[Vwdiesel] crazy cam gear removal (fwd)

[Val Christian]

Loading the pully with a puller helps.  Don't rely on the belt 
tension to help you, as it's force is vectored to potentially help
hold the pulley on.  High puller tension is not necessary.

If you can, pretreat with a light penetrant.  I like liquid wrench,
or Let-go.  Some people like PB.  WD-40 is too viscous to really help
on this sprocket.  

Sharp raps with a small hammer, or a larger hammer and a drift,
applied to the base of the sprocket (where it's thick near the camshaft)
will be helpful.  Use of a rubber hammer as old Bentley's suggest,
results in more force, but less shock.  Shock is the key.

Thermal stress, of heating things will help.  Unfortunately, the place you 
should heat is the camshaft.  Nice and hot, and real fast (oxy acetylene).
But I DO NOT RECOMMEND this, since that could damage the metal structure of
the cam shaft.  Heating to 400F is probably OK.  If you do heat, use
a soft flame on the camshaft, and apply raps to the sprocket as it cools
off.  I'd aviod a propane torch, as it's too large a flame, and too little
specific heat per area.

Keep the bolt and washer on, so that the sprocket doesn't fall and get 
damaged.

Puller tension is not a big deal.  You don't have to crank on the puller.
I've gotten difficult ones off without a puller.  If you have one, it's
OK, though.

If you can, soak overnight with the light penetrant.  

You have some light corosion, on a machined and compressed surface.  The
oxides of metal are harder than the metal, but they are also more brittle
than the metal, thus the value of shock.  Heating the camshaft helps
expand it, crushing the rust matrix.  However, the sprocket is softer
material than the camshaft, and therefore the matrix may not crush as well.
There probably is very little "material" holding things together.

Most VW diesels I've seen (well all from the factory) don't have a key in
the keyway.

If you still have trouble, give me a phone number, and times to call, and 
I will help you.  You will get it off, and with appropriate care, you will
not damage anything.

Val





Forwarded message:
> 
> it sounds like you're doing everything i've ever done.
> if there's another good trick out there that someone
> comes up with i'd love to hear it!!
> 
> as far as advice - i'd just say keep working on it.
> don't give up - sometimes they'll stick at first but
> then eventually give. but be careful about putting too
> much pressure or stress on that gear! unless you don't
> mind replacing it, which i guess you might end up
> getting stuck with. i'd just keep penetrating oil on
> it and let it sit along with putting pressure on it
> with the puller and tapping it lightly as well as the
> heat. i think all those things are good. just
> alternate from one to the other (or multiple at once -
> even better) and give it time to sit with the oil and
> puller just sitting on it with pressure. maybe it will
> move a hair? as long as it's not a big hurry then you
> should be able to get it off eventually.
> 
> oh yeah, make sure that your puller is really pulling
> straight. it can make a big difference, and sometimes
> they really seem to want to pull crooked in spite of
> everything! tho you having drilled it a bit should
> keep at least that part pretty good.
> 
> good luck!
> erik
> --- Bart Wineland <bwinelan at allegheny.edu> wrote:
> 
> > Thanks Sandy. I didn't describe my technique very
> > clearly but I am doing it 
> > just as you suggest. Grabbing through the gear holes
> > with the arms pointing 
> > into the center of the hub. I have rapped the head
> > of the sprocket bolt 
> > harder than I know I should, or want to and I did
> > not want to have to heat 
> > the gear but have done both, still with no success. 
> > I center punched and 
> > drilled the center of the gear bolt to keep my
> > puller stud from wandering 
> > off the bolt head and falling off, so I am getting
> > good pressure now on the 
> > gear and that bugger still won't come off.  I tore
> > my old junk engine apart 
> > a month or so ago just to practice and had no
> > trouble getting that gear 
> > off? I'll keep trying and thanks for your response.
> > 
> > Bart
> > 
> > At 06:58 PM 9/10/2004 -0400, you wrote:
> > >At 05:12 PM 09/09/04 -0400, you wrote:
> > >
> > >.  Right now I am beating my head trying to get the
> > > >stupid cam gear off. The bolt came out no problem
> > but the gear will not
> > > >pop. I know it is a tapered shaft with a key and
> > can't figure why it won't
> > > >come off.  I have a 2 jaw puller that is kind of
> > flimsy and keeps flying
> > > >off but it is the only one I have that is slim
> > enough to get behind the
> > > >gear.
> > >
> > >1. It is not keyed. there is a slot, but no key, as
> > it has to be
> > >"adjustable" to time the cam shaft at belt
> > replacement.
> > >
> > >2. It is unwise to use a puller that grabs the rim
> > of the sprocket, as it is
> > >cast iron like the pump sprocket, and can shatter
> > if subjected to that kind
> > >of abuse. Best to get a puller that will grab the
> > insides of the holes next
> > >to the hub.
> > >
> > >With the sprocket bolt in place (to protect the
> > threads) and backed out a
> > >turn or two, apply pressure with the puller, then
> > tap the center bolt of the
> > >puller while it is under stress. It should pop off.
> > >
> > >Sandy
> > 
> > _______________________________________________