Leaking quadrajet well plugs

I've been battling leaking well plugs on my quadrajet for awhile.

[@303nitzubishi4]

Thanks for the perspective on this issue. I have the long crank time and occasional fuel odor symptoms, but My main problem is fuel loading at idle to the point that the engine eventually floods and stalls. The only reason I passed smog last year is the kid had no idea what he was looking at and just override the errors coming out of the tailpipe sniffer. Got lucky that time but I'll be going in with a clean tailpipe this year if I can get those plugs sealed up!

[@pattygq]

Probably the reason the JB Weld is breaking off soo easily is because it was applied against a smooth surface. For JB Weld to be effective make sure you rough up the surfaces (file them) and prep them with brake cleaner or something that will remove all grease / fuel remnants.

[@chrishensley6745]

I use the permatex gas tank repair,the other stuff didn,t work for me either.

[@georgekalafatis7286]

Now that everybody tells everybody to drill and tap the well area you can't use the o-ring plugs because of the threads

[@omarghazzy]

What kind of screws did you use, try aluminum similar / close material as the body

[@drjohnsonhungwell5115]

I have one that was rebuilt but I only have this as an occasional problem and and running rich for a few minutes but other than that the carb works good but I know it's leaking down some .

[@earlstacey2709]

Seems like the best solution is to drop the quadrajet in the trash and put a better carb on

[@international2408]

In most cases yes.

[@johncasor9698]

1973 caddy 472 cid, i got this problem now...

[@international2408]

Nice engine! Yes this is a big problem with quadrajets. Beast luck i have had so far with the primary plugs is gently driving the original plugs in a little farther and taking a center punch and lightly staking the center.

[@beetee801]

Me too same engine. Same year. Rebulit the carb 5x before i figured this out.

[@satamanschmidt3428]

Why not try red Loctite on the set screws? It's a themoplastic and should have enough of give to prevent it from cracking.

[@international2408]

The heat/cooling cycles deteriorate just about every sealant that I tried. Marine Tex was the best that I found.

[@kc0rock]

Thank you for sharing this feedback. Disappointing to hear that neither the Marine or JB Weld epoxy did not work. Have same carb and leaking issue and was going to drill out and install Allen hex screws. Wondering if Permatex #2 would work better than the epoxy except there is not much thread length/strength one can impose on the Allen plugs. Have you found anything better then re-staking the old/new plugs?

[@international2408]

You're welcome. So far re staking the well plugs has been the best method and I recommend doing it over drilling/tapping the plugs. Permatex #2 may work but I've never used it on well plugs. The biggest issue with epoxy failing on these plugs is due to the constant heating and cooling of the engine, causing it to crack. Once the epoxy cracks, gas will begin to seep out and degrade the epoxy farther.

[@kc0rock]

Yes, and when the plugs are made up of steel [11 - 12.5] the coefficient of thermal expansion between them and the aluminum [21 - 24] are so different leading to the cracked epoxy. I have found aluminum plugs with 1/8" NPT threads but need more time to see if they would work for the secondaries. I believe the secondaries bleed gasoline more often than the primaries just due to the hole size being larger.

[@international2408]

Typically the older quadrajets with the brass plugs for the secondaries are the ones that leak (both at the secondaries and primaries)The quadrajets with the aluminum secondary plugs typically only leak at the primaries. If the carburetor is off the car an easy way to check which ones are leaking is to spray all the plugs with soapy water, next spray compressed air into the primary and secondary jets. You'll see bubbles forming on the leaking plugs. This test isn't perfect because the carburetor stays at room temperature the whole time but it usual works.

[@ls87gbody]

What do you think about brazing the well plugs? do you think the heat from brazing would ruin the air horn or warp it? brazing rod is really strong stuff.

[@international2408]

I have brazed cast iron in the past and i do agree, its strong. The only thing is im pretty sure these carb bodies are made of zinc, and zinc can be melted at a fairly low temperature with a propane torch. I'm not saying it's impossible, but I doubt it would work.

[@FOBWDave]

Thanks for sharing. I have a Dualjet 1980 same problem, any recommendations would be greatly appreciated.

[@international2408]

The best result i have had so far is lightly driving in the original lead plugs in just a bit farther and lightly center punching the plug in the center. It wouldn't be a bad idea to cover the plugs with epoxy after they have been drove in and center punched. Seal all is a gasoline resistant epoxy that seems to do mediocre, marine tex unfortunately gets brittle from the heating/cooling cycles.

[@ramthaLord]

Hi there Just a question can we welding( with copper ) without damage anything . thanks

[@international2408]

Hi, I'm not sure about welding with copper, but I did try to solder these once and it didn't work out.

[@smokeydabeecharlescoleman8365]

Why not remove the plugs and reinstall them with fuel resistant Teflon tape over the threads ?

[@international2408]

I attempted that before, the fuel and heating/cooling cycles turned the teflon gummy and leaked worse.

[@bigcurt011]

How many pumps should i get from a full fuel bowl on a cold start

[@international2408]

Never tried it but i would bet somwhere around 8 or 10

[@bigcurt011]

@@international2408 ok i only get 2 half pumps and a day before that after a long drive put my car in the garage came back out and i smelled raw gas...i put my nose around the air cleaner snorkel and it was strong smell or gas

[@international2408]

Good chance its leaking well plugs. Best way i found to check is after running the car, let it cool down for a little while and unbolt the 4 carburetor hold down bolts (fuel line still attached if possible) with the four bolts removed pick the carburetor up off the intake just enough to get a look at the well plugs. If they are wet, they are leaking.

[@bigcurt011]

@@international2408 awesome i will check that out asap

[@rvpirates]

Did you get them fixed?

[@international2408]

TheDavisonsJourney on this float bowl I drilled and tapped the primary and secondary well plugs and then coated the set screws with marine tex epoxy. That repair lasted roughly a year before the epoxy got brittle and began leaking again. I ended up using another float bowl that still had the original well plugs in it. I took a hammer and tapped them in a little farther then lightly staked the center to tighten then up. So far that has worked better than any epoxy I have used.

[@MichaelDavis-zp6wc]

@@international2408 m

[@gg56850]

quadrajunk

[@international2408]

I’ve called them that myself quite a few times. All depends on if they’re worn out and if you know how to adjust them

[@skylerkroll8878]

These do not leak nearly as much as people think they do.

[@international2408]

Every quadrajet i have ever owned has leaked at the primary well pugs. After you shut the engine off and remove the carburetor when the engine is still warm, usually the primary plugs will be wet.

[@pattygq]

@@international2408 ditto