On my 1956 Chevrolet 6100, I took the Vacuum Cylinder Assembly off the 2 speed rear axle to clean it up. Keep in mind I have no idea if this works or not, the vehicle has not been driven in who knows how long. Currently I have it running and am just finishing up doing a complete brake system overhaul.

Anyways, I took the unit off the axle to inspect and clean up as one of the hoses has been disconnected and mud dobbers may hay gotten in there. I took all 10 screws off the top and could not get it separated. Tried a chisel and then a small pry bar, and nothing. I took the two bolts off that hold the flange to the housing and when I was pushing the push rod dark fluid ( differential fluid?) came out the top hole of the housing. I am pretty sure the diaphragm in in good condition, because when I push the rod in and cover one of the holes with my finger it stays in place and only releases when I move my finger off the hole.

I have a few of questions:

One is it normal to have fluid in this unit? How big of a deal is that?

Should I keep trying to the the diaphragm housing apart or leave well enough alone? If so I may damage the actual diaphragm, does anyone have a part number for that diaphragm?

Attached is a picture of the two ports, as you can see the top has fluid and the bottom is bone dry.

Thanks for your input.

edit:

after posting this I found this post from 2017 - Post

and subsequent eBay listing for new diaphragm - Diaphragm

same questions though, is it worth trying to get this thing apart?
Attachments
20201205_153124.jpg (162.03 KB, 59 downloads)

Last edited by DougH6100; 12/06/2020 12:41 AM.
1956 Chevy 6100 2-ton Dump Truck
Resto Progress in Big Bolts
Story in Stovebolt Gallery
Google Photos