Alternator Belt Popped Off

97B4TDi

Veteran Member
Joined
Feb 5, 2007
Location
Wisconsin
TDI
1997 B4 Passat, 2013 Jetta Sportwagen TDI
I went to Chicago over the weekend and I accidentally popped the alternator belt off on and extreme hill start.

I understand I need to twist the tensioner to allow enough slack to put it back into place however when I do that the crow bar is in the way of putting the belt where it belongs.

Do you guys have any tips or tricks for popping back into place?
 

iluvmydiesels

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Nov 21, 2015
Location
phila area
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AHU
i use an adjustable wrench either 10" or 12" on tensioner arm. i think the tensioner roller has a nut or bolt on it that you can use. i find adj wrench works real good.
 

ToddA1

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Aug 3, 2011
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NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I use either an adjustable wrench at the bend of the arm, or a flat head screwdriver between the pulley and arm. Personally, I like the screwdriver better.

-Todd
 

Mongler98

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Mar 23, 2011
Location
COLORADO (SE of Denver)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
AHU or ALH
on the AHU, i jsut use a flat head screwdriver between the arm and the pulley, push it back, its tricky.

HOW did it just pop off? sounds like you have a faulty idle arm
 

97B4TDi

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1997 B4 Passat, 2013 Jetta Sportwagen TDI
Okay thanks guys that helps a lot.

I’m not exactly sure when it happened because I wasn’t aware anything was wrong until we were about 45 minutes outside of the city. We parked in a self parking ramp and in the entrance there was a steep incline I was held on with a car behind me waiting for cars in front of me to enter. Since my parking brake is currently stuck and non-functional you can imagine how tricky it was to pull off... with the “jerky” pull off and tricky pedal maneuvering I think it may have jolted the sucker off.

I’ll get everything put back in place and hope that was the cause.

Needless to say it seemed like one of the longest drives ever with the battery light on and not knowing how far you can run on just the charge remaining in the battery...

If it pops off again I’ll report back.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
technically, a diesel engine needs NO power at all to stay running, if the ECU gets no power, it would run like crap and you have no lights lol

I had this happen years back, but it broke the pully off the crank, sheared the bolts, i fixed it on the side of the road in town 200 miles away from home, i had some tools and i broke down irght next to a ace hardware so i was in luck for a easy out and new bolts, what happend was a bolt sheared off at a light, kicked up and when i got on the clutch it fell back down and into the belt breaking the other 3 bolts off !!!!!
inspect things around that area for missing bolts or nuts, might have happend to you from something that fell down there and just popped the belt off. or maybe a random rock that got up there and fell down, belts just dont come off unless they break or the pullies go out of alignment.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
AHU or ALH
on the AHU, i jsut use a flat head screwdriver between the arm and the pulley, push it back, its tricky.

HOW did it just pop off? sounds like you have a faulty idle arm
No Mk3 or B4 was shipped with an ALH, only Mk4 cars had the ALH and that's in a different forum.

If the arm is worn the spring sometimes doesn't work properly or sufficiently to keep the belt under tension. In that instance it can come off.

I find the adjustable wrench works well to operate the tensioner.

Steve
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
I also wonder why he keeps asking, in the A3/B4 forum, if the engine is an ALH.

But I have also had the belt come off when the bearing on the tensioner pulley goes bad. It's easy to check with the belt off it, not so much with the belt providing tension.
 

97B4TDi

Veteran Member
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Feb 5, 2007
Location
Wisconsin
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1997 B4 Passat, 2013 Jetta Sportwagen TDI
Finally started her up again today since I got the belt put back in place. The pulley was melted and worn which seems to be what the issue was.

I have the shaft out to do the pulley replacement but I was wondering what kind of grease I should use to re-lube the shaft?

Thanks!
 

iluvmydiesels

Veteran Member
Joined
Nov 21, 2015
Location
phila area
TDI
AHU
if you mean the tensioner pulley, i bet you also want to replace the spring pack. cannt say that it(a new one) takes grease(pulley i mean), for the pivot arm some good quality synthetic grease would work ok. check i dont know if its installed dry.
 

Windex

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Apr 1, 2006
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Cambridge
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05 B5V 01E FRF
if you mean the tensioner pulley, i bet you also want to replace the spring pack. cannt say that it(a new one) takes grease(pulley i mean), for the pivot arm some good quality synthetic grease would work ok. check i dont know if its installed dry.
Sometimes, if you have to guess at answers, it's better to stay silent. :rolleyes:

Replace the (plastic) pivot shaft bushings, pay special attention to any wear on the shaft - replace the shaft if it's really bad. Spring packs do wear out, but tensioner chatter happens more as a function of loading/unloading of the belt via the rotating mass in the alternator.

Although AHU/1Z cars were not equipped from the factory, it is a good idea to retrofit a clutched alternator pulley from an ALH - this reduces belt chatter significantly, and also reduces the loads on the crank pulley which can lead to wear on the pulley/crank and eventual timing issues or valve collisions (in bad examples). I would not run and AHU/1Z without one.

Coating the shaft with a good EP/moly grease works well for the tensioner shaft.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
there is an upgrade for that plastic pulley, i think its from a ford, i cant find the part number, look on the forums for the upgrade. it fits like a glove with a washer on the back side, all metal and no fuss. 360K miles on the clock and the stock spring is still fine, its not difficult to replace i think, but i never have.

I had no idea about the alternator upgrade, ill check into that.

Oh never mind, i found it
https://www.amazon.com/gp/product/B000C0YR1G/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
That's not a direct fit, you have to press the center out of the old pulley, provided it's the right one (not the weaker/smaller Chinese pulley), and press it into the new Ford Mustang pulley. Without it the pulley won't bolt on.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
That's not a direct fit, you have to press the center out of the old pulley, provided it's the right one (not the weaker/smaller Chinese pulley), and press it into the new Ford Mustang pulley. Without it the pulley won't bolt on.
well, it is on my AHU, what engine are you saying it does not fit?Other than needing a washer to get clearance, it fit perfectly.
 

KLXD

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Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Next time on a hill ease out the clutch until it'll hold on the hill then release the brake and get on the accelerator.

I takes a ell of a ill for the engine not to be able to hold the car from rolling back at idle. Reason being that the ECU wants to hold the idle speed. I adds fuel for you.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
not sure what the heck a glass filled polymer is or what it has to do with a steel bearing and pulley.
ITS ALL METAL
now im looking back at my order history and a week later i ordered this one
https://www.amazon.com/gp/product/B003SYXR1E/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
I think that i ordered this one as it didn't need a washer or something, i cant remember why i ordered it but its the one that's on the car, i just checked. Maybe the first one has a wrong picture, i cant quite remember, it was ordered back in 2012! i don't remember that far back for details that small lol
 

Steve Addy

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Joined
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Location
Iowa
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97 Mk3
If I’m seeing that bearing number correctly, that’s a 17mm ID and the bolt will need something to thread into.

It’s all metal? The description stated glass filled polymers.

-Todd
This one is no better than anything else considered before, you still have to obtain the threaded insert so you can mount it.

Personally I don't like the OE plastic pulley and should I have one fail on me I'd be upset, but TBH aren't we really dealing with a solution in search of a problem here? How many of these are failing? I've never had one fail...period.

Steve
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I did, plastic was warped, bearing was fine, infect it was in great shape but the pulley looked like an egg with about 5mm proud on one side and -5mm 90* to that.
 

ToddA1

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Aug 3, 2011
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NJ 08002
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'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)

Even this one has an unthreaded inner bore. You’ll definitely need something inserted, to thread into.


Personally I don't like the OE plastic pulley and should I have one fail on me I'd be upset, but TBH aren't we really dealing with a solution in search of a problem here? How many of these are failing? I've never had one fail...period.

I totally rationalize with you, as I’ve also never had one fail. While I have a cheap Uro as a spare, I’d rather be a bit proactive and change it now, before I’m changing it on the side of the road.

It would be nice to have one with a sealed and serviceable bearing, too.

Aren’t we all in search of a solution, to a nonexistent problem, here...? I recall someone driving hundereds of miles for a louvered fender well, lol.

-Todd
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Even this one has an unthreaded inner bore. You’ll definitely need something inserted, to thread into.





I totally rationalize with you, as I’ve also never had one fail. While I have a cheap Uro as a spare, I’d rather be a bit proactive and change it now, before I’m changing it on the side of the road.

It would be nice to have one with a sealed and serviceable bearing, too.

Aren’t we all in search of a solution, to a nonexistent problem, here...? I recall someone driving hundereds of miles for a louvered fender well, lol.

-Todd
True, I will agree that it was a long way to go, but it was for a rare part that was actually for protection. The inner fender liner doesn't hang as low on the B3 as it does for the B4 and the lower part of the cooler was exposed to what ever the wheel would toss that direction.

I could have gotten by without it but since the coolers aren't readily available anymore I thought it worth the effort to at least see if I couldn't keep it from getting damaged.

As for the tensioner roller I would welcome a replacement that was direct fit and more substantial but so far the only ones that have been posted up have the 17mm ID and most of the rollers out there are the type with the 15mm insert. I've looked for a while but so far still haven't found anything. If I needed to I might opt for the billet pulley from Grüven parts but that's a hundred dollar bill for something you really don't get to see.

Steve
 

97B4TDi

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Location
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1997 B4 Passat, 2013 Jetta Sportwagen TDI
Replaced the belt tensioner pulley and all is well again! Appreciate the help guys.

Probably wouldn’t hurt to keep a spare pulley and spring pack on hand.
 

ToddA1

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Joined
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'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
The problem is not that replacements aren’t available, it’s that they suck. The Ford roller can have just the bearing swapped out, not so with the VW pulleys
I’m 100% awareness that, it’s why I wrote:


I’d rather be a bit proactive and change it now, before I’m changing it on the side of the road.

It would be nice to have one with a sealed and serviceable bearing, too.

I’m still curious the failure rate on the aftermarket pulley. Anyone have any logged mileage, prior to failure?

My OE pulley is still good. Does it require destroying it, to get the 17mm center piece out, or will it press out?

-Todd
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
The center will just press out.

I’ve had one fail on me at around 80k and seen 2 others fail under 100k. It was new but had the smaller bearings and not the larger one. If they’re all that’s available I recommend changing them with the timing belt. I have changed the ones with the 17mm center due to them feeling dry but have never had one actually fail.

Steve, I may have a spare I can drop in the mail. I’ll have to check my stash.
 

ToddA1

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Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Hmmmmm..... I’m curious what the 17mm one will log. Makes me want to look at one and see if it can be relubed.

At around $5 each, for the Uro, you’ll log 200k before you reach the cost of the Mustang part.

-Todd
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
I tried.

I gently removed the seals from each side (it’s a double bearing and the 2RS seal pops right off) and added some grease but it didn’t help. By this time they weren’t dead but did feel dry, so maybe they were past recovering.
 

ToddA1

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Joined
Aug 3, 2011
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NJ 08002
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'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Lol, figures you tried.

Not trolling, but I’m curious how long the Mustang bearing will last, before needing replacement. I figure gassers don’t last that long and the pulley seems to be readily available.... is this a problematic part?

-Todd
 

turbodieseldyke

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Jun 6, 2010
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Free Mustache Rides
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98 jetta
At around $5 each, for the Uro, you’ll log 200k before you reach the cost of the Mustang part.
The cost advantage may be realized much sooner than that.

When my pulley failed, it killed the belt too. Since it happened in the middle of the desert, with no stores nearby stocking replacement parts, I had to buy a new (charged) battery to get me home. (Two batteries, actually. One was enough, so I returned the 2nd at my home store.)
 
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