I have a John Deere 490E excavator and I'm not sure how to properly align the serpentine belt that appears to power the fan, the alternator, and the water pump. I had installed a new belt last week and ran it for 2 hours and it completely shredded. Here is my video of me trying to check the alignment with a straight edge and string, but I am not sure how to do it properly: https://photos.app.goo.gl/YVgwYfGKdU2Z1wry8 Any advice would be much appreciated!
World class answer! I will try each of these things and report back. I know the idler pulley has a tiny bit of play in it already.
Ok, here is what I got done: https://photos.app.goo.gl/NVswQ273GZQYJfu57 I removed the idler pulley as that definitely has a tiny bit of play. I removed the self tensioner as a friend told me to replace the bearing on that if I'm going to replace the bearing on the idler pulley. The fan drive did not seem to have play. I had mounted this myself last time and may not have put it on perfectly straight though. I did have all the bolts all the way in, so I'm not sure. This may not be a problem. The water pulley does not have any play, but looks like it might be on at a bit of an angle to me. Can I pry this off with a pry bar? I tried it using a wrench as a pry bar and nothing happened. The alternator pulley does not have any play, but it does squeak a little bit when I turn it. Should I replace bearings on that one? This is my first time doing this, so I greatly appreciate all of your help! I've never done anything with pulleys or bearings before.
If the original belt was just seasoned and replaced for regular maintenance and the replacement belt shredded, you didn't have it placed correctly on one or more sheaves.
@heymccall brings up a good point. Was the original belt OK and the new belt shredded? No, don't attempt to remove the water pump pulley.
No, the original belt only was 1/3 the width of the new belt as material had been torn away from it too. Ok, I will leave the water pulley alone.
In your pictures your fan is not mounted right. Bad Bob
I had loosened the bolts for the fan in the video, which are in the photos you see, for testing. They are fully mounted and tightened when actually running.
Ok, so I went to Napa and replaced the two idler bearings there. I tried to replace the bearings in the auto tensioner, but we stripped out the sprocket bolt. Since I had no known issues with the tensioner, I decided to put it back in. The bearings and springs were untouched in it, so it's just like it was. I can order a new one online later if needed. Here is a video of the engine put back together and running: https://photos.app.goo.gl/DTTiU7NpsVJVXgXk9 L isten to the metallic grinding noise at 3:39 please. You don't hear it when off to the side, but you can hear it right over the fan belt. Is that normal? Should I try to find where it's coming from and replace or repair whatever it is? Could it be caused by a too tight auto belt tensioner? I didn't know exactly what angle / degree to reinstall that at.
Looks to me your alternator is misaligned but your video is not the best. Where are you located? Bad Bob
I am located near Graham, WA. You? Want to come help
I've run service calls up that way before so might not be out of the question. Doing some fun stuff this weekend I'll give you a phone number Monday. Bad Bob
Cool... I did the "start a conversation" thing and sent you my number too.
Okay, so I went into Napa at my local store where the owner actually let me go in the back and use his tools and such to rebuild my alternator as it was squeaking and having issues. The bearing past the brushes at the far back is squeaky and he did not have a replacement for it unfortunately. I ended up just ordering a new alternator through him, but I learned a ton by taking this one apart and putting it back together. My big question is that I have a time sensitive project that needs to be done. How risky is it to put in this alternator that I rebuilt and squeaks a bit and run the excavator for a few hours to get my project done? Should I wait or can I do it without causing too much more damage?
Seems the worst it can do is seize up and burn the belt.
True... I'll wait for the new one.
So here are my videos from this morning compiled into one six minute thriller: https://photos.app.goo.gl/YhmC8NSqfzW7uwJX7 I put the belt back on this morning and started up the machine. I heard a metallic screeching / tapping from the alternator. On further investigation, the fan blades were actually tapping the bracket / engine block. @Bluox had the very good point that someone likely put the wrong size alternator on the machine at some point. This is why the original belt was also eaten up to 1/3 it's size. The bearings are also squealing quite badly in it, which you can hear in a video. What is not shown is that I pulled off the alternator, took it into the Eatonville Napa where the super nice franchise owner worked with me (or rather he did most of the work) to disassemble the alternator and put in new bearings. We were unable to replace the rear bearing, so the alternator still squeals. I ordered one alternator from him ($400, overpriced but I owed him for his help) and another one ($75 from Rare Electrical) online. I think both he and I ordered the new ones based on the machine - John Deere 490E - rather than the bad alternators part number. I am curious to see if they are different than the one I have. I also want to rebuild the current alternator all the way for my own edification at some point, but I am going to need to get out one of the four long thin bolts that I overtightened and broke off to do that. I think that a new bearing in back and a bigger spacer to move it off the engine block might make this one usable? I am learning a LOT. I had no idea how an engine or it's accessories worked until I started digging into this. Interesting stuff!
For what it's worth --Prolly nothing. The John Deere parts book shows 3 different alternators available able for a 490E. Perhaps they all have the same physical dimensions, maybe not. I wonder if yours is the wrong one on it. https://partscatalog.deere.com/jdrc...xPRyw3NDk1MzpFUVVJUE1FTlQsMzMzMjE6Q0hBUFRFUl0
Thank you, that's my guess too.
So my new alternator from RareElectrical arrived. They claim it is a match to the John Deere 490E. However, the machine has a 2 prong plug and the alternator has a one prong plug. Am I missing something? https://photos.app.goo.gl/JcAzN2gZc8o4CMQWA https://photos.app.goo.gl/abhqRrZB8vYfxAQr9