How does a sediment bowl shutoff seal?

jCarroll

Well-known Member
Location
mid-Ohio
My BN Farmall has a "newer" sediment bowl assembly. Regardless of how tight I turn the shutoff
valve it leaks gas (very slowly) to the carb.
Before I drain the tank to "fix" this, I want to know what the seal mechanism is like,
so I know what I'm going to "see" when I have it off the tank.
It's the tank to bowl flow valve, not the glass bowl seal to the metal.
 
The ones I have taken apart to clean was metal to metal seal. I haven't had the occasion to take a newer one apart. I would assume they would be the same. I am guessing a burr of some kind or a small piece of rust trapped.
 
Loosen the collar around the shaft then screw the cut off all the way shut then tighten the collar.Then again its probably from the land of almost right so you need to add an in line cut off.
 
I bought over $65.00 in sediment bowls trying to find one that did not leak. Findly said the helk with them and put a rubber hose with a inline filter Problem solved.
 
If the bowl does not leak, and you cannot find out why the valve leaks, put a gas proof shut off (ball valve) after the bowl assembly and before the carb. I did - no more leaks into the crankcase. HTH
 
It is a metal to metal seal may have to take it apart take the stem out can probably see whats wrong may have to resurface some
 
Look at this picture. You can see the tapered end on the valve. This seats against a machined surface in the cast part of the sediment bowl. This not mating/sealing is what is causing your leak.

Several things can cause it.

1) someone over tightened the shut off. This mars the surfaces and ruins the valve.
2) the seat or valve has a imperfection on them so the two will not seal. I have polished the needle part and then taken a drill bit and tired it backwards to smooth the seat in the valve body.
30 Manufactured incorrectly and the seat/needle are not centered on each other. This is the most common issue with the imported sediment bowls.
cvphoto16107.jpg
 
Traditional I do the same thing only it’s just sediment assemblies. Those old ones are worth their weight in gold in my opinion.
 

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