Backhoe Kubota L45 TLB, Broken Backhoe Hydraulics due to Impact (dumbass operator error!)

MattTLB45 · Oct 13, 2015

My question is, What did I break?

Scenario: Driving tractor/backhoe down the road to job (3 miles distance), backhoe crowed-in tight, but full swing to the right. I did this to reduce the chance of an oblivious driver from hitting the backhoe. Conscious of the fact that the backhoe boom and bucket now stuck out ~2 or 3ft from the right side of the tractor, I paid attention and avoided road-side objects (road signs, phone polls and the like). However, I managed to overlook a low, drainage post/marker which I then hit (dumb-*** part) with the backhoe at about 12mph. It was a significant impact, enough to jostle the 9000lbs machine around quite a bit. A lot of instantaneous pressure on the backhoe actuation components.

Problem: Once I arrived on-site, ready to go, the boom would not move to the side of the impact. All other directions/operations work fine. No fluid leaks, no laboring of pump, no lack of back-pressure/feel on control stick, etc.

Question: Did I blow the internal packing/seal on the yaw cylinder(s) (there are two, left and right), damage the control valve or both?

Thanks,
Matt

KubotaToy · Oct 13, 2015

Having done something similar (backing up with the dipper out, hit a tree), I blew the packing. Dealer was worried about the valve but I started with the easy fix first. The packing was cut as if a torch cut it.

Based on my experience, if one is bad repack both.

MattTLB45 · Oct 13, 2015

KubotaToy said:
Having done something similar (backing up with the dipper out, hit a tree), I blew the packing. Dealer was worried about the valve but I started with the easy fix first. The packing was cut as if a torch cut it.

Based on my experience, if one is bad repack both.

Thanks for sharing your experience. Glad to hear it was the packing considering I already pulled the cyliders

Both are at the shop being rebuilt. It was a real joy removing the cylinders. Lol

KubotaToy · Oct 13, 2015

Hopefully they find bad packing, control valve work is a little more challenging. Btw, rebuilding cylinders is not a hard job, about 100 bucks for Kubota branded packing kit and 1 hour of time. Having several old pieces of equipment keeps me in practice.

4570Man · Oct 17, 2015

I always keep the backhoe out like normal when driving in the road. If some dumb ***** driver does hit the tractor I would rather have a backhoe arm in their engine block than me get hit.

jenkinsph · Oct 18, 2015

Hope the packing does the trick for you. I would add that keeping the backhoe centered and weight balanced is better for road travel too. I make sure my strobe, flashers are working and smv sign is clean and in place too.

MattTLB45 · Oct 26, 2015

Thanks everyone for your feedback. Turns-out it was the packing - in part.

Both cylinders blown-out - they showed me the damaged packings. Got'em back from shop, buttoned it all back up, still wouldn't move left! Was dreading busting into the valve body. Did some 'leak testing' (loosened lines at body to check fluid flow behavior) - it wasn't right based on valve position (started to freak out a little

). Pulled, jiggered bypass valve on top, reassembled and all works well. Phew!! Seems the shockwave that continued through the circuit after blowing the packings, jammed the bypass open or material from packing failure jammed it. Once clear, all was well. If left swing fails again, I'll know the first thing to replace.

Clearly I will always travel with backhoe tight, locked and CENTERED, going forward (as I always have in the past). Some lessons are hard-learned, dunno what I was thinking?!