Slow Hydraulic on BH77 Backhoe

[Porknuckle]

After letting my backhoe sit for a few months, I've noticed the swing of the boom is very slow from right to left. Swinging left to right works at normal speed, as does all other movements on the backhoe and rest of tractor. This backhoe has two pistons on each side of the boom which control the swing. Per another thread, I have tried releasing pressure on the 3-point hitch to the down position, but still no change. I have seen no fluid leaks, everything is lubricated. Any ideas on what else to check?

 

[Tarmy]

The two left/right cylinders work together to move the boom. If one has a blown seal...you can get that problem.

can you manually push the boom to either side...if so, probably have a bad cylinder/seal.

 

[dirtydeed]

Pull the access panel to the backhoe linkages and check to see that none of them are slightly twisted/out of alignment. Mine were when new and it caused the same issue with swinging to one side (left, actually) to be slowed a bit.

Mine is better now but I still need to find the "sweet spot" when swinging left.

 

[Porknuckle]

I cannot push the boom by hand, but I expect with only a blown seal on one cylinder I would still not be able to over-power the other. I checked the linkages and they look ok, but don’t have anything to compare to. I will say, after really focusing on the controls, it feels like the left swinging control doesn’t move as far as the right swing. Though this may be my imagination. Still diagnosing.

 

[Jack Rundel]

I cannot push the boom by hand, but I expect with only a blown seal on one cylinder I would still not be able to over-power the other. I checked the linkages and they look ok, but don’t have anything to compare to. I will say, after really focusing on the controls, it feels like the left swinging control doesn’t move as far as the right swing. Though this may be my imagination. Still diagnosing.

Did you ever figure this out? I'm having a similar issue on my BH77. Can't swing the boom manually either.

 

[nbryan]

I permanently removed the BH77 control levers' cover after first finding 2 linkage pins that they operate were loose where their connecting pins bolt to the valve control rods. That was causing rather sloppy controls operation of the affected circuits.

My post and pics of the issue and fixes:

BH77 Linkage

Anybody have the WSM for the BH77 that can share the procedure for adjusting/maintaining the linkage? I've watched the handful of youtube vids out there, but I think everyone is guessing on: 1) should the linkages be greased where they pass through the upper guides? 2) how tight should the...

www.orangetractortalks.com

Then once those pins were aligned properly again and re-tightened, and the cover plate put back on, the controls had stiffened up a lot but the second issue appeared:

The control levers were not able to travel their full range of motion in 3 of the 8 directions (2 levers - each left and right, forward and back - equals 8 directions) because the cover plate and rubber boot were interfering and stopping their motions before fully engaging the spools. Pulling off the boot helped a bit with by removing the rubber thickness, but wasn't enough. The levers still hit the metal cover plate at 3 spots.

Removing the metal cover freed the levers motion completely except for one - the boom lowering lever forward motion - which ALSO hit the horizontal cross-member of the safety rail tube in front of it before it was fully engaging the valves!

So I found a way to slightly bend the top of that bar forward enough so it cleared the boom lever.

FINALLY my BH77 had full control and range.