Rebuilding the Ford Model B water pump…

The original plan was to buy a rolling chassis with ALL original Model A parts. That way things would be easy… open catalogs and order replacement parts as necessary then bolt them on. Easy Peasy, right? . Of course that didn’t happen, I have a Model A motor with a Model B head and water pump that was frozen when I got it. Dad and I managed to get the pump to turn freely and run the engine for a few minutes, but I knew I needed to tear the pump apart and make sure it wasn’t going to seize up again or grenade. If it was a Model A pump I could go to almost any vendor and buy a new pump with new style ‘Leakless’ seals installed and just bolt it up. Not so with B pumps, they are kinda rare and no one makes the castings anymore. I could buy an overhauled one with exchange for $400 plus from one well known vendor, but I can’t see that kind of expenditure when all of the parts (including some spares) cost around $50. Oh, and after two weeks of looking I still can’t find any parts diagrams or overhaul instructions for B pumps. Yay….

Being typical me, I decided lets tear it apart and see just what we have got. So I unbolted the pump and brought it home with me.

First thing I noticed was the 1/4 inch or so of end play on the pump. Thats the amount of movement in the pump shaft from the front to the back of the pump, or how much the fan can move forward and backward without the pump itself actually moving. Model A specs (which I’m using cause I never could find Model B specs) call for .006″ to .010″ of movement. I could move it at least .250″ almost .300″ at some tries. Hmmmm. 25 to 30 TIMES the amount of end play is not a good thing. I was starting to worry just a bit. Time to take the fan off and get to the heart of this project.

Except the F’ing fan was stuck on that shaft. It’s a tapered shaft, tapers to the front, should just take a tap or a nudge to remove, but it’s not….. freaking…. moving. Seriously, I think someone thought that they could take the end play out by torquing the fan nut down and just hammered that fan onto the pump shaft. It took setting the fan on its nose, filling the back of it with PB Blaster, and then letting it sit for over twenty hours before the penetrating oil started to show on the front of the fan. It still took another 2 hours of persuasion to get the fan off the shaft. It was a bitter sweet moment when I got it loose, glad to win the struggle and worried what I was going to find under there.

After a bit of cleaning so I could see the casting I found evidence that the fan had enough movement to cut into the pump body in a few places. One spot around the lower base and one on the front of the grease fitting mount. The one on the grease fitting is the one I was worried about most. If it wears too deep then it cuts into grease channel to the front bearing. Thank goodness it hadn’t reached that point yet. The back of the fan pulley showed corresponding marks and I think the pulley is still good enough to use. Lets see what the internal parts look like.

Overall, not too bad. The pump shaft has some spot that need to be cleaned up, but the rest of the parts look almost brand new under all that old grease. In fact, I’d say the pump was overhauled and hadn’t had many hours of run time. The front roller bearing showed no marks on the rollers and the split race in the casting nose hasn’t worn in at all. Even the steel bearing washers at either end had no wear marks. So I mounted the pump shaft/impeller between center in the lathe and used 600 grit sandpaper to knock off the rusty spots, followed by 000 steel wool, and finished with leather embedded with white rouge polishing compound. Then I gathered my replacement parts and grease.

The only part I’m using that deviates from the original 1932 pump design is a new style seal and nut combination that replaces the original nut and lead packing. I figure I will give it a shot and see how it goes. Worst thing that happens will be that I have to pull the new-fangled piece out because it leaks and use the original nut and new packing.

Also, I have plenty of greases we use on the tractors and other stuff, but I went ahead and bought the grease listed at Mikes-A-Fordable with all the other pump parts since, well…. it was the recommended grease. It looks like this..

Time to put it back together. Not entirely sure if it’s right, but its the best I have based on how it came apart and how Model A pumps are assembled.  I start with putting the steel washer on the shaft that goes between the impeller and the back of the pump rear bushing.

That gives the impeller just a little space between the impeller casting and the bushing, as well as giving a smooth surface for the bronze bushing to ride against. Looking down the pump outlet we can see the impeller nestled back in its  happy place with just the smallest of gaps for clearance.

Before you can put the front bearing in place you have to put the new pump nut on the shaft and install the rear metal cup and felt for the front bearing.

I read that you have to fill the new nut with pump grease before installing it, so it’s packed with plenty on the inside and just a sheen on the pump shaft, I also figured I would pack some around the bushing face for the heck of it. I mean, why not? I got a whole tube of this stuff.

Now on to the front bearing area. The front bearing is located between two metal cups, two felt washers, and two steel end washers. It looks something like this when laid out on the bench.

So first in is the metal cup and felt on the end closest to the nut we just put on. I dislike installing these kinds of cups since they never seem to start straight. One edge always catches and cants them to one side. If you aren’t careful it will cause the cup to distort and you will need another cup. To try and prevent this I usually file the edge to a bevel and make sure the seal driver fits the shaft snugly and covers the entire back of the metal cup. Once it’s in place with the felt and steel washer it looks like this.

Next comes the bearing. Since I’m using the bearing that came out of it I don’t need to remove or reinstall the bearing sleeve that is in the casting. If I was to use the new bearing that I bought then I would replace the sleeve with a new one so that they would wear together. Putting a new bearing in an old sleeve is not a great idea, any wear that the old bearing left on the sleeve could cause premature wear on your new bearing. But, before you can install the bearing you have to pack the bearing full of grease. I was going to take pictures of this part, having been taught to pack bearings properly by the late Bill Lacy who had been packing them by hand since at least the ’30s according to the stories he’d tell if you could get him to. Bill was the ‘Grumpy Ole Man of the Shop’ when I first started working at the Harley dealership. A great guy and chock full of useful knowledge if he deemed you worthy of it. Rest easy Bill, you are missed. Anyway, its hard to take pictures of the process with one palm full of grease and the other holding a grease filled bearing. After the bearing is packed full of grease it goes in up against the steel washer.

Now this end gets a steel washer, felt, and retaining cup.

Grease for the front bearing and rear bushing are provided through the two angled fittings seen on the side facing the camera. Now I get to fix the end play issue. I’m not 100% sold on the idea, but many people and forums say that the easiest way to do it is with a collar. You just put the collar on the shaft, set the end play, and then tighten the set screw. Ok, if it works for them then it should work for me, right? It just sounds too simple and I’m worried one set screw won’t hold it…. but then I tend to overthink everything. Here is what the collar looks like.

The plastic washer goes between the collar and the metal cup we just put on. It’s just a wear washer, something sacrificial to keep a metal on metal contact from happening. It goes on like this.

Then you put the collar on, space it out the proper distance, and lock it down. I went with .010″ on the end play. It’s the max allowable on the Model A pump, but I figure it’s way more in spec than what it was… and since I have all that extra clearance where the pulley wore away the casting….

All that’s left it to put on the fan. I bought a replacement fan mounting hardware kit: new nut, woodruff key, and cotter.  The old woodruff was still in good shape so I used it, I’ll keep the new in the spares box. I am using the new nut and cotter though. I don’t trust the original nut after finding it cranked down like it was. The fan is installed snug but not tight, the keyed shaft makes sure it rotates and the nut is on far enough to get the cotter through it. I will secure the cotter after I install the pump back on the engine. No need to waste a cotter key.