Water pump blues

How many hours do you forsee it running? If many hours, I would purchase a new impeller because of the welding and lack of the ceramic seat.

I believe the washer that is part of the seal assy is the carbon, not referring to the ceramic one. There must have been some procedure to glue the replacement carbon washer to the rubber bellows, but have never heard it mentioned.

I recently put a couple of D318 water pump seals back together with some really good pliable 2 part adhesive made for gluing plate cooler gaskets to the plates. It is resistant to cleaning chemicals and hot water, so should be fine. The rubber bellows had pulled loose from the brass cup and the carbon ring was separated, I cleaned all the surfaces, applied a coat of adhesive and then pressed the parts together and bent the retaining tabs on the brass cup to hold it all in compression. Haven't used them yet, but they look like they should do the trick.

One if my impellers had the ceramic washer come loose, so I used JB weld to reattach it. I would measure and see if you can accomodate the ceramic washer (if you have it) without over crushing the seal bellows. I believe the impeller should be about 50 thousandths or less from the housing for best performance, closer the better without hitting in my opinion.

I replaced the seal on our D333 engine in the grader after we overhauled it and found the same as you, no washer on the impeller. Faced it in a drill press until it was polished and installed it. It's doing fine, but grader doesn't get a lot of hours. I believe the first cast iron ones must have been made without the washers until they realized how soft they were and how rapidly the carbon wore into the relatively soft cast they use. Or maybe folks have just been throwing the detached ceramic away and reinstalling the impeller just to get by.

You can also purchase a seal from industrial supply which comes with a ceramic washer that has a gasket in the center and on the back of it to seal it to the impeller. It can be hard to get it slid down the shaft enough to get the impeller started behind it to push it home, but still do-able!

I used JB weld but I think Silicone would work just as well or maybe even better. I have seen the carbon stick to the impeller and crack when the engine is first turned, but I don't think there's a lot of torque on that washer.

I wouldn't worry about the balance much. More worried about the impeller coming apart than the bearings. Have you checked with Regal? What they do stock is usually at a good price, but they don't stock everything.

d9gdon, I have the same problem with pumps here with the glued on ceramic ring. The moron at Cat that developed that unit should be sent to Siberia for something to do. I have found that the coefficient of expansion between the cast iron impeller and the ceramic ring is not the same and that is why the glue joint fails. It does not matter how careful you are in assembling the pumps, ie. no impact guns or hammering on things, that unit will fail. What I have done is to measure the thickness of the ceramic ring and weld up the surface of the impeller that the ring is attached to with wear hardening bronze sufficiently enough to allow machining down to the thickness of the ring. There can not be any pin holes or inclusion in the weld. This has solved my problems and I have not had any further problems since. We went through several impellers before and have not had to fix any since. I posted this solution several years on this board but it was deleted by someone, unknown who. Hope this helps you out. Like you it pissed me off to keep buying impellers when it was only the ring that was causing the leakage. Several years ago they were $100. plus. We have not had any problems with the seals leaking. Cheers, Larry.

If you think the coefficient of expansion is the problem, then use a different adhesive. Or like I mentioned, silicone gasket maker. Many pumps use ceramic seats bedded in a rubber grommet, so I believe the silicone would be perfectly adequate to retain the ceramic on the impeller. Even better in my opinion would be something like this. I have used this single part adhesive for plate cooler gaskets with good results.
http://www.skygeek.com/pliobond-pbc20-adhesive-general-purpose-5-pint-aircraft-braking-systems.html?utm_source=googlebase&utm_medium=shoppingengine&utm_content=pliobond-pbc20-adhesive-general-purpose-5-pint-aircraft-braking-systems&utm_campaign=froogle&gclid=COCUidj-iLUCFQsGnQodtgMA1w

If you want to go another route, you most likely can find a seal from WWGraingers or other industrial supply that has a replacement ceramic seat with a gasket to seal it against the face of the impeller. Need to use a water soluble lubricant on the shaft as you push the seat and gasket on far enough to get the impeller started. Once the impeller is going, you can press the whole shebang down without any difficulties.

It will be hard to braze and build that thickness (approxiately 3/16"?) plus enough to face it off leaving a perfect surface.

d9gdon, I'm not familiar with Airgas rod, that product sounds like regular brazing rod. I used Certanium, the number I don't have handy at the moment. This rod has the pink flux on it and it was a pleasure to use. I did not have any trouble welding up the cast iron impeller and after chucking it up in a 3 jaw chuck, I found it machined quite well but it is tougher than regular bronze rod. It has a slightly whitish yellow when machined. The big thing I found was using enough heat to make the rod flow and bond with the cast iron impeller. Thee was no warping of the impeller either. I had purchased a pre 1950 D315 power unit years ago and it had the brass impeller in it. The motor had been in a drag line and was somewhat neglected but I did a complete rebuild on it. As the old impeller was slightly damaged (not leaking yet) I elected to replace it. The replacement was a cast iron impeller with the ceramic washer. Naturally, it failed before it was put into service. I welded up the impeller and that was the end of the problem, I have since done several for D311's D315's. and D318's with no recurring problems. The price Cat wanted for these impellers was more than my cusomers and I wanted to pay. Piss me off and I find a solution. Cheers, Larry. I only have one impeller left and I am going to keep it. It is a brass one but it needs to be welded up in the seal run area and be remachined. I think our colder climate was the reason for the glue joint failure as there is more of a temperature swing up here in the Cdn north.