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[grifter]

As part of my overhaul I'm double checking (replacing) the diode pack in the alternator with bosch replacement. I done this on my 2.6 and remember the screws were bar steward tight. On this one - the 3.2 - I got all bar one screw out. It's got colour marks on the screws blue on 2 and green on one, and a remanufactured sticker on it. Lord knows why they put those screws on so tight is it to stop schmucks like me tampering with it? 

Managed to get them moving with my snap on big handle screwdriver but will need a tighter fitting screw tip for this one as it seems a rather shallow depth screw, so the normal screwdriver tip is too easily working its way out the screw before much pressure is applied. tried flattening the head a bit with a punch to give the screwdriver more grip to no avail.

Anyone had similar issues with these screws for diode pack?

[TheBoy]

Don't recall any issues, to the point I can't even remember what type of screws they are.

I'm sure I'm teaching you to suck eggs, but you know that Philips and Pozidrive are incompatible with each other...

[grifter]

Don't recall any issues, to the point I can't even remember what type of screws they are.

I'm sure I'm teaching you to suck eggs, but you know that Philips and Pozidrive are incompatible with each other...

Lol I've never even noticed that in all my time working in cars. Guess I'm more attuned to nuts and bolts, in saying that I think it's just a standard Phillips but wil double check, the other 2 loosened ok but as said we're really tight.

[TheBoy]

Using the wrong type means the tool doesn't properly fit, so tight screws will get mangled heads.

[Andy B]

and there's also the Japanese JIS cross head screwdrivers 

[Nick W]

The trick to not buggering up cross-head screws(of any flavour) is the correct tip, in good condition preferably new, fitted to an impact driver. The sort you hit with a hammer.
If you have any doubts about the quality of the screw, add some grinding paste to the tip


If there's any chance Loctite was used, heat as much of the screw and thread as you can before doing anything else

[Raeturbo]

Hacksaw a slot in the screw so as you can use a flathead👍

[TheBoy]

and there's also the Japanese JIS cross head screwdrivers 

And a few others...   ...but on a German alternator, any crosshead is likely to be the more common Pozi or slightly less common Philips

[grifter]

and there's also the Japanese JIS cross head screwdrivers 

And a few others...   ...but on a German alternator, any crosshead is likely to be the more common Pozi or slightly less common Philips

Think i may have been using a normal phillips on a pozi, as it wouldn't grip, but as i said was hellish tight, plus the other 2 screws loosned off (just) with same driver used.

[TheBoy]

You stand half a chance if you use the correct screwdriver type and size.  Philips and Pozi are not cross compatible due to profiles.

If you've now mashed the head, you can try an old impact driver, or you will have to resort to other means.

[Raeturbo]

As in reply #6

[Nick W]

You stand half a chance if you use the correct screwdriver type and size.  Philips and Pozi are not cross compatible due to profiles.

If you've now mashed the head, you can try an old impact driver, or you will have to resort to other means.

If you've mashed the head, the impact driver is unlikely to do any better than some random screwdriver. Use it first.


The problem is that crosshead screws are designed for machine assembly, and will cam-out to prevent overtightening. Unfortunately, that's precisely what you don't want when attempting to loosen the screw.