Bobcat 743 V2203 Rear Main Seal Replacement

[KC743]

I am getting ready to pull the engine again. After having broken crankshaft bolts removed by a machinist, I did not replace the rear main seal before reinstalling. Now I see dark oil coming from the rear of the engine compartment. I lifted the cab and no new leaks can be seen and i'm sure it would be clean oil if it was hydraulic oil. Has anyone replaced a rear main on a V1702 - v2203 and do you have any suggestions or tricks for removing and replacing. I have looked on the PDF version of the Service Manual and cannot locate any instructions. Antfarmer suggested replacing the pump rear seal while I was back in there. It is not leaking now. Are they a problem on this model and should I replace it at the same time? I hate to replace things that are not broken cause sometimes it creates more issues. Thanks in advance.

 

[frogfarmer]

Could be the rear seal but with the broken bolts and now a leak I would check the runout on the crankshaft. Seal is mounted in a housing and relatively easy to change. Another place to look is the welch plug for the cam bore. I have replaced several of these on high hour engine builds that were leaking for a long time. Welch plug may be covered by the flywheel housing. If you are confident in replacing seals and know you wont do more harm than good replace the pump seal. If you are only considering doing the seal because someone suggested it was a good idea and have reservations due to your skill level leave it alone. Another issue to consider is if the crank bolts that broke were due to being over tightened they may have bulged the crank just enough to cause a leak. While you have it apart check everything you can just for piece of mind. Always a chance the seal caught a shaving and just needs replaced.

 

[Tazza]

Personally i'd only replace the pump seal if it showed signs of leaking. With the engine out, have a look to see if it is at all wet. It's pretty simple to remove the engine later if needed, they don't seem to leak all that often, but it does happen.
The rear main is simple enough, remove the carrier, replace the seal and re-install.

 

[KC743]

Personally i'd only replace the pump seal if it showed signs of leaking. With the engine out, have a look to see if it is at all wet. It's pretty simple to remove the engine later if needed, they don't seem to leak all that often, but it does happen.
The rear main is simple enough, remove the carrier, replace the seal and re-install.

After removing rear main seal which was obviously leaking, I noticed a groove in what appears to be a race on the crank. It looks to be in the exact spot where it should be sealing. The Kubota dealer is not open till Monday. Does anyone know if this is servicable?

 

[mark18mwm]

After removing rear main seal which was obviously leaking, I noticed a groove in what appears to be a race on the crank. It looks to be in the exact spot where it should be sealing. The Kubota dealer is not open till Monday. Does anyone know if this is servicable?

I'm not familiar with your engine, but i would think you should be able to get a "off set " seal, one that the seal itself will ride on a different part of the crank. Or get a "speedy sleeve" to go over the crank if there are no flanges or counter weights in the way. A offset type seal might take a little detective work and a patient parts salesman to help dig threw parts books and compare the sizes of seals ans the location the seal itself is in on the new seal. Usually you can find one that the seal is in a slightly different location that will allow it to ride on a different part of the crank. If you have the part number of the old seal , there call a place that sells seals (I use Baum Hydraulics, they are on the web) they should be able to cross your numbers to a seal that should work.

 

[frogfarmer]

After removing rear main seal which was obviously leaking, I noticed a groove in what appears to be a race on the crank. It looks to be in the exact spot where it should be sealing. The Kubota dealer is not open till Monday. Does anyone know if this is servicable?

Depending on how deep and how sharp an edge the groove has in the crank it is very serviceable. I have dressed several cranks with the same issue with emery paper and installed a new seal. If the groove is very deep and pronounced a sleeve will need to be installed over the crank but still an easy task. It is very common to see this when the seals get old and hard. I would imagine you have a little room to play with in the seal housing that should get you out of the groove.

 

[KC743]

Depending on how deep and how sharp an edge the groove has in the crank it is very serviceable. I have dressed several cranks with the same issue with emery paper and installed a new seal. If the groove is very deep and pronounced a sleeve will need to be installed over the crank but still an easy task. It is very common to see this when the seals get old and hard. I would imagine you have a little room to play with in the seal housing that should get you out of the groove.

I went to the Kubota engine dealer and they sold me the rear main seal, metal bearing gasket, rear main housing gasket and a replacement crankshaft sleeve all for 53.38. The sleeve came off easy with a small 1/2 in 3 prong pulley puller with sharp 90 degree edges to grab the back of the sleeve. Several short bursts with the impact and it came off. To reinstall I used the flat side of my 5lb hammer to keep a flush hitting surface and used my 3lb hammer to knock it evenly onto the crank. Once it was on, I used the old sleeve to finish pushing the new sleeve on. I then used a medium chisel to lightly tap the old sleeve back off doing so evenly. I plan to reinstall motor as soon as the weather warms up as I am having to work outside. Thank you to all who have helped and I will hopefully post again with the word success.

 

[frogfarmer]

I went to the Kubota engine dealer and they sold me the rear main seal, metal bearing gasket, rear main housing gasket and a replacement crankshaft sleeve all for 53.38. The sleeve came off easy with a small 1/2 in 3 prong pulley puller with sharp 90 degree edges to grab the back of the sleeve. Several short bursts with the impact and it came off. To reinstall I used the flat side of my 5lb hammer to keep a flush hitting surface and used my 3lb hammer to knock it evenly onto the crank. Once it was on, I used the old sleeve to finish pushing the new sleeve on. I then used a medium chisel to lightly tap the old sleeve back off doing so evenly. I plan to reinstall motor as soon as the weather warms up as I am having to work outside. Thank you to all who have helped and I will hopefully post again with the word success.

Congrats it sounds like you have a good local dealer. Hoping for warmer weather here as well.

 

[KC743]

Congrats it sounds like you have a good local dealer. Hoping for warmer weather here as well.

After reinstalling the engine, I have only had about an hour to move some snow with it. It appears the new rear crank sleeve and rear main are doing great. I have noticed a few hydraulic leaks to attend to next. Thanks to all for the advice!