MTFCA Forum

Is the shut off valve in the brass and cast iron sediment bulbs the same? Can I take a valve from a cast iron one to replace the broken one in my brass bulb?

You can try it but the cast iron bulb is harder than the brass stem of the shut off lever. You might try to use something like a fine grade of lapping compound to help seat it in the cast iron bulb. If it were mine I would at least try it to see if it would work. There will be different opinions about doing it.

@ the least expect it to leak/weep some from different wear patterns.
Start the lap process with tooth paste. Slow & patience wins this race.

Thanks for the replies. I picked up a cast iron one at Hershey with a good brass valve for $1.00. After I returned home I read on a post here that it may be a different taper. Before I spend the time to get it out I thought I’d check to see if anybody has done it with success.

You can use fine valve grinding compound to lap the surfaces together, the add a thin layer of EZ Turn to prevent any leak.

Or you can just buy a new one! They are still being made!

EZ Turn is great stuff, but be cautious about where you put it so that you don't wind up getting a blob of it blocking your fuel flow. It really is impervious to gasoline. Don't ask me how I know this.

schwabd1 wrote: ↑

Thu Dec 05, 2024 3:30 pm

Thanks for the replies. I picked up a cast iron one at Hershey with a good brass valve for $1.00. After I returned home I read on a post here that it may be a different taper. Before I spend the time to get it out I thought I’d check to see if anybody has done it with success.

I have done this. OEM brass & OEM iron. I wouldn't expect a repop valve to fit with an OEM. Not tried it.

I bought a new one for one of my cars and was surprised how it was made and it looked pretty good. It’s one of the reproduction T parts along with the exhaust manifold that’s made well. I have bought both and recommend them.

My father and I use bar soap to lubricate the sediment bulb shut-off valve and the petcock.

It's also impervious to gasoline and readily available inside the house.

There is a difference in the tapers of the valves between the early brass ones and the later brass ones with the hex used to fit them. If your brass one has the hex, it should work.

Allan from down under.

Been there, been through this. Since I never had much extra money for the things I most enjoy, I have always bought a lot of junk parts for cheap and then had to work them over a bit to get a good piece I needed. So I have had good sediment bulbs with broken or missing handles and damaged bulbs with good handles. I have even made and welded on new brass handles onto good tapered brass valves.
I don't care what anybody says about "universal fit" and "part's interchangeability". Even back in their day, the cast iron bulbs and their tapered brass valves were NOT all alike! The *reason* I had to "make and weld on" a new brass handle to a brass taper valve was that I had a nice original bulb, and the only valve taper that came close to fitting it was missing the handle!
I have a few times re-dressed the brass tapered valve to make them fit an iron bulb better. As others have said, slow and steady is the way to go with a paste abrasive. I have often used fine engine valve lapping paste followed by a much finer paste (even used toothpaste myself a few times).

When I was gathering parts for my 1915 runabout, I wanted an appropriate brass sediment bulb for it. I frankly do not know if it was/is an original era one or a reproduction one, but I found a slightly damaged and bare-bones brass bulb with no valve, drain petcock, or main outlet front piece. Then the fun began.
First, I repaired the damage, it was dented such that the front outlet could NOT be installed. I annealed the brass and "screw-jacked" the dent out until the front outlet could be forcibly installed. Next I hand-carved some damaged treads until I could clean them up further with valve lapping compound.
Then came the tapered valve. I sorted through the several I had, NONE came close to a good fit! So I chose one that looked good and went to work. The tapers did not match, so I determined which way I had to alter it and began by cutting it carefully with a large sharp flat file. Before going very far, I began checking the fit using a colored paste to locate high and low areas.
After I got the taper close to a decent fit, then I went to carefully hand spinning the tapered valve in the bulb with valve lapping compound. Again, often checking the fit with Prussian blue.

If you want to know how long all of that took? I will tell you that it was a nice "basket weaving session" (that means longer than you want to know!).
But my 1915 has an appropriate brass bulb that looks and works great! (And nobody really gets to see it unless they crawl under the car!)

I too use bar soap as a gasoline-proof lubricant.