Hi folks,

940 SW 2.0 Turbo 1997

This is a persisting issue that I do not know how to resolve.

After only 10000 Km, today, the alternator belt (which was visually perfect two days ago when I inspected it, literately disintegrated, so bad that caused the A/C belt to slip off the pulley (I found it perfectly intact at the bottom of the splash screen). Never seen anything like that, out of the blue.
Luckily, I was not far from home.

I think this is due to a misalignment with the crankshaft pulley, as I think the alternator pulley is at least 2mm inward (towards the back of the car) comparing to the crankshaft pulley

See those two images I took some years ago, so see what I am talking about:

https://i.postimg.cc/hGbHm9BP/IMG-20210130-141702.jpg

https://i.postimg.cc/L63CNmWN/IMG-20210130-141714.jpg

The two rubber bushings that keep the alternator in the bracket are new, so I really do not know how to push the alternator forward.

Why did it move back? That I do not know, but I think after 26 years parts may move. I am basically the only person who work on this car since day 1, it is well maintained, and never had an accident.

Clearly something has moved with the time, not the bracket, it has never been touched and it is like welded to the block.

The only way I see to fix this is to play with the two rubber bushings, in theory the front one should be 2 mm thinner and the back one 2 mm thicker.
I have no idea how to modify them, and this is assuming the misalignment is the culprit.

Do you have any ideas on how to fix this?

As always, I can count on your help, wonderful Vfreaks! :)

Alex

Dear Metallo,

There are many issues affecting V-belt life, such as:
1. Pulley alignment & bushings
2. Pulley size
3. Pulley wear & smoothness
4. Belt quality & its rubber compound
5. Belt tension
6. Heat soak within engine compartment
7. Climate factor
8. Belt contamination
9. Alternator bearings
10. Crank pulley


The life of alt V-belt depends on a careful balancing act between the above factors. Sometimes you win sometimes you get in-between

Factor 1 - This self explanatory

Factor 2 - This regarding heat transfer. The big crank pulley gets the most heat from the engine and transfer it to the alt pulley. The alt pulley (being small) unable to quickly dissipate the heat. Thus the belt is sort of being "roasted" in between and this shorten its rubber life.

Factor 3 - Pulley does get worn over time. Check the contact surfaces to see any wear lines which slowly "eats" the belt.

Factor 4 - This self explanatory

Factor 5 - Low tension causes slipping thus affects grip and causes more wear. High tension weakens the belt's backbone (fabric backing) causing the belt to gradually losing tension. Lower tension causes slipping and this becomes a vicious cycle.

Factor 6 - Heat soak causes the rubber to gradually harden. Hardened belt rubber gradually slips and this goes back to Factor 5.

Factor 7 - Similar effect to Factor 6

Factor 8 - This self explanatory

Factor 9 - Worn alt bearings causes the belt to do "micro-jumps" (ie. slipping) in between engine revolutions. You'll see this as "belt flutter" or vibration along its length while running. Similar effect to Factor 5

Factor 10 - Spook has spoken ; )


I noticed that the alt belt is the one most affected. The power steering and AC ones could run almost indefinitely

My current practice is to replace the alt belt once every year or 1.5 year. I use BANDO a cheap Japanese brand easily obtained in Malaysia. I'm done using OE or Continental.

No more surprises!

Regards,
Amarin

Hi All,

Today I added the two washers and re-assembled everything.

I can tell you that I found countless pieces of belt and wire everywhere, see image below:

https://postimg.cc/hX41zj11

Now everything looks aligned, also to my eye, which is very good when it comes to measurements :)

https://postimg.cc/wtCNVTLP

https://postimg.cc/zLg75Qks

https://postimg.cc/4HJQ6xTG

Let's see how long will the alternator belt last this time.

@Amarin: I am interested in your statement about Bondo belts, I will check them out.

Enjoy the long weekend!

Alex

Hi,

Wow, you had that much play or space front to rear. You just threw them in like lettuce between bun slices.

Glad you made some movement on it as I was thinking everything was tight between the bushings.
Must be more that meet the eye here.
I was thinking of leaving one flange to the inside since the bushings spacers actually hold the alternator.
Some alternators use long tube through the housing on the bolt that gets held.
You would pinch the housing up against the bracket.
The washers would have to have a larger center hole than the tube or spacers to be just fillers.
Goes to show you how much I know of the 900 series.

The camera shows to my eyes some misalignment still.
From the way the Air Conditioner belt runs below in the back ground is not a very good reference but it looks it.

I hope you used a straight edge off the crankshaft face and measured the same distance of width over to the belt there.
The distance should be match coming off the straight edge over to the front alternator belt.
Notice I say “belt distance” as the web, on each side of a V belt groove, can vary their locations slightly.

Again, where is the second belt for the second groove on the alternator.
Doesn’t the water pump pulley have two grooves? I cannot see it all.
The water pump still looks empty of any belt. I’m clueless.
You should need longer belts to do any of that power transfer.
Only One belt would be under a bunch of strain!

As far as quality of belts our Malaysian friend has pointed out that Continental is losing in the traditional V-belt market by his standards.
Goodyear was and is the better belt by far but their management never had a real good distribution system in the automotive sector.
Too many profit only minded chain stores and other parts houses wanted to sell volume to be competitive and to heck with a longevity value.

Goodyear industrial belts always ran longer than any other belt due to the composition of its rubber alone.
Then they added the slanted notch that made them more quieter. That marketing splashed over to the automotive sector and kept people in New Jersey working.
That is until Goodyear, like General Electric, started getting smacked down by the stock market ideology to stock holders. GE was always a cut throat company to their contractors and now the knife is trimming differently.
Selling things off was a salvation and they do that if they could be top dog or actually own the market.
They still make airplane engines, locomotives and generators for power plants world wide.
They sold off most of or all the domestic appliance business.
Both companies are not as great as they used to be. It takes lots of work to be innovative as I know that all too well.

As far as BANDO belts go they were absolutely the worst belts alive 30 years ago. They have gone through their tribulations to get better or die!
I have not been in the industry of anything for the last 18 years but that doesn’t mean I still don’t follow technology.
I wouldn’t have made good wages in my working years by standing with my nose stuck in a corner somewhere. I found books and the internet and kept my common senses intact.

By looking into BANDO web site they have come a long ways! You have to capitalize it to get it spelt correctly.
They might be a replacement for good standard V-belts since in the automotive world as that design has lost a lot of advantage to being an engineering choice.
Front wheel drive engines and their tight spaces caused the engineers to paint the floors in different ways. But they still get stuck into corners without a good exit.

Some things I see are quite atrocious for the new young consumers.
I have a Maytag clothes washer and a GE refrigerator that’s 45 years old and working with minimal part replacements over the years.
Its No wonder that I own some 240 Volvos. They are my rolling part stores. One can feed the others for longer than I can imagine, for someone with the right mindset.
Trouble is the winds of change are under seizures of all types.


Back to your car….. On a 240 there are two belts going over the water pump shaft.
The torque needed to power the alternator should be the same for both cars of at least 80 amperes.

I’m suspicious of what you have going under there to obliterate a belt in such a manner?
Only one belt bugs me!😵‍💫

Phil

FYI Phil, no dual alternator belts in our RWDs since the 140s and early 240s. In part, dual belts were probably used to help deal with the added mass of turning the viscous fans. The early viscous fans were a bit heavier than the later ones. Any dual pulleys you see now are vestigial or done in order to accommodate a number of fitments with the same alt. Volvo and others like Goodyear sold belts in matched pairs to assure equal characteristics. You paid extra for the privilege. As matched pairs weren't always commonly sold, the next best option was to try finding belts with the same lot number. A number of such comments here on the Brickboard in its early days. Way back, when you ordered the two belts from FCP (before they became FCPEuro) they advertised they would pick matching lot numbers out of the parts bin. Dual belts were problematic in that over time the outer belt stretched a bit more than the inner belt, so one would start to squeal before the other. The advice was rather than tensioning to make the squeal go away and as that would place additional load on the water pump and alt bearings, to switch the belts back to front at every oil change, a habit I made at the time. One minor issue was that when one of the dual belts let go, it would occasionally get caught in the other belt and take it out.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

The dual belts were part of the 240 to its last days in June '93. The reason for them was they spanned three pulleys, so the contact area was in each case much less than 180 degrees. Of course, the change to two-pulley drive arrangement and alternators on the cold side of the motor was a significant advantage the 7/9 cars had over the 240.
--
Art Benstein near Baltimore

"If you can't laugh at yourself let me do it." -seen on a tee shirt

I don't at all doubt you're right about all 240s having dual belts as the pulley geometry didn't change. Odd I didn't recall the dual belt on the family '89 240 I used to work on, in fact I rather remember it was single and different from my '85 240 and earlier 140.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Dear Metallo,

Hope you're well and stay so. I've stood aside, in the hope that those wiser will shed light on the mystery of fast-shredding drive belts.

When was the crank pulley last inspected? If it is on the way out - if the rubber that bonds the core to the outer steel section, on which the belts ride, has failed - then the belts will not run true.

Take some white paint and draw a line from the crank pulley bolt towards the face of the pulley. Continue the line across the rubber section and to the front face of the pulley.

Drive and see if the single painted line separates into two segments, that don't align. If so, the crank pulley has given you the last measure of faithful service.

Hope this helps.

Yours faithfully,

Spook

“…. The only way I see to fix this is to play with the two rubber bushings, in theory the front one should be 2 mm thinner and the back one 2 mm thicker.
I have no idea how to modify them, and this is assuming the misalignment is the culprit….”

It’s been many years since I replaced the rubber bushings on our old 740. However, I do recall that some of the bushings are installed in the bracket from the aft side and some installed from the forward side. Since there is a shoulder on one end of each bushing, inserting them from the wrong direction can move the accessory fore or aft or by about 1/8”.

The alternator-crankshaft pulley alignment doesn't look all that bad in your pictures.

A better way to check alignment is with the belt installed and under normal tension then placing a straight edge across the face of the pulley with the far end at the crank pulley. You can do the same from the crank pulley back to the alt pulley, needing to measure for equal offset from the straight edge to determine alignment. The alternator pulley is a fairly long span and as long as the straight edge ends up within, say, about 1/4" of alignment at the crank pulley when installed and tensioned then I wouldn't expect failure in 10K unless you're operating in severe conditions.

When belts are tensioned the alignment changes slightly, especially when the rubber mounting bushings are getting older, but also due to minor freeplay in the assemblies. When it's just pulleys a bit too much out of alignment, it's more commonly a matter of noise, squealing, belt glazing and signs of premature wear before a catastrophic failure happens.

o It would help if you posted the make and exact size marking of the belt you used, also how long it was installed for that 10K.
o Take your broken belt and folding it backwards fairly tightly in a number of places, is there much sign of cracking?
o Was it making any noise during running prior to failure?
o Did it fail with a separation at the belt joint seam and frayed ends there or elsewhere along the belt?
o Especially, please try to describe how you determine the belt tension. If you use the finger deflection method, try to describe how hard you are trying to press and how your fingers are held. If you use the twist method, how far were you able to twist it between the tips of your finger and thumb?
o Was the belt tension similar to that of the A/C compressor belt? Similar to that of the PS pump?
o Was the belt at all fluttering in use?
o If you lay the broken belt in the alt pulley and press down, does the surface ride dead even, above or below the outer edge of the pulley?

My best guess at this moment would be an inferior belt, an incorrect belt size, an over-tensioned belt, and much lower down the list something unusual happening at the pulleys.

If the belt size is correct and you're not over-tensioning, I would be very tempted to think the first belt might be faulty and to put on another belt and see if it happens again. You could spend hours trying to get all the pulleys into better alignment and for no great purpose other than your satisfaction if it was just a faulty belt.

I'll mention that for years now I've been using a proper belt gauge (Krikit) using different specs for new and used belts and based on belt width, not span. Takes all the guesswork out of it and helps keep my belts stay quieter for longer.

And you're right, Volvo accessory pulleys are often not in perfect alignment with the crank pulley and those rubber accessory mounting bushings don't at all help. Eventually the mounting holes wear a bit and the bushing are a lot easier to pop in and out. Worse still, there is no easy method of correcting for this other than removing the entire mounting bracket and elongating slots or shimming behind at the block. Way back, I once shimmed between the alternator mounting bracket and the block in order to improve alignment, but won't be trying that again anytime soon, not worth the effort as I had to remove it a couple of times as I kept dropping fasteners down in behind, the second time there was nothing behind, it had rolled way down the garage.

If you think alternator pulley alignment is a pain, wait till you try checking the A/C compressor pulley. Keeping that pulley in perfect alignment after tensioning is a bit of an art. It can become a trial and error process of tightening the rear adjuster bracket bolt first then adjusting it tighter to force the front out a bit to achieve alignmemt, then tightening the front bolt. If you get too carried away you can easily break the long 10 mm adjusting bolt. Using a pry bar can help take the strain of the adjuster bolt, also backing the bolt tension off a bit after the A/C compressor is locked in place.

I can't remember you saying where your non-North American '97 940 came from before finding its way to NS. I figure people have to really love their cars to transport them across oceans.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Hi,

First of all I’m a 240 man but this looks like something the the 900s inherited.

The 240 brackets are casted as junk because the bores that support the bushings are not inline to each of their respective axis. I had to bore mine straight on one car and then made up solid PVC bushings from rod stock.
That eliminates all that wiggle that rubber gives to the whole affair.
To the life of me I do not understand the reasoning to rubber mount a rotary component. It emits no reciprocating sounds like older A/C compressors.

Apparently failure to change from what vendors sold and offer as a cheap bolt on package had influence upon the engineering and the bean counting departments.

One has to remember back to the late 140 and early 240 series that Sweden didn’t need to sell air conditioning for their snow and ice mountain populations around them.
Expansion into a more global foot print, i.e. the Americas thirst for more luxury cars Volvo had to play catch-up.

I will suggest that you might try turning the front rubber bushing around to remove the flange to allow the alternator to shift forward and then shim the play at the rear with washers in front of the rear bushings inner flange.
Otherwise you will have to look at slotting the bolt pattern rearward that is holding bracket itself moves to keep it looking more factory correct.
Again I’m a 240 guy and I have never studied how that whole affair was devised to fit on the opposite side of the same red block engine. Up, high Makes for easy pickings in a PNP yard.

I guess since I have seen that the distributor was move to the back of the cylinder head putting the alternator in that space moved it away from exhaust heat.
So why did it move? Well, you cannot say that the rubber failed due to heat?
It might be that the alternator housing was swapped during a repair or by a rebuilder.
It’s not uncommon for a casting boss to change on either side, in so being, an overlooked detail.

I would recommend using a straight edge across the faces of at least one pulley to measure from.
You really need two contact points to project a straight line “outward” for a true alignment in the direction you are looking.
Checking for a parallel axis’s in relationship to the crankshaft’s length front to rear is important too but should be taken care of, up to a point, by the bracket.
The straight edge should strike across four points for flatness top and bottom.
Two spots on each pulley face adjusting allowing for manufacturing variations. Thick or thinnesses of the sides can vary as you will inevitably find.


You’re lucky that this alternator is driven by a belt.
Straightness is still required for proper belt seating of the cords.
A belt Climbing on one side will cause twisting within pulley diameters.
This happens upon entry and exiting creating Stress fatigue.

An angled tooth notch, invented by Goodyear and removed from our market by Continental with a buyout negated many things, of which, one was the noise of that action.
The belt is allowed to squirm or slide between the V and not get pinched, per se?
The extra length, diagonally of the tangents, increased heat dissipation.
Rubber contracts when warmed.
The opposite of a normal material. Like brass is to steel or water’s properties.
Serpentine multi grooves belts stop squealing after a few warm up rounds.
It’s yelling fatigue but does eventually gets worse when ignored.
Just ignore yourself in brushing teeth and they will go away!
Belt in the belly pan, seems correct. 😬

SO, you are on top of it! 👀

Phil

Hi All,

Thank you for your feedback.

This belt was a Continental 11.9x1013, which matches the Volvo 973487.
First time I tried a different brand from Volvo because the genuine ones did not last longer than 20K, during the last years.

Originally, Volvo belts used to last 40,000 Km

Still I do not think the Continental is bad, I am convinced the alignment is the problem.

This is the image my wife sent me of what was left when she suddenly saw the red battery light pop-up:

https://postimg.cc/BtM8DzpB

Again, this belt was perfect two days earlier.
No noise, squealing or so etc.

Guys, I have been doing this for 26 years, I know how the tension should be and all that stuff. I really think with the years parts wear and move, so I need to compensate some way where the bushings seem to fail, I will play with them and see where I get to.

@Dave: LOL, yes I love my car, she crossed the ocean from Italy :)

I will keep you posted.

Thank you!
Alex

Like Phil, I'm also partial to 240s. I've very little experience with the 940 I helped my late MIL pick out 20 years ago, compared to that gained on its predecessor in the Volvo lineup.

Nonetheless, the only accessory belt story I enjoyed on that 940 began with an alternator belt looking very much like the one in your image.

Spook's post got my thumbs up below. This is what caused an occasional misalignment of the belt at times much in excess of two millimeters.


--
Art Benstein near Baltimore

"If you associate enough with older people who enjoy their lives, you will gain the possibility for a full life." -Margaret Mead

That's the correct belt size and Continental is a very trusted brand, only one I ever use. That many years says you more than know how to tension belts by now.

That's one seriously damaged belt. The cover backing is frayed and separating, a sign it might have been wearing against something on both sides, such as riding low in a pulley. If it broke and got caught up in another belt or behind a pulley then I wouldn't expect damage like that to be the entire belt. It's almost like it was running over a seized or wobbly pulley.

I'm guessing it was hanging by a thread for some time before finally letting go. To go from near pristine to that in a matter of days is indeed surprising.

Have you considered the possibility of rodent damage getting part way through one side then the rest hanging by a thread for a few days? Rodents generally prefer wire insulation, but drive belts have been known to be on the menu. They need to wear their teeth down and will go for anything of the right texture.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now