73 Quadrajet Leaking???

[Jimmy P.]

The weather here in SW PA. has really been unseasonably warm for this time of year, so I decided to take advantage of it. I took my air cleaner off to make it easier to switch out the Delco Remy 1115202 coil that came with the car to an OEM Delco Remy 1115270 BR that belongs on the car. While doing so I noticed a stain on the intake in front of the carb. I appears to be coming from the small round screen (plug) in front of the carb. I'm not a mechanic, so I'm wondering if this can easily be fixed by me, or should I have my mechanic fix it, if in fact it can be fixed? Any help as always would be greatly appreciated. I've included photos below.
Thank you

[Edward J.]

Re: 73 Quadrajet Leaking???

Jimmy, I think if you clean the area off and apply some JB quick weld to the plug area it that may stop the leak, that plug on the front may not be serviceable. I believe its a lead plug inserted by a machine.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Thanks Ed,
I believe you are correct in that it does have a lead looking outer edge. I'll clean up around it, to try to see exactly where the leak is. Can't tell if it is coming around the edge, or in the lower center area. Its not real wet there, so it is not coming out fast. Is this a common issue with the Q-jets?

[Joe L.]

Re: 73 Quadrajet Leaking???

The weather here in SW PA. has really been unseasonably warm for this time of year, so I decided to take advantage of it. I took my air cleaner off to make it easier to switch out the Delco Remy 1115202 coil that came with the car to an OEM Delco Remy 1115270 BR that belongs on the car. While doing so I noticed a stain on the intake in front of the carb. I appears to be coming from the small round screen (plug) in front of the carb. I'm not a mechanic, so I'm wondering if this can easily be fixed by me, or should I have my mechanic fix it, if in fact it can be fixed? Any help as always would be greatly appreciated. I've included photos below.
Thank you

Jimmy------

This is a very common problem with certain Q-Jet carburetors (Chevrolet Q-Jets use the side fuel entry which creates the manufacturing necessity for the plug; many other Q-Jets use a front fuel entry eliminating the need for the plug).

This is called a "spun-in" plug. It consists of a soft metal perimeter seal with a cone-shaped, inner steel plug. I don't know of any way to replace these plugs with an original configuration plug. You could try sealing it externally with JB Weld as Edward suggests. However, I don't think it will seal well over time but it's worth a try. The best way to correct this problem is to remove the plug entirely and fill the orifice with epoxy.

Another method I've thought about but never tried is this: tap the orifice for an appropriate size pipe plug, SAE or metric. Then, install an internal drive pipe plug with sealer.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Joe,
Can all of these suggestions be done while the carb is on the car or will it need to be removed? Like I mentioned above it isn't too bad now, but will it get worse if not corrected? Will the alterations effect judging of the carb?
Sorry for all the questions, but everything I'm experiencing now with my 73 is new to me, and I'm learning so much as I deal with every issue that comes along.
Thanks

[Patrick H.]

Re: 73 Quadrajet Leaking???

Jimmy,

Has the car ever been restored? Any carb work ever done? And do you know how to disassemble a Quadrajet?

If it were me I would look into one of the companies that regularly restores/rebuilds Quadrajets. They can often do a simple repair like this and send the carb back to you. If you know how to properly disassemble the carb and send them just the main body then it's even easier.

The odds of finding a local mechanic still schooled in Quadrajets that can properly do a repair like this are quite low. If you're handy you MIGHT be able to use a fuel resistant epoxy and do it yourself, but I would not do it with the carb on the car.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Patrick,
I did have the carb rebuilt in March by a local mechanic who does all my work. He worked for a GM dealer in the late 60's and 70's before starting his own business and is very familiar with the Quadrajet. This just started doing this. I wanted to see what you guys suggested. I won't attempt to take the carb off myself, I'll let him take a look at it, and have him repair it.

[Joe L.]

Re: 73 Quadrajet Leaking???

Joe,
Can all of these suggestions be done while the carb is on the car or will it need to be removed? Like I mentioned above it isn't too bad now, but will it get worse if not corrected? Will the alterations effect judging of the carb?
Sorry for all the questions, but everything I'm experiencing now with my 73 is new to me, and I'm learning so much as I deal with every issue that comes along.
Thanks

Jimmy-------


ANY fuel leak is a serious issue. So, whether it gets worse, or not, it needs to be corrected.

I would imagine that an epoxy repair is going to have judging consequences.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Thank you guys, I will have it fixed ASAP. It's just one thing after another with these old cars

[Russ S.]

Re: 73 Quadrajet Leaking???

When I had the Holley rebuilt for my 66 vette by a carb restorer he left the plug alone and sealed over it with epoxy. Been good so far which is about four years. Small deduct in judging.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Hi Russ,
Thanks for the reply. I just met with my mechanic and we discussed the issue. He said the same as all of you, and that is to repair with an epoxy or JB Weld. But, the carb needs to removed to make sure I get that area completely dry. He would be happy to do the job, but he assured me that I do have the mechanical skills needed to remove the carb myself and make the repair. So, I am going to attempt this and I will be carefully removing the carb (and documenting everything with pictures so I can remember where everything goes). I'll be able to bring it into the house where it is much warmer for the epoxy to cure. I was just wondering if there is any one type of fuel resistant epoxy that is better than the other. Hopefully, one of you guys who have done this will chime in. I don't have much luck with JB Weld, its never worked very well on anything I've tried. But I know that many stand by it and use it all the time. Wonder if anyone has any pictures of one that has been repaired with epoxy, so I could see where it was applied.....
Thanks,

[Patrick H.]

Re: 73 Quadrajet Leaking???

Doing a Google search shows that JB Weld seems by far to be the most popular. I would use the version that comes in two tubes that you then mix and apply. I would not buy one of the stick formulations.

To fully prevent a leak you may have to consider epoxy inside of the fuel inlet, in other words on the back side of the leak. I suspect that could be done and the fix would be invisible from the outside.

Here is a photo of an outside applied fix:

http://www.onallcylinders.com/wp-content/uploads/2013/05/QJet.jpg

As I use epoxy frequently when bedding rifle stocks I can see how this was done neatly. If you're not used it much you may want to buy some JB Weld and practice with it before trying the carb fix.

If you lived 2 states closer I'd have you bring it over and show you how.

PS. A Q-tip lightly moistened with WD-40 works great to wipe up epoxy mistakes, and make the edges look good. Have LOTS of Q-tips handy with some WD-40 in a container ready to use. The Q-tip only has to be damp, not wet or dripping.

[Jimmy P.]

Re: 73 Quadrajet Leaking???

Thanks Patrick,
WOW, if I didn't know any better you would think that the repair was the way the carb came it looks so nice and neat. As for the JB Weld, I've only used the two tube type. I'm going out in the garage now to remove the carb. The weather has been so crazy warm here I want to work on it while I can.
We'll see how this goes?

[Joe L.]

Re: 73 Quadrajet Leaking???

Hi Russ,
Thanks for the reply. I just met with my mechanic and we discussed the issue. He said the same as all of you, and that is to repair with an epoxy or JB Weld. But, the carb needs to removed to make sure I get that area completely dry. He would be happy to do the job, but he assured me that I do have the mechanical skills needed to remove the carb myself and make the repair. So, I am going to attempt this and I will be carefully removing the carb (and documenting everything with pictures so I can remember where everything goes). I'll be able to bring it into the house where it is much warmer for the epoxy to cure. I was just wondering if there is any one type of fuel resistant epoxy that is better than the other. Hopefully, one of you guys who have done this will chime in. I don't have much luck with JB Weld, its never worked very well on anything I've tried. But I know that many stand by it and use it all the time. Wonder if anyone has any pictures of one that has been repaired with epoxy, so I could see where it was applied.....
Thanks,

Jimmy------


JB Weld IS an epoxy. I believe it's "fortified" with micro-fine steel particles. In any event, most, if not all, epoxies are gasoline resistant.

I do not understand why you've had problems with JB Weld. As long as you use equal parts from the two tubes and mix it thoroughly, it should work fine. This is exactly what you have to do with any epoxy.

[Patrick H.]

Re: 73 Quadrajet Leaking???

Thanks Patrick,
WOW, if I didn't know any better you would think that the repair was the way the carb came it looks so nice and neat. As for the JB Weld, I've only used the two tube type. I'm going out in the garage now to remove the carb. The weather has been so crazy warm here I want to work on it while I can.
We'll see how this goes?

Tip - loosen fuel lines first, and attach them loosely first when reinstalling. The other 4 bolts are easy.

I think you could set the carb on its nose (where the leak is), apply JB inside, and let it self-level to fix. I'm going to go inspect a Q-jet and see if that's feasible too.