Kevman12

Just got a 1959 vette with fuel injection running after sitting for a year. It runs good, but noticed fuel leaking from the plug pictured,

Leaking from the plug pictured.
which is located on the passenger side of the fuel injection unit. . What is the fix for this issue. The Fi unit has been rebuilt some years back. I am hoping the plug can be drilled out and replaced, or some simple solution. Please advise, thanks,

jim lockwood

Go to your FLAPS and buy a 21mm expansion plug. This will be a little larger than the SAE-sized original and it will fit snugly once installed.

I remove these plugs by first drilling a hole about 1/4" in the center and then using a steel pin punch to lever it out.

When replacing a plug on a unit I'm NOT also rebuilding, I use a Q-tip covered in grease to swab out any drill chips from the chamber behind the plug.

Next I clean the entire area occupied by the plug with lacquer thinner. I also clean the new plug.

I mix a small amount of JB Weld and apply it all around the inside of the ridge which surrounds the plug.

I tap the plug into place ensuring it is fully seated all the way around.

Then I use a hammer and a large diameter pin punch to pound on the center of the plug, expanding it and forcing it out and into the ridge.

And finally, I use my hammer and a cold chisel to make three indents in the ridge, each separated by 120* from the others. The purpose of this is to lean portions of the ridge over, further securing the new plug.

If there is any of the JB Weld showing, I finish by wiping it away with a paper towel and lacquer thinner.

Clear as mud?

plaidside

Jim is right on with his instructions.
The only thing I would add is the expansion plug is called a "Welsh or concave" plug. It might be hard to find because it is not like the common cupped type.
Joe

Kevman12

Jim, can I keep the unit on the vehicle? Also, do you have a part number to order for the plug? I don’t know what flaps is. I appreciate your thorough response.

DZAUTO

Jim is very much on the money with this.
A leaking plug on the side of the fuel meter is somewhat common after several years.
The ideal fix is to replace it with a new welch plug and SEAL itl
For MANY years, like Jim, I used JB Weld. but during a conversation with John DeGregory several years ago, he told me about a product he used for this purpose, and subsequently I have switched. I now use a 2-part epoxy product, PC7.
I thoroughly clean the seat/groove where the plug seats.
After mixing the 2 parts together, I thoroughly smear the PC7 in the groove where the plug seats, install the plug, FIRMLY tap the center of the plug to expand it for a very tight fit. I use lacquer thinner of Brake cleaner to wipe any of the sealant from around the plug and leave it along for at least 24hrs.




This is, OR WAS, the Dorman welch plug(550-008) that was the perfect fit. It is now discontinued.I routinely bought 2-3 from my local O'Reilly store until they were no longer available. Then I started searching everywhere for some place that may have some. I found a source in Penn that had about 40--------------I bought all of them and gave about half to John DeGregory.
I have routinely replaced the plug on all rebuilds, and simply destroyed the old plug. NOT ANY MORE! When I have the fuel meter apart, I knock out the old plug from inside. I have a long, skinny screwdriver that I have slightly bent the end about 2in. I insert it in the spill port and lightly tap it our. If it is usable, I clean it good, inspect the perimeter to be sure it is undamaged and smooth. Then I use the PC7 as above, to re-seal it in the hole.



Good luck finding a new plug. Jim says he uses a 21mm plug from the local auto parts store. I have not searched for a 21mm plug, but if they are available, it would be good to acquire 2-3.

jim lockwood

It will be easier to make the repair if the unit is on the bench. However, if you have the dexterity to do the work with the unit on the car (I don't), then sure, why not.

FLAPS == Friendly Local Auto Parts Store.

I don't have a part number for the plug. They aren't difficult to locate.

Be careful asking for a Welch plug. As often as not, if you ask for a Welch plug, you'll end up with something similar in appearance to the freeze plugs in your engine:




What you want is an expansion plug, so named because its diameter expands to seal:




Unless you intend to do major fuel meter disassembly (which I don't recommend), you won't be able to use Tom's screwdriver trick to pop the old plug out. You'll need to do as I recommended and drill a hole then lever the plug out with a pin punch.

If you decide to use JB Weld, as I do, you can get that at any hardware store. You won't have a problem with it.

Good luck!

Jim

DZAUTO

That is EXACTLY correct. I have ZERO issues with the JB Weld. Before switching to the PC7, per John's recommendation, I used it on MANY FI units with ZERO issues.
By the way, I found the PC7 at ACE Hardware. Other retailers may sell it.