2H alternator (12V) on my 1980 HJ47 has been dying a slow death. After a lot of sleuthing, I found a new one in AU. It just arrived today. However, the new one has a different configuration of lines into/out of the vacuum pump than the old one. The old one had a vacuum line and TWO oil lines (to the block). This new one has a vacuum line but only ONE oil line (to the block). Best guess, after consultation with another more learned than me in these and many other things, is that my old alternator had a return oil line going back to the block but the new one does not have one or need one. If that's the case, I am tempted to plug the return line at the block and go with the single oil line. Didn't see anything in the older posts so thought i'd throw this out to the masses to see if anyone has seen this before. Thanks in advance for offering clarity.
2H Vacuum Pump Configuration?
- Thread starter hayseedlawguy
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Take some pics and post them here. Maybe someone here will be able to help after seeing a pic.
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AFAIK they all should have 2 lines connected to the block.
The vacuum pump needs oil for lubrication and cooling so that one line from the block (to supply that oil).
And the pump must discharge the air it sucks (as well as the spent cooling/lubricating oil) somewhere ... so that that's the second (larger) line to the block.
- Thread starter
- #4
Thanks for intel. Stand by for pictures.
- Thread starter
- #5
Here's one pic. If you'll look at the old one, you'll see there's a hole in the cener of the vacuum pump. There's a hose that threads into that hole and connects to the block.
Thanks. I'll try and post a pic of the hoses, specifically where they attach to the block.
Thanks. I'll try and post a pic of the hoses, specifically where they attach to the block.
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- Thread starter
- #6
Here's another pic that shows the two hoses attached to the block. The lower hose (i.e. the one that does not have the muffler clamp attached) threads into the infamous third hole in the old vacuum pump. The upper, silver colored hose (i.e. with the muffler clamp attached) fits onto the flanged fitting of the vacuum pump. Hope this helps.
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Again, my question, admittedly naive, is whether i can simply plug the lower hose at the block.
My manual shows only two hoses attached to the vacuum pump so its a mystery why i ended up with a 3rd.
. Again, my question, admittedly naive, is whether i can simply plug the lower hose at the block.
My manual shows only two hoses attached to the vacuum pump so its a mystery why i ended up with a 3rd.
Looking at your picture, the one at the bottom is the vacuime, the one sticking out the back is the oil return, the 12mm-14mm nut on the side of the pump is the oil inlet.Remove that and fit the oil pipe. Dont forget the two copper washers.
it must have an oil return. take the new pump, blow into the oil-in, and where the air comes out is the return line.
J
J
whitey45
SILVER Star
Brian, the plug on the right side in the pic above,take that out,this is the 3rd connection!
- Thread starter
- #10
You're right - that is indeed the third hole! I hadn't noticed it because it's not threaded into the vaccum pump itself but rather threaded into the alternator casing (actually into a little bell housing that marries up to the vacuum pump). Just hooked everything back up and I'm rocking. Huge thanks guys. Would have felt pretty stupid taking it to my regular Troopy mechanic to figure that one out - hope he never finds out!
