Ahhh yes, a very Volkswagen failure...

[Qaaaaa]

Post-1985, Volkswagen decided to save eighteen cents per car by not keying their crankshafts. Instead, crankshaft sprockets are kept in rotation with the crankshaft with a nifty little notch and tab setup (other manufacturers probably do this too, but I don't own non-VWs). The sprocket tab thingy looks like this:

However, after hundreds of thousand of miles, sufficient abuse, and moisture intrusion, the tab can break off or the notch can widen, like so:

You'll notice that these pictures are kinda crappy. That is because I took them, because these are from my Golf, which I am finally digging into.

There are two main methods of fixing this. The first is replacing the crankshaft, which I could do, but this is the hard way, and I am somewhat lazy and have very little to lose.

The second way is to "fix" the crankshaft. There are two ways of doing this- welding on additional material and grinding it down to the correct spec, or tapping the nose of the crankshaft and putting in metal dowels that are matched to the sprocket. The harder way is to pull the crankshaft and do this all in a vice/with a drill press. Again, I am very lazy, leading me to the easiest way of fixing this, taking a sprocket and drilling it in a press, then using the sprocket as a template to drill the crankshaft, allowing pin installation.

Wish me luck.

[RallyDarkstrike]

@qaaaaa said in Ahhh yes, a very Volkswagen failure...:

Post-1985, Volkswagen decided to save eighteen cents per car by not keying their crankshafts. Instead, crankshaft sprockets are kept in rotation with the crankshaft with a nifty little notch and tab setup (other manufacturers probably do this too, but I don't own non-VWs). The sprocket tab thingy looks like this:

However, after hundreds of thousand of miles, sufficient abuse, and moisture intrusion, the tab can break off or the notch can widen, like so:

You'll notice that these pictures are kinda crappy. That is because I took them, because these are from my Golf, which I am finally digging into.

There are two main methods of fixing this. The first is replacing the crankshaft, which I could do, but this is the hard way, and I am somewhat lazy and have very little to lose.

The second way is to "fix" the crankshaft. There are two ways of doing this- welding on additional material and grinding it down to the correct spec, or tapping the nose of the crankshaft and putting in metal dowels that are matched to the sprocket. The harder way is to pull the crankshaft and do this all in a vice/with a drill press. Again, I am very lazy, leading me to the easiest way of fixing this, taking a sprocket and drilling it in a press, then using the sprocket as a template to drill the crankshaft, allowing pin installation.

Wish me luck.

Well, that all sounds like a PITA....good luck!

[MM54]

Not only did they save eight cents on the key, they reduced the BOM which made the accountants happy AND saved up to 10 seconds on the assembly line - it's a win-win-win for them and a huge pain in the ass for everyone else!

[Qaaaaa]

@mm54 I mean, it took 25 year of abuse for this to happen. Most cars don't last long enough for an issue like this to crop up. Mk3 VWs are well past the stage of their life cycle where wear items are failing and new common problems are popping up- at this point, there's only weird shit, like this, that's breaking.

[pip bip]

@qaaaaa they do it to force upon dealers literally a million dollars worth of tools to repair them