Oil/water pump rebuild nightmare HELP!

[haristocrat]

Hi guys, need your expertise here! The TL;DR is I can't get the enduralast coolant seal outer ring OUT of my pump for my second attempt at a rebuild. The full story is as follows:

In 2024 I bought a 1987 K75s with ~68k miles on it (although speedo/odo was not working, so who knows?)
Was well maintained but had sat for many years, wasn't getting fuel. I cleaned out the tank, changed fuel sender, pump, etc, and it started right up. Have been changing things slowly, tyres, shocks, fixed speedo, all going well so far.
Finally got around to changing fluids and noted oil in the coolant i.e bad seals in the oil/water pump.
This started the saga of the oil/water pump rebuild...

I bought the enduralast kit from EME and followed the YouTube video from kennyraceboy to the tee.
Put everything back together and filled the coolant with distilled water and ran it and HEY PRESTO no leaks, looked great.
Of course I couldn't leave well enough alone and decided to do a radiator flush to clear out the oil that was still in the coolant with each exchange.
I bought the Zerex 4-in-1 radiator conditioner and added it and distilled water.
Soon after starting up there was a steady drip of coolant from the weep hole. Flushed the system a couple times with water and drip accelerated to a steady trickle. Bugger! Maybe the Zerex ate the seal?

So at this point I felt I had no choice but the pull the pump off again, and do a second rebuild. I bought the same kit again from EME (https://www.euromotoelectrics.com/product-p/pumpkit870.htm) and am working to remove the seals I just put in so I can replace them again, and do a better job I guess. I was planning to follow the procedure of tapping in the oil seal first, then the coolant seal into pump housing, then use the shaft bolt and washers to pull the shaft up rather than tapping the coolant seal onto the shaft and housing together (which is what I did last time as per Kennyraceboy).

The major problem now is that I can't for the life of me tap out the old coolant seal. I started tapping it out but what came out was the centre shaft seal and spring which separated from the outer metal portion of the coolant seal. There appeared to be some coolant/oil residue on the inside of the shaft seal so I suspect that is how the coolant was making it through to the weep hole, rather than around the outside of the external portion.

The outer metal ring of the coolant seal now seems completely embedded in the pump housing and as I tap it with a screwdriver from the oil side it is just deforming it and tearing it to pieces. I am at a loss as to how to get this out safely without damaging the very soft aluminium pump housing on all sides.

HELP PLEASE! Any suggestions are appreciated.
Pictures attached of what I'm dealing with.
Obviously I can't do anything else with this stuck in there.
Appreciate your help!

[natalena]

That's pretty mangled. Have you tried applying a heat gun and pulling straight out with needle nose grips? This might be a case of patience and micro wiggling to get it out.

[caveman]

haristocrat,

As far as your question on how to get the old seal housing out of the pump housing......

I agree with natalena, you may also be able to get hold of it with a small pair of vice grips and rig up a slide hammer. Or twist and tear the the old one out.

This statement is what concerns me.....

"tapping the coolant seal onto the shaft and housing together"

The video you referenced that gentleman used a special tool to install the seal into the pump housing. The part link you gave shows the installation tool as recommended not part of the kit. Did you get that tool and use it to install the seal?

The water seal is a spring loaded ceramic face seal that will crack if any compression force is applied to it. When it is fitted up properly the shaft bolted up will have the ceramic faces in the middle of the spring zone of the seal.

If this makes no sense to you I or maybe someone better at the english language will try to make it clearer.

[haristocrat]

That's pretty mangled. Have you tried applying a heat gun and pulling straight out with needle nose grips? This might be a case of patience and micro wiggling to get it out.

Thanks. The thought of heating it did cross my mind, including maybe ice-ing the seal whilst heating the housing. But that seemed cumbersome. Will give heat a go in any case. Don’t have a heat gun but will try with a hairdryer.  Am a bit concerned about fatigueing the metal on the upright section and having it break off entirely so have been trying not to wiggle anything.

[haristocrat]

haristocrat,

As far as your question on how to get the old seal housing out of the pump housing......

I agree with natalena, you may also be able to get hold of it with a small pair of vice grips and rig up a slide hammer. Or twist and tear the the old one out.

This statement is what concerns me.....

"tapping the coolant seal onto the shaft and housing together"

The video you referenced that gentleman used a special tool to install the seal into the pump housing. The part link you gave shows the installation tool as recommended not part of the kit. Did you get that tool and use it to install the seal?

The water seal is a spring loaded ceramic face seal that will crack if any compression force is applied to it. When it is fitted up properly the shaft bolted up will have the ceramic faces in the middle of the spring zone of the seal.

If this makes no sense to you I or maybe someone better at the english language will try to make it clearer.

Thanks for the reply. I failed to mention that I did purchase the pump application tool (https://www.euromotoelectrics.com/product-p/pumpkittool628.htm) which mates with both the outside and inside of the pump as it is being pushed on. I didn’t have a press however, as is recommended by EME, so tapped it in with a rubber mallet. Took quite a lot of tapping..more like a rapping. Do you think this accounts for the failure?

There is a lot of conflicting info on this rebuild out there. I think it stems from the fact that the design of the seal keeps changing. There is no “blue goo” on the inside shaft-side of the coolant seal in the version I have. It’s just on the outside and the inside is just a metal cylinder that I think is designed to have a close tolerance with the shaft. This being the case it does seem better to apply the seal to both the housing and shaft together (as EME/enduralast recommend) rather than pull up the shaft through the seal after putting it into the housing. I’m a bit confused to say the least.

Thank you for the suggestion on the slide hammer. Didn’t know such a thing exists. That seems like it may be perfect to pull this out. You don’t know what you don’t know… will see if a mechanic friend of mine can help.

Anyway any advice on the correct way to reinstall after it’s out would be super appreciated.

[stokester]

I've rebuilt the pumps on both my bricks - the first one twice because I was unaware that the spacer bushing size changed with the new seal.

Not sure about the EME kit as I ordered my parts from BMW and the seals had the "blue goo" on it.  The procedures I used is -> https://ibmwr.org/index.php/2003/05/01/water-oil-pump-rebuild/ which describes using a piece of PVC to start the seal and using the impeller bolt to press it in.

Worked for me.

[2000rsv]

As an 'expert' at rebuilding my K75 water/oil pumps several times (because I kept screwing it up) - make sure you are using the new stamped steel impeller versus the OEM cast one.

That cost me two rebuilds to learn.

[haristocrat]

To follow up: I ended taking the pump to a local mechanic (Brennan motorsports—I highly recommend Matt!) who tapped the old seals out and pressed the new set back in for me with a hydraulic press in front of me. No fuss no muss! Charged me $20! I reinstalled, put fluids in and the brick is running great, no leaks.
Moral of the story: I think the enduralast seals really do need a hydraulic press to install correctly. Suspect when I hammered it in it was slightly misaligned.

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[Laitch]