Cliff's Quadrajet Parts and Rebuild Kits
General Category => Quadrajet Carb Talk and Tips => Topic started by: davel on November 10, 2019, 08:49:29 PM
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I'm just posting this as a reference for anyone attempting to remove the idle mixture screw caps on their Quadrajet. This particular carb is model #17059226 from a 1979 G20 Van with a SBC400. The idle mixture screw caps on this carb are hardened so it's not possible to drill through them.
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20kit_zpspm98kzxl.jpg)
This rotary accessory kit can be purchased from Harbor Freight for $20
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20cutoff%20wheel_zpsupnato2i.jpg)
It contains a number of different abrasive cutting wheels. This one is the smallest and it cuts right through the hardened steel cap.
(https://oi1377.photobucket.com/albums/ah78/davidliatti/cap%20in%20baseplate_zpssoqa6jru.jpg)
I chucked it in a cordless drill and made 3 horizontal cuts through the cap and 2 light vertical scores. Then used a small punch and hammer to break a hole in the cap.
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20cap%20removal_zpsng4yl43q.jpg)
You can now hook the cap with the thread of a drywall screw. Grab the screw under the head with a locking pliers and drive the cap out by tapping up on the pliers with a hammer. It takes some force.
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20screw%20in%20cap_zpsxb6t39hu.jpg)
Voila!
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20mixture%20screw_zpssymdrynz.jpg)
This method leaves very light score marks on the front of the base plate by the mixture screw holes. These marks can easily be removed with a file.
Online I couldn't find any images or dimensions of the cap or it's depth in the baseplate in relation to the mixture screw. So here's that info.
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20cap%20length_zps0rqq6rf3.jpg)
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20cap%202_zpsagf0rk7k.jpg)
(https://oi1377.photobucket.com/albums/ah78/davidliatti/1%20cap%20and%20screw%20length_zpsodccubvj.jpg)
Different model/year Quadrajets may have different types of caps. That I don't know for sure. But this cap actually fully encapsulated the screw head inside the baseplate.
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...very nice write up with pictures...now would be a good time to cut grooves in those mixture screws to allow use of a regular flat head screw driver.
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I sell metric threaded idle mixture screws that are longer and stick out of the baseplate plus slotted for a screwdriver, the are $8 per pair......Cliff
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Cliff....what are the measured length of your custom mixture screws?
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Why are the pictures all blurry?
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Not sure about the length but they are about 1/4" exposed from the edge of the casting for easy access......
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Why are the pictures all blurry?
Uh-oh. Problems with the Photobucket account...I'll try to attach the images below.
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images
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Thank you :)
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nice work thanks . i do it a little different i weld them i weld a washer on first and then a nut and pull with slide hammer can't tell that i was ever there .fwiw