The Stovebolt Site Forums The Shop Area Engine Shop Rochester BC 1-Barrel w/stripped and stuck fuel inlet fitting

Just purchased a Rochester BC 1-Barrel that has a stripped and stuck fuel inlet. The carburetor is an exact match for my 1954 Hydra-Matic restoration project so I would like to repair it if possible. I tried PB Blaster and WD 40 and the fitting will not budge. Does anyone have any suggestions? I decided to stop before I did any further damage. The pics below show how it looked when I got it and then after I worked on it some after soaking it and trying to turn the nub with some needle nose vise grips.

That's a 1/8" NPT pipe thread, and it's going to be pretty tight. You probably need to use a straight-flute "E-Z Out" and a little heat to get it to budge. Use a Propane torch, but only after you disassemble the carb and get the float, and the needle valve and seat out of it. If you can wait a while before tackling the project, I've got an inspection job pending in B'ham in the next few days. I'd be glad to help out if you like.

I've used candle wax on stubborn threads at times. Get the casting hot enough to melt a candle or some parrafin, and apply it liberally before trying the EZ out.
Jerry

Like Jerry said, a bit of heat will definitely help. Someone probably used some sealant on the threads that has hardened up and glued it in place. Heat will help loosen the sealant and also expand the body away from the fitting a bit.

Thanks guys! I will disassemble the carb and try the straight-flute "E-ZOut" with heat and parrifin.
I appreciate the offer to help Jerry but I may be a little further out of the way than you would want to deal with. I am about an hour outside of B'ham. As for waiting, I am in no big hurry, I just don't want to inconvenience anyone.

I've been averaging driving over 1,000 miles a week in 9 states for the past several months- - - -"out of the way" is sort of a relative thing! I was in Nashville today, and it looks like it's going to be Memphis tomorrow, then maybe 80 miles NE of Memphis before heading home.
Jerry

You guys are scaring me about heating up a carb casting. They warp by just being on top of a motor. Maybe Jerry would agree that after getting out the guts, that you bolt it back together to keep it from warping, and don't unbolt till cool.......I would get it out without heating. Very carefully slitting the threads and peeling, if I had to. I have done that with success. Plan B, C and D would be rethread, helicoil and buy a new top. Nice to see that it has the tag.

If it's that corroded/rusted, that the fitting is locked, don't be surprised if it is unbuildable for other reasons.

I hear ya, but the carb is useless now so he has nothing to lose by trying.

Hey.............I was still typing. I have the worst timing.

If the insides of the fitting are not buggered, you could turn a piece of steel for a tight fit, then the fitting will not collapse with vise grip use.

Ed

I think i have a used air horn i can give you if you want it .

Thanks for all of the input and the generous air horn offer Guys! I will disassemble the carb and bolt it back together and go from there. I think the better half has some other plans for me for the next few days but I will keep y'all posted on how it works out (or not). Jerry, if you are looking to extending your road trip one day, I am about 20 min from I-22. I am still working on getting my project moved to our garage, so there isn't much to see. However, it would be nice to be in your presence with all of your wealth of knowledge concerning these old trucks. (Maybe I would absorb some of it through osmosis.) I do know that I have a long road ahead of me and I will need all of the help I can get.

Just to argue with myself. six to one, half a dozen to the other..........bolting it back together, before heating, adds more heat sink. Making it harder to heat the specific stuck fitting. So I'll stay with not heating, as my input. FWIW.

I agree that heating the casting will be risky but I do think it is the best way to remove the fitting without destroying the female threads. I wonder if it has thread locker on it to stop a prior leak, in that case the heat will do the trick. Slow and gentle will get you there.

Several thoughts come to mind:

(1) I need to find an impossible task that takes Jerry's fancy enough that he would make a trip to Lake of the Ozarks. Would be an honor and privilege to have him visit.

(2) I may be biased, but unless you are wishing to experiment, why bother with trying to remove this thing. As mentioned by Bart, if the fitting is stuck that badly, the casting probably has other issues. And while Rochester B's are not "a dime a dozen", they don't miss it far (scrap price is 45 cents/pound). Surely one could find a better core if one is truly in love with the B.

(3) While I rarely disagree with Jerry on a carburetor, I would suggest to someone who has not done this before that a toaster oven has better and more uniform heat control than a propane torch. Zinc alloy begins to "slump" at roughly 450 degrees F. VERY EASY to overheat a spot rendering the casting totally useless (except for 45 cents/pound).

Jon

If it is loc-tited into place, the female threads will likely be shot. Like Jon stated, worse case scenario you will still get 45 cents a pound for it.

I think it is the "correct" number, per the tag, for his truck and may be hard to find. Just guessing as reason to save. But the tags transfer easily

Keep the helpful information coming guys! I am enjoying the education! Working on "Honey Do's" today, but maybe I will get a chance to revisit the carburetor tomorrow. I have a heat gun with variable heat settings that would supply just enough heat to melt the paraffin Jerry was talking about without producing additional scrap. I already have enough of that! So I guess I will be going with with mild heat, EZ Out, and paraffin method, unless I hear of any other more helpful suggestions.

Good point, Jon! I'm accustomed to being VERY careful when torch-heating pot metal, zinc alloy, etc. Another option would be to carefully drill the fitting out until you're close to the minor diameter of the thread, then chase the thread with a 1/8 NPT tap. If it's necessary to cut it slightly deeper, no problem- - - -the thread is tapered. I think I've got a couple of Rochester B paperweights, or parts of them, anyway, so if a replacement air horn is needed, I could probably provide one.
Jerry

I'll try to explain my method. Jerry's pipe tap ain't bad either.

I slit the offending part with a tool that fits the occasion. Tiny drill bit, dremel. cold chisel, or thin the ID with a drill. Obviously this is delicate because you don't want to touch the carb threads very much. Normally I can stand a slit in the threads because a new bolt does not care about a vertical slit. BUT in your case it may leak. Anyway, since you have some stick-up to grab with a tight adjusted vice grip, twist it inward like trying to coil up a spring. If it is split or thinned, it will peel away from the carb. Maybe a piece at a time but eventually it cleans up. Grab the fitting wall, not the whole filling OD, when twisting and winding it inward. (after slitting/separating)
None of this is easy. We all use all kinds of ways to get threads fixed. The brass fitting will be harder than the aluminum/zinc carb. Use that to your advantage.
Jon's toaster oven with controlled heat is good except your next food item will smell like gas. That's just extra flavor to a Stovebolter.

Awesome suggestions! I am in no hurry, and this is a matching numbers carb, so thanks!

Ok, I said that I would keep y'all posted so here is how it went. I tried the mild heat and the EZ-Out method and the fitting would not budge. Eventually, the nub that I had to grab onto did not exist so the next step was to drill and try to thin the metal enough so maybe the EZ-Out would work but still no luck, it was stuck. After thinning the metal I tried to pick it out, but that still did not work, the brass is harder than the carb casting so after a few tries I quit. Then, I went outside and took a deep breath of Ozark Mountain air to get up enough courage to drill to the inner most diameter of the fitting threads and after doing so I somehow still had brass showing in the hole. I tried picking again before resorting to the tap, but still did not feel comfortable due to the hardness of the brass. So I broke out the 1/8” NPT tap Jerry had mentioned and proceeded to very carefully chase out the brass a little at a time. It actually worked! I almost gave up several times, but I finally got the tap working square in the hole and chased the threads a little bit at a time. As Jerry also mentioned, I was able to take the tap a little deeper, so it worked out great. I checked all of the other jets and fittings and they are not stuck and the carburetor appears to be in otherwise excellent shape
.
While I am not a big fan of the Rochester BC Carburetor either, it is what came with this truck originally and I feel very fortunate to have this fixed. I truly appreciate all of the input and help from everyone that responded to this post. I may be old, but this is proof that an old dog can learn new tricks!

Nice save!

"I love it when a plan comes together!"

Good show! Slow and steady progress beats getting frustrated and breaking something every time!
Jerry

Nice Job.

The thing that saved you is there was already a concentric hole in the fitting to guide your drills. I just got done removing a broken bolt and because of the location, there was no way I could get the drill exactly centered. I did wander into the threads a bit, but it finally came loose (using a little heat and vice grips to turn the stub on the back side.) There were still enough threads that a new bolt could grab on to. Saved me from having to buy ANOTHER helicoil kit (of course I didn't have the size needed.)

Perseverance pays off.

Sweet! Don't you love it when things work out like that?

Yes! I was getting very discouraged, but fortunately with everyone's help everything worked out!

Now it is time to study up on the "Rebuild" process. I know that Jon (carbking) has posted some very interesting and "Very" helpful information concerning Rochester carburetors in the past. (Very generous concerning his obvious dislike for this model.) His knowledge concerning all models is extraordinary. If I had only known about flushing the lines, the glass bowl fuel filter, and the "Carter Magnatrap" back in 1997 I would probably be a lot better off right now. My problem was rust particles getting past the fuel filter and clogging the carburetor. (The fuel filter I was using was totally useless!) This truck ran for many years without a fuel filter with no problems, then after the introduction of unleaded fuel, and then ethanol fuel, its fate was sealed. I now have a glass bowl type filter from Jim Carter and I will also be purchasing a "Carter Magnatrap" if they are still available. Thank you Jon!

I know that Jon (Jon G) has also posted information on "Straightening the Rochester B and BC castings" that is quite involved and quite thorough. Jerry also weighed in on his post on how to clean the carburetor which sounds a lot better than the cleaner I used to use. There is an abundance of information available that I will need to familiarize myself with before I begin this process and I am excited that I can now proceed to this next step!

On a side note, I have been researching the numbers on the carburetor and while they are an exact match for what is on my truck, I did find that according to a publication at "restorecarsclassifieds.com" (.PDF Attached) the tag appears to be for a 1956 "powerglide". If you look at "Chevrolet 6 CYL. Trucks 1954-Early 1955 235" Eng Auto. Trans they had a Model No. BC 7005921 with a Repl. Carb. Model No. (7005921, 7007181, 7009255) 7009911. As you can see from a picture in my post, the tag reads 7009254 with the air horn stamped 9265. If you look at "Chevrolet 6 CYL. PASS. CARS" the Repl. Carb. Is (7005922, 7007181, 7009254) 7007200. As you can see, the replacement numbers do appear to interchange for this truck and the passenger vehicle. (i.e. 7007181) So from what I can gather, the correct number is BC 7005921, but what I have is BC 7009254, or the same carburetor with a different number and I am satisfied with that. I encourage anyone to weigh in if I am incorrect in this assumption. I just did not want to perpetuate incorrect information since I had originally thought this was a "matching numbers" carburetor for a 1954 3100 Hydra-Matic and as you can see from the tag in one of the carburetor pictures, that is not exactly correct.

This may help... Here is a simplified spec sheet copy that has the both the 7005921 and 7009254 listed. I note just a few differences, two having to do with the choke and one in the power circuit. Although the 7005921 is correct for your truck with auto trans if I understand, the 7005921 was used also in standard transmission cars. The calibration of the 7009254 for "Powerglide" was a bit different than the standard trans cars. Is it of practical concern? Probably not, unless you are looking for "numbers matching" perfection.

Thanks for the information!