AAZ crank bolt problem?

[wyldman]

The crank gear uses one bolt to secure it to the crank snout.It's gotta be tight.The original bolt never usually came loose,they only come loose if someone has messed with it,and not replaced the bolt,or torqued it properly.

The pulley bolts hold the damper and pulley to the crank gear.They don't usually come loose,but should be replaced any time it's apart,as they are dirt cheap.

The crank bolt doesn't have to come loose to have the crank gear fail.The gear can break the key off inside,or the crank snout will break at the keyway.I have done quite a few and the bolt was still tight,just the gear or the crank failed.

[ibmserf]

Ok thanks for all your help wyldman.  I think I've got it all sorted out now...ps.  I talked a VW service centre and they said by '96 they had changed the end of the crank to the D-style.  This means I shouldn't have the problem with the crank gear I suspect.  I will just change the tensioner, belt and make sure the bolt is ok.
Thanks again!

[BlackTieTD]

they might have mis-informed you....didn't that style continue into '97 at least?

[wyldman]

To the best of my knowledge,the 1.9L IDI motor NEVER came with the newer style crank.The only ones that would ever have it are ones that had been replaced in the field by a VW dealer due to a crankshaft problem under warranty.Even that didn't start happening till mid 98 or so.

I have a 97 in the shop now,with a failed crank gear\blown motor.It is the old style.

The only way to know for sure is to pull the crank gear off,and look at it.If your going to make sure the bolt is ok (you will have to remove and replace it with new,then pull off the gear and look.Why do all that work and chance it ?

[fspGTD]

Moved to troubleshooting section - not power enhancement related.

[MadCityMike]

In case anyone's interested, here's a couple of pics to show the difference between the "upgraded" harmonic balancer and the stock one the motor came with.    You can see on the old one that the timing belt wore away a bit of metal.  On the new one the belt pulley portion is solid all the way to where it mounts to the crank gear unlike the old style where the pulley surface rides on a rubber cushion.

[Charel_MK3]

Hi, i'm somewhat new to the MK3 AAZ scene but i have some questions about the crank pulley problem.

I was browsing around in ETKA and i found the following part numbers:
(the numbers in front correspond with the numbers on the screenshot)

(9) 028 105 243T : vibration Damper
(12) 028 105 246 : Thrust washer
(14) N 905 771 01 : 12 point head bolt
(6) N 903 487 01 : Cheese head bolt
(4) 028 105 263 E : Toothed Belt Pulley

Which of these above need to be replaced to avoid the crank problem?

The harmonic silencer seems to be the vibration damper, and the thrust washer sits between the silencer and the pulley.

Do i have to replace all of these? or just some parts?

Thx...

a pic from in ETKA



the bottem crank is the AAZ one...

[Charel_MK3]

Can anybody tell me what to replace? to avoid the problem?

[QuickTD]

Can anybody tell me what to replace? to avoid the problem?

 Replace the crankshaft, the crankshaft pulley and the bolt, use the parts for an AHU TDI. There is no real way to make the 1.9TD setup more reliable.

 Once they have failed I weld and machine the crank to accept the TDI pulley, so far it has proven to be a permanent fix. There are many, many threads on the subject, search for "crank bolt"

[r1_theone]

hello people
i have experienced the crank bolt failure,now i have fixed my engine back(especially the cylinder head valves wich was affected by the breaking of the crank bolt) and now i noticed that the cranck pulley is needed to be replaced immediatelly.
 i want to ask mad city mike or any other forums member's help to fin me the cranck pulley is sohown in picture.
i'm from east europe and imposibile to find it overe here
 thank you for your time to read my problem and wait for your help ASAP

[houseofdiesel]

It is very easy if you want to avoid the problem, maintain your car very simple and very easy...and don't be cheap which might be a very large problem for most owners of diesels...
I have yet to work on an AAZ with a properly set up serpentine belt system and this is one of the reasons that the bolt or gear fails, the tensioner for the serp belt is worn out all the time letting the belt flop/vibrate/create noise and this stresses the crank dampner and creates pulses/vibration/play...
If you notice the crank dampner is wobbling you must replace it, no choice. Yes they retail for $558 something...don't like it don't drive a VW. They usually last 8-10 years, then the rubber is dried and out of balance.
You also have to replace the bolt for the crank gear everytime the timing belt is replaced and properly torqued. Thread locker does nothing here, I have witnessed lots of bolts that had lock tite on the threads but the bolt head broke off leaving the threads in the crank. It is a certain torque plus half turn I believe, YOU NEED A TOOL TO HOLD THE CRANK. The nose of the crank must also be inspected closely if the pulley wobbled, usually it will not be perfect and needs to be slightly machined, if not the new gear will wobble too causing the belt to wear against the pulley.  Be very careful here, I have seen many machinists do poor jobs with the crank nose...
Then replace the serpentine belt tensioner (028-903-315R) and lever (028-903-308G)and bushings (028-903-313) if needed, and install a one way clutched pulley on the alternator (028-903-119AA) as the TDI's jhave...
This will ensure a long life for the crank. I know of many 1.9s that have lasted 500kms mostly 93-95 Passat tds. The key is having someone that actually cares replace the timing belt everytime, otherwise your going to have problems.
The TDI gear is also recommended however I have seen many botched installs of those too, it is very critical to machine it straight which few can actually do.
Greg

[r1_theone]

thank you for your precious info and also for the info i found on this web site.
unfortunatelly i do not afford to pay 600$ on this pulley but i found one at www.worldimpex.com at 60$,is now bought and waited to come and i will replace them instantly.
also the parts you mentioned have something between 2000-4000km since last replacement and i hope everything goes fine after the pulley exchange.
i also want to know about " the crank nose that machined jobs"
 what it is supposed to be done?
 thank you and best regards