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#1
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Quadrajet fuel inlet leak
Hopefully I'm not doing anything too stupid here but this is the situation.
I took my 7040263 off the car so I can have it recalibrated for my new motor. I put the other Qjet I have back on the car and I have a leak at the fuel inlet. It's hard to tell but I think it coming from the fuel line to inlet fitting. I have the filter and spring installed with the gasket between the inlet fitting and the carb. everything went together easy. Threads all look good. It's been a while since I've done this but I think the fuel line fitting and the flared fuel line is just a compression seal against the brass inlet fitting, right? I even switched the inlet fitting and gasket from the other carb and same thing. It's a pretty brisk leak too. like a steady drip. What am I missing? Thanks.
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#2
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You might want to check the where the fuel line is flared. A small crack may have developed there from compressing it too many times.
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#3
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I was wondering about that. It looked OK at a glance but I didn't really do a super close inspection. If that's the problem what type of flaring tool do I need to fix it?
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#4
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Yea, that was a typical thing in the 80s-90s. Inwould epoxy the inlet Threads until advized about "value". Well i still epoxy the inlet and have not had any troubles with leaks nor values.
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#5
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Would be better to start out with a new fuel line, than try and patch up the old one. Just remember.......gas has a tendency to burn!
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#6
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A regular 45 degree brake flare kit, you just need a single flare. Maybe your tubing flare as JSuchma stated is cracked, or maybe it is distorted. Check how the flare nut seals against the flare as well. It is a compression fit so all surfaces have to be right on.
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#7
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Buy a new fuel line if there is one available. If you shorten and re-flare the old one it may be too short and not fit correctly. Also if you are not experienced you may have trouble getting a good flare.
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#8
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Quote:
Can I replace the line without taking everything off the front of the motor?
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#9
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Quote:
Quote:
In fact, I think it's Federal regulation. If you're using some other kind of tubing, the flare might be different. |
The Following User Says Thank You to Schurkey For This Useful Post: | ||
#10
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My bad, I use stainless. Mild steel is double.
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#11
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The Flare ought conform to the Seat. Either Steel or Brass inlets have seats that wear, so DO inspect the inlet seat.
Leaks from the inlet-carb Threads is where i used epoxy to fix. Annnnd that is where a darn good inlet seat gets committed. |
#12
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Any fuel, or brake line is always double flared, and yes, it's a federal requirement for safety. Your flares on a Q Jet equipped car are 45 degree double flares.
To the OP, a cracked flare on a fuel line is fairly common, I've seen it many times. When the line is leaking, and reasonable torque has no effect on the leak, the flare is generally cracked. look very carefully at the flare, you should be able to see the crack by careful examination. Usually if a line is cracked, you're not going to be to shorten it, and re-flare it, better to make a new one, or buy a pre made one. OEM lines are steel, but if you're not restoring a car to judging standards for a show car, I would use the newer material called Ni-Copp. It's a alloy of nickel, and copper line that is much easier to flare, and bend than steel is. It's also impervious to salt and corrosion, not that you'll have corrosion problems with a fuel line near the carb. The main reason I use it is it's much easier to work with I use it on all lines exposed to salt under my own cars, and trucks. I use it on fuel lines, transmission cooler lines, and brake lines, great stuff. Higher end luxury cars have adopted using it on their cars too. |
The Following 3 Users Say Thank You to Sirrotica For This Useful Post: | ||
#13
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OK. So I need a new line. Son of gun. Tomorrow I'll go look at my pump, I think it's a side mount but I don't know if it's factory or not.. Can anyone tell:
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#14
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Your fuel pump with those two parallel lines next to each other must be the large canister one as in my photo here.
This would make it a 70 to 74 type pump since it has the large canister and a vapor return line. federal Mogul / Carter made two different pumps like this ( M6405 and M6122) and I can only assume that the difference lies in where the output line to the carb comes off, or at least that’s my best guess. Note that these stock replacement type pumps are good up to 450 hp, so if your motor is over that now, or will be down the road you should be looking at a higher output pump now anyway! I hope this helps some and others chime in to add more info.
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I do stuff for reasons. |
#15
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You never mentioned the old carb leaking before you pulled it. Only leaked when you installed this replacement carb. Are you sure it's the line, before you start replacing parts. How about throwing your old carb back on and seeing if pressure makes it leak?
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#16
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Quote:
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share Last edited by jhein; 03-11-2022 at 01:55 PM. Reason: photo added |
#17
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The previous carb wasn't leaking for sure. I didn't put that whole carb back on but I did swap out the fuel inlet fitting and gasket from the previous carb to make sure it wasn't the inlet fitting or gasket and it still leaked. It seems to be at the fuel line to inlet fitting where it's leaking.
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#18
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If you wipe off the flared area of the fuel inlet line with brake clean or the like, and then color it up with black or blue marker then when you tighten it up and remove it you will see the witness marks show up as to if it’s completely seating or not.
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I do stuff for reasons. |
#19
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If the flare on fuel line is worn you might use a proper sized fiber or copper gasket inside the fuel inlet fitting for positive seal.
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#20
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Another check to verify that it's the flare fitting
Disconnect the fuel line temporarily.
Install a brass flare fitting with a barb for 3/8" hose (like the pic below) into the carb inlet. Pull the metal fuel line off to one side slightly and install about a foot-long piece of 3/8" fuel injection hose in a loop, off to the passenger's side, so that the other end of the line can be attached to the barb on the brass fitting. Tighten both clamps securely and then start it up and check for leaks. If the leak is gone, your fuel line connection is leaking. If the leak is still there, it's not the fuel line. If the leak is is gone, but you need to drive the car while you are waiting on your new fuel line, you could temporarily cut the existing fuel line back by the thermostat housing and connect the fuel injection line directly to the brass fitting on the carb. Maybe even put a good, metal fuel filter in it, if you'd like. Good luck! |
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