Please help, dumb newbie mistake

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Roozter

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Apr 3, 2007
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I was looking over my recently purchased '99 751C and checked the hydraulic fluid. It was just slightly over half way between the two marks. I added about 1/2 quart of 10W30 while parked on level ground and this brought it up to two lines from the top.
Then I went and parked it out back with the rear end pointing up a slight grade (about 5%) while shutting it down I noticed the trans light came on, and I lost all hydraulic function.
I panicked and called my dealer (that I bought it from) and he said to double check that the parking brake was not on, and the traction lock was not on, etc. I did all that and still nothing works.
Then, I re-checked the fluid level after reading in the service manual that improper fluid level could cause this problem. Guess what? Now it reads just a hair above the top mark! Is my hydraulic fluid too full? Will taking some out fix the problem? Did I cause major failure to something in the hydraulics? I found in the manual how to drain the hydraulic fluid when doing a fluid change. However, it seems that siphoning 1/2 a quart out of the reservoir would be easier.
Any thoughts? And yes jokes and laughter are appropriate! I had no idea these machines could be that sensitive! It seems that running the hydraulic fluid closer to half full on the dip stick is a better idea than closer to full, since these machines would almost always be operated on less than level ground!
Thanks everyone!
 

farmboy55

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I've never seen a machine shut down due to a overfill. I would ck out some other things first like the hyd filter, see if it may be blocked. How long have you had this machine? dennis
 

Roozter

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I've never seen a machine shut down due to a overfill. I would ck out some other things first like the hyd filter, see if it may be blocked. How long have you had this machine? dennis
I've only had it since last Thursday. It has a re-built Puegot and I have put the first 8 hours on it.
So, I may have some other more serious issue? The only thing I did was grease the fittings and top off the hydraulic oil. It has been colder here, in the high 40s but I let it warm up 3 minutes before moving it also.
I'll check the filter also, thanks. I sure hope it is not a major problem. Maybe I should have my dealer send out the mechanic that he offered. I told him I would try removing some hydraulic oil first.
 

skidsteer.ca

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I've only had it since last Thursday. It has a re-built Puegot and I have put the first 8 hours on it.
So, I may have some other more serious issue? The only thing I did was grease the fittings and top off the hydraulic oil. It has been colder here, in the high 40s but I let it warm up 3 minutes before moving it also.
I'll check the filter also, thanks. I sure hope it is not a major problem. Maybe I should have my dealer send out the mechanic that he offered. I told him I would try removing some hydraulic oil first.
It won't drive or lift or dump? Does the engine labour when you try to drive, lift or dump, if it sounds exactly like it doesa when your little it sit still then it sounds like the main drive belt from the engine to the pumps came loose or broke.
This drives everything but your alternator and waterpump. I had the belt tensioner fail last fall and the belt came loose and everything (except the engnie) just stops.
Regards
Ken
 

Roozter

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It won't drive or lift or dump? Does the engine labour when you try to drive, lift or dump, if it sounds exactly like it doesa when your little it sit still then it sounds like the main drive belt from the engine to the pumps came loose or broke.
This drives everything but your alternator and waterpump. I had the belt tensioner fail last fall and the belt came loose and everything (except the engnie) just stops.
Regards
Ken
Ken,
Yes, all it will do is run the engine. I can vary the throttle, but the Bobcat won't move (drive) lift, or dump. It seemed to gradually quit becuase I drove it from the font of the yard to the back, re-attached the bucket and backed up to park it. Then I was messing with deciding whether to park it with the bucket rolled all the way back or resting on the ground, when it quit working. The engine will not labor at all when pushing the peddles, or moving the handles it just keeps running, like you are not working anything.
The trans light is on all the time now, when the engine is running, and that makes me nervous to run the engine at all since, the service manual described that pump failure can occur in less than 60 seconds with no or low hydraulic flow.
 

skidsteer.ca

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Ken,
Yes, all it will do is run the engine. I can vary the throttle, but the Bobcat won't move (drive) lift, or dump. It seemed to gradually quit becuase I drove it from the font of the yard to the back, re-attached the bucket and backed up to park it. Then I was messing with deciding whether to park it with the bucket rolled all the way back or resting on the ground, when it quit working. The engine will not labor at all when pushing the peddles, or moving the handles it just keeps running, like you are not working anything.
The trans light is on all the time now, when the engine is running, and that makes me nervous to run the engine at all since, the service manual described that pump failure can occur in less than 60 seconds with no or low hydraulic flow.
IF... the belt broke running the engine won't hurt it becasue the pumps not turning. To check the belt take the plastic cover off on the flywheel end of the engine (held on with little metal spring clips on the Kubota powered one, 2 minute job) and look for hunks of V belt a busted belt or a belt tensioner (idler pully) thats hanging in there all crooked.
The belt can come loose to and the machine just loose power, will drive but not with any authority. Often this symtom is accompanied by the squealing sound of the belt slipping as the demand on the egine exceeds the level the loose belt can transmit to the pumps.
Ken
 

Roozter

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IF... the belt broke running the engine won't hurt it becasue the pumps not turning. To check the belt take the plastic cover off on the flywheel end of the engine (held on with little metal spring clips on the Kubota powered one, 2 minute job) and look for hunks of V belt a busted belt or a belt tensioner (idler pully) thats hanging in there all crooked.
The belt can come loose to and the machine just loose power, will drive but not with any authority. Often this symtom is accompanied by the squealing sound of the belt slipping as the demand on the egine exceeds the level the loose belt can transmit to the pumps.
Ken
Ok,
I made it home siphoned some oil out of the reservior and took a look see in the engine compartment.
Looks like you hit the nail on the head Ken! I tugged on the belts, I could see, and there is a tensioner pulley that is loose. the belt looks fine. The pulley is spring loaded and I can move it away from applying tension by hand. It appears that when it is tight it will be very close to the frame on the bucket side of the engine compartment.
I am reviewing the service manual and can't find specs for the belts. I will tighten the pulley with the standard automotive 1/4 inch play and see how that works.
I hope to take some picture also, maybe someone can help me upload them afterwards.
Thanks and I will keep ya posted!
 

Fishfiles

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Feb 8, 2007
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Ok,
I made it home siphoned some oil out of the reservior and took a look see in the engine compartment.
Looks like you hit the nail on the head Ken! I tugged on the belts, I could see, and there is a tensioner pulley that is loose. the belt looks fine. The pulley is spring loaded and I can move it away from applying tension by hand. It appears that when it is tight it will be very close to the frame on the bucket side of the engine compartment.
I am reviewing the service manual and can't find specs for the belts. I will tighten the pulley with the standard automotive 1/4 inch play and see how that works.
I hope to take some picture also, maybe someone can help me upload them afterwards.
Thanks and I will keep ya posted!
Doesn't sound like you are looking at the right belt , Roozter , the spring loaded belt is the blower fan belt and should sprind freely , the drive belt is behind the plastic cover held on by three sping clips and the idler is held in place by one 3/8 bolt , fishfiles
 

Roozter

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Doesn't sound like you are looking at the right belt , Roozter , the spring loaded belt is the blower fan belt and should sprind freely , the drive belt is behind the plastic cover held on by three sping clips and the idler is held in place by one 3/8 bolt , fishfiles
Ok, I tightened the bolt but the pulley still moves. This belt runs vertically on the left side (when facing the engine from the rear). The pulley assembly looks just like the one described as the Tensioner Pulley in the Blower Housing/ Fan Gearbox section of the manual. But I don't think it is that pulley. This belt takes power from the engine up to another pulley that I think is on the hrdraulic pump. You also have to remove the airbox to easily reach the pulley.
Anyhow, I don't want to break the damn thing, and my dealer will send out a mechanic to fix it tomorrow (no charge).
I'm trying to figure out how to post the pics.
 

Roozter

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Ok, I tightened the bolt but the pulley still moves. This belt runs vertically on the left side (when facing the engine from the rear). The pulley assembly looks just like the one described as the Tensioner Pulley in the Blower Housing/ Fan Gearbox section of the manual. But I don't think it is that pulley. This belt takes power from the engine up to another pulley that I think is on the hrdraulic pump. You also have to remove the airbox to easily reach the pulley.
Anyhow, I don't want to break the damn thing, and my dealer will send out a mechanic to fix it tomorrow (no charge).
I'm trying to figure out how to post the pics.
Here's a link to the gallery anyway.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=1&currentitem=0&path=Roozter_751C
 

Tazza

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Here's a link to the gallery anyway.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=1&currentitem=0&path=Roozter_751C
As far as i'm aware that isn't the belt that drives the pumps. The one that drives the pumps is basically 2 or 3 V belts that are bonded to a backing to make it one belt. It should be about 1 1/2” wide. I think its the one you can see in the first picture behind the plastic cover. It will be a large belt because it has to transmit ALL the power from the engine to the pumps, a single V belt simply can't handle that.
If you have your dealer coming over at no charge let them sort it out for you. It does sound like a loose or broken belt to me.
 

skidsteer.ca

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As far as i'm aware that isn't the belt that drives the pumps. The one that drives the pumps is basically 2 or 3 V belts that are bonded to a backing to make it one belt. It should be about 1 1/2” wide. I think its the one you can see in the first picture behind the plastic cover. It will be a large belt because it has to transmit ALL the power from the engine to the pumps, a single V belt simply can't handle that.
If you have your dealer coming over at no charge let them sort it out for you. It does sound like a loose or broken belt to me.
Look on the opposite end of the engine under a plastic cover abour 12 or 14” across, held on with steel spring clip, you will find a 3 or 4 wide V belt.
Watch the service guy because you need to check the tension on that main belt every couple 100 hours
The one your looking at just drives the fan that cools the rad, waterpump and alternator
Ken
 

Tazza

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Look on the opposite end of the engine under a plastic cover abour 12 or 14” across, held on with steel spring clip, you will find a 3 or 4 wide V belt.
Watch the service guy because you need to check the tension on that main belt every couple 100 hours
The one your looking at just drives the fan that cools the rad, waterpump and alternator
Ken
*slaps forehead*
Of course, the power is always taken from the fly wheel end, not the front. I should have taken a bit more notice....
It may be an idea for the service guy to check the idler. I remember the joy Ken had when his failed, he couldn't just replace the bearing it wore the whole assembly out real bad.
 

Roozter

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*slaps forehead*
Of course, the power is always taken from the fly wheel end, not the front. I should have taken a bit more notice....
It may be an idea for the service guy to check the idler. I remember the joy Ken had when his failed, he couldn't just replace the bearing it wore the whole assembly out real bad.
Great stuff!
Ken, Tazza, Fishfiles,
Much thanks for the info. Unfortunately, I have to be at my regular job all day and the mechanic is going out to the house this morning. I do have the service manual and I'll just have to get more acquanted with this machine.
Form all your knowledge it appears what I thought was the problem was not it at all. I am assuming the spring loader tensioner, that fishfiles correctly identified, is not supposed to be rigidly tight? thus the spring?
I did not look at the other side of the engine but it sounds like I should pop off the cover you are talking about just to have a look at what is in there.
At least I did remove and re-install the airbox, so I did some work on it, just not productive. :)
Since the service call is “free of charge” I'm sure I did not get a steal of a deal on this Bobcat but if his service continues to be good then I think it will be worth it to me.
Thanks everyone!
 

bobbie-g

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Great stuff!
Ken, Tazza, Fishfiles,
Much thanks for the info. Unfortunately, I have to be at my regular job all day and the mechanic is going out to the house this morning. I do have the service manual and I'll just have to get more acquanted with this machine.
Form all your knowledge it appears what I thought was the problem was not it at all. I am assuming the spring loader tensioner, that fishfiles correctly identified, is not supposed to be rigidly tight? thus the spring?
I did not look at the other side of the engine but it sounds like I should pop off the cover you are talking about just to have a look at what is in there.
At least I did remove and re-install the airbox, so I did some work on it, just not productive. :)
Since the service call is “free of charge” I'm sure I did not get a steal of a deal on this Bobcat but if his service continues to be good then I think it will be worth it to me.
Thanks everyone!
Scott, as Ken and Tazza have said, the hydraulic pump drive belt is on the right end of the engine (as you stand behind the engine). The one on the left just runs the alternator and the fan. The drive belt on the right is about an inch thick, and is tensioned by an idler above the belt. Really hard to see in there, I usually pull the battery to give some access room. As Ken said, there are 2 or 3 clips (hang on to them when you pop them loose!) that hold the plastic shield in place. Once the shield is off, you can sort of access the belt and idler. The idler is tensioned by I think a spring, but for sure by a bolt coming down from the top, with a double nut arrangement. The belt should be pretty tight. There's a tool to use to check its tension, but for your initial troubleshooting purposes, just make sure the belt feels pretty tight. I agree, the most likely cause of your complete hydraulic system "failure" is a loose/broken belt, perhaps a broken tensioner. or maybe a tensioner that was not secured well and backed off. All the functions except the noise on that machine run off the main hydraulic pump, driven by this belt. It quits, and yer dead in the water all the way around. No bucket moves, no wheel drive, no arm lift, nothin'. --- I've never had a problem with an overfull hydraulic reservoir on my 751C causing a warning light, and I ran it over one day. --- Shoot me an email and I'll send my phone number we can talk you through some of this stuff in real time. ---Bob
 

Roozter

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Scott, as Ken and Tazza have said, the hydraulic pump drive belt is on the right end of the engine (as you stand behind the engine). The one on the left just runs the alternator and the fan. The drive belt on the right is about an inch thick, and is tensioned by an idler above the belt. Really hard to see in there, I usually pull the battery to give some access room. As Ken said, there are 2 or 3 clips (hang on to them when you pop them loose!) that hold the plastic shield in place. Once the shield is off, you can sort of access the belt and idler. The idler is tensioned by I think a spring, but for sure by a bolt coming down from the top, with a double nut arrangement. The belt should be pretty tight. There's a tool to use to check its tension, but for your initial troubleshooting purposes, just make sure the belt feels pretty tight. I agree, the most likely cause of your complete hydraulic system "failure" is a loose/broken belt, perhaps a broken tensioner. or maybe a tensioner that was not secured well and backed off. All the functions except the noise on that machine run off the main hydraulic pump, driven by this belt. It quits, and yer dead in the water all the way around. No bucket moves, no wheel drive, no arm lift, nothin'. --- I've never had a problem with an overfull hydraulic reservoir on my 751C causing a warning light, and I ran it over one day. --- Shoot me an email and I'll send my phone number we can talk you through some of this stuff in real time. ---Bob
Hey everyone,
Here's an update on my 751. Evidently I have several problems...
1. The pulley on the left side, that I thought was loose (correctly identified by Ken and Tazza), would not go back into the bracket straight. The mechanic (and I) had to remove the bracket and put helicoil in it to get the bolt to go in straight. Removing this bracket is not easy. We had to remove four very difficult to reach bolts that would be impossible to do without a wobbly socket adapter and two people. Then it appeared we had to remove the hydraulic connections to the hydraulic pump and drain the reservoir. That still did not help and the mechanic somehow coaxed it out with pry bar and hammer ( I was working on my swing set project at this time) Upon examination of the spring loaded fan belt tensioner pulley, it was not installed correctly and was missing the o-rings on each side and had improper size washers causing the pulley to fail.
2. Examination of the blower fan revealed some pretty severe gear backlash from the gearbox that drives the blower fan and the gearbox will have to be replaced. When spinning the fan gearbox pulley by hand it made a regular rattle noise.
3. The mechanic said one of my loose wires should go to a hydraulic fluid temp sensor that is missing and will have to be replaced.
4. The battery had hold down bolts but no strap and therefore was loose in the engine compartment. The loose left hand battery tie down bolt likely caused my problem of no hydraulic operation.
5. Finally, the source of my original problem was the drive belt tensioner on the right hand side of the engine. Probably the loose battery tie down bolt got angled into the drive belt / pulley area and caused the tensioner bolt for the tensioner pulley to snap. That made my machine stop working.
It is not repaired yet, but the machinery dealer I purchased it from is covering all parts and labor to fix all these items. I don’t have the replacement parts list yet but will give an update when I do. He said it came to $1800 in parts. I was beginning to realize I did not get the best purchase price on this machine and probably paid high retail, but with this service and parts warranty it looks like it is turning into a good deal. I just have to cross my fingers that nothing else will go wrong before I am done with the machine and resell it.
 
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