Leaking Pump Seal - Ruined Motor Bearing

[BobY]

During the past few weeks, I've noticed that my pump has gotten louder, with a "grinding" sound. Today, I could stand it no longer, so I opened up the machine to see if I could isolate the sound to the motor or the pump. It was clearly coming from the motor.

I called Chris Coffee, and their excellent and friendly technician described a similar problem that he saw recently, where a leaking pump had damaged the motor. He replaced both.

I pulled the pump off, and lo and behold, I found a whole bunch of wet crud in the cavity between the motor and the pump drive shaft:



I then removed and disassembled the motor, and found that the ball bearing on that end was "grinding". It also looked terrible:


Interestingly, the corroded bearing was a KBF part that didn't look very well sealed against moisture entry. The bearing on the other end of the shaft was an SKF part, and looked to be of a higher quality (although I don't really know anything about ball bearings).

So I went to a local motor repair shop and picked up a replacement bearing (equivalent to SKF #6202-2Z) for $5. With a bit of judicious tapping, I replaced the bearing, reassembled everything (hate putting those side covers back on!), and my 1 1/2 year old S1 is nice and quiet again!

Of course, I will change out the pump as soon as a replacement arrives. Hopefully the crud won't build up too quickly... there is a small drain hole in the shaft cavity, but it was plugged up by the crud. I wonder how often these pumps leak. It would be great to be able to replace just the shaft seal, but it would probably be hard to get just those parts.

Question: do I need a PF manometer in order to set the pressure on the new pump?

[Niko]

Wow, that's the deepest anyone has gotten with their pump except for one guy who bought a pretty used S1 on eBay.
You do need a group pressure gauge to adjust the pump pressure.

Is there anything you can compare the pump noise to so we can get a better idea of what to listen for incase any of us experience the same thing?

Perhaps it failed because your kitchen is so beautiful...
Sorry, couldn't get that nice kitchen out of my mind.

[BobY]

Thanks, Niko!

I'd have to say that the bad bearing sounded something like my bean grinder, but not as loud. In terms of volume, it was like an electric pencil sharpener, if anyone remembers what that sounds like.

With the new bearing, all I hear is a low-frequency humming sound, and of course the jet plane whoosh of the pump as it builds up pressure.

[Niko]

I'm still wondering how that happened...
You have the distinct honor of being the only one on record with a failing S1 pump.
Do you have any thoughts on how this may have occurred? So the pump never had a good seal against the motor and it slowly build up moisture and corroded?...

[BobY]

Well, that makes me feel pretty special!

The problem appears to be at the seal around the pump shaft (Part 5 in this diagram)


Because a small amount of water was leaking out here, it entered the cavity where the motor and pump shafts connect to each other. This water should have been able to escape through the drain hole at the bottom, but it must have gotten clogged up. Surprising, because I use a water softener/filter. I wonder what all this crud is?

This isn't a completely unheard of problem... as I mentioned, the technician at Chris Coffee had very recently encountered this on a customer's machine.

[jackiechang]

Great report Boby. I think the crud is from aluminum. Thanks for the heads-up.

[Niko]

You should feel special, this is a great thread. I look forward to seeing what happens next.

[Barry]

great report and great pictures! The pump will likely be preset to an acceptable pressure, however, if you want to get a precise reading, you will need a pressure guage. Given your level of technical expertise, I would encourage you to lookup my thread on this subject and build one vs. buying one. It will allow you to get a dynamic vs. static pressure reading.

Regards,
Barry

[BobY]

Thanks, Barry. I did see your posting re building a PF gauge, and I've already ordered a Wika gauge from gaugestore.com. I'm surprised that the PF fitting is just a 3/8" thread... I thought it would be some weird metric thing that is only used on portafilters!

Bob

[Niko]

You seem pretty resourceful, that's why I didn't even bother mentioning building your own pressure gauge.
Post pics of the one you build also, I'd like to see it in action.

Go Leafs!
Go Jays

[Barry]

Thanks, Barry. I did see your posting re building a PF gauge, and I've already ordered a Wika gauge from gaugestore.com. I'm surprised that the PF fitting is just a 3/8" thread... I thought it would be some weird metric thing that is only used on portafilters!

Bob

Actually, you are correct, the thread is not a perfect 3/8, however, using a little teflon tape will take care of the difference. Mine has never leaked. Thanks again for your posting.

Regards,
Barry

[mgannon]

Sadly, I just had exactly the same failure happen. Got my machine in December of 2005, so I got about 3 years out of it (2-4 shots a day). New pump and motor are on the way (thanks, as always, to Roger at Chris Coffee for the helpful and quick service).

[chas]

When you get the new pump, can you let us know if it's the same brand the machine came with or a different one?

[JohnB]

Did the pump actually fail or was it just that front seal leaking? Looks like the seal would be easy to change once you pulled the front cover.

[mgannon]

Not sure whether the pump "failed" or not. The motor would not turn due to the failed front bearing (and loads of crud/corrosion/etc. jamming everything up). Once I removed the pump, it was quite difficult to turn, which I was told is not normal. I haven't attempted to tear down the pump. I may do that, and just keep it in reserve if it appears to be repairable, which is what I will do with the original motor if it turns out that I can replace the failed bearing. I was able to get the bearing off the shaft, now it's just a matter of finding a replacement bearing (which Roger told me they do not have at their shop).

[chas]

What does Chris charge for the motor? The pump is listed on the website but not the motor.

[JohnB]

I've ordered many bearings & seals through my local Napa using the bearing # & seal dimensions. If you have a bearing supply shop locally they can get any bearing/seal that isn't specially made for an equipment manufacturer. If the pump is bound up it probably isn't worth bothering with unless the replacement cost was excessive.

[mgannon]

What does Chris charge for the motor? The pump is listed on the website but not the motor.

The motor was about $150 (cant remember exactly - might have been 149, 159, etc.). I found the bearing on e-bay - $8.00.

[mgannon]

Same brand of pump. Looks just a teeny bit differnet (i.e., a very slightly different outer brass casting) but you have to look pretty closely to notice. One annoyance is that the threads on the output side of the pump aren't alligned exactly the same as the orignal pump, so the fitting that screws in to the outlet doesn't align toward the back of the machine like the original. If the original allignment was 12:00, this one bottoms out around not quite 1:00. Made it a real pain in the arse to hook up the output line.

When you get the new pump, can you let us know if it's the same brand the machine came with or a different one?

[cdnpaul]

This was a great thread! I was able to replace my bearing today and my machine is SO much quieter now.

[algrilli]

Recently, I noticed a small puddle of water under the machine, but further back than usual. I traced it to water stains coming from where the pump meets the motor. A few emails to Jason at CCS and I had the unit opened up. The pump was failing, but the motor was not ruined. It spun freely and worked fine when switched on. I only had to replace the pump. I never knew there was a problem because the machine was acting perfectly fine. Good thing I noticed the leak. The little weep hole at the bottom of the motor saved me - it was letting out excess water before it reached the bearings, though eventually it could have become clogged with mineral deposits from evaporating water. Here are some pics of the leaking pump and the mineral buildup from the water leaking into the motor area. Notice the water stains coming down the motor mount.