New Bradco Backhoe has a problem!

kneedeep · Jul 7, 2013

Just got a long weekend that is dry enough to do some much needed dirt work with my new toy (per the wife!), Mahindra 509 Backhoe mounted on my tough as nails 3510.
Had 2 water control pipes/risers that leaked and were installed in the wrong place that I needed to dig up. The ground around them was hard, but Backhoe/Tractor did a great job, never strained the hydraulics or tractor at 2000 RPM, always got a heaping 20" bucket load every time and very happy with the BH running off tractor hydraulics instead of the pump. Enough praise, it works great as setup.

The issue-

-

After digging the around one side of the first pipe (it was almost 5' deep), I was moving to the other side about 25 yds around and felt something dragging. The boom was down and BH bucket was dragging like a anchor. Stopped and raised it back up and it drifted down. The only cylinder doing this is the boom. The bucket and dipper will hold in any position but the boom will drift down in about 5 seconds. I continued to use it and was able to get both pipes dug up with the boom drifting down. It seemed to drift down with dipper in or fully extended out about the same amount of time.
The Dealer that I purchased from was closed for the holiday weekend so I have to wait till they reopen to speak to them.
Checked my manual and it says:
PROBLEM POSSIBLE CAUSE REMEDY
Backhoe fails to hold up;
Dirty oil Drain and refill oil, replace filter
Oil leaking past cylinder - Replace packings
Oil leaking past control valve - Replace or repair worn section
Faulty relief valve - Clean or replace

Clean oil and full. No external leaks or any noise. BH works good, just have to keep the boom lever back enough to hold the boom up to operate.

Anyone have a similar experience with a new Backhoe?? :confused3:

MapleLeafFarmer · Jul 7, 2013

nope... on my BH65 Kubota backhoe it will hold up for weeks on end if tractor parked before even noticing the slightest leak down.

If bouncing around the yard moving dirt or snow in the winter etc... with FEL, the backhoe bucket may leak down very very little almost unnoticeable. Boom/dipper move nada...

If I remember I put in the 2 transport pins if I am making a lot of work but not using the BH.

BeeferMan · Jul 8, 2013

Sounds like you're in store for some warranty work - as your manual says, either the cylinder packings are leaking by internally, or the valve is leaking. How fast does it drop?

J_J · Jul 8, 2013

You may have blown a bucket piston seal.

The BH bucket valve spool may be leaking.

If your BH work ports have reliefs, they might be leaking.

When you fully extend or fully retract the bucket, does the BH relief activate?

You could install or plug a 3000 psi hyd gage in the BH circuit and do some trouble shooting.

dfkrug · Jul 8, 2013

kneedeep said:
The bucket and dipper will hold in any position but the boom will drift
down in about 5 seconds.

Yeah, 5 sec is a bit fast. When the oil is cold is it much slower?

Anyway, as your manual says, you could have a leaky cylinder gland, but you would see the oil
externally. You saw no external leaks, so the cyl and hoses are OK. (A piston seal leak would
have to push oil thru a leaky valve.)

The valve is designed to leak internally somewhat, since it is just a spool inside a hole with a
tiny amount of clearance. My boom will drop to the ground in about 15-30min if the oil is hot;
that's OK. If that valve section is out of spec, it should be replaced under warranty.

Bradco certainly uses a work-port RV, prob set to 20 or 30% higher than the main RV. It
could be bad or dirty. You can remove it from the valve section and plug the hole to test it.
Or it could have visible dirt or a broken spring, etc.

kneedeep · Jul 8, 2013

BeeferMan said:
Sounds like you're in store for some warranty work - as your manual says, either the cylinder packings are leaking by internally, or the valve is leaking. How fast does it drop?

It drops all the way down in 4-5 seconds with tractor running or not, hot or cold