Roof Leak Potential

[jbfunfinder]

I accidentally ripped both of the white PVC caps off of the 1 1/2" vent pipe jacks which protrude the roof of my 2012 FF 189 FBS while taking off the Tyvek cover. I lost one of the caps and the hold-down tabs are broken on the second one. When I climbed up to try and figure out how I would replace them, I peered down into the vent jack housing and noticed that factory installers had failed to seal the vinyl roof sheet around the 1 1/2" ABS vent pipe. (See pictures at link below) You can see the ABS pipe protruding through the luan plywood and also see that they just used a knife to roughly cut the vinyl roof material to allow about 1/2" of the pipe to protrude. I am no roofing expert, but it seems like there should be sealant around the pipe so that rain water which is forced up under the cap during driving does not flow into the ceiling area below the vinyl.
What thoughts do you have on two topics: How to find replacement caps (BPC MFG.) and what sealant should I use? Thanks in advance for your responses.
See 7 pictures : https://plus.google.com/photos/102411481952184097449/albums/5851894536496251841

 

[LJAZ]

You can get universal spring loaded vent caps to replace that broken one. Something like this:
http://www.pplmotorhomes.com/parts/rv-vents/rv-plumbing-vents.htm
Or contact the manufacturer. I googled BPC mfg and came up with this company:
http://www.lasallebristol.com/contact-us/ompany that appears to be the corporate owner:

As for leaks under the membrane it's a bit hard to tell for sure from the photo but that vent likely has a flange that's screwed to the roof plywood that should create a pretty tight seal and prevent any rainwater from seeping in between the plywood & the membrane.

 

[jbfunfinder]

Thanks LJAZ. I will check at the local rv supply as the combined cost plus shipping of these caps is way to expensive.