T300 - Low Hydraulic Charge Pressure

[trevelynzx]

Hey guys, I've got a 2006 T300. Rented a trencher attachment and ran it for about 12 hours. Since then the T300 beeps at low idle and shows an error code: 05-14, extremely low hydraulic charge pressure. Bought the service manual but can't get much insight from it. A buddy looked at it and said the drive belt seems tight. We pulled the relay cap off of the pressure sending unit which let the machine run (instead of shutting it down when it's at a low idle).

Couple things:
1) Before pulling the relay the machine would beep at low idle and shut down in about 15 seconds. However, if I boosted the throttle the warning would clear and the machine seemed to operate normally.

2) After removing the relay the machine seems to have little to no hydraulic power to operate the lift & tilt at low idle. At high idle I feel like the machine doesn't have as much power as it should but it does operate. If I had to guess I'd say it seems like it lost 25% of its total power when at high idle.

3) I was running it yesterday at about 60% throttle. When moving forward/ backward there was a noticeable whining noise that seemed to be coming from both drive motors. Raising the throttle stopped the whining but it worried me because I'd never heard that before. (I did tighten the tracks that morning before beginning so I relaxed them a little bit. That didn't help the whining, but as mentioned above the throttle did.)

I feel like the low hydro pressure message is legitimate especially given that the machine seems underpowered. Should I get another pressure sensor? Any other diagnostic advice?

 

[brain55]

I'd put my money on a drive belt. I've worked on a bunch of them and that error was almost always the belt slipping, either from being loose or oil soaked or coming apart. Your symptoms support that being the problem too.

Brian

 

[trevelynzx]

Hey Brain - thanks so much for the quick response. After lurking here for a few weeks and calling my local Bobcat dealer that is the same conclusion that I'm coming to. What threw me for a loop was the fact that the belt shows no visible signs of deterioration, and even my buddy thought it seemed OK. However, the Bobcat service guy I talked to seemed to think it could be the drive belt as well. The service guy told me to look for a tensioner and that it should be at the 3 o'clock position, but it turns out my machine is one that doesn't have that type of adjustment - according to the service manual it's just a matter of replacing the whole belt. Is that something I should get done professionally? I'm not afraid of making repairs if it's straightforward - any "gotchas" that I should watch out for?

Anyway, one other thing - I changed the hydro filter and the fluid looked very clean, so I'm keeping my fingers crossed that the pump isn't getting ready to blow apart... Only 2000 hours on this machine so I was expecting many more years from it! Got 50 acres of woods and rundown farm buildings to upkeep/ demo and this track loader was gonna be well worth the money. Anxious to get it back in order and keep the diesel burning...

 

[brain55]

The belt isn't that tough to change, the hardest part is prying down the tensioner while tightening the bolt. I take the battery out to give myself more room.

Brian

 

[SSdoxie]

The drive belt replacement procedure is in the Hydrostatic section of the Service Manual and in the Preventive Maintenance section of Operator Manual.

If a new drive belt doesn't cure it you should have the dealer do a pump flow test on it.

 

[trevelynzx]

Hey guys, thanks for all the tips. Today I removed the old drive belt and slipped the new one on. To be honest the old one didn't look bad - the teeth seemed to be in good shape and the belt overall didn't look too worn.

However, when I attempted to loosen the tension spring to relieve pressure on the old belt for removal, I ended up shearing the bolt that attaches the tension spring end block to the tensioner pulley. :duh: Here's a shot of that -


Once that happened I had to remove the whole tensioner pulley/ tension spring apparatus to get that repaired. In doing so I noticed that the internal bearing of the tensioner pulley looks like it had blown out its grease. Pic of that -


You can see the cover piece in the upper left is filled with grease. The bearing near my finger isn't budging. So I think this could be my entire problem. I'm going to see if I can take that bearing apart to repair it or if I'll just have to buy another one from Bobcat. I'm going to have to buy a new end block for the tension spring anyway so I'll probably just get both.

It's always something!!! But hopefully I'm on to the source of the "extremely low hydraulic pressure" problem... I'll update as I go for anyone interested.

 

[trevelynzx]

By the way, I've got to find a way to remove the sheared stump that was left in the tensioner pulley - you can see it in the middle-right of the first picture I posted above. Any suggestions? I was thinking of drilling it, heating it up, and then using a screw extractor. Not even sure that it's threaded though.

 

[trevelynzx]

Quick update --

Replaced the sheared bolt and a few deteriorated gaskets. Put everything back together (including the new belt) and tightened the tension pulley down hard against the belt. Fired the machine back up and unfortunately had the same problem - 05-14, extremely low hydraulic charge pressure.

The dealer is telling me I may be looking at a new charge pump. Any way to know for sure? Already spent $600 on troubleshooting... I'd like to make sure I get it right this time.