kubota B20 water pump replacement

[misterfixit1967]

1990 Kubota B20 water pump bearing let go today taking out the last core of the radiator with the plastic fan. Need to get some tips on removing the radiator. Remove hood? Remove bottom orange support for hood? Planning on cutting the lower hose since it's hose clamp is totally inaccessable. Any more hints? Pictures? Diagrams?

Bob

 

[dfkrug]

Bob, since you don't have a parts book, you can go to Messicks.com and view the
PDF file for the radiator and related pages, no charge.

My B21 was not like your B20, but I suspect you have to remove the hood
and grille to get to the rad support bolts.

 

[troutsqueezer]

http://www.tractorbynet.com/forums/parts-repairs/185242-kubota-b21-waterpump-replacement.html

This is a reference to a B21 waterpump I replaced. Don't know if it will help. I did not remove the hood but having removed it later when I did some restoration work, I realized I should have removed it for the water pump replacement because it was pretty easy to remove and gave me all kinds of room to manuver.

 

[azbinder]

Just having done this a few weeks ago, remove the hood and grille assembly as a complete unit. Disconnect the wiring at the lights. You will then have to work the hood assy forward and up. It can be done, just take your time. I then pulled the radiator by removing the two mounting brackets from the frame. Also, I would recommend the the belt be replaced at this time as it will be a lot easier. You will have to disconnect the front hydraulic pump and move it about 1/2 to 3/4 inches.

 

[misterfixit1967]

Thanks for the replies. We did remove the hood and bottom cover by sliding the hinge pin out first (remember to leave the fel up so the pin can come out). The radiator was trashed. A new one cost $860 so we decided to get the old one recored for around $250. It will be done in a few days. Still trying to find the water pump locally. Again thanks for the help!!

 

[troutsqueezer]

I would take the old one with you when picking up the new one for comparison purposes.

 

[dfkrug]

A new one cost $860 so we decided to get the old one recored for
around $250.

Yes, you can have rads built from scratch for way less than the cost of a new one from
the manufacturer. Also, look for rebuilt water pumps on the web. We recently found
a rebuilt wp for a Deere for about 1/3 of new ($80 instead of $250).

 

[misterfixit1967]

I'm beginning to wonder just what caused the fan blade to contact the radiator. I mounted the water pump in a vice with pulley, spacer and fan blade attached and measured the motion of the blade tip as I cocked the shaft in the pump. Total motion was around .080 inches at the blade tip, which means the fan blade tip can move .040 off nominal center. I find it hard to believe that the clearance between the fan and the radiator is such that a 40 thousands of an inch slop could have caused such a catastrophic failure. Does anyone know what the nominal spacing between the radiator and the fan is? I can't measure it now since the rad is in the shop being re-cored. I certainly will measure it when the radiator comes back. The water pump bearings are not noisy and other than some slop as measured above works well and does not leak. I'm thinking maybe the motor to radiator spacing has changed?? Broken mount somewhere?? The radiator mounts were tight and all seemed well when my son disassembled it. Any thoughts or clues out there? . . . :confused2:

 

[radioman]

most likely a stick went in and out when you didnt know...

 

[misterfixit1967]

possible but unlikely. We were moving dirt and gravel on the lawn when it happened. No sign of sticks or stones in the fan shroud area on disassembly tho. . . . . :confused3: