So I just installed a new fan belt on my e55. I've been running the machine for about 20 hours just fine and however the belt broke again. I thought the first belt broke just because of age or wear and tear (its been on for at least a couple hundred hours) but now I'm thinking its something else given the brand new 2nd belt ripped apart after only 20 hours of use. If it matter any, the first belt had a clean rip. The 2nd belt was shredded. The fly wheel also has the air condition belt for the compressor on it so I'm thinking the fly wheel is fine. The wheel on the alternator seemed solid. I couldn't see very well the 3rd wheel and not sure what it even drives. Anyway - if people have some strategies to figure out why this happened that would be great (or what to look at or to check). In the meantime I guess I'll install a new belt so see if it was just an anomaly or if something else is at play Thx Ron
Check each pulley and idler. Make sure the tensioner is applying appropriate tension. Makes me wonder if something is worn and pulley is slipping out of alignment. Also make sure the belt is routed correctly. Sometimes that’s tricky.
Thanks for the tip JD - That belt, however, is a "pry on" belt - i.e. there is no tensioner. What do you mean to make sure the belt is routed correctly ? There are no grooves or anything on the belt...although there are grooves on the pulley wheels.... thanks in advance Ron
Can you post some pictures of belt and pulleys if possible.
I never heard of a pry-on belt. The belt tension is controlled by either a spring loaded tensioner or by adjusting the alternator position. If your E55 does not have a tensioner then you need to get the factory specs for the belt tension and set it to that. A new belt will fail quite soon if the tension is too high.
I have…but this is a first for me to hear of it in equipment. It’s a cheap crappy throw away econobox car “innovation”.
Stretch (sansa)? Belt. Lisle and others make a tool for install. Some BMW engines have them When they fail they can turn into a very long spaghetti like string. Wraps around crank pulley and sometimes gets pushed through the crank seal. Big leak then. If enough gets through can be found in oil pump pick screen. Flat belt on grooved pulleys seems like a possible problem.
I’m guessing you got over-zealous with the pry bar and damaged the belt during the install. I wonder if a stretch-fit install tool like what Subaru or Gates sells would work better than a pry bar?
Lisle one
When I get back to the machine later this week I will try and remove the belt and take some pictures. The new belt is torn to shreds so not sure what is left but engine was too hot to reach down and grab anything and I had to leave. It was identical to the previous belt which just snapped a few week ago. I have the same instructions that Coaldust posted in my service manual that say to use a pry bar I actually was able to feed on the flywheel by hands while turning the engine with a pry bar - wasn't easy but I did not want to damage the belt with a pry bar. So i guess i was wrong about the fan belt not having ribs as the description of the belt on the website says it does it has ribs. ( https://shop.bobcat.com/ca/7010894-fan-belt .). I did buy an OEM belt from a Bobcat dealer. He also mentioned that the belt was a "pry on" belt (he may have used a different term) and that my system did not use a tensioner. The manual also does not mention anything about a tensioner or to adjust the tension I sure hope the shredded belt did not push the bearing seal as MKS mentioned - it did turn into a spaghetti type of mess. I was able to visually inspect the wheel on the alternator (looked fine) but not the water pump. It doesn't look easy to get to.....damn! By all accounts it would appear I have to examine the wheel on the alternator and wheel on the water pump. Doesn't seem like there can be any other culprit.
I suppose the water pump or alternator could be seized.
I've installed those belts on Subaru vehicles and the new belts come with a plastic "slide" tool, along with a plastic "pry bar", install was easy, I'm surprised your belts don't come with same. But I got nothing re your current problem. I suppose it's not impossible that you got a faulty belt for your 20hr one.
Me either. Guess we are too old!
When I get back to the machine later this week I will try and remove the belt and take some pictures. The new belt is torn to shreds so not sure what is left but engine was too hot to reach down and grab anything and I had to leave. It was identical to the previous belt which just snapped a few week ago. I have the same instructions that Coaldust posted in my service manual that say to use a pry bar I actually was able to feed on the flywheel by hands while turning the engine with a pry bar - wasn't easy but I did not want to damage the belt with a pry bar. So i guess i was wrong about the fan belt not having ribs as the description of the belt on the website says it does it has ribs. ( https://shop.bobcat.com/ca/7010894-fan-belt .). I did buy an OEM belt from a Bobcat dealer. He also mentioned that the belt was a "pry on" belt (he may have used a different term) and that my system did not use a tensioner. The manual also does not mention anything about a tensioner or to adjust the tension I sure hope the shredded belt did not push the bearing seal as MKS mentioned - it did turn into a spaghetti type of mess. I was able to visually inspect the wheel on the alternator (looked fine) but not the water pump. It doesn't look easy to get to.....damn! By all accounts it would appear I have to examine the wheel on the alternator and wheel on the water pump. Doesn't seem like there can be any other culprit. View attachment 288713 So probably silly question - but if the water pump or alternator were seized then the wheel that the belt runs on would not turn, correct? I couldn't get my hands in their because engine was so damn hot and then I had to leave the job site and not back until Friday......
Well, yes. Thus, destroying the belt in short order. More likely, one rib of the belt was hanging over a pulley and eventually shredded it. Its an easy mistake to make in a tight engine compartment.
Thanks Coaldust. When I picked up the new belt at the dealer yesterday I talked to one of the mechanics and that's exactly what he said. and I have to say I never checked if the belt was completely over the water pump wheel...it's very hard to get a good look at but rest assured this time I will! I'll update thread once it's back on and I have run the machine for >20 hours
It was fairly obvious in the above case The front of the engine and main serpentine belt were covered in oil. The failed stretchy belt was for ac compressor only. I unwound the string from the crank pulley and it stopped so I removed the crank pulley and then pulled the rest from the crankcase. In this case it’s recommended to pull the pan to check the sump screen because trouble codes indicate variable valve control problems.
Get yourself a mechanics mirror and a good light it helps for stuff like this.
Okay - i put the new belt on today after untangling the previous belt (see pic). The new belt went on fine just like the previous "new" belt. I have run the belt for 6 hours today. I have some pics before I ran, while running (could not upload the video) and after 6 hours. I did check the wheel on the alternator and it turned true and had no play. Same with wheel on the fan. Its possible that the belt was not on one of the wheels properly but I highly doubt it. I will just keep checking and hopefully surpass the 20hr mark I did before. Maybe I (hopefully) had a defective belt. The tangled mess of last belt. The one before this belt had been on for over 200 hours and was a clean snap Pic above showing belt on the fan (flywheel) Picture below - belt at end of day Anyway, I hope I am not back at this forum in the next couple of days because that means the 2nd new belt had a problem..... Thanks everyone for their insight and tips
If the belt in the last pic that says “stretch” on it is the one you just put on, you have an alignment issue somewhere. You can see bad wear on the inside edge of the belt already. Reading back through it looks as if the inside belt is the one you’ve changed. Either way, something looks amiss about the belt marked stretch fit.
Hmmm.....okay. yes, that inside belt (to the left) is the one I just changed. So where do you think is the likely mis-alignment? Alternator, flywheel, fanwheel...I'm not sure how to tell...
Just saw stretch in your note. That is not the one I just replaced. That is a couple hundred hours old
Off a tooth, bud. You gonna shred it again.
Good eye! That edge is surely worn already.
I will order a new pump belt - seems like it needs replacing. In terms of being off a tooth I know the pictures aren't great so I took a closer look. I think the belt is in place. I posted some more pics a bit closer up. If you think they are still off a tooth let me know
Coaldust's red arrow to the AC compressor has two grooves visible, and that front belt shows wear. The wear could be from rubbing the failing back belt, that failure could have thrown the front belt off a groove or two on the compressor. Put it on straight, and it might run fine for many years. Does this have a solid crank pulley or any kind of harmonic balancer?
I would look at the belt/pulley relationship with a mirror or cellphone picture from below the red arrow upwards to see how the belt and pulley groves line up
Yes, the visible grooves in the AC pulley are suspicious, but the real test is alignment. A straight edge is the standard, but just looking at that belt with the exposed grooves looks like the belt is at an angle to the groove, that's a tough viewing angle to judge. Take a picture from each end with a ruler on the recessed pulley to show the alignment, will be close enough. It's not like the alignment is adjustable, just make sure nothing is broken or otherwise messed up and the belt is in the right groove and you should be good.
Ah...okay. I see I've been concentrating on the fan/alternator belt which is the one that snapped and then shredded....i will look more closely at the AC belt to see it is still off a tooth. I'm not sure if it has a harmonic balancer or not. Thanks for drawing my attention to this!
Thanks CDust and Delmer. I was focused so much on the fan belt that I have been replacing that I didn't look closely at the AC belt. I looked this morning and as you guys picked out it was off a tooth. I moved it over and it seems to be on all the teeth now. Thanks for helping me out. Took a before and after picture - hopefully this looks good to everyone!
Looks good from my house lol
I'm not sure what's going on but only getting 200hrs out of a belt seems way too short of a lifespan.
Hi Keif - the belt may well have over 200 hours. But that is all I have put on the machine since I purchased the machine so that is why I said 200 hours. I should have clarified that....thx
So an update to this saga. After putting on the 2nd belt and triple checking everything (as per pics above with you guys) I ran the machine for about 15 hours this time and the belt shredded yet again . I talked to the Bobcat service techs and they felt something was out of alignment and that I needed a technician to remedy echoing aharts comments. So I bite the bullet and had the machine floated to the local Bobcat dealer for their service technicians to take a look. Gave them the history, showed them the pics I had posted here, etc. They went through all the wheels and alignment of everything looked great. They put the new fan belt on (they called it a stretch belt as ahart mentioned) and ran it for a while. The belt ran a bit hot in their opinion so they took it off. They noticed a bit of rubber residue built up on a couple of the wheels so they cleaned it up with a brush and solution and reinstalled the belt. They said that this residue shouldn't have caused the problem but was the only thing they could really find. The bottom line to me was "we didn't find any smoking gun". That really wasn't what I wanted to hear. They replaced the compressor belt at the same time and I had them do a bunch of other unrelated service since the machine was in the shop. Anyway - I'll be back at the job site in a couple of weeks once i get the unit floated back and will give the machine another run - and will update thread if I make it past 20 hours....or if I do not Thx again for all your help