older 630 bobcat hydraulic problems

[dennis1951]

I have an older 630 bobcat skid loader has picked up a hydro problem in the turning of the vehicle. Seems to be ok when U first start but after about 15 minutes in colder weather the turning ability will almost be 0. It squeels like it is bypassing somewhere. I check the hydraulic pressure to a quick coupler on the boom that is an auxilary port and it had about 2000 psi holding the leave over the pressure would drop to around 1500 psi. We cleaned the brass filter in the block on top of transmission. Hate replacing things that may not be bad. Would appreciate any help this thing is my back saver.

 

[Tazza]

I was going to say it sounds like the bronze filter, but you cleaned that.
Have you replaced the main hydraulic filter?
Could the oil be too thick? causing cavetation, this will make the pumps get hot fast and reduce pressure due to air bubbles. Is the oil tank full of foam when it squeels?

 

[dennis1951]

I was going to say it sounds like the bronze filter, but you cleaned that.
Have you replaced the main hydraulic filter?
Could the oil be too thick? causing cavetation, this will make the pumps get hot fast and reduce pressure due to air bubbles. Is the oil tank full of foam when it squeels?

Yes we changed the hydraulic filter and fluid, havent seen any foam looks clean. I am not sure about the auxilary hydraulics thou the lever for the forward right travel is the same as the auxilary. I may have to take the control valve a part for the lift, tilt, travel and auxilary port I just am not having problems with all the other controls except the turn part. Seems like even the forward and reward travel are ok it just slows down the turning. I appreciate Ur help

 

[Tazza]

Yes we changed the hydraulic filter and fluid, havent seen any foam looks clean. I am not sure about the auxilary hydraulics thou the lever for the forward right travel is the same as the auxilary. I may have to take the control valve a part for the lift, tilt, travel and auxilary port I just am not having problems with all the other controls except the turn part. Seems like even the forward and reward travel are ok it just slows down the turning. I appreciate Ur help

Driving straight puts less load on the drive pumps, when you turn, it really loads it down.
It could be pump wear causing the loss of power, yet you did say the main hydraulic pressure started at 2,000 PSI when cold and dropped off, this does indicate wear, as the oil warms it gets thinner and can by-pass the worn pump parts. It could also be the relief, can you try screwing it in a little to bump the pressure up a little more?

 

[Cregg101]

Hi Dennis, I was reading your post because I have a 630 also. I wish that I could help with your issue but I am a Bobcat newby. But maybe you could answer a question or 2 for me about the 630. I bought what was a junker I guess you would say and rebuilt it. I knew when I bought it that it have an engine fire which burned up all of the wiring harness, but what I didn't know was the engine broke a rod and knocked a hole in the block which is what started the fire. So needless to say one engine, 23 hydraulic hoses and MANY hours of hard work and figuring out what goes where I am much deeper in this thing than I had intended to be. But it runs great and all of my hydraulics seem to work fine once all of the air finally worked out of the system. My question is how do I get the drive leaver to control the aux. hydraulic lines? I can not get the leaver/stick to move side ways at all. What am I missing? Thanks Cregg