v belts loosen

[jb86]

1991 MK2 jetta 1.6 turbo diesel.
car has a/c and power steering.
3 belts.
i installed continental belts when i bought it - also a continental timing belt.
have driven about 800mi.
the v belts loosen. i keep tightening. after about 600mi, i lost the alternator belt. of course i was on a 250mi (round) trip. but drove it with all electrical turned off. fortunately, didnt get stuck in traffic and had the fan kick on.
the alternator belt is the inner one. it takes me about 2hrs to replace all 3 belts.
so, another set of belts. retensioned after a little driving.
i did notice the idler on the alternator belt looks out of line with the a/c compressor. so i added about 3/32" thick washer behind it.
now looks a little out of line with the alternator.
all three belts loosen a fair amount, but, when the alternator belt does, it vibrates real good at idle.
id like to install a serpentine belt.
i may be able to figure out a way of fitting it to the geometry of my engine. but 2 questions
which crank pulley? because its a diesel, i needs to be a harmonic balancer, like maybe a TDI crank pulley? not a light one from a gas engine.
and, i read that the alternator on a serpentine equipped car has a clutch in the pulley. some how it relieves tension on the crank pulley when it goes under load. other wise, the immediate load can damage the crank pulley bolt, i.e.; eventually break the bolt.
any ideas?
jon

[VWCaddy]

Not sure if this applies to the later models, but I found a problem with the A/C bracket on my '81:
http://www.4crawler.com/Diesel/CheapTri ... #ACbracket

No matter how tight I had the belts adjusted, they would always loosen up in a few weeks until I did the above repair.

[wayland]

Are your pulleys rusty? I've had this happen with several cars I've bought which had been sitting for a while. After a couple of belt changes and a few thousand miles the rust wears off and it's OK again.

[joat]

first thing to check is if the pulley's alignment... a straight edge placed on the outside of one pulley should align with the next pulley ( and so on ) if they don't, the belt wears on one side, and gets looser, then finally wears out and flips off the pulley....shim (or reduce) behind the offending pulley to get things to align as close as possible....

I used to loose a belt every 1,500Km till I aligned the alt in the bracket holder ( shifted to the right 1/4" by cutting the alt base and adding a washer to make up the removed material on the opposite side)

[Quantum TD]

All good points. I would look for pitting of the pulleys. Even if the rust wears off, the pits will move the belt side to side, and cause the belt to wear. Check that first, then alignment.

On the serpentine conversion. Your best bet would be the 1993-1998 AAZ, AHU or 1Z tensioner serpentine setup.As you noted, you will have issues with the crank nose being weak. The clutched pulley on the alt will help, but the only way to ensure that the keyway on the crank does not waller out is to install a TDI-style crank sprocket. This involves milling the nose of the crank to accept the sprocket. A user here (and elsewhere) came up with a neat idea to do this on the car. Here's a link. But, be careful, do not go to this site without killer virus protection and firewall. The site is infected and is being cleaned up:

http://www.vwdiesel.net/forum/index.php?topic=25135.0

Research AAZ crank nose failure. That will give you an idea of why you want to switch to the D-shape TDI sprocket.

Good luck!

[DanHoug]

i went from the miserable 3 belt system with AC and PS to one belt... no AC, no PS.

life has never been better! belt stays tight. thermostat changes involve 2 bolts on the housing, easily reached. way less engine vibration. everything easy to reach. the car does not need power steering and i actually prefer the road feel at speed without the pump running-- i can literally 'feel' when the road is getting slippery by the steering wheel.

changeover involved a non-ac, non-ps alt bracket and the old alt from the donor vehicle.

-dan

[Vdub-bub]

If you are up to it, take a look at a couple of solutions to the loose belt problems in this thread.

viewtopic.php?t=8173&highlight=

I'm not sure if this is the best way of recommending a thread, but it seems to work.