Winter travel = cracked water pump housing

Grumpy_G

Last weekend on my way back from AZ to Central OR I stopped in northern Nevada for a couple of hours of shuteye. When I got up at 3am to continue my journey the truck showed -2F  . After I got home and checked everything the pump ran continuously and there was a lot of air coming out the faucet. No leaks though so I figured it's the pump. Being the kid that took his Christmas presents apart the day I got them (and studied mechanical engineering later) I did just that with the pump. To my surprise there was no damage inside, the diaphragm and the plastic valves were fine. Took a while of testing and investigating to determine the pump housing had a crack. It's not very noticeable, see the white line in the pic: 



Amazing that this tiny crack allowed the pump to suck so much air. Easy fix though: 



Hey I didn't say it was a pretty fix ! Below my test setup in the shop 



I took a (mis-) calculated risk by not blowing out the lines before heading north. Until 6 in the evening I was still traveling in 40F+ weather and if the night time temps would have been in the 20s it wouldn't have been a problem. Didn't expect -2F..... 

[Deleted User]

Bummer, but cool fix! Do you have a cassette toilet or the regular kind? If regular kind,  check your toilet too. There is a part on the toilet that holds water And is subject to freeze damage. Hopefully you're in a 320 with a cassette! 

Grumpy_G

No it's a 2015 with the regular black water tank setup. Toilet appears fine, it was just a little above freezing inside when I stopped and turned on the heat. The pump sits on the front wall behind a cover so it gets much colder there. 

[Deleted User]

oh got it! Yes, that area is more vunerable.   

fstop32

@Grumpy_G, thank you for giving me the motivation to implement an idea I had for that pump area on my 2015.  My idea is to run a loop of heater hose through the driver side bench area, under the shower and then turn the corner where it does its 180 degree turn under the pump.  A lot of my ideas never get beyond my brain pan so your pump problem has given that nudge I need.  
If your 2015 has convectors in the driver side bench (I removed mine) it should be pretty easy to extend the hose from one convector and bring it back and hook it back to the other convector.  I think the heat that comes off the hoses should really help out in that pump pocket.

YanniLazarus

... and, dear engineer, your patch material was (drum roll, please):

Grumpy_G

@fstop32 Somewhere in the back of this rattled brain I have this memory that some models had a small convector in the bathroom area. Might have been on the clam shell model ? My 2015 does not have a convector on the driver side, only two in the back and one on the passenger side. 
@YanniLazarus Just some random silicon I had left over from fixing my hydration pack (yes foodsafe !). As it was a leftover and halfway cured already I had to cut the tube open which is why it is applied so, ahem, liberally.  

ScottG

Grumpy_G said:

@fstop32 Somewhere in the back of this rattled brain I have this memory that some models had a small convector in the bathroom area. Might have been on the clam shell model ? My 2015 does not have a convector on the driver side, only two in the back and one on the passenger side. 
...

Very recently someone posted a pic of a newer model that had a small convector in the space behind the toilet. I don't think previous 320s ever had a convector in the bath area, but I'm not 100% certain with regard to the CS-S models

The driver's side convectors--the ones under the bench--were dropped some time during the 2015 model run. Mine (built in Dec. 2014) does not have this convector either.

Denny16

It seems the TaB320s with the cassette toilet have the rear washroom convector up by the toilet area…. 

Cheers 

fstop32

@Grumpy_G, I too have seen a pic recently on the forum that showed a convector below the water pump and you could see it through the access hatch behind the toilet.
While I have a couple of 8" convectors (driver side bench) left over from my rebuild I quickly decided whatever I do to get heat back there will not involve a convector I might have to go diving for in the future.  I think a run of heater hose will be simple with little risk of leakage.