UTU water pump parts

[karl f]

finally got the U's water pump apart after waiting for a dremel tool from Santa for a couple years and then puddles to dry in the work area...Amazing what grinding a rusted mis-shapen pin into a solid surface to strike with a punch can do for effective pin removal.
I also found a pin at Fastenal that should be identical to the original groov-pin (their illustration on web and in paper catalog is wrong): #11104742. 3/16x1. Not sure about the hardness or anti-corrosion treatment, but it's at least a groov-pin type.
The "incorrect" roll pin usage goes back to the dealers in my opinion. There is a NOS box of parts on the farm that was purchased in the 70s, the impeller seal, shaft bushing, shaft seal, and a roll pin are all stapled together in a parts bag.

my questions: What parts do you reuse or eliminate when doing the impeller seal? What's supposed to be different between old/new? I'm observing some differences. The original has a retaining ring on the impeller for the seal (damaged when removed, seemed rotten). Also it looks like the replacement impeller seal design has been simplified, there is no inside part to fit the shaft tightly. The parts kit i got from Welters has only the impeller spring loaded component, and the oil seal.
any dos and don'ts while i'm in there? Going at it with the I&T for a UB.

thanks
karl f

 

[Charlie Biler]

Changing the water pump seal is a pretty straightforward process on a U or G series tractor engine. First you just drive out that old steel roll pin. Normally that is easier said than done. Originally the retainer pin was just a cotter pin. Later on a rust resistant, copper plated, pin was used. This happened around 1965. Today we use a stainless roll pin to simplify things. Using a plain steel roll pin will generally cause serious problems. The corrosion will make things difficult to disassemble, and it makes the drive shaft deteriorate rapidly.

After that you turn the impeller off by turning it clockwise. Make sure you throw away all of the old Schwitzer-Cummins type seal pieces. This includes the brass piece at the base of the seal well. If you leave in any pieces; it will not go together easily, and it will probably leak. The new design seal is much better than the originals. This improved seal design has been used since 1966. It seals on both the base of the seal well and on the drive shaft. The older seal assembly only sealed on the shaft and it needed that brass retainer to hold it all together. If the shaft was slightly pitted on the old design pump seal, you had a slow leak, or worse.

Never use grease, silicone, or any regular lube around the seal assembly. Silicone will destroy the seal face. Oil based lubes will attack both the seal face and bellows assembly. Use only evaporative pump assembly lube or a drop of pure antifreeze on the shaft for assembly purposes.

Always inspect the iron face where the seal face rides. Circular wear rings are okay, but radial cuts are a sure sign that the seal face needs to be refaced or replaced. There is one allen headed set screw that holds the face/ bearing cage in. Never remove more than 0.02" inches from the original face, when refacing. Use a high speed positive rake tool in your lathe when refacing. Generally negative rake carbide tools will give a poor finish on this material. When you have that face/ bearing cage off, make sure to change the oil seal in there. Remember; the lip of the seal faces to the engine oil, meaning that the lip points to the operator's seat.

When you spin the new seal and impeller on, be careful not to overtighten the threads. Remember that counterclockwise is turning the impeller on. Many times those threads are very worn and they can strip. The impeller generally is fine, but the shaft is what rusts away. Once the impeller is on, gently tap in the new stainless roll pin and replace the cover. If I can do it, anyone can do it. With a proper rebuild; your grandkids will have no problem doing it next time. The weep hole does two things. It keeps the grease away from the water seal by providing somewhere for the grease to travel. The weep hole is also the last chance device to keep water out of the oil and oil away from the seal. Keep crud and paint out of the weep hole.

Now go turn some sod.
Charlie

 

[karl f]

thank you. Just the reinforcement info i was looking for. it is also very well written, so maybe in 2124 our ancestors can decipher it when researching this non hovering and non auto pilot yellow object.

so when you say throw all the old parts away, you mean that nothing will hold the seal in the impeller if you were to tip it seal side down? there were 2 brass retainer rings in the old one, one around impeller and one around accessory shaft. I see how the installation wouldn"t need those rings after all, just making sure the larger ring on the impeller is unnecessary now, especially since mine came out in 4 pieces.


The pin that was in mine was a solid pin with 3 teeth or flutes on one end (see image link). The I&T manual for a UB seems to indicate that as the stock pin in that era. My UTU is 49 or so. Of course 40-50 years of rust made the outer edges of the pin soft and out of shape. The dremel tool took care of that quickly so i had a solid surface to punch out


more about this pin, the one i got from fastenal is a solid groov-pin like the linked image. It is zinc finish low carbon steel. Will that be adequade for corrosion resistance for 20 years? or should i find a stainless roll pin or copper cotter pin?

thanks
karl f

 

[Charlie Biler]

Personally; I advise persons to never use dowel pins or groove pins for rebuilding water pumps. Taper pins are only used after some one previously used them on a task. If you get the shafts backward, taper pins are about as good as winding a watch with a hammer.

420 stainless or 18-8 spring (roll) pins are the choice for water pump work. Zinc coating is good for keeping the pin from rusting in the box it came in. Copper coated pins are far better, but not as good as stainless pins. Before stainless slotted and coiled roll pins became available; I used 360 brass pins and flailed the front end with a sharp center punch, after installation. If I had to swage one out, they did no damage being removed and they never swelled from rust.

I might get shot for posting this, but here goes. Saunter on over to www.minneapolis-moline.com and look under the parts sources page. Send me an email after you find my name.

Happy motoring.
Charlie