Bobcat 630 Charge Pressure at Pressure Switch Port

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If you got it out easily enough, you may not need to pull the engine. But at least grease the universal joints on the motor, ensure there is no play or tight spots.
Can you look up my profile and send me an email? i will have a picture of the vane pump somewhere, it's pretty straight forward. just ensure you keep the vanes in the rotor, it ensures that the wear on the vanes is the same side as it wore in. Even then, a new cartridge isn't that expensive for the hydro pump.
What should I use to flush out the wheel motors and hoses before I install the pump? Can I use diesel or mineral spirits? I'm thinking about running motor drain line to a bucket and one of the other lines to a bucket and using a funnel to pour something in the line and through the motor and out of the other lines into the bucket.
 
What should I use to flush out the wheel motors and hoses before I install the pump? Can I use diesel or mineral spirits? I'm thinking about running motor drain line to a bucket and one of the other lines to a bucket and using a funnel to pour something in the line and through the motor and out of the other lines into the bucket.
I wouldn't run anything through it other than oil. Do you think there is metal or something else in the motors? if so, you will need to pull them apart and clean them properly.
 
I wouldn't run anything through it other than oil. Do you think there is metal or something else in the motors? if so, you will need to pull them apart and clean them properly.
I don't want to pull the motors just to look. I'm not sure if there's anything in them, but I should flush out the old stuff before I hook to the pump. I don't know the history of the machine, but I do know a wheel motor was replaced at some point.
 
I don't want to pull the motors just to look. I'm not sure if there's anything in them, but I should flush out the old stuff before I hook to the pump. I don't know the history of the machine, but I do know a wheel motor was replaced at some point.
There really isn't much oil that sits in them, If you are really concerned, you can lift the machine off the ground then rotate the tyres to get the oil to spit out, add fresh oil in the suction side for that direction to sort of purge it.
 
There really isn't much oil that sits in them, If you are really concerned, you can lift the machine off the ground then rotate the tyres to get the oil to spit out, add fresh oil in the suction side for that direction to sort of purge it.
I pulled the hoses off the motors and drained what fluid I could. I think my vane pump is wrong. I have some conflicting diagrams of the correct orientation. My parts manual shows the arrow on the pump( on the left side of the machine) pointing down. Tazza's photo shows the arrow pointing up. I do not have any charge pressure reading on my gauge and none of the bucket functions. Think I'm going to drain the fluid and swap it around and try again. Anyone have pictures of their vane pump arrows?
 
I pulled the hoses off the motors and drained what fluid I could. I think my vane pump is wrong. I have some conflicting diagrams of the correct orientation. My parts manual shows the arrow on the pump( on the left side of the machine) pointing down. Tazza's photo shows the arrow pointing up. I do not have any charge pressure reading on my gauge and none of the bucket functions. Think I'm going to drain the fluid and swap it around and try again. Anyone have pictures of their vane pump arrows?
The arrow faces the direction of rotation, crank the engine over and note the direction and make sure the pump is pointing that way too.
 
As soon as I get home, I'll check it out. Thanks!
Well, I had the pump wrong. Changed the direction on the ring. I now have bucket hydraulics but still very little charge pressure. I have been cycling the bucket functions a few times and shutting down the engine to let it rest overnight and again during today while I'm at work. Still no drive to the motors. I have it on jack stands and can barely get the wheels to turn. (They spin free by hand) Hoping it just needs to work the air out. Wondering if I possibly mixed up the wear plates when I had the hydrostat pumps apart? I'm trying to take my time with this
 
Well, I had the pump wrong. Changed the direction on the ring. I now have bucket hydraulics but still very little charge pressure. I have been cycling the bucket functions a few times and shutting down the engine to let it rest overnight and again during today while I'm at work. Still no drive to the motors. I have it on jack stands and can barely get the wheels to turn. (They spin free by hand) Hoping it just needs to work the air out. Wondering if I possibly mixed up the wear plates when I had the hydrostat pumps apart? I'm trying to take my time with this
It is always possible you got the plates mixed up. Good practice is to do one side at a time so this doesn't happen.
You will note that the plates have slots cut in them to allow oil through and into the centre valve block. These slots will have a small section machined through the brass at one end of these slots, they must be installed to be at the leading edge in the direction that the rotating group runs on them.
Say the rotating group runs on the wear plate in this direction ---> the slot should look sot of like this: -======) The - is the small groove, the === is the slot and the ) is the rounded end of the slot.
Hopefully that makes some sense
 
It is always possible you got the plates mixed up. Good practice is to do one side at a time so this doesn't happen.
You will note that the plates have slots cut in them to allow oil through and into the centre valve block. These slots will have a small section machined through the brass at one end of these slots, they must be installed to be at the leading edge in the direction that the rotating group runs on them.
Say the rotating group runs on the wear plate in this direction ---> the slot should look sot of like this: -======) The - is the small groove, the === is the slot and the ) is the rounded end of the slot.
Hopefully that makes some sense
I don't think I mixed them up. I ran it last night and it is doing the exact same thing as before I did the pump. Low charge pressure and very little drive to the wheels. I think I am going to cap the charge pressure hose going to the hydrostatic pump. If the charge pressure increases to by-pass pressure, the pumps still leak excessively. If the pressure does not increase, the problem is probably the bypass valve or something other than the pump. I need to go buy caps and plugs for the line since I do not have any hydraulic fittings laying around the shop. I may pick up the fittings to bypass the motors also since that may help my troubleshooting. Do you know what size caps and plugs I would need to purchase? I'll measure them tonight, but maybe someone knows the sizes. Thanks, Lance
 
I don't think I mixed them up. I ran it last night and it is doing the exact same thing as before I did the pump. Low charge pressure and very little drive to the wheels. I think I am going to cap the charge pressure hose going to the hydrostatic pump. If the charge pressure increases to by-pass pressure, the pumps still leak excessively. If the pressure does not increase, the problem is probably the bypass valve or something other than the pump. I need to go buy caps and plugs for the line since I do not have any hydraulic fittings laying around the shop. I may pick up the fittings to bypass the motors also since that may help my troubleshooting. Do you know what size caps and plugs I would need to purchase? I'll measure them tonight, but maybe someone knows the sizes. Thanks, Lance
Sadly i don't know the size caps you need, but the idea does sound like it may work.
Charge pressure is regulated by a relief mounted in the drive pump body.
 
Sadly i don't know the size caps you need, but the idea does sound like it may work.
Charge pressure is regulated by a relief mounted in the drive pump body.
Just finished reviewing before and after photos and it looks like I reversed the 2 drive motor hoses on the right hand side of the pump. After work, I'll swap them and report back.
 
Just finished reviewing before and after photos and it looks like I reversed the 2 drive motor hoses on the right hand side of the pump. After work, I'll swap them and report back.
Drive motor hoses would only reverse the direction it turned.... Not casue an issue with charge pressure.
 
Drive motor hoses would only reverse the direction it turned.... Not casue an issue with charge pressure.
The hoses were switched at the pumps so each pump fed both motors. Now the right side is acting normal . The front pump lever has a noticeable vibration to it when the swash plate is moved. I'm not sure if one of the pistons is stuck, but the pump is coming apart again this weekend. The left side did not want to go forward or reverse. The cap and plug on the hose to the hydrostatic pump was a great idea. With the hose capped, the charge pressure came up to about 180 PSI which is where the cold weather by pass is set. That immediately tells me the problem is excessive leakage through the hydrostatic pumps.
 
The hoses were switched at the pumps so each pump fed both motors. Now the right side is acting normal . The front pump lever has a noticeable vibration to it when the swash plate is moved. I'm not sure if one of the pistons is stuck, but the pump is coming apart again this weekend. The left side did not want to go forward or reverse. The cap and plug on the hose to the hydrostatic pump was a great idea. With the hose capped, the charge pressure came up to about 180 PSI which is where the cold weather by pass is set. That immediately tells me the problem is excessive leakage through the hydrostatic pumps.
Pulled the pumps and determined I put the assembly together wrong. Put it back together and now the right side is driving with real power and the left side is weak. Getting ready to pull the left drive motor. Do I need to remove the chains to pull the drive motor? Thanks, Lance
 
Pulled the pumps and determined I put the assembly together wrong. Put it back together and now the right side is driving with real power and the left side is weak. Getting ready to pull the left drive motor. Do I need to remove the chains to pull the drive motor? Thanks, Lance
I think it depends on the model, the earlier ones had a tapered shaft that you needed to go into the chain case to remove the sprocket. The newer ones i believe were just 4 bolts and it slid out.
 
I think it depends on the model, the earlier ones had a tapered shaft that you needed to go into the chain case to remove the sprocket. The newer ones i believe were just 4 bolts and it slid out.
Thanks. I'll look into it this week. I keep reading about timing the drive motors when you assemble them. Is there a good written procedure for timing the motors? I have the service manual, but I can't see the reference to timing anywhere. I know the previous owner had drive motor issues and I'm wondering if he got the timing right.
 
Thanks. I'll look into it this week. I keep reading about timing the drive motors when you assemble them. Is there a good written procedure for timing the motors? I have the service manual, but I can't see the reference to timing anywhere. I know the previous owner had drive motor issues and I'm wondering if he got the timing right.
Look up my profile and send me an email, i'll send you the manual for timing the motor. It's not hard to do, but it's one of those jobs that you think, is it right, could it be a little more that way? am i one tooth out?
 
Look up my profile and send me an email, i'll send you the manual for timing the motor. It's not hard to do, but it's one of those jobs that you think, is it right, could it be a little more that way? am i one tooth out?
I was able to swap the hoses on the pumps and verify both pumps are good and the wheel motor is bad. Looks like removing a drive motor on this thing will be quite the job. I tried removing the caliper plate last night and decided I need to loosen all the bolts for the pump and lift it up in order to remove the caliper plate. I read on another post about removing the front chain and rotor and working the rear chain off the sprockets once the motor is unbolted. We'll see how that works. My machined has the Ross motors on it. I do not see mention of a timing procedure for them in the manual.
 
I was able to swap the hoses on the pumps and verify both pumps are good and the wheel motor is bad. Looks like removing a drive motor on this thing will be quite the job. I tried removing the caliper plate last night and decided I need to loosen all the bolts for the pump and lift it up in order to remove the caliper plate. I read on another post about removing the front chain and rotor and working the rear chain off the sprockets once the motor is unbolted. We'll see how that works. My machined has the Ross motors on it. I do not see mention of a timing procedure for them in the manual.
If you don't need to time it, that will be nice.
Hopefully it won't be too hard to get the motor out to work on it. Worst case, i guess you could work on it in place? if it is just the main seal, you could technically do it in the machine, just won't be fun....
 
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