Vacuum pump and oil pump are binding

[ezekiel]

Just replaced my oil pump and now my vacuum pump will not seat without binding against the oil pump.

I know there were different oil pumps, were there also different vacuum pumps?  Both are slot-type.

I can't compare the old oil pump to the new one because the previous was too short (ran for about a minute with no oil pressure before I figured out what was up) and the original one from the engine was a spline-type and I tossed it.

The vacuum pump is also new, because the engine originally had just a block off plate, but I can't put that back on because the gear I have is for a spline-type oil pump.

Cliff-notes: I'm dead in the water with a binding oil pump and vacuum pump.  Did they make different length vacuum pumps?

[theman53]

Rabbit on Roids did post sometime ago about different oil pump/vac pump lengths.

[truckinwagen]

there are different length oil pump shafts, long and short.

and there are vac pumps to match, I had the same issue, but the other way around(short shaft oil pump and a vac pump for a long shaft oil pump)
which meant that the vac pump installed without issue, but didnt drive the oil pump.

killed my bearings.

you need to find another oil pump, or another vac pump, so they match.

[ezekiel]

Is that 2 different diesel oil pumps, or 2 different oil pumps for all 8V's.  Cause I've had a short shaft and a long shaft oil pump in the car.  the short one wouldn't engage the vacuum pump, and no the long one is to long.  Is it possible the short one I had was a gasser oil pump?  Are they different?

thanks guys!

[fatmobile]

What kind of vacuum pump?
 There are 2 types.
If it's the diaphram type, check the brass bushing in the base,
 see how the metal gear is wearing into it.
 You say it's new,
 but you mean new-to-you right? ,... it's a used pump?

[ezekiel]

It's a vane-type pump, and yes, new to me.

One thing I noticed with the vane pump was that if I take the top off, I can move it up and down quite a lot.  Enough to make up the amount I need.  Is it possible to disassemble the vane pumps? 

[Quantum TD]

Are you sure you've got it seated right? You have to carefully line up the slot with the gears on the intermediate shaft. You may have to try it a few times (eyeball the slot, line up the pump with the slot, then rotate it a few degrees in either direction until is seats fully). It can be tricky, but it will work. Basically, you're trying to line up two things: the slot on the keyway, and the gears on the intermediate shaft and vacuum pump. The internals of the vacuum pump will rotate slightly when they push down onto the intermediate shaft gears, at which point the slotted opening will not line up with the oil pump shaft. So, you have to "predict" the amount the pump shaft will rotate when it slips down onto the intermediate shaft gears.

I don't think you have a mismatch problem. Here's why.

Sounds like you have a 1.5 block (only the 1.5 would have had a block off plate for the vacuum pump, as only the late 1970s Rabbits came with vacuum boost assisted brakes, and AFAIK, only the 1.5 came with the splined oil pump shaft). So, you went with a slotted oil pump shaft, which is obviously longer than the original. That means, that ANY 1.6 vacuum pump should work with that oil pump, unless you bought our oil pump from Prothe, in which case anything is possible for Chinese manufacture.

The ONLY way you should have binding is if you have a modern 1.6 oil pump (which is sounds like you have), AND you have a 1.5 liter Vacuum pump. The slots on the 1.5 vacuum pump are MUCH closer to the bottom of the shaft. In such an instance, you would have binding in a big way.

Take a look at the pic below. The pump on the left is off a 1.5. Notice how far down the slotted opening is. The pump in the middle is a 1.6 rotary pump, and the one on the right is a 1.6 vane pump. The two on the right have deep recesses to accept the shaft of the oil pump. The 1.5 on the left does not. It would bind on any 1.6 oil pump, and not seat fully into the recess on the block for the pumps shoulder.

[ezekiel]

Thanks guys, I'll give it a shot again tomorrow, with the vacuum pump top off so I can spin it around and try and get it in there.  I didn't realize it was tricky, it seemed seated, but the distance it needed to go was about the length of the slot, so that could definitely be it.

The engine is a 1.6TD from Europe.  It had mk2 mounts (atleast I think they were mk2) and I had to swap all my mk1 stuff over.  It had no vacuum pump, and had the block-off stuff, as well as the splined oil pump.

The vacuum pump I have is definitely like the middle one, with the deeper slot.  The first oil pump I put in with the short shaft probably would have worked with the one on the left.

[Rabbit on Roids]

Are you sure you've got it seated right? You have to carefully line up the slot with the gears on the intermediate shaft. You may have to try it a few times (eyeball the slot, line up the pump with the slot, then rotate it a few degrees in either direction until is seats fully). It can be tricky, but it will work. Basically, you're trying to line up two things: the slot on the keyway, and the gears on the intermediate shaft and vacuum pump. The internals of the vacuum pump will rotate slightly when they push down onto the intermediate shaft gears, at which point the slotted opening will not line up with the oil pump shaft. So, you have to "predict" the amount the pump shaft will rotate when it slips down onto the intermediate shaft gears.

I don't think you have a mismatch problem. Here's why.

Sounds like you have a 1.5 block (only the 1.5 would have had a block off plate for the vacuum pump, as only the late 1970s Rabbits came with vacuum boost assisted brakes, and AFAIK, only the 1.5 came with the splined oil pump shaft). So, you went with a slotted oil pump shaft, which is obviously longer than the original. That means, that ANY 1.6 vacuum pump should work with that oil pump, unless you bought our oil pump from Prothe, in which case anything is possible for Chinese manufacture.

The ONLY way you should have binding is if you have a modern 1.6 oil pump (which is sounds like you have), AND you have a 1.5 liter Vacuum pump. The slots on the 1.5 vacuum pump are MUCH closer to the bottom of the shaft. In such an instance, you would have binding in a big way.

Take a look at the pic below. The pump on the left is off a 1.5. Notice how far down the slotted opening is. The pump in the middle is a 1.6 rotary pump, and the one on the right is a 1.6 vane pump. The two on the right have deep recesses to accept the shaft of the oil pump. The 1.5 on the left does not. It would bind on any 1.6 oil pump, and not seat fully into the recess on the block for the pumps shoulder.

thanks quantum.. this would picture would have helped me explain everything to everyone quite a while back. no one understood what i meant by the oil pump shaft and drive gear on the vac pumps are way WAY different. and in some instances, you could end up with a non rotating oil pump.

[Quantum TD]

thanks quantum.. this would picture would have helped me explain everything to everyone quite a while back. no one understood what i meant by the oil pump shaft and drive gear on the vac pumps are way WAY different. and in some instances, you could end up with a non rotating oil pump.

Yeah. I had some Suki guy come out to my house to compare his pump to some of my pumps and blocks. He was getting intermittent oil pressure. It turns out the upper should of the shaft had worn into the brass bushing about 1.5mm and the shaft kept popping out of the keyway.

[fatmobile]

Quantum TD, you can press the pin out, pop that gear off and use the bushing inside the vacuum pump.
 They are the same bushing and the one inside has nothing riding against the top of it, swap em'.
 I know that; for the same reason I know there are 2 pumps with different lengths.
 I had a vacuum pump bushing wear and let go of the oil pump,
 stranded in New Mexico and NAPA gets me the wrong oil pump.

I'm not sure the distance the gear sits from the bottom matters, it would just cause the seal to sit farther down the oil pump shaft.
 How far does the gear sit from the vacuum pump when pushed up against the pump, compared to the other?

Does the oil pump have a hole down the center?
 There was a vacuum pump with an oil line coming from the oil filter mount,
 it wasn't fed up through the center of the oil pump shaft.
 I think that had something to do with it being shorter.

 Also with the great pictures provided, it's a good chance to notice there is a seal inside of the gear, that keeps oil pressure from leaking around the oil pump shaft.

[ezekiel]

I got it to go in today, then proceeded to puke all 4 quarts of oil onto the ground because my oil filter wasn't making a seal with my volvo sandwich plate for some reason.  Pulled it off and put the non-oil-cooler threaded pipe on there just so I could run it.  I'll figure out why it wasn't making a seal later so I can then hook up my oil cooler.

thanks guys.

[Rabbit on Roids]

how short of a period of time did it take to puke all the oil out? i think i would be pulling the oil pan and checking my bearings.

[ezekiel]

It didn't ever really start before it puked it all out.  It had air in the lines so it would try to start and die 2 seconds later.  It was fixed, and it ran last night very well.  Ran very quietly, no knock, I just gotta hope it stays that way.  I don't think there was any damage done to it.