Im working on a 1992 volvo 940 GL, no turbo or anything. and the alternator belt just snapped on the road, its gone, so no way to identify what was originally there. normally id just search the auto parts stores website itll tell me what i need, wouldnt that be lovely if that always worked correctly. but it gave me a 39 inch(roughly 1000mm) belt, cant get it on with the tensioner bolt undone as far as it will allow its just a bit too short. then i got a different belt said to work for a 91, it was 51 inch(12-1300 mm) way too long, so a rough estimate coupled with a tape measurer tells me that it would be roughly 43 inches to work properly, slip over and have just enough slack to be able to tighten, at least i think. im kinda eyeballing this whole thing but the belt that size is $40 as apposed to the $9 belts ive been trying and its rather difficult to get to the auto parts store with no working vehicle to drive so i figured i would ask

1. does anyone here know the actual proper size of a 1992 volvo 940 GL alternator belt?

2. does anyone here know if im doing something wrong trying to replace it, i loosten the tensioner bolt all the way to swing the alternator inwards, then slip it on then tighten it back up correct? nothing actualy needs to be disconnected other than of course the belt for the ac which i just cut off because it doesnt work and the tensioner for that is broken...



i added photos, the first one is the 51 inch belt, the second is an old 39 inch belt

pivot bolt, fully extended

 

ok so one more update, looking at that picture the bracket had plenty more give available, so i pulled the pivot bolt all the way out, it didnt have much further to go, and now it swings freely all the way to the end of that little bracket, so the belt goes on perfectly fine that way, no problem there, the problem is the bolt isnt long enough to reach the hole with the belt on. and even if i could force it leaning on a crow bar or something, i dont want it hanging on by 1 or 2 threads that just asking for trouble, so i figure my best option is to get a longer bolt. not the solution i wanted, but long term i think its going to be a better solution give more options to me for possible future belt replacement. if anyone else has any further input trust me i am all ears but i think that is the way i have to go sadly

 

The adjustment bolt in the picture is too short, it's not the right OEM size.

 

yea it doesnt seem like it is the right size, whether it came that way originally i couldnt tell you, i figure it probably didnt but i bought it second hand so i think that may be what led to all of this i just couldnt really see till i went to snap a picture of it from behind

 

that bracket/adjuster is an available part:
https://www.ipdusa.com/products/1658...-volvo-1378789


the other thing to note, there's a couple rubber bushings holding the alternator, they get tired and hard, and cause the alternator to sit at a slight angle, which causes it to eat belts. best to replace those with the poly-urethane bushings that places like IPDUSA sell, except I'm not finding them right now :-/

 

good call ill look into the bushings, never really had a problem before and to be perfectly honest it might be the original 30 year old belt for all i know lol, but im not apposed to preventing a possible issue as long as it doesnt cost an arm and a leg. and as far as the tensioner i appreciate that one ill keep that in case i cant find the proper bolt by itself, id rather not pay $40 for a $4 bolt though if i can help it lol. from what i can gather through research and measurements it appears to just be an m6-1 thread, 50mm length on the one i have, would need to be roughly 70-90mm to give it full range of motion, havent double checked the fitment guide at the hardware store yet or tried any bolts with that thread but once i find out exactly what size bolt will be needed i will post my findings here

 

most longer bolts don't have thread their full length, that will be an issue.

 

sadly youre not wrong, ill have to special order something most likely for a long term solution but my plan for now was to get a 60mm bolt for a dollar or 2 from one of the local shops, because this 50mm one can touch the hole and if i could pull hard and screw it in at the same time i could probably get a few threads in just not nearly enough to hold and its not really in a good position to do that, so that will give me 10mm of threading, and the bolts ive seen appear to have about 20mm of threading, so that should suffice till i can special order something that is fully threaded

 

Instead of dealing with the bolt issue, you could always find an old belt and cut it and then determine the length you need by butting the cut ends up to one another as tight as you can on the pulley while your pulley adjustment is near it's loosest adjustment. Leave a little adjustment to get the belt on. Then simply measure the outside length and match it up.

 

yea the give it had woulda required a rather odd length belt one that i could get but would cost $45 and thats a lot especially for a part that is not exactly permanent. it took a bit to get around to it but i found the proper bolt, it was in fact an M6 thread, i got a 65mm long one from lowes, its not full threaded its got about 15mm of thread but at that length it has plenty of bite with just enough room to tighten well before you run out of threads

now judging from everything ive learned and seen here, 65mm should technically cut it, but i would not go under 80mm full thread, seems 90mm is easier to find though so thats what im getting

these are the bolts im ordering now that im certain about the dimensions. $15 aint too bad considering the alternative

 

one final update on the situation. i got the bolts in today and installed one. 90mm is just a hair longer than what would be ideal. the end of the bolt hits something a couple mm shorter and it would be perfect. 85mm would be the best, 80 should easily get the job done well. the 90mm does work, but just not in the way it was meant to

 

should be easy enough to trim off 5mm with a fine tooth hacksaw, then round and dress the end with a fine cut smooth file.

 

yea wouldnt be the hardest thing in the world, but it functions as is so eh. lol. honestly it probably wouldnt even need the full 5mm probably like 2 or 3 max, but its literally just hitting the back of the bracket no real harm done. just wanted to make sure i posted my findings in case anyone else ran into a similar issue down the road and needed a new adjustment bolt for any reason, instead of paying $40 plus shipping you can get a 75-85mm M6-1 full thread bolt for a fraction of the price that will fix things right up

 

You can make your own with threaded rod and a nut from the hardware store. I welded the nut to the rod, but you could double-nut it with thread locker. The original threaded bolt is 80 mm long.
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