You need to get a little creative and maybe even have someone machine a
sleeve for you. A 3/8" threaded rod and nut (9/16" hex) make a perfect
puller set up. The nut will actually fit the pin and will even clear the
snap ring. The trick is that the sleeve has to fit inside the water pump
opening and the water pipe connection on the block and it should be notched
to rest on the piston, supported by the recess for the pin. It should not
rest on the side of the piston especially the ring groove. Resist the
temptation to simply pull on the pin putting pressure against the case. This
will put a side load on the connection rod which can damage the rod bearing.
After this happens when the engine fails in the future we can blame it on
the stretch bolts not the bad action dome earlier. The snap rings should be
replaced. When putting the pistons back into the cylinders they should be
inserted from the top. A ridge breaker should be used to cut the carbon
ridge. Hone the cylinders lightly. They already have some wear and removing
even a few thousandths will leave you an engine with piston slap. Note the
pistons and the pins are directional. Keep track. Clean everything. The
piston pins are only tough to remove due to carbon deposits. Solvent and
keep working them in the pistons until they can slid through with just some
hand pressure.  I have learned to remove all the cylinders to clean tem
really well, especially the top O-ring grove. I also use a bit of lapping
compound and lap the cylinders into the heads to get the top of the
cylinders really clean. This is the most important gasket sealing area. The
top o-ring is just there to keep coolant out of that space. The top gasket
is what holds back the compressive forces.

For the head nuts they should be replaced or at least cleaned with a thread
chaser. The threads need to be lubricated and the sealant only goes on the
flange. Do NOT fill the cap nuts with anything as that will hydraulically
prevent them from going all the way down. Apply the never-seize or lubricant
of choice to the stud threads only. If you have stud that doesn't tighten up
you should replace it.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jim Felder
Sent: Wednesday, October 03, 2012 1:06 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Trouble getting WBX piston out

I managed to get the heads off of all the waterboxer's cylinders but one...
and that one I had to stand on in the driveway and whang it with a hammer
like it was a brake drum. Anyway it's out and now it needs to go back in. I
have the wrist pin pulled out of the piston about 1/4 inch past the piston
edge, so I've made a little progress, but now it seems that it does not want
to move any more, at least with what I am moving it with. I have a bolt on
my puller, about 3 pounds, and I put the head through and catch it on the
far side of the wrist pin, working from the front of the engine.

Does anyone know of a better way? A better choice of puller tools (I don't
have any fancy expanding collets)? Would about an hour of propane on the
piston crown loosen things up around the wrist pin?

Got the heads back, want to get on with this project.

Jim