My '74 2.0l Kombi had a few problems, so I've pulled the motor out for a bit of a look around. There was a burnt exhaust valve which was expected, and the oil leaks seem to be coming from the dipstick bellows, but what I'm not sure about is the low oil pressure.
The light used to come on when braking on downhill slopes, if the oil wasn't really topped up. I figured that the mains or big ends were shot, but now that I've got it apart, I can't find anything wrong with it. Even the shells on the camshaft look perfect.
I've read John Muir's section on the bypass valves, and I'll try to get that big screw out tonight to see if that's the problem, but if it's not, then where do I start looking ? I havn't pulled the oil pump apart, but do they ever give problems anyway ?
It would give me the miseries big time if I put it together again and it still had oil pressure problems.
Any ideas ?
Thanks,
Nitram

Maybe your oil light sender is knackered and grounding somehow ??

I don't think so, because it seems related to revs. If you rev it up a bit the oil light goes out. Has anyone ever had any probs with oil pumps, or are they usually pretty bulletproof ?

Ive seen problems in similar designs in hydraulic system but not in vws. wear in the pump was the cause

Hey Nitram hows it goin dude,its a bit late for this BUT http://www.1800vw.bizhosting.com/qa_lowerendck.htm 

our kombi had this problem when we bought it, unbelievably the oil pressure relief valve had been assembled wrong ie
somebody put spring in first, then piston , then screw in plug!!
doubt if it is the same cause in your case, but worth me posting anyway

What was your oil temp? Oil weight? What was the oil pressure?
On my old motor (2L) the oil light would flicker on/off with the motor at idle (~700rpm) once the oil was over ~120C. Keeping the revs up kept the oil light off.
The oil light can come on with oil surging in the sump, but I have mainly seen it when cornering, not braking.

Now you have cheacked the bearings and end play are to spec, and you are checking the relief is good, so some ther things to consider, a blockage in the oil filter or cooler (is it still a stock setup?) will drop pressure at the pressure switch.
There is an o'ring between the suction tube and the case which can cause the pump to suck air if it's perished (can only check with the case split), Also check the welds in that steel tube for cracks. The oil pump needs to be a very neat fit in the case for a similar reason, and confirm the oil galleries line up correctly. Oh, I assume the strainer is clean and in good nic also.
The pumps do wear, but all the type 4 pumps I have removed all appear servicable. You need to check the length of the gear compared with the width of the housing.
Also check the little things like the cam followers etc. Excess wear in them will cause leakage from the oil pressure gallery.

If all checks out OK, you can buy larger pumps. Stock is 24mm gears. Schadec make nice aluminium pumps with 26, or 30mm gears.

Richard