Fuel drain on PT36

[Fujimo]

David I agree with Shane remember you have a tank full of fuel. If you are worried Crack open the other fuel cap.or you have a bad as shop vacuum.

[dave.mills]

I have about 297 gallons in the tank. When the vacuum hits and the tank buckles, it pushes fuel up through the filler neck so I have to be pretty careful. I've ordered 2 brass fuel shut offs and will await delivery in a few days. A 3/8 inch and a 1/4 inch. I also have plugs of all sizes as a last resort.

[sfedeli]

David, FWIW, I have always been hesitant to install a valve there because of the feared consequences from hitting a rubber retread or other road debris at 55 MPH. It would easily snap off if it is hanging down. If you were to install a short street elbow, facing rearward, and screwed a valve into that- it would significantly reduce the blunt force on the drain valve. You may also consider removing the handle from the valve (assuming it's a ball-style valve with a lever) for the same reason.

[dave.mills]

Shane, All,

Shane makes a good and thoughtful point.The side rails welded to the bottom of the tank do protect it somewhat, but as you say, it could still be hit as you suggested. I did buy a ball-style and rejected it for that reason; the handle is so long it would not take much to open it on the road. My current valve is actually above the bottom of the tank collector (pic attached), although it could still be hit by debris. I've ordered a brass valve that was used on the old hit-and-miss Maytag engines. I'm thinking it will be recessed also, so I'm undecided about the elbow. I did buy an iron elbow; sort of don't like to mix brass with iron with steel. (Probably not a good scientific reason for that.)

I think it important to note the effectiveness of the vacuum; the valve leaks at a rate of one drip every 2 - 3 seconds normally. After I apply the vacuum for a few seconds and shut it off, the remaining vacuum after dissipation of a minute or two still keeps the drips to 30 seconds apart!

Picture #1 is the shop vac hose duct taped to the fuel inlet.
Picture #2 is the current valve. (Pls ignore the residue of my putty attempts. Is this the original BB part?)
Picture #3 is the brass valve I've ordered.

[Bill Pape]

#2 is a valve that BB used for fuel and the bottom of the air tank for emptying moisture or water

[Bob Johannesen]

Originally Posted by dave.mills

..........If anyone knows if there is a vent on the 300 gal tank, that would be helpful. ........Dave

Mine has one...I have pushed fuel out of it before......don't ask!


.

[dave.mills]

Success! Easy job after a lot of prep. Thanks to Fujimo and Shane for the shop vac tip, wtwtw for vent (mine did not have one, at least that leaked), Rick for advice on the warning light, gcyeaw for the dowel trick. dieselbird01 for the JBWeld 8277, and all others that help with comments.

Replace 1987 PT36 Fuel Tank Drain Valve

This is one method of cleanly replacing the fuel drain valve using a shop vac to prevent any spillage. Job takes 1-2 minutes; preparation takes a lot longer. I have a pit which made job easier. I have electric in pit, so I could plug / unplug shop vac as needed. Did job without assistance.

Preparation;
1) Verify old valve is ¼ inch NPT. If it looks like picture #1, it probably is.
2) Get replacement valve with male ¼ NTP. ($16 Ebay ZKSTUFF) Picture #2
3) Get ¼ inch NPT plug as backup replacement. Also got radiator petcock as backup.
4) Get ¼ inch NPT elbow if desired. (I did not use it)
5) Get ½ inch dowel as emergency backup replacement. Picture #2
6) Taper shape dowel to fit tightly into ¼ inch female NPT.
7) Get thread sealant. I used Permatex 1B. Picture #3
8) Get Nitril gloves – optional. Picture #5.
9) Get shop vac with hard plastic end on hose.
10) Park BB over pit if possible – makes it a much easier job.
11) Remove fuel filler cap.
12) Use duct tape to seal shop vac hose to fuel filler. Picture #4.
13) Turn on vac for quick test for vacuum leaks. Tank will buckle loudly if sealed properly.
14) Any valve leaks should stop when vacuum is turned on.
15) Open valve to prove vacuum works. You should hear air sucking into tank from open valve.
16) Gather tools.
1. ¾ inch combination for removing old valve
2. 9/16 inch for my new valve
3. rags
4. lights
5. sealant
17) Test remove old valve using ¾ inch wrench.. (just see if it will turn willingly) I needed cheater pipe.
18) Clean old valve. (vac could suck in any debris)
19) Dope dowel
20) Dope new valve, wait until sticky.
Actual Job:
1) Turn on shop vac.
2) Remove old valve. Careful for debris. Wipe thread hole with clean rag.
3) Carefully screw in new valve using 9/16 inch wrench. I put valve handle pointing to rear of coach to lessen chance of it opening from being hit by road debris. (Thank you Shane.)
4) Shut off shop vac and check for any leaks. Pictures 6 & 7

[Rick Davis]

Atta boy.

[Bill Pape]

Thanks David,
I took a bath on this repair a bunch of years ago, did not know about the shop vac trick.

[dave.mills]

Bill,
I didn't know it either. All credit to Paul Brown (Fujimo). It works great.