Hi there - my fan belt just broke and I need to replace it. I searched the forum but didn't see any posts. I found this on youTube ( ). Looks like i have to remove front counter weight, drain all the hydraulic fluid, pull out the hydraulic pump - holy cow!!! Just want to confirm that's what it takes to change the fan belt. Any tips as I'm doing this would be appreciated. Thx Ron
There is a lot of posts on here on this topic. Just search "Case Fan Belt". Basically, just unbolt and loosen the coupler between the engine and hydraulic pump shaft and slide that coupler back enough to slip a belt through. The coupler is likely to not move easily. Oil and maybe an air hammer to loosen it up.
I had my fan belt go on my 580C. Man O Man. Its a massive job to remove everything to get to the Hydro pump to remove it. I read a few posts on the topic and decided to go with a Linked belt. Ordered one off of Amazon, installed it and never looked back. They are kinda expensive, But considering that it took me 1/2hr to install, worth every penny. I'm at the point that if I have to change the Linked belt every year, so be it. Still easier and faster that removing the whole front end of the excavator. Just my 2 cents.
Thanks KC - i looked on Amazon and couldn't find one - could you send me the link for the one you bought....thx
The fan belt KC bought for his 580Ck C will not work on your 580K. You most likely do not need to remove the pump. The hoses may allow you to slide it forward enough to get the belt thru the split coupler. I think you have a serpentine belt and that eliminates a linked belt. I would never advise anyone to use a linked belt. It could break, and go unnoticed until you cooked a motor from overheating.
I just loosened the 4 bolts - the issue sliding it back is there is a steel hydraulic hose in the way and it doesn't want to move back much....I think i got it to move maybe 1/8"......does this mean I've got to take the hydraulic pump off ?
Those steel lines can sometimes be the reason the pump has to have them removed to be able to slide it back. Look for a clamp(s) that may be holding the line(s) from moving.
Thanks Tinkerer - I'm now second guessing myself. There seems to be 2 sets of 4 bolts that holds the hydraulic pump in place. In the image below the bolt labeled Bolt#1 has 4 bolts and the bolt labeled bolt#2 (which i have partially loosened) also has 4 bolts. Both seem to have to do with the hydraulic pump. I'm thinking its actually the set of 4 bolts labeled "Bolt #1" that need to be loosened. Reason being I'm not sure how I would slip the belt over if it were the set of bolts labeled Bolt#2. And if I am correct then the shaft of the hydraulic pump needs to be rotated as you loosen them. Question #1. Can anyone confirm which set of 4 bolts need to be loosened (Bolt labeled #1 or labeled #2) ? Another couple of questions..... Question #2 I didn't hear the fan belt snap but I know it was there and working about 30 minutes prior as my alternator was making a weird noise (turned out the fan was loose on the alternator and it was rattling). The reason I found out the belt snapped was the engine stopped/stalled. Does the fan belt power the fuel pump ? And that's why the engine stopped ? I waited 30 minutes and then started the engine for 30 seconds and moved the backhoe to level ground so it seemed to be working.... I hope I didn't do any damage to engine..... Question #3. Somewhat related but as well as the fan belt snapping the "roller" (not sure what you call it) that is attached to the alternator and that the fan belt runs around fell off - maybe they are related but it appears the bolt came loose - anyway, I screwed the roller back on to the fan belt but when I spin the roller it has a very slight wobble - I'm assuming I should replace the alternator or the roller so there is no wobble ? (it is very minor but you can tell it doesn't run true) Question #4. I read in a post that one should make sure the "idler" is properly adjusted otherwise it will rip apart your belt. Can anyone point me to where the idler is and how to adjust it ? Is it the same mechanism as the tension roller ? Thanks for everyone's input - its been a life saver !!! (and bank account saver ) Thx Ron
JBrady posted some good information already. Be aware that there are 2 different models of 580k's and they have their own parts books as a result None of those bolts need to be loosened or removed. Only the 4 bolts on the pump flange need to be removed. Bolt #1 and the other three of them are holding front 1/2 of the pump coupler to the engine crankshaft. The bolt labeled #2 is holding the front engine mount to the block. Tighten it back up and use torque wrench to whatever it is supposed to be. It is quite normal for the fan belt tensioner to wear out and fail. It cannot be repaired. A complete new one is needed. I am posting an image of the pump with it's 4 mounting bolts. There are no steel lines preventing it from being moved forward enough to get the fan belt through the coupler. In the lower RH corner is an image of the hydraulic suction screen it should be cleaned and inspected.
Thanks Tinkerer - in the diagram you posted what bolts need to be loosened ? Perhaps I have a different model as I don't see any other bolts to unfasten on my machine ....
...and in my picture - where in reference to the bolts #1 and #2 would be the flange bolts be that i need to loosen ?
I might chime in here, just to recommend removing 4 × bolts marked #1. Then to use a prybar to slide the coupling away from the front pulley about 5-10mm & slide the new belt through the gap. The adapter is sometimes unable to slide due to rust on the pump spline - then using a air hammer on the coupling works well to free it up. Leave all the pump mounting bolts alone as there is no need to touch them at all.
Thanks Alrman - i will give that a try.
Ok - I have loosened the 4 bolts marked #1. Probably silly questions but all the bolts need to be completely removed correct (in order to get belt through). 2nd question - I am assuming i need to pry back the unit where my screw driver is wedged in in front of the fly wheel/pulley (labelled pry here) and not behind it where i've labelled it "Do not pry here" ? I've loosened the bolts just to see what would slide out and I have a bit of movement in the housing- there is hardly any room to get your finger in there - not sure how I'm going to unscrew the bolt the whole way. And besides "prying" the housing back what other way is there to move the hydraulic housing out of the way - again, very tight space to work. Thanks again Ron
Yes the bolts need to be removed. It will ,separate from the pulley where you have the screwdriver. Do not pry behind the pulley. It is bolted to the crankshaft. Prying there will distort it or break it.
Back the top bolt out using an open end wrench, then turn the crankshaft a 1/4 turn until another bolt is on top, remove it. Lather, rinse, repeat. You can usually turn the crank with the bolts you are working on.
Well - I am happy to report all went well! This never happens with projects like this for me - usually bolt is rusted on, or as many stated the unit wouldn't back off easily or something happens making it not straight forward - or what i thought would happen was that I couldn't get bolts back in because I really could not apply and forward pressure. But all the nuts backed out and the unit slide out nicely and the belt when in fine and all bolts went back together - I will say that the space is tight but so thankful I didn't have to remove counter weight, drain hydraulic fluid, remove hydraulic pump etc. That would have been a killer. (Note this recap is really for me 5 years down the line when I have to replace the fan belt and forgot everything I did today) Thanks all for your help and confirmation of the process. I do have another question about anti freeze but will post it separately.
Good day. Its not even been a year since i replaced my fan belt (thanks Tinkerer & Mitch for your invaluable guidance) and my fan belt broke again and wrapped itself up nicely around the crankshaft. The root cause of the problem was an improper installation of the pulley on the alternator - my fault. I did not put on (actually did not have) a "wobbly" washer installed between the pulley and nut which was apparently super important according to the Case mechanic I visited. The alternator wiggled the nut free, stripped the thread on the alternator shaft, ruined the pulley and then the belt got off the pulley and the rest was history. It took me a good 4 hours to dig up the remains of the belt around the shaft. I had to do this otherwise I would not be able able slide the coupler back after loosening the 4 bolts mentioned above in order to slide the new belt on. Anyway - i bought a Case OEM alternator (4 times the price of an aftermarket) so I would have all the right parts, a new pulley and new fan belt and installed everything. At least I had practice from last year so while it still took me a while I got it done. EXCEPT for one problem - and that is, once i start the engine the pull "slips" off the main wheel a bit. I don't recall if this happened on the new belt I installed last year, but I do recall for sure that the belt before that was missing a strip along the edge and while it worked for a number years like that it did finally give way last November. I wondering if its always run that way because something has always been out of alignment So my question is, how do I remedy this "slip". I don't see anything obvious I could adjust. I'm wondering if the pulley off the alternator is maybe pulling the belt away. The only thing I could do there is put a spacer between the pully and fan to "move" the pulley out and thus maybe correct the slip but there are strict instructions from the alternator manufacturer that says "Do NOT alter configuration" of the alternator. I've tried several times putting the belt back on track but as soon as the engine starts it slips off a bit... Any ideas or suggestions ...???? And what are your thoughts of running it like if I can't fix - probably a rhetorical question - I suppose running it like that I will eventually ruin the belt.... Help! Thx Ron
Check the alignment of the new alternator pulley with the rest of them. Did you check the belt tensioner pulley for any wobble in it ? Also the belt tension. The tensioners commonly fail. Is there any wobble when you push n pull on the fan blades ?
Thanks Tinkerer for the quick reply. The alignment of the alternator pulley looks pretty good (i.e. in line) with the other wheels. The belt tensioner pulley did not have any wobble in it - however, I would say that looking at it, it looks a bit crooked (see pics). I don't know what is normal. Its possible that the tensioner has failed although it has a wicked spring/tension on it (it was very hard to pull it so that I could get the belt on the alternator pulley). What are the signs of a tensioner that is not working properly Also - you can see the wear marks from the belt on the bottom wheel of the tensioner - the belt mostly runs on the left side.... ....any thoughts ? Thx Ron
You need a new tensioner. They fail often because of the pressure on the bearing and shaft.
Okay thanks - is that because the gap you see in the picture ?
Yes It is showing wear.
**TIP - There is a way to eliminate the belt tensioner on these 4-390 engines - especially on a backhoe. Remove the tensioner from the engine - dispose. Under the alternator, there is a short 6mm plate used to hold the alternator in place - remove it & dispose. Fabricate a small adjusting bracket (as used in any old school alternator) from 25mm x 6mm flat. Use it in place of the small plate. Adjust fanbelt as like in the old fashioned days. Less load on fanpost; water pump; alternator bearings + cheap!
Translates to 1 inch by 1/4 inch flat bar and looks about 4 1/2 inches long.
Thanks Arlman for the tip. By the time I saw this I had already ordered the tensioner. After installing the new tensioner, the belt stayed on all the wheels so thanks again for everyone's help. The new tensioner did have more tension (not a ton) so i don't think that was the problem with the old tensioner - but perhaps the roller/wheel on it was just not 100% perpendicular and caused the belt to slip off the fan wheel....just a guess.
You could see the old tensioner was failed. The spring may have had tension but you could clearly see it was not sitting square.
Looking at the top picture you can see the difference in the angle between the tightener pully and the belt edge, replacing the tensioner was the right fix