Ford 555B loader backhoe swing issue

[cropfarmer57]

Trying to resolve a new issue that started after replacing the swing bushings on my mid 80's 555b backhoe. Pulled the swing post pins and the swing cylinder pins and rolled the complete hoe assembly from the tractor to allow me to replace the swing bushings. Rolled things back together after installing the new bushings, thinking this wasn't as hard of a job as it could have been. To my surprise when I ran the tractor to test the swing it now only swings about 30 degrees from center each way??? With hydraulic lines disconnected the boom swings freely. Didn't change the dynamics of the swing post and all functioned normal before the new bushings were installed. Been studying the repair manual with little insight available. No symptoms like this even suggested in the troubleshooting. Anyone have past experience with the swing hydraulics??? Looking for any ideas to fix this-

 

[TractorTech]

Welcome to TBN!

It sounds like you got some foreign material in the line, clogging the restrictor.

 

[cropfarmer57]

Thanks for your insight with my predicament. Have suspected an issue with a restrictor but haven't had the system open to contaminate a restrictor. Coincidence?? Could be. Not convinced that one clogged restrictor would have the same limiting effect both left and right? Speed is the same. I will pull the restrictors next chance I get as it's easy to get to them. Thanks

 

[EddieWalker]

How positive are you that you put the hoses back on correctly?

 

[cropfarmer57]

I never opened the hydraulic system at all. I was able to slide the swing post and boom apart enough to get at the bushings without pulling the hoses. Thanks for your reply.

 

[cropfarmer57]

I have taken both restrictors out for inspection with no issues noted. Also opened up sensing valve and bypass valves with all looking ok. The swing locks up against hydraulic pressure when rotated to the point where both cylinders need to retract to finish the swing. If I swing the boom to where it locks up I can then shut the tractor down, move the lever and rotate the boom to full swing. What's going on????

 

[EddieWalker]

It doesn't make sense to me. Have you looked up the schematic drawings at Messicks.com? They have them for all the parts on my 555E. Maybe they have them for yours too? Here in Tyler Texas, the New Holland dealer has been very helpful with helping me figure out problems with mine. They print out pages from their manuals, and the guys in the shop have explained to me how to fix it. I personally think they would rather I fix it then have them do it, so they have always been very helpful.

 

[TractorTech]

Very strange indeed. It is definitely a hydraulic lock caused by oil bypassing a swing piston.
I had similar happen on my 550, but it happened over time, has chain swing and chevron packing. Your piston seals are mych more robust, but I just can't think of anything else. Awfully strange coincidence if so.

 

[cropfarmer57]

Thanks guys. To Eddie - Haven't looked at Messicks but have the Ford repair manual showing supply oil, return oil etc. To Tractor Teck, I am familiar with the chain swing where each cylinder works opposite throughout the full swing. The mechanics of the 555B is such that the cylinders work opposite only until the extending cylinder crosses over the pivot pin. Then BOTH cylinders are retracting to finish the swing. How is this possible when the extending cylinder must now retract with the lever still sending pressure to extend??? Is the other retracting cylinder supposed to overpower to pull against the extending cylinder to complete the swing? Beginning to suspect that pressures may be contributing to the problem. Haven't checked pressures as my shop is in MN and I am currently in AR where my machine is.

 

[Seven Gables]

Thanks guys. To Eddie - Haven't looked at Messicks but have the Ford repair manual showing supply oil, return oil etc. To Tractor Teck, I am familiar with the chain swing where each cylinder works opposite throughout the full swing. The mechanics of the 555B is such that the cylinders work opposite only until the extending cylinder crosses over the pivot pin. Then BOTH cylinders are retracting to finish the swing. How is this possible when the extending cylinder must now retract with the lever still sending pressure to extend??? Is the other retracting cylinder supposed to overpower to pull against the extending cylinder to complete the swing? Beginning to suspect that pressures may be contributing to the problem. Haven't checked pressures as my shop is in MN and I am currently in AR where my machine is.

I agree with others strange , especially since you never opened up the hyd. System. I’m not at all familiar with the swing system you’ve got . If you could possibly post some good pictures of the swing system and the hydraulic components involved would probably help us. Is there any holding/check valves incorporated into the system? If so may be a fault there.