After the installation of new master and wheels and while trying to bleed the system as per the TM. I noted that there was no passage of fluid from the bleeder. Removal of the complete bleeder allowed fluid to pass. Further inspection revealed a ton of dirt and rust clogging the bleeder screw passage. Hand reaming with a drill bit corrected the issue. Obviously the clog was from the exposure to gunk and water from pointing straight up. Covering the bleeder was the appropriate fix.
I remembered from my VW Beetle repair days about the rubber "mushrooms" that all air-cooled VW's had over the bleeder screws on the backing plates to keep the dirt out. I searched these out and found that that they could still be obtained at a cost of $1.25 each. The VW part number is 211-611-483. I found them cheapest here
http://www.jbugs.com/store/merchant.mvc ... Code=18101
They are just a push on rubber nipple that will keep gunk out of the bleeder screws. I have installed them on the hydrovac and on all the bleeders on the wheels. I figure it is cheap insurance for rust and such.
Bill
