lathe to the shortest one. Not a huge deal.

Same boat exactly! I got the fan shroud out this evening. Mountains of greasy dirt! Having that out gives you excellent access to the pump however. Did you pull the compete pump assembly or just the rear two hydrostatic pumps?

 

[aaron187]

Same boat exactly! I got the fan shroud out this evening. Mountains of greasy dirt! Having that out gives you excellent access to the pump however. Did you pull the compete pump assembly or just the rear two hydrostatic pumps?

I just pulled the one rear hydrostatic drive pump. Just has a top and bottom bolt. Maybe a 15/16" size. Tje bottom bolt was a freaking pain to get off. Why would you pull two? I just grabbed the part that broke.

 

[HanSolo]

I just pulled the one rear hydrostatic drive pump. Just has a top and bottom bolt. Maybe a 15/16" size. Tje bottom bolt was a freaking pain to get off. Why would you pull two? I just grabbed the part that broke.

I was just curious about that bottom bolt. I haven't even been able to see that yet. So the latest on mine is I got the shroud out and found several issues. The shrould has a signifigant gash.

So after removing A LOT of greasy dirt, I made a scab out of sheet metal and pop riveted that to help hold the plastic together. There's a weep hole at the bottom of the shroud that allows water to escape. This one was completely blocked by crud in the belly pan and water, grease and dirt mixture would collect in the shroud. Everytime the machine was started up that mixture would be thrown all over the shroud, flywheel, u-joint and up into the hydraulic cooling coil. I believe that abrasive mixture probably contributed to the u-joint failure. I'm going to add a few more weep holes in the bottom of the shroud.

Another problem I found as I was degreasing was a hydraulic hard line almost sheared by flying parts. I'll have to pull that and replace or maybe look into splicing a hose on to the end by the control valves. I think there's plenty of clearance from moving parts there.

I got the replacement u-joint from Bobcat and I'll need to find a triple square socket to fit the 5/16" screws that attach the u-joint to the adaptor plate and coupler. Several of the original screws were sheared off but I was able to extract the remains and I'll salvage eight off the original u-joint to make those attachments.

It's been a productive weekend and I'm pleased with progress. Perfect rainy weather now for degreasing. I also pulled the fuel tank to get at the attaching bolts for the large suspending braket on the pump. I'm assuming that once I pull that bracket the pump will be floating and I'll be able to lift it and access the bottom bolt that attached the rear pumps to the hydraulic pumps. Correct?

 

[SkidRoe]

I was just curious about that bottom bolt. I haven't even been able to see that yet. So the latest on mine is I got the shroud out and found several issues. The shrould has a signifigant gash.

So after removing A LOT of greasy dirt, I made a scab out of sheet metal and pop riveted that to help hold the plastic together. There's a weep hole at the bottom of the shroud that allows water to escape. This one was completely blocked by crud in the belly pan and water, grease and dirt mixture would collect in the shroud. Everytime the machine was started up that mixture would be thrown all over the shroud, flywheel, u-joint and up into the hydraulic cooling coil. I believe that abrasive mixture probably contributed to the u-joint failure. I'm going to add a few more weep holes in the bottom of the shroud.

Another problem I found as I was degreasing was a hydraulic hard line almost sheared by flying parts. I'll have to pull that and replace or maybe look into splicing a hose on to the end by the control valves. I think there's plenty of clearance from moving parts there.

I got the replacement u-joint from Bobcat and I'll need to find a triple square socket to fit the 5/16" screws that attach the u-joint to the adaptor plate and coupler. Several of the original screws were sheared off but I was able to extract the remains and I'll salvage eight off the original u-joint to make those attachments.

It's been a productive weekend and I'm pleased with progress. Perfect rainy weather now for degreasing. I also pulled the fuel tank to get at the attaching bolts for the large suspending braket on the pump. I'm assuming that once I pull that bracket the pump will be floating and I'll be able to lift it and access the bottom bolt that attached the rear pumps to the hydraulic pumps. Correct?

just curious, but won't a regular 12 point socket fit those bolts? I have run across them before and that was what I used. HTH. Great job so far, thanks for the pictures!!

 

[HanSolo]

just curious, but won't a regular 12 point socket fit those bolts? I have run across them before and that was what I used. HTH. Great job so far, thanks for the pictures!!

That's what my racing buddy suggested. I'll give them a try.

 

[Tazza]

That's what my racing buddy suggested. I'll give them a try.

I too use a standard double hex socket for these. They seem to fit just fine.

 

[aaron187]

I too use a standard double hex socket for these. They seem to fit just fine.

Yea a 12 point 10mm is what it is I think. that maimed metal line will need a replacing in my opinion. My pump is still at the shop. Haven't heard back from them yet on an estimate.

 

[HanSolo]

Yea a 12 point 10mm is what it is I think. that maimed metal line will need a replacing in my opinion. My pump is still at the shop. Haven't heard back from them yet on an estimate.

I was able to get the coupler off the damaged u-joint with a 5/16" 12-point 1/4" drive socket. I used those four screws to put the adapter plate on the new u-joint. I was going to try and use some of the what I thought were the same size screws in the damaged u-joint but after pulling one - they are longer and I think metric. So I picked up four caps screws to joint the coupler onto the new u-joint. I'll contact the local Bobcat on replacement hydraulic tube price and waiting to hear back from the machinist on the flywheel.

 

[Tazza]

I was able to get the coupler off the damaged u-joint with a 5/16" 12-point 1/4" drive socket. I used those four screws to put the adapter plate on the new u-joint. I was going to try and use some of the what I thought were the same size screws in the damaged u-joint but after pulling one - they are longer and I think metric. So I picked up four caps screws to joint the coupler onto the new u-joint. I'll contact the local Bobcat on replacement hydraulic tube price and waiting to hear back from the machinist on the flywheel.

I agree that the tube line needs attention. If it wasn't s deep, i'd just braze it up, but it looks like it has crushed the tube line pretty badly and will cause quite a restriction.

 

[aaron187]

I agree that the tube line needs attention. If it wasn't s deep, i'd just braze it up, but it looks like it has crushed the tube line pretty badly and will cause quite a restriction.

I'd be more concerned about that blowing rather than a restriction because the metal is thin

 

[HanSolo]

I'd be more concerned about that blowing rather than a restriction because the metal is thin

I agree on the tube. Local Bobcat quoted $73.59 for the factory part. That seems reasonable compared to $65.40 for a rear lift arm pin (remember that from the purchase photos). I think I'll get another quote on the tube from Volunteer Hose. The pin is available from used parts dealers. I'm a little concerned about the clearance on the caps screws I used on the u-joint to coupler. I beveled the tops a little to create a bit more space when the u-joint bends. Do you think the alinement of the crank to input shaft of the pump is within a degree or two?

 

[Tazza]

I agree on the tube. Local Bobcat quoted $73.59 for the factory part. That seems reasonable compared to $65.40 for a rear lift arm pin (remember that from the purchase photos). I think I'll get another quote on the tube from Volunteer Hose. The pin is available from used parts dealers. I'm a little concerned about the clearance on the caps screws I used on the u-joint to coupler. I beveled the tops a little to create a bit more space when the u-joint bends. Do you think the alinement of the crank to input shaft of the pump is within a degree or two?

Ouch, that is expensive for a pin. I just get a length of 1 1/4" 4140 steel and cut it to length and drill a hole for the bolt.
Depending on the tools you have available at home, you can always cut the dented section and weld it up. Just re-bend some of the angles to get it to sit right. Even if you can get an off cut from a hydraulic shop and braze it on.

 

[SkidRoe]

I agree on the tube. Local Bobcat quoted $73.59 for the factory part. That seems reasonable compared to $65.40 for a rear lift arm pin (remember that from the purchase photos). I think I'll get another quote on the tube from Volunteer Hose. The pin is available from used parts dealers. I'm a little concerned about the clearance on the caps screws I used on the u-joint to coupler. I beveled the tops a little to create a bit more space when the u-joint bends. Do you think the alinement of the crank to input shaft of the pump is within a degree or two?

How hard is that tube to get at? If you have to pull things to get at it, suddenly spending $73 on an original part doesn't sound too bad, especially if it is nice and accessible right now. Just sayin'....