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Just picked up a sweet 68 Delmont 455 and the 2 barrel carb is leaking quite a bit from the large gasket in the middle.
Should I rebuild or upgrade? I know with my cutlass with a 4 barrel the opinions were to stick with the original. The care starts and runs just fine right now other than the leaks.
Pooling on the right and also on the left Dripping from the drivers side Dripping from the passengers side
Leave it alone unless it drips any raw gasoline, the picture depicts only seepage unless there was raw gasoline that evaporated.
If the red paint peeling on the intake manifold just below the carb is from gasoline leaking then it should be fixed. If it leaks raw gasoline the carb should be disassembled, cleaned, a rebuild kit and a new float installed.
If there is liquid gasoline vs gasket seepage repair it. Tightening the gasket is not likely to fix this problem.
Last edited by Sugar Bear; Nov 12, 2024 at 09:14 AM.
Rebuilding that 2 barrel carb will be cheap and easy. Don't screw around with a raw gas leak. Get a rebuild kit and find the section in your CSM and rebuild it.
Mr. Gravy, keep that 2 bbl. Get a carburetor rebuild kit and, if necessary, a new float. While the carburetor is apart investigate the possibility of a problem with the float and/or the float valve. Check for damaged sealing surfaces on the carburetor pieces. It's best to address this situation before the flames erupt. Carry a fire extinguisher if you don't already do so.
The float should be brass and lasts forever. The needle valve will leak after it gets old and the rubber insert that does the sealing gets hard or dirty. That may well be all you need. I have "several" of those carbs on my Olds and that is what goes out eventually.
I had a heck of a time locating a brass float for my 2GC. Even a brass float from NAPA leaked and sunk. I eventually found an online source for a brass float and it worked. But until you do, don't rule out the OEM type plastic floats. Mine lasted 40 years and numerous rebuilds.
I had a heck of a time locating a brass float for my 2GC. Even a brass float from NAPA leaked and sunk. I eventually found an online source for a brass float and it worked. But until you do, don't rule out the OEM type plastic floats. Mine lasted 40 years and numerous rebuilds.
Do you have a good kit recommendation or are they all mostly the same?
The float should be brass and lasts forever. The needle valve will leak after it gets old and the rubber insert that does the sealing gets hard or dirty. That may well be all you need. I have "several" of those carbs on my Olds and that is what goes out eventually.
Mr. Gravy, keep that 2 bbl. Get a carburetor rebuild kit and, if necessary, a new float. While the carburetor is apart investigate the possibility of a problem with the float and/or the float valve. Check for damaged sealing surfaces on the carburetor pieces. It's best to address this situation before the flames erupt. Carry a fire extinguisher if you don't already do so.
Mr. Bear, have another look at that last photo.
Ive been watching videos and I’m hoping to get to the rebuild middle of next week, thank you !!
I've yet to use a rebuild kit that doesn't work OK as most are the same. Mostly gaskets, check *****, accel pump plunger and float valve, maybe a spring. I think I got my last ones from RockAuto (local place no longer stocked them). Needle valves are reused unless damaged. I've never seen them in any kit.
Last edited by JohnnyBs68S; Nov 14, 2024 at 11:37 AM.
Ok well I went out to mess with it the other day and noticed that the choke was wide open and the lever was limp and I can’t seem to figure out if I’m missing something. I’m uploading some pics and videos. Could whatever is causing the choke to be wide open also be causing the bowl to flood and leak gas ?
Throttle needs to be depressed to let the choke close, give it a try and let us know.
Post a picture of the black round disc/choke thermostat face so we can see it's index position (7 lines/hashes),
The choke setting is dead center. I’m not home right now but I’ll try when I get there.
I'm only familiar with the QJet on my 74. Once cold it stays tensioned and mostly closed until the pedal is depressed which allows it to snap fully closed.
This 2barrel one though is completely limp with no tension whatsoever and wide open and I just don’t know if that’s normal or not.
Does the choke move freely? If it feels stuck at wide-open and you determine that it is rubbing the inside of the air horn, then your air horn may be warped and could possibly allow leakage from the float bowl. I had this happen from tightening the air cleaner bolt too tight which pulled-up the center of the air horn pulling in the sides causing the choke flap to bind on the ID of the air horn. Take the air cleaner hold-down bolt out and tap the hole with a hammer to see if that frees-up the choke. You might need to remove the air horn and see how flat the bottom surface is.
If everything is moving freely, then check the clocking of the thermostatic spring behind the round black dial. As you turn it counter-clockwise (I think), it should apply spring pressure to the green slotted choke lever and close the choke (you may have to blip the throttle to prevent the high-idle cam from limiting movement of the green slotted choke lever). If turning it does not close the choke, then the spring may not be engaging the choke lever on the inside of that round housing.
On another note, it appears that you are either missing a small washer under that choke rod w/ the cotter-pin, or that cotter pin needs to be a round C-clip like that other rod in your photo.
Last edited by JohnnyBs68S; Nov 27, 2024 at 03:35 PM.
X2 on JohnnyB's post...look into the throat of the carb for polish marks on the sides from a sticking choke plate. Overtightened air cleaner housing will cause this as stated.
Does the choke move freely? If it feels stuck at wide-open and you determine that it is rubbing the inside of the air horn, then your air horn may be warped and could possibly allow leakage from the float bowl. I had this happen from tightening the air cleaner bolt too tight which pulled-up the center of the air horn pulling in the sides causing the choke flap to bind on the ID of the air horn. Take the air cleaner hold-down bolt out and tap the hole with a hammer to see if that frees-up the choke. You might need to remove the air horn and see how flat the bottom surface is.
If everything is moving freely, then check the clocking of the thermostatic spring behind the round black dial. As you turn it counter-clockwise (I think), it should apply spring pressure to the green slotted choke lever and close the choke (you may have to blip the throttle to prevent the high-idle cam from limiting movement of the green slotted choke lever). If turning it does not close the choke, then the spring may not be engaging the choke lever on the inside of that round housing.
On another note, it appears that you are either missing a small washer under that choke rod w/ the cotter-pin, or that cotter pin needs to be a round C-clip like that other rod in your photo.
Thanks man!! The choke plate moves freely there is no sticking, but I haven't messed with the dial yet and will do that this am. And yes I noticed that it seems to be missing some hardware in comparison to the other similar parts. I’ll look into replacements.
Ok update, got my kit and took the choke apart and polished the bore and got that working great.
Hadn’t leaked since until yesterday and I happened to be looking at it when it started and noticed it’s not the body but rather the fuel inlet.
Gas is bubbling out and rolling over over the top and front of the carb and dripping so identified the leak.
HOWEVER now I can’t get the inlet out. Either the tube from the Inlet or the inlet from the carb body. The FSM just says remove the line.
I’ve tried gently to move the inlet while holding the fuel line nut and vice versa and they seem to be stuck together. The fuel line begins to twist no matter what I do and now the line nut is starting to strip because it’s soft brass apparently.
Try to get the penetrating oil under the nut, the seizing is probably between the nut and the tube. If the flare nut wrench starts to round the tubing nut stop. You may have to use
locking pliers on the nut. Using a wrench prevent the inlet nut from moving at all, tightly clamp the locking pliers on the nut and then strike the locking pliers in the loosening direction with the palm of your hand.
Tubing nut/ flare nut/line wrenches are all that should be used normally on these fittings but locking pliers may be necessary and so may be replacing the steel line.
On reassembly wrap Teflon tape on the tube under the nut and on the nut threads. The tape isn't to seal it, it is to prevent seizing. Don't allow any tape onto the flare, that is the seal.
HOWEVER now I can’t get the inlet out. Either the tube from the Inlet or the inlet from the carb body. The FSM just says remove the line.
I’ve tried gently to move the inlet while holding the fuel line nut and vice versa and they seem to be stuck together. The fuel line begins to twist no matter what I do and now the line nut is starting to strip because it’s soft brass apparently.
don’t know where to go from here help
How about some off-the-wall advice?
If you're going to remove the carburetor, anyway, to rebuild it, don't disconnect that line at all at the carburetor. Rather, disconnect it at the fuel pump. Then remove the carburetor with the fuel line still attached. Then put the fuel line fitting at the carburetor (circled in yellow in the upper left in the photo below) in a vise and turn the whole carburetor to loosen the fitting. Or put the smaller fitting to the right of this one in the vise, whichever is easier to get into the vice. The vise will do a much better job of holding the nut than a wrench will, even a flare wrench.
On my '73 Delta 88 (with a 350/2 bbl), I needed to remove the metal carb line, and it was already a semi-twisted mess. It came off easily enough, but I was not going to reuse it if I could find a replacement. Inline Tube makes these, but they didn't stock what I needed for my engine. Fortunately, I live only a half-hour from them, so I drove over there with my old carb line, and they used it as a pattern to make a new line. Took about 1.5 weeks, and it turned out great. If you're not able to visit in person, I'm sure you could send them your old line to use as a pattern (if they don't stock what you have). I'm sure these custom jobs with correspondence by mail are what they do most of the time. This is assuming, of course, that you want to replace that line.
Here's a photo showing the new carb line installed, and I've indicated where you might be able to disconnect the line from the pump. Things won't look exactly the same on your car for several reasons, but it should be similar enough.
Here's a photo of the old carb line. The right end is where it was twisted, and this is the side that connects to the carb. You can see how flattened it is from being twisted. This is the way it was when I got the car. It still ran fine, so fuel was obviously getting through that kink, but I wanted to replace it. If yours ends up looking like this after removal, you may want to go for a new one.
Try to get the penetrating oil under the nut, the seizing is probably between the nut and the tube. If the flare nut wrench starts to round the tubing nut stop. You may have to use
locking pliers on the nut. Using a wrench prevent the inlet nut from moving at all, tightly clamp the locking pliers on the nut and then strike the locking pliers in the loosening direction with the palm of your hand.
Tubing nut/ flare nut/line wrenches are all that should be used normally on these fittings but locking pliers may be necessary and so may be replacing the steel line.
On reassembly wrap Teflon tape on the tube under the nut and on the nut threads. The tape isn't to seal it, it is to prevent seizing. Don't allow any tape onto the flare, that is the seal.
Awesome advice thank you 🙏🏽 hopefully the soak loosens it all up
If you're going to remove the carburetor, anyway, to rebuild it, don't disconnect that line at all at the carburetor. Rather, disconnect it at the fuel pump. Then remove the carburetor with the fuel line still attached. Then put the fuel line fitting at the carburetor (circled in yellow in the upper left in the photo below) in a vice and turn the whole carburetor to loosen the fitting. Or put the smaller fitting to the right of this one in the vice, whichever is easier to get into the vice. The vice will do a much better job of holding the nut than a wrench will, even a flare wrench.
On my '73 Delta 88 (with a 350/2 bbl), I needed to remove the metal carb line, and it was already a semi-twisted mess. It came off easily enough, but I was not going to reuse it if I could find a replacement. Inline Tube makes these, but they didn't stock what I needed for my engine. Fortunately, I live only a half-hour from them, so I drove over there with my old carb line, and they used it as a pattern to make a new line. Took about 1.5 weeks, and it turned out great. If you're not able to visit in person, I'm sure you could send them your old line to use as a pattern (if they don't stock what you have). I'm sure these custom jobs with correspondence by mail are what they do most of the time. This is assuming, of course, that you want to replace that line.
Here's a photo showing the new carb line installed, and I've indicated where you might be able to disconnect the line from the pump. Things won't look exactly the same on your car for several reasons, but it should be similar enough.
Here's a photo of the old carb line. The right end is where it was twisted, and this is the side that connects to the carb. You can see how flattened it is from being twisted. This is the way it was when I got the car. It still ran fine, so fuel was obviously getting through that kink, but I wanted to replace it. If yours ends up looking like this after removal, you may want to go for a new one.
Ive been looking for a fuel line all morning just in case haha. I know inline tube and have used them before but didn’t know I could send one in so thank you!!
I don’t know if I need to rebuild the carb if this fixes the leak, it seems to be running great other than this leak! But it’s a great idea if I donor if it remains stuck
If you can't break it loose at the carb go with jauntys' suggestion and see if a local hydraulic shop will bend a new tube for you. Don't strip the threads in the carb, step carefully on reassembly.
Ok so I couldn’t get either end of the pump to carb line to come loose so I twisted the top end and snipped the connection at the fuel pump.
I ordered a new stainless steel line along with choke tubes for this car and my 74 Cutlass. None of the choke tubes fit either car but I was able to tweak the 455 fuel line to get it to fit BUT now I’m having a few other problems.
1. The fuel still seeped out where the fuel line inlet meets the carb (my original problem) despite replacing the gasket and using teflon tape and tightening best I could.
Three observations about problem 1
a. The fuel inlet threads in mostly by hand: it is not very tight, seems pretty obvious liquid could seep back through loose threading.
b. The little orange gasket is very thin and hard. it’s difficult to see how it could do much of anything if it’s the only thing standing between seal or leak.
c. The Teflon tape seems to dissolve immediately when it comes into contact with fuel. This was obvious because it took a few tries to get things reconnected and check for leaks. Is there something else I should be using to wrap the threads? Perhaps I have the wrong type of tape?
All this being said, where it’s at right now is that the fuel inlet stopped leaking for the moment when I made like 10 passes on the threads with Teflon tape. However I can’t see how this would be sustainable considering I was only able to run the car for less than a minute because of my next issue.
Problem 2
The fuel line connection to the fuel pump adapter leaks no matter what I do. The flare doesn’t seem to be mating perfectly to the male end inside the little brass adapter because it is leaking up from in between the line and nut, through the threads as far as I can tell. Do these things truly have to be perfectly aligned like an interstellar space dock haha? It’s been a struggle trying to tweak the line to get both ends to fit, don’t seems like a tall order to have the angle be perfect.
I googled around and ordered some little 3/8” copper flare gaskets for flammable liquids but I don’t know if they’ll do the trick.
any ideas?
Last edited by Cinnamon Gravy; Feb 2, 2025 at 07:17 PM.
I don't think the threads on the filter housing-to-carb were ever intended to be sealed (I don't think these are NPT threads), the "seal" is at the little red / orange gasket. I would use a thin layer of Permatex black on both sides of that gasket before assembly to the carb (leave the fuel line to filter housing disconnected so that there is not external stressing on that assembly preventing squared-up engagement of the filter housing threads into the carb). Don't over-torque this since the threads here are cut into aluminum and are not the strongest. Let that set up a bit before attaching the fuel line. Get these lined up the best you can by tweaking the tube. Always torque the fuel line at the carb filter housing by holding the filter housing with a wrench to prevent disturbing the seal between the filter housing and carb.
That fuel line on my car had a twist in it next to the filter since before dad sold me the car in '81. It never leaked until about 2 years ago. Inline Tube had the replacement for this application,, but it still required a little tweaking to fit at both ends properly.
You can try to double gasket the inlet nut and putting sealer/tape on the threads do nothing. Sometimes the sealing surface on the inlet nut get damaged or out of square and need to be resurfaced. If need be I have a guy who can helicoil the inlet threads and resurface the sealing surface. The sealing surface is on the airhorn not the nut.
I don't think the threads on the filter housing-to-carb were ever intended to be sealed (I don't think these are NPT threads), the "seal" is at the little red / orange gasket. I would use a thin layer of Permatex black on both sides of that gasket before assembly to the carb (leave the fuel line to filter housing disconnected so that there is not external stressing on that assembly preventing squared-up engagement of the filter housing threads into the carb). Don't over-torque this since the threads here are cut into aluminum and are not the strongest. Let that set up a bit before attaching the fuel line. Get these lined up the best you can by tweaking the tube. Always torque the fuel line at the carb filter housing by holding the filter housing with a wrench to prevent disturbing the seal between the filter housing and carb.
That fuel line on my car had a twist in it next to the filter since before dad sold me the car in '81. It never leaked until about 2 years ago. Inline Tube had the replacement for this application,, but it still required a little tweaking to fit at both ends properly.
Awesome thanks so much I’ll pick up some Permatex Black today. Thanks again!!
You can try to double gasket the inlet nut and putting sealer/tape on the threads do nothing. Sometimes the sealing surface on the inlet nut get damaged or out of square and need to be resurfaced. If need be I have a guy who can helicoil the inlet threads and resurface the sealing surface. The sealing surface is on the airhorn not the nut.
Thats not a bad idea !! Since finding my original leak at the inlet, this will be my last attempt to fix it without a rebuild because otherwise it’s running fine. If I do end up rebuilding I might reach back out to you about your guy
Update, the copper flare gaskets worked at the pump end of the line and the permatex black at the fuel inlet in the carb!!
it’s been running great ever since but yesterday day I noticed a few drops of fuel coming off the throttle side so I’m just gonna call it and pull it off for a rebuild.
