The Ford Barn

cavalierhome · 03-05-2022, 12:31 PM

So, I found my carburetor leak, the cap jest is stripped out and leaking, the bottom of the carb is striped out. Are there oversized Cap jest or a way to insert a new thread into the bottom?

Any Idea apreciated.

Cheers

J Franklin · 03-05-2022, 12:38 PM

J-B Weld if nothing else is offered.

cavalierhome · 03-05-2022, 02:32 PM

Quote:

Originally Posted by J Franklin

J-B Weld if nothing else is offered.

I think that is what they had used before and it let go.

Cheers

cavalierhome · 03-05-2022, 02:40 PM

I would use a helicoil but I don't know what size the tread on the Cap jet is.

Brentwood Bob · 03-05-2022, 03:01 PM

Omit.

cavalierhome · 03-05-2022, 03:04 PM

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Quote:

Originally Posted by Brentwood Bob

Replace the bottom casting.
I have several.
I sent you a pm.

I don't see a PM

goodcar · 03-05-2022, 03:22 PM

Quote:

Originally Posted by cavalierhome

I would use a helicoil but I don't know what size the tread on the Cap jet is.

I might be wrong but I think the threads on the jets are metric.

Bill G · 03-05-2022, 04:12 PM

I don't think a JB Weld fix is going to get it tight enough to not leak and the tip of the jet might not be at the correct height. I vote for getting a new casting.

Oldgearz · 03-05-2022, 05:10 PM

LOOK ON EBAY. THEY HAVE A BOTTOM CASTING FOR $49.99. Search "model A zenith carburetor on EBAY".

old ugly · 03-05-2022, 06:40 PM

Quote:

Originally Posted by Brentwood Bob

Replace the bottom casting.
I have several.
I sent you a pm.

this is the best way to go. i hope this works for you.

Gene F · 03-05-2022, 07:38 PM

Quote:

Originally Posted by goodcar

I might be wrong but I think the threads on the jets are metric.

They are, plus they are pipe-thread. I bet some do-gooder taped it.

Get another lower casting.

Joop · 03-06-2022, 10:05 AM

Cavalier home

Do you have a Zenith carburetor?

cavalierhome · 03-06-2022, 10:10 AM

Quote:

Originally Posted by Joop

Cavalier home

Do you have a Zenith carburetor?

Yes it's a Holley I think.

Bud · 03-06-2022, 12:22 PM

There is an article in the current Restorer magazine for repairing threads in the carburetor casting with Helicoils.

Tom Endy · 03-06-2022, 12:52 PM

Some years back I repaired the cap jet threads in a Zenith by applying a coating of JB weld. It worked well. Attached article describes the jets threads used in the Zenith.

Tom Endy

cavalierhome · 03-10-2022, 09:43 AM

So I think I found a good way to fix the Jet issue.

I didn't want to go with helicoil because they allow fluid to leak passed the threads I think.

I decided on time-sert

I found out the threads on the Cap jest are 5mm .75 pitch

I was not able to find a time-sert in 5mm .75 pitch, but I could find 5mm .80 pitch, so I figured they are so close I could just chase the time-sert with a .75 pitch tool.

It turns out the jet is pipe tread and works perfectly with the .80 pitch time-sert.

So I threaded the jet location for the time-sert an used an old jet to chase it in.

It seems to be fine, and I hope it works well.

It seems to hold vacuum but it is hard to tell because there are so many ways that passage receives fluid. If it still wants to allow some small amount of fluid over the long term to get passed the threads I will remove the time-sert and reinstall it with some ultra copper RTV. I have used that stuff to fix all kinds of leaks on race cars and it works. But I want to test this without it at first to see

I have the carb ready to go except the secondary well didn't come with the rebuild kit so I have one coming in.

Once I finish that I will try the carb and see if it still leaks gas while parked.

I will let you all know, and if it works I hope this helps somebody else someday.

johnneilson · 03-10-2022, 10:04 AM

That sounds good
question though, isn't a 5mm x .8 an IMP 10-32?

I know on machinery I have seen 10-32 and 5mmx.75 interchanged.

John

cavalierhome · 03-10-2022, 10:38 AM

Quote:

Originally Posted by johnneilson

That sounds good
question though, isn't a 5mm x .8 an IMP 10-32?

I know on machinery I have seen 10-32 and 5mmx.75 interchanged.

John

Sincerely I don't know but it might be worth finding out.

cavalierhome · 03-10-2022, 10:43 AM

Quote:

Originally Posted by cavalierhome

Sincerely I don't know but it might be worth finding out.

Seems o be similar but not exactly the same:

https://www.emuge.com/sites/default/...ill-CardV5.pdf

Brentwood Bob · 03-10-2022, 07:38 PM

Latest Restorer has an article on installing inserts.

03-05-2022, 12:31 PM	#1
cavalierhome Member Join Date: Feb 2022 Location: Stormville New York and Naples Florida Posts: 60	Leaking Carburetor leak found HOW can I fix this? So, I found my carburetor leak, the cap jest is stripped out and leaking, the bottom of the carb is striped out. Are there oversized Cap jest or a way to insert a new thread into the bottom? Any Idea apreciated. Cheers

03-05-2022, 12:38 PM	#2
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 6,370	Re: Leaking Carburetor leak found HOW can I fix this? J-B Weld if nothing else is offered.

03-05-2022, 02:40 PM	#4
cavalierhome Member Join Date: Feb 2022 Location: Stormville New York and Naples Florida Posts: 60	Re: Leaking Carburetor leak found HOW can I fix this? I would use a helicoil but I don't know what size the tread on the Cap jet is.

03-05-2022, 03:01 PM	#5
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,420	Re: Leaking Carburetor leak found HOW can I fix this? Omit. Last edited by Brentwood Bob; 03-06-2022 at 06:24 PM.

03-05-2022, 04:12 PM	#8
Bill G Senior Member Join Date: Jun 2017 Location: Walla Walla, WA Posts: 1,062	Re: Leaking Carburetor leak found HOW can I fix this? I don't think a JB Weld fix is going to get it tight enough to not leak and the tip of the jet might not be at the correct height. I vote for getting a new casting.

03-05-2022, 05:10 PM	#9
Oldgearz Senior Member Join Date: Aug 2020 Location: Sagle, Idaho Posts: 371	Re: Leaking Carburetor leak found HOW can I fix this? LOOK ON EBAY. THEY HAVE A BOTTOM CASTING FOR $49.99. Search "model A zenith carburetor on EBAY".

03-06-2022, 10:05 AM	#12
Joop Senior Member Join Date: May 2010 Location: Glendale, AZ Posts: 3,021	Re: Leaking Carburetor leak found HOW can I fix this? Cavalier home Do you have a Zenith carburetor?

03-06-2022, 12:22 PM	#14
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 851	Re: Leaking Carburetor leak found HOW can I fix this? There is an article in the current Restorer magazine for repairing threads in the carburetor casting with Helicoils.

03-10-2022, 09:43 AM	#16
cavalierhome Member Join Date: Feb 2022 Location: Stormville New York and Naples Florida Posts: 60	Re: Leaking Carburetor leak found HOW can I fix this? So I think I found a good way to fix the Jet issue. I didn't want to go with helicoil because they allow fluid to leak passed the threads I think. I decided on time-sert I found out the threads on the Cap jest are 5mm .75 pitch I was not able to find a time-sert in 5mm .75 pitch, but I could find 5mm .80 pitch, so I figured they are so close I could just chase the time-sert with a .75 pitch tool. It turns out the jet is pipe tread and works perfectly with the .80 pitch time-sert. So I threaded the jet location for the time-sert an used an old jet to chase it in. It seems to be fine, and I hope it works well. It seems to hold vacuum but it is hard to tell because there are so many ways that passage receives fluid. If it still wants to allow some small amount of fluid over the long term to get passed the threads I will remove the time-sert and reinstall it with some ultra copper RTV. I have used that stuff to fix all kinds of leaks on race cars and it works. But I want to test this without it at first to see I have the carb ready to go except the secondary well didn't come with the rebuild kit so I have one coming in. Once I finish that I will try the carb and see if it still leaks gas while parked. I will let you all know, and if it works I hope this helps somebody else someday.

03-10-2022, 10:04 AM	#17
johnneilson Senior Member Join Date: Jun 2010 Location: 34.22 N 118.36 W Posts: 1,181	Re: Leaking Carburetor leak found HOW can I fix this? That sounds good question though, isn't a 5mm x .8 an IMP 10-32? I know on machinery I have seen 10-32 and 5mmx.75 interchanged. John __________________ As Carroll Smith wrote; All Failures are Human in Origin.

03-10-2022, 07:38 PM	#20
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,420	Re: Leaking Carburetor leak found HOW can I fix this? Latest Restorer has an article on installing inserts.