62 vacum connection

[Roger B.]

Where does the windshield vacum canister connect to for a vacum?
How can I check when conected if the canister holds a vacum?
thanks
Roger

[Christopher R.]

Re: 62 vacum connection

The vacuum cannister gets its vacuum from the left rear carburetor mounting stud. That stud is hollow into the manifold.

The vacuum cannister has 2 ports. 1 is open into and out of the can. That one goes to the system. The other too goes into the can, but it has a check valve, so that vacuum can be sucked out, but no air can go in. This second one is where the hose from the carb stud attaches.

You can test them with a Mityvac, or by attaching a hose and sucking on them.

If you're diagnosing this system, you'll want the hose diagrams from the AIM.

[Greg S.]

Re: 62 vacum connection

Christopher is correct for the carb vacuum source for a 250 and 300 horse. The 340 horse has vacuum pulled from the center rear of the carb using a special fitting. The mounting stud is solid on the 340. I am not sure about the fulie.

[Stephen G.]

Re: 62 vacum connection

FI cars come off the FI "doghouse" drivers side rear.

[Terry B.]

Re: 62 vacum connection

I've been investigating getting my windshield washers working on my 340HP 62 and find I am missing the vacuum connection. I've looked at the aftermarket vendors and haven't found the plumbing I think I need. Part of that is the take off from the carb.

I noticed a carb (from a 67) on Ebay http://cgi.ebay.com/ebaymotors/62-Co...item3eee4bbcfd the second and third pictures seem to show some of the hardware I am missing. Can anyone confirm that the orange tube is for the vacuum connection for the windshield washers?

[Christopher R.]

Re: 62 vacum connection

1. Greg, the 340 also uses that special hollow stud (p/n 3749170). See Section 396, Sheet 1.00 of the 1962 AIM in the options section in the back. On the 250 and 300, the distributor vacuum advance hose is connected there, and the windshield washer hose "tees" off of it. On the 340 (because there's no distributor vacuum advance), the windshield washer hose goes directly to that stud.

2. Terry, I don't know what's up with that carb. I didn't think 3269s were made after 1962. After 1962, the 3721 was the service replacement carb. On the 3721 and other 63-65 AFBs, that orange line is for the distributor vacuum advance line. On the 3269, I believe that hole was plugged. Somebody who knows more than me about 1962 to 1965 Corvette AFBs needs to weigh in on this.

[Gregory C.]

Re: 62 vacum connection

Greg,
Gregg Cesario in FL with a '62 327 340hp.
You can check out the meet pictures from Vinnie Peters. Mine is the only fawn beige entry.
I got deductions for not having a functioning windshield washer hoses with reservoir and canister set up at the Regional in Tampa last month.
I have now corrected the problem with all the hoses from the WW correctly EXCEPT the carb vacuum connection to the vacuum canister.
I have been going crazy trying to figure out that fitting which currently has a threaded plug in place.
Your guidance / advice as to where I can get it.
I tried Zip with no luck but I may be searching incorrectly.

Update,
Greg, when I used your P/N 3749170 it popped right up on Zip - a whopping $12 repro part.
As you accurately stated, the P/N is not displayed in the AIM just noted as Category 2 covering non displayed P/N's.
Follow on questions however, is there a routing diagram showing the correct path of the hose from the vacuum canister to that special carb fitting and is the vacuum canister connection at the top or bottom fitting ?


Thanks in advance...

[Gregory C.]

Re: 62 vacum connection

Greg,

This story keeps unfolding but I think this last piece I uncovered has wrestled it to the ground and it was uncovered quite by accident.

Turns out that the P/N 3749170 was the right church but the wrong pew intended for the vacuum advance which is stand alone for a dual point 340 hp option. Odly enough I found it while browsing through the Paragon catalog while searching on pg 75 with a schematic of a 58-62 WW w/o FI is located. Suddenly I saw Detail A and a blow up of the area with p/n 755 and lo and behold, there was the picture of the fitting. I then searched the catalog on 755 and it took me to page 76 where the p/n was located / described !

It is the missing piece of how the vacuum canister connects to the carb to obtain its vacuum. Cost is ~$20, has a 1/8 nipple / threaded L shaped configuration. and is available through multiple sources such as Paragon (P/N 755), Zip (P/N FI 157). However, be careful in your searches with sites other than these two cuz' some vendors offer the labeling as a plenum FI part or do not carry it at all (Corvette Central).

This part may also be for a FI engine but this is the correct one for the 1962 340 hp AFB carb. The vacuum port for the WW is located at the rear center of the carb close to the top of the intake manifold. Additionally, if you have a vacuum in place hexed threaded bolt installed, it needs to be removed and replaced with this (755 / FI 157) part. However, use caution not to replace the hexed headed threaded bolt with this L shaped threaded / nipple part unless you are ready to hook up the vacuum canister hose to the WW. I did not try it but likely the engine car will not run well.

Additionally, you need not remove the carb to exchange parts as a Paragon tech tip.

Good luck...