Pipeliner825
Member
Hey Guys, First time posting in this Forum but long time 3rd Gen. Operating Engineer. 35 years to be exact. I'm hoping someone can help with an issue on a 1992(?) Ford 655C Backhoe I recently purchased for use around property.
When I went to look at it at the previous owners, it had the usual wear and issues an older machine with high hours has. No big surprises. It had the infamous oil leak beneath the steering motor that dripped onto the floor mat at your feet. Not a fast leak, a drip every 5 or 10 mins. Didn't surprise me as I almost expected it. I've installed new seal kits in a couple of steering motors and tore down and rebuilt one as well. Ford's owner's manual has great step by step instructions. I'm starting this far back in explaining my problem because it may clues that all add up to someone knows the problem. I have an idea but, some agreement or answer in another direction is invaluable in saving time and money.
Long story short(er), still long, I purchased hoe and did the normal maintenance. I noticed the PS getting a little hard at times and checked PS fluid which was low and filling brought it back to normal. A few meter hours later I checked PS and was low again however, the drip from orbital steering motor didn't equal the amount of oil needed to fill pump again and there wasn't another PS fluid leak anywhere. So... suspecting a bad front PSP seal, I checked the engine oil and sure enough, it was high. Telltale sign of PS fluid leaking into the engine oil system. The pump was original so instead of rebuilding, I purchased a new one from Dynamic Industries and would rebuild old in my spare time (yeah right) for a stand by pump. Replaced old pump with new and all was good, just the motor seal drip at steering wheel.
Now, it got cold. Very cold, very fast. I got in one day and there was a LOT more oil than usual on mat under steering wheel. First I thought someone had spilled oil filling the trans right next to puddle. Until I started engine and oil came pouring out under steering column. I figured the cold had finished the seals to complete failure so I ordered an upper seal kit and installed in motor. Got motor reinstalled, started engine and boom, same thing! Oil gushing out. Checked my lines for seal, the top of motor where spool protrudes at top, All Dry. I then figured a total rebuild of orbital was what was needed so, being these suckers cost anywhere between $500 for an aftermarket that requires hard line and mounting fabrication, to $1800 for direct fit new, that's what I did.
Very complicated and ingenious system these orbital motors. Akin to an automatic transmission. It was an interesting process to rebuild.
Checked and triple checked my work as I went. I am no stranger to mic's and machinist tools along with skills taught to me by great mechanics, machinists and fabricators. Not that I can't f&ck up, anyone can, it happens however, read on if you are still with me....
R
Happy with myself, I reinstalled my pride and joy, money saving, rebuilt orbital motor and crossed my fingers as I turned the key. Dejection as I watched the oil gush from around the top of motor seemingly more than before!! Humbled in an instant.
Removed motor and brought it back to the shop to find where In the process I F'd up. Tearing the motor down I dropped a tool and when I bent over to get it, the angle of my view and the light revealed a hairline crack around nearly 1/3 of the top of the motor. Upon closer inspection, I could see someone else had noticed it before me. It was drill-stopped on one end! Money being tight and me being stubborn, I decided to try and repair it. I figured brazing would do the trick since I am not experienced with welding cast steel. I beveled and brazed the housing and in the process of reassembling, the metering disc fell off the bench, landed on a rubber shop mat and broke into 3 pieces!! Sh!t!!! The manual doesn't lie when TWICE they warn to be very gentle with the discs that make up the valve. It was cast as well. A machinist told me it had to do with oil permeation into the piece to increase the life by reducing wear? IDK, sounded feasible to me.... Anyway, after no luck finding parts and lacking the mill to make the metering disc I purchased an new orbital motor for $550 from mybrokentractor. My 655c was listed in the specs as a candidate for this replacement pump and the sales person assured me it would work.
Jumping to the chase, finally, rebent hard lines to fit, Fabricated the mount to fit and replaced low pressure "T" (tank) connection with same ID soft hose to ease the labor on this old guy. I filled pump with fluid and as I was turning steering wheel to bleed the air, I bumped the left max position where the wheels stop turning and went to turn back right and it wouldn't turn. Not power assisted anyway. The orbital motor worked as it should and turned the wheels with effort and the front bucket down but I could see the oil wasn't flowing in motor.
Let's see... I maxed out wheels so pump pressure increased and set the relief valve off and wouldn't turn back the opposite direction so... the relief valve stuck open. Easy fix right? Not so fast. I told you to bear with me. lol. Chasing that idea (which has wasted more of my time than I care to admit) I took back reservoir cover off and pulled top of relief valve out and discovered some tiny metal chips and found that pressing the stem up and down against the spring, it was sticking. So I cleaned up stem and top hole by with compressed air (I never pulled bottom plug of relief valve and not sure why? That's a lie. I'm lazy and thought I found the problem is why.) Put back together, filled oil and started motor. Nothing. Just like last time, orbital worked with force and turned wheels but No Oil flow. Ok, Ok now I know what it is. At least what I hoped it was. A sheared woodruff key. Removing pump confirmed it. Replaced pump, AGAIN and started motor. Everything was working like a charm! I bled all the air performing the bleeding procedure and Zero leaks. Until I bumped the left wheel stop position again and the oil flow stopped like before. ANOTHER sheared woodruff key, oh joy.
So here I sit typing this, I haven't yet pulled pimp to replace the sheared key. At least that's what I believe. Who knows with these Chinese, Harbor freight woodruffs. It could be a snapped pump shaft with my luck lately.
FINALLY, my question. Is it my suspicion of the relief valve not sticking open but, sticking CLOSED and when I max out the steering, making the pressure larger than the shear force of the woodruff key? I
I keep running through my head the original cracked orbital motor that seemed to suddenly give way after that very cold night. Was there condensation in system, being low on oil, that froze and enlarged the crack in old housing like a water pipe does? I used the original hardlines for ps fluid system and just rebent. No kinks or obstructions in them and the fact that the new orbital pumps manually and works both ways until you happen to max out either direction, seems to suggest it's not a hydraulic loop flow problem. I think. Does the new replacement motor not have the right flow allowance to loop the oil at max or do I just need an adjustment on valve pressure?
IDK. I'm over thinking I'm sure. What I do know is, I write too dam much so I will shut up now and take my "new guy" hazing. Hopefully in the ball busting there will be some relief in the form of an answer. Thanks for putting up, Stay safe!
Pipeliner825
Multiple tags may be separated by commas.eplacement pump,
When I went to look at it at the previous owners, it had the usual wear and issues an older machine with high hours has. No big surprises. It had the infamous oil leak beneath the steering motor that dripped onto the floor mat at your feet. Not a fast leak, a drip every 5 or 10 mins. Didn't surprise me as I almost expected it. I've installed new seal kits in a couple of steering motors and tore down and rebuilt one as well. Ford's owner's manual has great step by step instructions. I'm starting this far back in explaining my problem because it may clues that all add up to someone knows the problem. I have an idea but, some agreement or answer in another direction is invaluable in saving time and money.
Long story short(er), still long, I purchased hoe and did the normal maintenance. I noticed the PS getting a little hard at times and checked PS fluid which was low and filling brought it back to normal. A few meter hours later I checked PS and was low again however, the drip from orbital steering motor didn't equal the amount of oil needed to fill pump again and there wasn't another PS fluid leak anywhere. So... suspecting a bad front PSP seal, I checked the engine oil and sure enough, it was high. Telltale sign of PS fluid leaking into the engine oil system. The pump was original so instead of rebuilding, I purchased a new one from Dynamic Industries and would rebuild old in my spare time (yeah right) for a stand by pump. Replaced old pump with new and all was good, just the motor seal drip at steering wheel.
Now, it got cold. Very cold, very fast. I got in one day and there was a LOT more oil than usual on mat under steering wheel. First I thought someone had spilled oil filling the trans right next to puddle. Until I started engine and oil came pouring out under steering column. I figured the cold had finished the seals to complete failure so I ordered an upper seal kit and installed in motor. Got motor reinstalled, started engine and boom, same thing! Oil gushing out. Checked my lines for seal, the top of motor where spool protrudes at top, All Dry. I then figured a total rebuild of orbital was what was needed so, being these suckers cost anywhere between $500 for an aftermarket that requires hard line and mounting fabrication, to $1800 for direct fit new, that's what I did.
Very complicated and ingenious system these orbital motors. Akin to an automatic transmission. It was an interesting process to rebuild.
Checked and triple checked my work as I went. I am no stranger to mic's and machinist tools along with skills taught to me by great mechanics, machinists and fabricators. Not that I can't f&ck up, anyone can, it happens however, read on if you are still with me....
R
Happy with myself, I reinstalled my pride and joy, money saving, rebuilt orbital motor and crossed my fingers as I turned the key. Dejection as I watched the oil gush from around the top of motor seemingly more than before!! Humbled in an instant.
Removed motor and brought it back to the shop to find where In the process I F'd up. Tearing the motor down I dropped a tool and when I bent over to get it, the angle of my view and the light revealed a hairline crack around nearly 1/3 of the top of the motor. Upon closer inspection, I could see someone else had noticed it before me. It was drill-stopped on one end! Money being tight and me being stubborn, I decided to try and repair it. I figured brazing would do the trick since I am not experienced with welding cast steel. I beveled and brazed the housing and in the process of reassembling, the metering disc fell off the bench, landed on a rubber shop mat and broke into 3 pieces!! Sh!t!!! The manual doesn't lie when TWICE they warn to be very gentle with the discs that make up the valve. It was cast as well. A machinist told me it had to do with oil permeation into the piece to increase the life by reducing wear? IDK, sounded feasible to me.... Anyway, after no luck finding parts and lacking the mill to make the metering disc I purchased an new orbital motor for $550 from mybrokentractor. My 655c was listed in the specs as a candidate for this replacement pump and the sales person assured me it would work.
Jumping to the chase, finally, rebent hard lines to fit, Fabricated the mount to fit and replaced low pressure "T" (tank) connection with same ID soft hose to ease the labor on this old guy. I filled pump with fluid and as I was turning steering wheel to bleed the air, I bumped the left max position where the wheels stop turning and went to turn back right and it wouldn't turn. Not power assisted anyway. The orbital motor worked as it should and turned the wheels with effort and the front bucket down but I could see the oil wasn't flowing in motor.
Let's see... I maxed out wheels so pump pressure increased and set the relief valve off and wouldn't turn back the opposite direction so... the relief valve stuck open. Easy fix right? Not so fast. I told you to bear with me. lol. Chasing that idea (which has wasted more of my time than I care to admit) I took back reservoir cover off and pulled top of relief valve out and discovered some tiny metal chips and found that pressing the stem up and down against the spring, it was sticking. So I cleaned up stem and top hole by with compressed air (I never pulled bottom plug of relief valve and not sure why? That's a lie. I'm lazy and thought I found the problem is why.) Put back together, filled oil and started motor. Nothing. Just like last time, orbital worked with force and turned wheels but No Oil flow. Ok, Ok now I know what it is. At least what I hoped it was. A sheared woodruff key. Removing pump confirmed it. Replaced pump, AGAIN and started motor. Everything was working like a charm! I bled all the air performing the bleeding procedure and Zero leaks. Until I bumped the left wheel stop position again and the oil flow stopped like before. ANOTHER sheared woodruff key, oh joy.
So here I sit typing this, I haven't yet pulled pimp to replace the sheared key. At least that's what I believe. Who knows with these Chinese, Harbor freight woodruffs. It could be a snapped pump shaft with my luck lately.
FINALLY, my question. Is it my suspicion of the relief valve not sticking open but, sticking CLOSED and when I max out the steering, making the pressure larger than the shear force of the woodruff key? I
I keep running through my head the original cracked orbital motor that seemed to suddenly give way after that very cold night. Was there condensation in system, being low on oil, that froze and enlarged the crack in old housing like a water pipe does? I used the original hardlines for ps fluid system and just rebent. No kinks or obstructions in them and the fact that the new orbital pumps manually and works both ways until you happen to max out either direction, seems to suggest it's not a hydraulic loop flow problem. I think. Does the new replacement motor not have the right flow allowance to loop the oil at max or do I just need an adjustment on valve pressure?
IDK. I'm over thinking I'm sure. What I do know is, I write too dam much so I will shut up now and take my "new guy" hazing. Hopefully in the ball busting there will be some relief in the form of an answer. Thanks for putting up, Stay safe!
Pipeliner825
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