Check out this site. It should help you. "T"

http://www.corvette-101.com/vacuum.htm#tools
my7T12010-02-22 13:29:34

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Click on images for Before and After pics!

Great.  Thanks

I have something from Doc Rebuilds thats called " What, Where and how to troubleshoot The headlamp and wiper door vacuum system". I don't have it on my computer. If I did I would send it to you. I don't think I'm smart enough to scan it. Maybe someone else has this.

I guess I am smart enough. I now have this on my computer. Private Message me and I'll email it to you.

Once you fix the leaks you can add an Air tank with a one way valve to store vacuum.  That way when the engine has some vacuum, it will store it and the one way valve keeps it when the engine vacuum is low.  These are used to compensate for the low vacuum caused by the cam.  JEGS and Summit and others sell them as aftermarket Air tanks just for low vacuum caused by the hot cams.

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Really don't think its the cam, if the system is vac tight,  check valve, relays etc are ok it doesn't take long  after start up for the system  to operate correctly, don't forget to check the fresh air inner and outer door lines and valves if you have AC, and heater controll, valves, and lines, they are also part of the system. anips2010-02-26 10:04:01

the additional tank helps and be sure the entire system has only ONE check valve. Does anyone have a schematic for the windshield washer sytem - where the hoses go on a 1969 vette?

the WW washer runs off of the WW motor, the larger center hose on the white washer assy goes to the bottle, the two smaller hoses go to wiper washer nozzels on the WW arms, if it doesn't work you might have to replace the white WW washer assy, or there might be a problem with the WW motor anips2010-02-26 15:44:31

once the Vac. Sys. is Vac. tight it really doesn't use Vac, the only time it uses Vac. is when you open or close the HL's or wipers or fool with the heater or AC, or there is a leak, you are really not constantly opening and closing those accessories, the original tank should be big enough, the add on tanks are mainly for big camed, carbed, street driven race motors with big ports and runners that don't make a whole lot of vacume, the add on tank is mainly a reserve tank for the power brake booster which you would probley use alot, for our vette's 12hg of vac. should be ok and when everything is right with the Vac. system the headlite and WW door should open and close smartley.anips2010-02-26 16:38:22

Thanks for the wiper layout but how does it fit with the headlight washers. There are three large fittings on the headlamp washer side (black pump) and the ones as you describe on the wiper side (white pump).

Sorry Nicholas, I went by my 72, I forgot 68-69 had headlite washers, my 69 is gone so I can't go look, looking through my 69 GM service manual all it tells me that  the HLwasher only works with the HL's on  and you have to hold the washer buttom down to make the solenoid  work and pump water to the nozzles on the low beam lites, I haven't found hose routing yet even if its in the manual, I'll look around through my other manuals and see if I can find something, again sorry.