Vacuum Issue

[BlastIt]

My buddy has a 85 Jetta with a 1.6 NA. When starting cold there is little to no vacuum. If you let it sit there and warm up still little to no vacuum. You have to drive it for a little while to get vacuum to work the brakes. It has the vane style vacuum pump. Things we checked were the vane pump and it seemed ok. We replaced the rubber seals in the pump. We check the oil pressure it was in spec (on the low end).Checked the oil pump to make sure it was not loose or clogged it was not. We installed a diaphragm vacuum pump and it worked fine vacuum right away. Does that mean the vane pump is bad or have we overlooked something? If the vane pump is bad is there a rebuild kit for them? Any thoughts or suggestions?

Thanks
John

[Quantum TD]

It sounds like the pump is bad. It could just be the check valve, but that is not sold as a separate part. There is no rebuild kit, of which I am aware.

[theman53]

I have one doing the same thing. I will watch to see if you get it figured out. Mine seemed to work fine after about a mile or so down the road, but I didn't like waiting for brakes. I also trashed my master cylinder at that time I believe from pushing too hard.

Libbybapa has a thread I think of repairing the check valve with some after market solution.

[R.O.R-2.0]

what about putting some grease, or vaseline on the vanes? and smear some on the inside of the housing.. or will it mess the vanes up?

[BlastIt]

Libbybapa has a thread I think of repairing the check valve with some after market solution.
[/quote]
 Would you have a link to it? I tried searching for it wasn't able to find it.

[theman53]

http://www.vwdiesel.net/forum/index.php?topic=27851.0

Not libby...not fixing the check valve, but might help you.

BTW this was the one I was thinking of.

[R.O.R-2.0]

the check valve has nothing to do with the operation of the pump, because i know of people fixing these by taking the check valve out (because they broke the plastic hose barb off it) and then drilling and threading the cover to accept a brass hose barb. works fine afterwards, even without the check valve.

maybe the vanes are gunked up, take the top off the vac pump, and clean the inside with carb cleaner..

almost sounds like there is an oil of some sort in there, and it has degraded, and gotten sticky. and it wont let the vanes release from the shaft and come in contact with the sides of the vac pump.. if the vanes dont freely move, then it will have a hard time making vacuum.

[theman53]

I took mine apart and the vanes are free it just doesn't work. I suspect his is similar. The only thing I could think of is maybe there is a restriction in the oil port and it just takes a long time to get oil up there. Good luck and let me know what the fix is as mine I just replaced with another and it works fine

[BlastIt]

We had this one apart also. It got cleaned up, checked the lash for the gears. We went over every piece of it can't find a reason why it will not work properly. I guess we'll end up swapping this one. We may try to change the vanes and see if that makes a difference.

[macka]

get a newer style pump, you can score them off of the early mk 3s too