Should I replace the crankshaft center bolt on a 1Z TDI engine in an Audi 80 (year of manufacture: 1/93)?

Hi.
Before I go any further: I used the search function -- but I didn't become very knowledgeable .

Bei meinem Audi 80 Avant TDI, Bj.1/93, MKB 1Z steht in Kürze ein Wechsel des Zahnriemens an. Dass hierbei Spannrolle etc. mitgewechselt werden, versteht sich von selbst. Aber wie sieht es mit der Zentralschraube der Kurbelwelle aus? Der Vorbesitzer hat den Wechsel des Riemens bei Audi in Italien vornehmen lassen. Auf der Rechnung taucht KEINE neue Zentralmutter auf. Aufgrund der Suchfunktion weis ich nun, dass die festeren Schrauben eine ringförmige Erhöhung am Schraubenkopf besitzen. Falls sich beim Wechsel herausstellt, dass bereits die festere Schraube ( 12.8 ) verbaut ist, muss diese dann trotzdem erneuert werden oder sollte man dann lieber diese Schraube unangetastet lassen? Falls die 'weiche' Schraube drin ist, wird sie auf jeden Fall gewechselt. 'Gave.' Is there actually a recall for this problem at Audi? If so, the KWP screw should have been replaced by now, especially during the last belt change (at an Audi service center in Italy), right?

So: Should you replace a screw if it's hard or not?

Thank you and best regards.
Hermann.

Hello.

'Personally, I would definitely replace that screw!'

The screw has already come loose on mine, and it was the 'heavy-duty' one that was installed!

Hello,

Is it also a good idea to check the screw between the timing belt replacement intervals?
Perhaps try tightening the screw?

It definitely makes sense to do that, especially if you already know it's a weak point! And checking things never hurts, right?

I probably wouldn't follow up.

Was there a recall from Audi regarding this issue? If so, and if the 'soft' screw is still in use, can one still insist on having this action performed?

Are there any opinions on whether it's advisable to replace a potentially already installed 'hard' screw during a belt replacement?

Thank you.
Hermann.

[Translating...]http://home.arcor.de/sgrafen/salatoel/kw_schraube/kw_schraube.html

@didl.

I was already familiar with that. Does this work instruction also apply to Audi vehicles? Also, this work instruction specifically refers to the soft screws.

I'm concerned about whether a potentially existing, hard, completely solid screw that isn't 'leaking' should also be replaced. The fact that the cost is negligible, at just under 2 Euros, is really secondary. } It has no relation to a valve, lettuce, or a total engine failure.

Regards,
Hermann.

Hello,

"There's a 12.8-grade screw in there, and everything seems solid, so I wouldn't do anything. If you absolutely have to remove the washer, use the Allen screws. Disassembly won't improve the situation; either you have sufficient contact pressure, in which case everything will be fine, or not. In that case, it's only a matter of time before something goes wrong."

In Formula 1, they use ultrasound devices to measure the torque of screws even after they've been tightened. Maybe you have good connections with Schumacher or Montoya.

Best regards,
Christian.

palmstrollo wrote:

@didl. I was already familiar with that. Does this work instruction also apply to Audi vehicles? Also, this work instruction specifically refers to the soft screws. I'm concerned about whether a potentially existing hard, completely solid, and "non-leaking" screw should also be replaced. The fact that the cost is negligible, at just under 2 Euros , is really secondary. It has no relation to a valve, lettuce, or a total engine failure. Regards, Hermann

.

Since the central bolt is a stretch bolt, it should always be replaced.
A stretch bolt is almost always pre-tensioned with a specific torque and then tightened according to the angle of rotation.

@lofthouse:

While your statement about stretch bolts is technically correct, there's no need to replace the central bolt of the crankshaft pulley during a timing belt replacement. If anything, only the bolt on the camshaft sprocket is usually loosened.

BTW, this is also much easier because even a hobbyist who hasn't had a good breakfast can easily achieve the correct torque for this screw .

Regards,
Alex.

donalexo wrote:

Even a hobbyist who hasn't had a good breakfast can achieve the correct torque for this screw.

Hi Alex,

Well, I needed a lot of force, and I'm not exactly weak . Even my long 3/4-inch breaker bar from Hazet didn't significantly reduce the required amount of force. Furthermore, the screws that are standard on the VW 3099 tool tend to bend. These also need to be replaced with high-strength 12.9 grade screws (-> e.g., brake caliper screws).

Simple question: When replacing the timing belt on a 1Z or any of the four-cylinder engines, can the vibration damper be left in place? On the 5-enders, it has to be removed, probably because there's a cast protective cover underneath the pulley. (I haven't done this myself yet).

Since I will soon be facing the issue of timing belt replacement myself: How is it done on a 1Z engine? What steps do I need to perform? I think tools will be less of a problem after seeing what's available in that other thread by Dieselmartin.

Best regards, WarLord.

@Christians
Der Schwingungsdämpfer muss ab, geht gar nicht anders, da du sonst den unteren Teil der Zahnriemenabdeckung nicht wegbekommst. Mich werden jetzt vielleicht gleich einige steinigen... aber wenn du eine super 6mm-Imbus-Nuss hast, also keine so halb abgewetztes Ding, die 4 Schrauben auch gut aussehen, dann kannst mit ein Prellen und einem Schlagschrauber zumindest die Schrauben easy entfernen. Der Schwingungsdämpfer selber sitzt leider etwas fester auf dem Zahnriemenritzel fest, da dieser im Innenteil aus Alu ist und das Ritzel aus Stahlguss - Kontaktkorrosion. Caramba and a gently used tire iron can help.

Best regards,

Dominique.