Is this a stock vacuum pump?
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- Zoltan
- Posts: 136
- Joined: 18 years ago
- Location: Honolulu, HI
Is this a stock vacuum pump?
I am in the process of replacing the alternator, but it looks like the shaft of the rebuilt alternator is about 1/16" too long, so when I bolt on the vacuum pump, it locks up. I learnt this by almost setting the V-belt on fire when I restarted the truck. There are some size discrepancies, so I am wondering if I have a stock vacuum pump, or something else. Here is what the pump looks like
On the back side, there are 3 tiny screws that attach the back cover to the pump, which is different from the picture shown in the FSM. When I looked at the specs in the 82-83 FSM, my pump seems to be way larger.
Vane length "A"": 15.24mm vs 13-14mm (FSM)
Vacuum pump housing ID: 59.75mm vs 57-57.1mm (FSM)
It seems unlikely that the pump wore down 2.65 mm from the specs.
On the back side, there are 3 tiny screws that attach the back cover to the pump, which is different from the picture shown in the FSM. When I looked at the specs in the 82-83 FSM, my pump seems to be way larger.
Vane length "A"": 15.24mm vs 13-14mm (FSM)
Vacuum pump housing ID: 59.75mm vs 57-57.1mm (FSM)
It seems unlikely that the pump wore down 2.65 mm from the specs.
Last edited by Zoltan 17 years ago, edited 1 time in total.
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
- asavage
- Site Admin
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- Location: Oak Harbor, Wash.
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Re: Is this a stock vacuum pump?
TTBOMK, the automotive diesel vac pumps are all interchangeable. Did you read this thread?Zoltan wrote:I am in the process of replacing the alternator, but it looks like the shaft of the rebuilt alternator is about 1/16" too long, so when I bolt on the vacuum pump, it locks up.
- Zoltan
- Posts: 136
- Joined: 18 years ago
- Location: Honolulu, HI
I did. I did not remove the rotor from the pump, so there's no possibility that I put it back in the wrong way. I only removed 2 vanes, and I measured the ID of the house through the gaps where the vanes go.
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
- asavage
- Site Admin
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Um, was Philip in that last post? Gotta stop doing that, Philp!
Zoltan, I have a working assy. on an '82 SD22:
If you really need the info, I can pull the vac pump off and measure the rotor's protrusion from the back face of the alternator. May not be able to do that until Sunday though.
Zoltan, I have a working assy. on an '82 SD22:
If you really need the info, I can pull the vac pump off and measure the rotor's protrusion from the back face of the alternator. May not be able to do that until Sunday though.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- philip
- Deceased
- Posts: 1494
- Joined: 18 years ago
- Location: Southern California, USA
Re: Is this a stock vacuum pump?
There is nothing preventing you from TRYING assembly with the rotor installed the other way and then see if it still binds up when turned by hand.zoltan wrote:I did read it. I did not remove the rotor from the pump, so there's no possibility that I put it back in the wrong way.
-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
- Zoltan
- Posts: 136
- Joined: 18 years ago
- Location: Honolulu, HI
It's most peculiar... the reason why the vacuum pump was locking up was that I tried to use an O-ring that was 0.7mm thicker than the original. The new alternator shaft was the perfect size.
First, I went with Philip's suggestion and tried to flip the rotor... however, in my vacuum pump, one cannot put the rotor in the wrong direction. One side of the rotor is machined out (about 2 quarter coins deep) and the back cover has a corresponding circular protrusion. So if one tried to put the rotor in the wrong direction, the back cover would not be able to go back on, it would stay 2-3mm ajar.
This picture shows the old O-ring on the left and the new one I tried to use on the right. As you can see the new one is almost a perfect match as ID is concerned.
Here you can see how the new O-ring fits the groove on the vacuum pump (I am still hoping that some one recognizes what kind of vacuum pump I have).
However, when one looks at the side profile, the old O-ring is much flatter than the new one (1.72mm vs 2.54mm).
I didn't want to believe, that such a small size difference would make the pump lock up, so I switched back and forth b/w the 2 O-rings twice to ascertain that THAT was the problem... But no doubt. I guess what might have happened was that when I bolted on the vacuum pump with the new O-ring, the uneven clamping force (the bolts are not 120 degrees apart, they are distributed somewhat unevenly around the circle) must have caused the housing warp a tiny bit, which led to the lock-up.
A valuable lesson learnt: "One should not screw with O-rings, because they will screw you back !!"
First, I went with Philip's suggestion and tried to flip the rotor... however, in my vacuum pump, one cannot put the rotor in the wrong direction. One side of the rotor is machined out (about 2 quarter coins deep) and the back cover has a corresponding circular protrusion. So if one tried to put the rotor in the wrong direction, the back cover would not be able to go back on, it would stay 2-3mm ajar.
This picture shows the old O-ring on the left and the new one I tried to use on the right. As you can see the new one is almost a perfect match as ID is concerned.
Here you can see how the new O-ring fits the groove on the vacuum pump (I am still hoping that some one recognizes what kind of vacuum pump I have).
However, when one looks at the side profile, the old O-ring is much flatter than the new one (1.72mm vs 2.54mm).
I didn't want to believe, that such a small size difference would make the pump lock up, so I switched back and forth b/w the 2 O-rings twice to ascertain that THAT was the problem... But no doubt. I guess what might have happened was that when I bolted on the vacuum pump with the new O-ring, the uneven clamping force (the bolts are not 120 degrees apart, they are distributed somewhat unevenly around the circle) must have caused the housing warp a tiny bit, which led to the lock-up.
A valuable lesson learnt: "One should not screw with O-rings, because they will screw you back !!"
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
- philip
- Deceased
- Posts: 1494
- Joined: 18 years ago
- Location: Southern California, USA
The 1982 FSM page BR-15 does not show the three phillips screws securing the center plate to the pump housing. I know my truck's vacuum pump does not have them. But the 1984 FSM page BR-13 does show those screws. So ... you've got the later version.( )Zoltan wrote:A valuable lesson learnt: "One should not screw with O-rings, because they will screw you back !!"
Good sleuthing!
-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
- asavage
- Site Admin
- Posts: 5433
- Joined: 18 years ago
- Location: Oak Harbor, Wash.
- Contact:
I'm guessing that the fatter o-ring caused the pump's backplate to distort into the rotor. Either that, or the whole assy. cocked when tightened. Either way, I'm glad you got it sussed.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- Zoltan
- Posts: 136
- Joined: 18 years ago
- Location: Honolulu, HI
So is it for a SD22 or SD25? I noticed oil dripping from the O-ring this morning so I will have to go back to the dealer to get the right one.the 1984 FSM page BR-13 does show those screws. So ... you've got the later version
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
- asavage
- Site Admin
- Posts: 5433
- Joined: 18 years ago
- Location: Oak Harbor, Wash.
- Contact:
The SD is just chock full of weird-sized o-rings. I ran into the same problem with the oil cooler o-rings. IIRC, those o-rings were NLA from Nissan, and I didn't pursue the forklift supplier angle, but I'm sure they would have been available there.
I think I went to O-rings West and bought some. Min. qty was (50), so I may still have (48).
I think I went to O-rings West and bought some. Min. qty was (50), so I may still have (48).
Last edited by asavage 17 years ago, edited 1 time in total.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
- philip
- Deceased
- Posts: 1494
- Joined: 18 years ago
- Location: Southern California, USA
What does "later" suggest? Ask the partsman to compare part numbers for an '82 SD22 vs an '84 SD25. Has to be <$50 for one of each.Zoltan wrote:So is it for a SD22 or SD25? -snip.the 1984 FSM page BR-13 does show those screws. So ... you've got the later version
-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22
"Im slow and I'm ahead of you"
- Zoltan
- Posts: 136
- Joined: 18 years ago
- Location: Honolulu, HI
Woah.... $7.20 ! I prematurely placed an order at Nissan to find out later tonight that it was leaking at the fittings of the VP connecting hose... Part# is 14688-61503, but the parts clerk couldn't tell if it was still available. We are having huge winds lately and his internet connection was down.Has to be <$50 for one of each.
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
- philip
- Deceased
- Posts: 1494
- Joined: 18 years ago
- Location: Southern California, USA
- asavage
- Site Admin
- Posts: 5433
- Joined: 18 years ago
- Location: Oak Harbor, Wash.
- Contact:
Philip, I think it's $7 for the o-ring to the alternator, not the hose, I think that's what Zoltan was saying.
Regards,
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Al S.
1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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