843 lost all hydraulic fluid but where did it go?

[HanSolo]

This machine has been running pretty well for 4 years. I'm doing site work for our new garage apartment so I've been putting in some hours with the bucket and backhoe attachment. I was back filling the water service trench when the left side drive seemed to stick a couple times. After about 10 minutes both sides of the drive didn't want to go forward so I backed up to my parking spot about 80' away. When I tried to pull forward a little, the pump is really making noise now. I shut it down and checked fluid - no hydraulic. But I hadn't seen any fluid loss while working and no puddle under the machine. So I added about 10 quarts of 30W and nothing is showing on the dip stick. Loosing that much fluid would have shown on the ground or in the chassis. Unless the fluid loss was in the chain case... is that possible on that series loader?

 

[Lowe.Buuck]

You probably blew a drive motor seal and pumped all your hydraulic oil into the chain case.
Loosen the drain plug and check your fluid level.

 

[Tazza]

You probably blew a drive motor seal and pumped all your hydraulic oil into the chain case.
Loosen the drain plug and check your fluid level.

I'm with Lowe.Buuck
If the case drain filters got plugged, the extra pressure can push past the drive motor carrier seals. Worn bearings in the carrier can do the same.
Check your chain case fluid level, that will be where it's gone if you have no external leaks.

 

[HanSolo]

I'm with Lowe.Buuck
If the case drain filters got plugged, the extra pressure can push past the drive motor carrier seals. Worn bearings in the carrier can do the same.
Check your chain case fluid level, that will be where it's gone if you have no external leaks.

Thanks gents. I spoke to a heavy equipment mechanic with Bobcat experience and he said the same. This will be a major repair and I'll probably wait till the garage is done. Too big a job to do in the field. That will be a good time to go through the whole machine. I'd love to find another hydraulic leak that's been going on for years.

 

[HanSolo]

Thanks gents. I spoke to a heavy equipment mechanic with Bobcat experience and he said the same. This will be a major repair and I'll probably wait till the garage is done. Too big a job to do in the field. That will be a good time to go through the whole machine. I'd love to find another hydraulic leak that's been going on for years.

Okay, I finally got this 843 in the shop. Oddly, with all the hydraulic fluid out of the final drive motors the beast rolled nicely with shoves from a rental skid steer. I got the rear axles up on jacks and rear wheels off. I added 5 gallons of hydraulic to get the lift arms raised and put two pieces of angle iron on the rams to keep them there. As long as I don't engage the drive controls it keeps hydraulic fluid. With a slight tilt to the front I pulled the fill plug on the chain case and got about 10 gallons of milk shake and then pulled the drain plug for another 5 gallons. Not much debris so that's good. I checked the end play on those rear axles and it's very minimal. The left axle has a drip from the seal so I'd like to replace that. The right appears to not be dripping so that might be okay. I'm going to get some photos up tomorrow as there's a difference in those axles and the right tube has a weld repair that's significant. Sure is nice to have a great big shop to work on this thing!

 

[HanSolo]

Okay, I finally got this 843 in the shop. Oddly, with all the hydraulic fluid out of the final drive motors the beast rolled nicely with shoves from a rental skid steer. I got the rear axles up on jacks and rear wheels off. I added 5 gallons of hydraulic to get the lift arms raised and put two pieces of angle iron on the rams to keep them there. As long as I don't engage the drive controls it keeps hydraulic fluid. With a slight tilt to the front I pulled the fill plug on the chain case and got about 10 gallons of milk shake and then pulled the drain plug for another 5 gallons. Not much debris so that's good. I checked the end play on those rear axles and it's very minimal. The left axle has a drip from the seal so I'd like to replace that. The right appears to not be dripping so that might be okay. I'm going to get some photos up tomorrow as there's a difference in those axles and the right tube has a weld repair that's significant. Sure is nice to have a great big shop to work on this thing!

https://i1336.photobucket.com/albums/o644/trscca12re/20181124_075240_zpsgrh64az0.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075247_zpsv4qbnwmx.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075258_zpsfnyvqj7t.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075317_zpsnbtajtjz.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075303_zps4zoewyho.jpg https://i1336.photobucket.com/albums/o644/trscca12re/20181124_075226_zpswp6xkazj.jpg Note that the right rear wheel hub is different than the left. It has 3 retaining bolts while I assume the left has a single under the cover. Also note the presence of welds on that right tube. I suspect that axle sustained real damage at some point and the tube was repaired and the axle replaced. Perhaps by an earlier serial number part. I'll research that tonight.

 

[HanSolo]

https://i1336.photobucket.com/albums/o644/trscca12re/20181124_075240_zpsgrh64az0.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075247_zpsv4qbnwmx.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075258_zpsfnyvqj7t.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075317_zpsnbtajtjz.jpg http://i1336.photobucket.com/albums/o644/trscca12re/20181124_075303_zps4zoewyho.jpg https://i1336.photobucket.com/albums/o644/trscca12re/20181124_075226_zpswp6xkazj.jpg Note that the right rear wheel hub is different than the left. It has 3 retaining bolts while I assume the left has a single under the cover. Also note the presence of welds on that right tube. I suspect that axle sustained real damage at some point and the tube was repaired and the axle replaced. Perhaps by an earlier serial number part. I'll research that tonight.

Obviously struggling to get links to my Photobucket to work. Not seeing the HTML tool box when booted in Windows and browsing with IE. Used to work fine...

 

[HanSolo]

Obviously struggling to get links to my Photobucket to work. Not seeing the HTML tool box when booted in Windows and browsing with IE. Used to work fine...

 

[Tazza]

Looks like someone has messed with the axles before, there is a two piece one, i believe they are 1 piece in this model from the factory.
The extra fluid will probably mean your case drain filters are plugged (if fitted) and/or you have bad seals allowing fluid to go from the motor into the chain case.

 

[HanSolo]

Looks like someone has messed with the axles before, there is a two piece one, i believe they are 1 piece in this model from the factory.
The extra fluid will probably mean your case drain filters are plugged (if fitted) and/or you have bad seals allowing fluid to go from the motor into the chain case.

Indeed Tazza. I was able to ID that odd axle as a 943 part. Those three bolts on the hub are for that model. It took me a couple hours to get the high pressure hoses off. It's really tight space to work in so you have to use a 1 1/2" crow's foot on those fittings. It's not going to be fun trying to get those back on. So I've got the final drive motor on my bench and I'm going to follow the 843 service manual and put new seals back in. I'll also replace the quad ring seal on the gear box where the splined shaft goes in. There's an outer O-ring but I'm not seeing it in any of the drawings.

 

[HanSolo]

Indeed Tazza. I was able to ID that odd axle as a 943 part. Those three bolts on the hub are for that model. It took me a couple hours to get the high pressure hoses off. It's really tight space to work in so you have to use a 1 1/2" crow's foot on those fittings. It's not going to be fun trying to get those back on. So I've got the final drive motor on my bench and I'm going to follow the 843 service manual and put new seals back in. I'll also replace the quad ring seal on the gear box where the splined shaft goes in. There's an outer O-ring but I'm not seeing it in any of the drawings.

Got the final drive motor disassembled this morning following the manual. Pretty easy and surfaces look good with no scratches or scaring. Ordered seal kit for LPS and hopefully will have the motor back together this weekend.

 

[Tazza]

Got the final drive motor disassembled this morning following the manual. Pretty easy and surfaces look good with no scratches or scaring. Ordered seal kit for LPS and hopefully will have the motor back together this weekend.

Good to see you have the manual to get the timing right, every time i do a motor, i second guess myself if i have it right, each time it is spot on.
One thing i did find helped me, was to use grease for the pins and springs to assist with re-assembly of small parts that fall out when trying to line things up.

 

[HanSolo]

Good to see you have the manual to get the timing right, every time i do a motor, i second guess myself if i have it right, each time it is spot on.
One thing i did find helped me, was to use grease for the pins and springs to assist with re-assembly of small parts that fall out when trying to line things up.

I got the seals Friday and put the drive motor back together. The tip on the grease work well thanks Tazza! Now I've got another issue. I was taking a closer look at the gear housing to order the large oil seal (NA at LPS). The splined drive has got a lot of end play and sounds really bad when I spin the wheel hubs. https://youtu.be/tgDXjtr4rxU That gear housing will have to be pulled. So yesterday I dug into removing the control sticks, throttle lever and ultimately the pump cover. What a major PITA! Getting to the bolts on the control sticks was really tough. And while I'm struggling to get those out on the right side, I noticed the hub cover was off on that side's gear housing and that exposed shaft has play also. There's going to be a point when these issues are more time and cost than benefit to me. I think the break point will be if there's damage to the case of the gear housing. So today I'll going into the chain case and drop the left side gear housing and we'll see how bad it is.

 

[Tazza]

I got the seals Friday and put the drive motor back together. The tip on the grease work well thanks Tazza! Now I've got another issue. I was taking a closer look at the gear housing to order the large oil seal (NA at LPS). The splined drive has got a lot of end play and sounds really bad when I spin the wheel hubs. https://youtu.be/tgDXjtr4rxU That gear housing will have to be pulled. So yesterday I dug into removing the control sticks, throttle lever and ultimately the pump cover. What a major PITA! Getting to the bolts on the control sticks was really tough. And while I'm struggling to get those out on the right side, I noticed the hub cover was off on that side's gear housing and that exposed shaft has play also. There's going to be a point when these issues are more time and cost than benefit to me. I think the break point will be if there's damage to the case of the gear housing. So today I'll going into the chain case and drop the left side gear housing and we'll see how bad it is.

Oh wow, your bearings are shot. Hopefully new bearings will be all it needs, depends on how the bears look inside.
That's the problem, the further in you get, the more you find.....

 

[HanSolo]

Oh wow, your bearings are shot. Hopefully new bearings will be all it needs, depends on how the bears look inside.
That's the problem, the further in you get, the more you find.....

Yeah, those are shot. Looks like the input and output shafts on the left need bearings. The right side will need bearings on the output shaft (input looks tight). So deeper in I go. Pulled the control linkage on the peddles and sticks. Pulled the brake peddle and pump cover. Then I was able to open the front cover off the chain case. That left input shaft inner bearing is clearly dangling. So to get those gear housings off you have to get the rear chain case cover off. I was able to get all the bolts out and wiggle it from under the pump. But there's not enough room to get the housing bolts off inside the chain case so the pump has to come out. I'm hoping to split the pump between the right and left drive pumps. I did that when I first got this machine but pulled the left drive pump out the engine bay. I got all the hoses color coded and pulled off.

 

[Tazza]

Yeah, those are shot. Looks like the input and output shafts on the left need bearings. The right side will need bearings on the output shaft (input looks tight). So deeper in I go. Pulled the control linkage on the peddles and sticks. Pulled the brake peddle and pump cover. Then I was able to open the front cover off the chain case. That left input shaft inner bearing is clearly dangling. So to get those gear housings off you have to get the rear chain case cover off. I was able to get all the bolts out and wiggle it from under the pump. But there's not enough room to get the housing bolts off inside the chain case so the pump has to come out. I'm hoping to split the pump between the right and left drive pumps. I did that when I first got this machine but pulled the left drive pump out the engine bay. I got all the hoses color coded and pulled off.

As you need to dig in this doop, you may have had more success by disconnecting the chain case from the chassis. It's actually easier than you may think. You then have full access to the chain case.
Bolts around the axles, drive motor hoses, front pump mounting bolts and a few linkages and the you jack the chassis up and roll the chain case out.

 

[HanSolo]

As you need to dig in this doop, you may have had more success by disconnecting the chain case from the chassis. It's actually easier than you may think. You then have full access to the chain case.
Bolts around the axles, drive motor hoses, front pump mounting bolts and a few linkages and the you jack the chassis up and roll the chain case out.

This week was all about work and generating income for this project and bills. "you may have had more success by disconnecting the chain case from the chassis" Interesting idea Tazza. Unfortunately I'm too deep into the disassembly to go that route. I also think that method would be super easy with a car/truck lift (I will have one someday). I'm undecided on splitting the hydraulic pumps or removing whole. Looking today, I suspect there's yet another cover that has to be removed to access the rear axles and chains. That would require removing the complete pump assembly.

 

[Tazza]

This week was all about work and generating income for this project and bills. "you may have had more success by disconnecting the chain case from the chassis" Interesting idea Tazza. Unfortunately I'm too deep into the disassembly to go that route. I also think that method would be super easy with a car/truck lift (I will have one someday). I'm undecided on splitting the hydraulic pumps or removing whole. Looking today, I suspect there's yet another cover that has to be removed to access the rear axles and chains. That would require removing the complete pump assembly.

You should'tn need to split the pump to gain access, would it be easier to just pull the pump out? Then you have full access to the rear inspection plate.

 

[HanSolo]

You should'tn need to split the pump to gain access, would it be easier to just pull the pump out? Then you have full access to the rear inspection plate.

"You should'tn need to split the pump to gain access, would it be easier to just pull the pump out?" Exactly what I did today. Getting to the rear bolts was a real stretch for my short arms. Looks like I've got great access to the gear box mounting bolts but the chains will have to come off. So what's the level of difficulty pulling those back together and putting in a master link? Of course the manual calls for special tools.