Terex PT 70 - Auxiliary Hydraulics Power

[CMess]

I am pretty new to the skid steer world. I did a pretty significant amount of research before purchasing a skid steer, but I haven't been around them long enough to know when something "just isn't quite right" with my machine. I bought this machine in an effort to tip-toe (side business) into the brush cutting/mulching industry around here and also get some personal use out of the machine. I primarily run a SkidPro 72 inch open front industrial brush cutter on high flow. About a week ago, while doing some bucket work, my cousin blew the seal on my hydraulic fluid filter. He replaced the filter and added hydraulic fluid back to the machine. Everything seemed fine afterwards. I was using the brush cutter the other day and noticed two things: 1. my hydraulic power seem to diminish a lot easier than before and 2. the hydraulic recovery time for the brush cutter seemed to take longer. The engine RPM never bogged at all during these issues. The blades definitely need to be sharpened which would help number 1 (cutting/mulching production), but more concerning was the increased hydraulic recovery time. When i got off the machine it seemed to be a little low on hydraulic fluid, but I didn't notice any leaks. Also I ran the cutter for about 40 minutes, so if there was a significant leak I would think that i would have simply ran out of hydraulic fluid? My question is, is it possible there is a small leak or a pressure leak somewhere that would reduce my power in cutting and then also increase the hydraulic recovery time? As i said before I haven't been around this machine long so I learning as i go. Any thoughts would be appreciated!

 

[SkidRoe]

Seems odd that a seal would blow on a filter, unless it is on the pressure side. Sounds to me like something is restricting the flow, or bleeding off pressure or both. Have you had your relief valve pressure checked? FWIW - SR

 

[SkidRoe]

Seems odd that a seal would blow on a filter, unless it is on the pressure side. Sounds to me like something is restricting the flow, or bleeding off pressure or both. Have you had your relief valve pressure checked? FWIW - SR

It could also be something on the attatchment itself. Do you have any other hi flow attachments to try it on?

 

[CMess]

It could also be something on the attatchment itself. Do you have any other hi flow attachments to try it on?

No, I don't have any other attachments... and no, I haven't had my relief valve pressure checked. Since everything was running relatively normal, I just kept on mulching. Like I said before, I'm just really trying to learn when something "just doesn't feel right" with the operation of the machine before something tears up real bad... As far as the seal on the filter goes, my cousin just said that he had dumped a load of dirt, auxiliary hydraulics weren't even hooked up, and it started gushing fluid out of the belly pan. When he raised the cab fluid was coming out of the top of the filter around the seal. When he took it off, the seal looked blown/broken.

 

[SkidRoe]

No, I don't have any other attachments... and no, I haven't had my relief valve pressure checked. Since everything was running relatively normal, I just kept on mulching. Like I said before, I'm just really trying to learn when something "just doesn't feel right" with the operation of the machine before something tears up real bad... As far as the seal on the filter goes, my cousin just said that he had dumped a load of dirt, auxiliary hydraulics weren't even hooked up, and it started gushing fluid out of the belly pan. When he raised the cab fluid was coming out of the top of the filter around the seal. When he took it off, the seal looked blown/broken.

That is very odd for a filter seal to blow out like that, especially when there is very little load on the hydraulic system. My guess is the cause of your filter blowing and the lack of hydraulic performance are related.
I wish I could help you pin point the reason better, but I have little experience with these types of machines.
What is you local dealer like? Think he would help you out without taking you for a ride?
Cheers - SR

 

[CMess]

That is very odd for a filter seal to blow out like that, especially when there is very little load on the hydraulic system. My guess is the cause of your filter blowing and the lack of hydraulic performance are related.
I wish I could help you pin point the reason better, but I have little experience with these types of machines.
What is you local dealer like? Think he would help you out without taking you for a ride?
Cheers - SR

The service manager at the local dealer (bobcat) is pretty straight forward. I haven't asked him about this issue yet but I did speak with him about another issue a couple of weeks ago. I'm going to keep researching and take a closer look tomorrow before I give him a call. Thanks for the feedback.

 

[mmsllc]

The service manager at the local dealer (bobcat) is pretty straight forward. I haven't asked him about this issue yet but I did speak with him about another issue a couple of weeks ago. I'm going to keep researching and take a closer look tomorrow before I give him a call. Thanks for the feedback.

I think getting the hydraulic pressure readings on your auxiliary circuits would be a good first step. If nothing else, you can rule that out if it is with in spec. It may sound un-necessary, but if you don't check it, the dealer will & it could be a cheap repair now vs. letting it go on for a while. Just trying to lead you in the right direction. (Pressure is typically indicative of flow.)

 

[CMess]

I think getting the hydraulic pressure readings on your auxiliary circuits would be a good first step. If nothing else, you can rule that out if it is with in spec. It may sound un-necessary, but if you don't check it, the dealer will & it could be a cheap repair now vs. letting it go on for a while. Just trying to lead you in the right direction. (Pressure is typically indicative of flow.)

Thanks for the responses! As it turns out, the hydraulic fluid filter that my cousin installed a week or two ago had vibrated loose. I didn't notice it earlier this week when I checked. I tightened it and that seemed to be what the problem was. No other issues so far. I'm going to keep my fingers crossed. Thanks for all the help.

 

[SkidRoe]

Thanks for the responses! As it turns out, the hydraulic fluid filter that my cousin installed a week or two ago had vibrated loose. I didn't notice it earlier this week when I checked. I tightened it and that seemed to be what the problem was. No other issues so far. I'm going to keep my fingers crossed. Thanks for all the help.

Glad to hear that it was an easy fix. Hopefully that is it.
Cheers - SR

 

[mmsllc]

Glad to hear that it was an easy fix. Hopefully that is it.
Cheers - SR

You are a LUCKY DUCK!!

 

[CMess]

You are a LUCKY DUCK!!

Well, I'm back. It looks like that wasn't the real problem. I started cutting for a little while yesterday and noticed the same problems of no hydraulic power and reduced recovery time for the cutter. Then all of a sudden, a little vibration in the lines so i shut it down. Tried to restart the cutter and it wouldn't spin. I ran it by the Bobcat dealer and hooked a flow and pressure meter to the low flow and told me that i didn't have any flow coming out of the auxiliary hydraulics. The boom, tilt, and drive motors are working fine. Aren't the boom and tilt hydros powered by the same pump as the auxiliary hydros? I left the machine with them for a diagnosis. Any thoughts?

 

[SkidRoe]

Well, I'm back. It looks like that wasn't the real problem. I started cutting for a little while yesterday and noticed the same problems of no hydraulic power and reduced recovery time for the cutter. Then all of a sudden, a little vibration in the lines so i shut it down. Tried to restart the cutter and it wouldn't spin. I ran it by the Bobcat dealer and hooked a flow and pressure meter to the low flow and told me that i didn't have any flow coming out of the auxiliary hydraulics. The boom, tilt, and drive motors are working fine. Aren't the boom and tilt hydros powered by the same pump as the auxiliary hydros? I left the machine with them for a diagnosis. Any thoughts?

Sounds like some sort of valve problem to me - either the solenoid got weak then died, or something is jamming up the spool.
Have they found the issue yet?
Cheers - SR

 

[CMess]

Sounds like some sort of valve problem to me - either the solenoid got weak then died, or something is jamming up the spool.
Have they found the issue yet?
Cheers - SR

After a week sitting at the Bobcat dealership and no diagnosis (they were backed up with work), I went and picked it up. I have done some research and spoke to a couple heavy equipment mechanics. Everybody kept telling me to start with the solenoids and electrical parts. I checked the solenoids with the screw driver test and they seemed to be charging/activating fine. When we would engage the hydraulics you could see the hydraulic lines pressurize and hear the engine bog a little as is everything was working. However the cutter wouldn't spin. Even though the Bobcat dealership told me there was no flow coming from my hydraulics, I asked them if I could bring my cutter up there to be hooked to another machine just to rule out the hydraulic motor on my cutter. When he hooked the cutter up and flipped the switch on the Bobcat my cutter didn't spin. So it looks like it is be the hydraulic motor on the cutter. It's under warranty and another motor will be here today. Hopefully this is my issue. I'm going to install the new motor this afternoon and will let you know if that fixes the issue. With that being said, if this IS the issue, I'm not sure why the flow meter at the dealership would indicate that I didn't have any flow coming from my hydraulics? As I said before, the service manager seems to be a straight shooter and doesn't seem to be the type just to try make some easy money on me just because I am inexperienced with skid steers. So if it IS my hydraulics on the machine, I will be checking the spool next. I really appreciate the help.

 

[Tazza]

After a week sitting at the Bobcat dealership and no diagnosis (they were backed up with work), I went and picked it up. I have done some research and spoke to a couple heavy equipment mechanics. Everybody kept telling me to start with the solenoids and electrical parts. I checked the solenoids with the screw driver test and they seemed to be charging/activating fine. When we would engage the hydraulics you could see the hydraulic lines pressurize and hear the engine bog a little as is everything was working. However the cutter wouldn't spin. Even though the Bobcat dealership told me there was no flow coming from my hydraulics, I asked them if I could bring my cutter up there to be hooked to another machine just to rule out the hydraulic motor on my cutter. When he hooked the cutter up and flipped the switch on the Bobcat my cutter didn't spin. So it looks like it is be the hydraulic motor on the cutter. It's under warranty and another motor will be here today. Hopefully this is my issue. I'm going to install the new motor this afternoon and will let you know if that fixes the issue. With that being said, if this IS the issue, I'm not sure why the flow meter at the dealership would indicate that I didn't have any flow coming from my hydraulics? As I said before, the service manager seems to be a straight shooter and doesn't seem to be the type just to try make some easy money on me just because I am inexperienced with skid steers. So if it IS my hydraulics on the machine, I will be checking the spool next. I really appreciate the help.

I wonder if they didn't test it and just assumed it was the machine and not the cutter. As you did the tests and noticed that the hoses moved when under load tells me there is pressure and flow....

 

[CMess]

I wonder if they didn't test it and just assumed it was the machine and not the cutter. As you did the tests and noticed that the hoses moved when under load tells me there is pressure and flow....

I replaced the hydraulic motor on the cutter yesterday and everything worked great. Looks like that was it... Tazza, I watched them test it. However, I couldn't see the gauges because i was sitting in the machine, but I was there when they hooked the flow meter to it. Also, we all had originally assumed that once the cutter wouldn't spin that the cutter motor was the problem. I just simply took it by the Bobcat dealership to rule out that it was the machine. The service manager told me to just bring it by and he would hook a flow meter to it and rule out the machine in 10 minutes. And that's when he said "there's no flow so it is your machine." And that started this long term trouble shooting scenario. I was basically looking for a problem with my auxiliary hydraulics that wasn't there. Which led me back to the cutter motor... Either way, the cutter ran fine yesterday evening and had none of the previous whining in the motor. I really do appreciate all of your input and help. I have learned a good bit about the hydraulic system on my machine in the last 2 weeks. Thanks!

 

[SkidRoe]

I replaced the hydraulic motor on the cutter yesterday and everything worked great. Looks like that was it... Tazza, I watched them test it. However, I couldn't see the gauges because i was sitting in the machine, but I was there when they hooked the flow meter to it. Also, we all had originally assumed that once the cutter wouldn't spin that the cutter motor was the problem. I just simply took it by the Bobcat dealership to rule out that it was the machine. The service manager told me to just bring it by and he would hook a flow meter to it and rule out the machine in 10 minutes. And that's when he said "there's no flow so it is your machine." And that started this long term trouble shooting scenario. I was basically looking for a problem with my auxiliary hydraulics that wasn't there. Which led me back to the cutter motor... Either way, the cutter ran fine yesterday evening and had none of the previous whining in the motor. I really do appreciate all of your input and help. I have learned a good bit about the hydraulic system on my machine in the last 2 weeks. Thanks!

Glad to hear it is fixed.
Cheers - SR