troutsqueezer
Veteran Member
Thought I would make this post for posterity, in case someone down the road is suddenly faced with replacing the water pump on their Kubota B21. Now they can have something to reference to.
Just got my new (used) B21 a couple of weeks ago and after a few hours use, the water pump started leaking fluid from the weep hole in the side of the pump. Good thing I noticed some wetness on a couple of rocks I was driving over at the time so the engine never overheated.
My first action was to search TBN looking for water pump replacement advice. I found a little but nothing for the B21 specifically.
The first thing to note is there are two pumps available and only one will work, depending on your engine serial number. Finding the serial number on the engine can be an exercise in itself. I found mine in a place not mentioned in any publication nor post. It was stamped into the side of the engine block right above the engine model number which is cast along with the block. This is near the exhaust manifold. It took me quite awhile because the number was covered with engine grime.
When I received the pump, I was careful to make sure it was a match before I took it home from the dealer but careful as I was, I failed to see that two of the standoffs, or raised bolt holes, as it were, were slightly taller than my original housing. I didn't notice this until I had the permatex on and was putting in the two longer bolts and realized that they would not reach the threads. Everything else about the pump was OK so I figured they sent me the right water pump but someone at the factory made a slight adjustment to the mold and did not take the bolt length into account. Of course, this longer bolt is not a standard size carried in any of the local hardware stores. I wound up putting the assembly on my mill and milling those two raised standoffs down about .100".
This is the setup.
You can see the two tall standoffs (or whatever they're called). I haven't milled them yet in this pic.
Here's the water pump in place, hoses not hooked up yet.
As mentioned in previous posts, overall the replacement is not hard to do. The only tricky part is removing the fan and pulley before you can pull the radiator. You have to feel for the bolts and maneuver the socket wrench to make it work. It's tricky reversing that process as well (reassembling) but it can be done with a bit of fiddling.
Everything else is a snap.
Here's to many hours of enjoyment on my new tractor.
Just got my new (used) B21 a couple of weeks ago and after a few hours use, the water pump started leaking fluid from the weep hole in the side of the pump. Good thing I noticed some wetness on a couple of rocks I was driving over at the time so the engine never overheated.
My first action was to search TBN looking for water pump replacement advice. I found a little but nothing for the B21 specifically.
The first thing to note is there are two pumps available and only one will work, depending on your engine serial number. Finding the serial number on the engine can be an exercise in itself. I found mine in a place not mentioned in any publication nor post. It was stamped into the side of the engine block right above the engine model number which is cast along with the block. This is near the exhaust manifold. It took me quite awhile because the number was covered with engine grime.
When I received the pump, I was careful to make sure it was a match before I took it home from the dealer but careful as I was, I failed to see that two of the standoffs, or raised bolt holes, as it were, were slightly taller than my original housing. I didn't notice this until I had the permatex on and was putting in the two longer bolts and realized that they would not reach the threads. Everything else about the pump was OK so I figured they sent me the right water pump but someone at the factory made a slight adjustment to the mold and did not take the bolt length into account. Of course, this longer bolt is not a standard size carried in any of the local hardware stores. I wound up putting the assembly on my mill and milling those two raised standoffs down about .100".
This is the setup.
You can see the two tall standoffs (or whatever they're called). I haven't milled them yet in this pic.
Here's the water pump in place, hoses not hooked up yet.
As mentioned in previous posts, overall the replacement is not hard to do. The only tricky part is removing the fan and pulley before you can pull the radiator. You have to feel for the bolts and maneuver the socket wrench to make it work. It's tricky reversing that process as well (reassembling) but it can be done with a bit of fiddling.
Everything else is a snap.
Here's to many hours of enjoyment on my new tractor.
