Oil sumps and such

[foreverska]

Is there a reason studs are used here instead of bolts? I get it on parts that are particularly hard to line up but I wouldn't consider sumps or plates one of those items. I think the studs are pretty squirrely without a bottom to the hole. I'm getting some leakage from my sump so I need to drop it and wondered if I could just replace the studs with bolts. I don't see why not but I'm no master mechanic.

They're pretty standardly 6MMx1.0, right? There's no funny year dependent stuff? (Oct '69)

[helowrench]

When I mounted a deep sump, I wandered in to Lowes, and purchased grade 8 internal hex screws in the appropriate thread.
this allowed me to use a nice t handle allen key upon installation.

It is preferred to use studs on the drain plate, as these get removed often, and the repetitive usage of a bolt in the softer engine case will wear out the threads over time.

[Marc]

...the repetitive usage of a bolt in the softer engine case will wear out the threads over time...

Indeed...and in a pretty short time, too. One stud also performs double duty as the holddown point for the oil pump pickup pipe - it's longer, and has a shakeproof nut & flatwasher up inside that's nearly impossible to reach on an assembled engine. Without it, the pickup can swing up a little - it's not likely to come completely out (that'd obviously be a disaster) but if it works loose, air can be drawn in where the tube enters the case, and aerated foamy oil doesn't lubricate well.
With a deep sump there's no longer concern about wearing out the threads from repeated use, so one could justify using bolts for the other five..but personally I prefer to Loctite longer-than-stock studs in place and use shakeproof nuts on the sump side.
The newer Berg sumps have counterbored holes and special shouldered nuts which eliminate the need for the longer studs...at least until you lose one of the nuts

[Phil69]

Use the original Vw nuts or buy some dome nuts. Always replace the gaskets,copper washers and anneal them before fitting.
Never torque beyond 5ftlbs you will pull the stud out of the case eventally.
A good tip I was given was to flat the sealing side of the sump plate with some 800 grit paper and a drop of oil. Either on a flat piece of glass or a surface plate.
I never use any sealant and have never had problems with leaks from the sump area.

[Marc]

...A good tip I was given was to flat the sealing side of the sump plate with some 800 grit paper...

I've never found it necessary to be that fastidious (on the stock steel sump plate, anyway)...I place the plate rim-down on a concrete floor, and "invert" the dimple at each stud hole if needed by centering the ball of a small ball-pein hammer on it, then smacking with a larger hammer.

I know, I know, it's bad practice to strike a hammer with another hammer but I've never had one chip from this relatively mild abuse...wear safety glasses if you're paranoid.

[Phil69]

I've never found it necessary to be that fastidious (on the stock steel sump plate, anyway)...I place the plate rim-down on a concrete floor, and "invert" the dimple at each stud hole if needed by centering the ball of a small ball-pein hammer on it, then smacking with a larger hammer.

I hadn't thought of doing the job like that to be honest Marc.
It saves buying expensive sand paper as most concrete floors tend to be flat enough just to take off the worst.
Anther good tip.

[Marc]

Since all you're doing is pushing back the dimpling which develops around the stud holes, the floor needn't even be particularly flat.

[aussiebug]

I just cut my gaskets out of nice thick gasket paper and let them take up any slack/unevenness.

Oh - and occasionally flatten any unevenness out of the alloy oil strainer plate with gentle blows of a hammer on a flat surface.

It's worked for me for 40 years.