Geith coupler disconnecting from rear bucket pin

[dewbee]

I've got an older Geith coupler QH110 serial # 227604 that's on a Volvo ec330b lc trackhoe. I'm having trouble finding parts and not 100% positive what parts need to be replaced.

The engaging plate goes around the rear pin on the bucket but if i set the bucket on the ground and lightly curl out the engaging plate will come unhooked from the rear bucket pin. There seems to be decent play where the engaging plate connects to the rod on the hyd cylinder. I don't think the rod is bypassing the seals inside the cylinder. The hooks where the front pin sits does have some wear. I believe its a mixture of a lot of things slightly worn that's allowing enough play for the rear pin to release.

Not sure if I'm better off trying to rebuild this coupler (if i can even find parts) or just take it all off and attach the bucket directly to the excavator. I don't use any other attachments. Only problem with doing that, the pins on the bucket will need to be line bored out to fit directly to the trackhoe and even then I think I'll have to install new pin bosses for everything to fit properly.

I guess my main question is what would be the cheapest way to get this fixed so I can get back to work? Thanks.

 

[heymccall]

Let's pretend for a moment that you've latched the bucket on.
Then you took both hoses off.

At this point, the cylinder packing and the load check valve on the cylinder hold the sliding jaw in place.
For clarity, the fixed jaw surrounds the stick pin, and the sliding jaw captures the link pin.
So, either the cylinder seals are worn out (most likely) or the check valve is defective.

In my experience with geith couplers, it has always been the cylinder packing (seals).
When the seals begin to fail, that material will find its way back the the control solenoid. Upon removal of the control solenoid cartridge, if you find green plastic (at least on the older ones), the the cylinder is the issue.
Should you want to remove the cartridge, park the machine with the bucket in full carry position, on the ground (bucket cylinder chrome all the way out. Then, shut off the machine, vent the tank pressure, then proceed to crack all four lines to verify no pressure. At this point, you can remove the coil (usually 3/4 wrench), then unthread the spool cartridge from the manifold. Anything that looks like plastic debris will indicate cylinder packing failure.

 

[heymccall]

Let's pretend for a moment that you've latched the bucket on.
Then you took both hoses off.

At this point, the cylinder packing and the load check valve on the cylinder hold the sliding jaw in place.
For clarity, the fixed jaw surrounds the stick pick, and the sliding jaw captures the link pin
So, either the cylinder seals are worn out (most likely) or the check valve is defective.

In my experience with geith couplers, it has always been the cylinder packing (seals).
When the seals begin to fail, that material will find its way back the the control solenoid. Upon removal of the control solenoid cartridge, if you find green plastic (at least on the older ones), the the cylinder is the issue.
Should you want to remove the cartridge, park the machine with the bucket in full carry position, on the ground (bucket cylinder chrome all the way out. Then, shut off the machine, vent the tank pressure, then proceed to crack all four lines to verify no pressure. At this point, you can remove the coil (usually 3/4 wrench), then unthread the spool cartridge from the manifold. Anything that looks like plastic debris will indicate cylinder packing failure.

 

[HarleyHappy]

Myself, if you’re only using one bucket, I would take it off.
That all depends though on age and condition of machine.
The value of the machine, to you and if ever wanted to sell.
Fixing a couple of cylinders is definitely easier than line boring and cutting and installing new pin bosses.

 

[John Shipp]

"Only problem with doing that, the pins on the bucket will need to be line bored out to fit directly to the trackhoe and even then I think I'll have to install new pin bosses for everything to fit properly."

Does the bucket have smaller diameter pins than the quick hitch coupler then?

 

[masterwelder]

Generally the pins used to pin the coupler to the machine are the same diameter that would be used to pin the bucket to the machine.

 

[John Shipp]

Wondering why need for line boring or new bosses to fit directly? Usually a grinder and/or some shims and you're in business. The pins that connect the dipper to the quick coupler should be hardened pins to go in greased bushes in the dipper & H link, then the pins in the bucket that the coupler grabs onto should be regular steel (not hardened). Going direct without quick coupler use the pins from the dipper side of the coupler directly in the bucket bosses.

 

[dewbee]

Update. Still having issues. I capped off they hyd cyl and the pilot check valve and the bucket stays on but its pretty lose which I figure is from losing hyd fluid while capping off so that tells me the issue is upstream. Even though the Rexroth spool valve looked perfect other than o rings looked a little worn I replaced it with a brand new one (same exact specs) and its still falling off. I've even unplugged the spool valve in case it was getting ghost power telling it to unlock and that didn't help. The only thing left in the system that's hyd is the manifold under the spool valve where all the hyd hoses connect and the lines themselves.

 

[dewbee]

Wondering why need for line boring or new bosses to fit directly? Usually a grinder and/or some shims and you're in business. The pins that connect the dipper to the quick coupler should be hardened pins to go in greased bushes in the dipper & H link, then the pins in the bucket that the coupler grabs onto should be regular steel (not hardened). Going direct without quick coupler use the pins from the dipper side of the coupler directly in the bucket bosses.

The pin size on the machine is 100mm rear and 110mm front vs the bucket is both 100mm so i'd have to make the front pin 10mm bigger for the pin to fit

 

[dewbee]

Generally the pins used to pin the coupler to the machine are the same diameter that would be used to pin the bucket to the machine.

its a geith bucket and both pins are 100mm. volvo is 100mm on the rear and 110mm on the front

 

[John Shipp]

Might be worth a shot contacting Geith technical department and asking the question there. I did this with some other brand (think it was Miller) and they were helpful and sent out the part needed.

 

[ExcavatorPartsVincent]

Since the machine side is 100 mm rear / 110 mm front and the bucket is 100 mm / 100 mm, I would not rush into boring the bucket until you separate two issues.

First, prove the coupler lock mechanically. With the bucket safely on the ground, measure the gap between the sliding jaw or engaging plate and the rear pin when it is fully locked. Also check whether the rear pin is actually the right diameter for that coupler pocket and whether the pin is worn egg-shaped. A few millimetres of wear in the jaw pivot, rear pin or bucket ears can look like a hydraulic problem because the latch never gets full bite.

Second, isolate the hydraulics at the coupler cylinder only after locking it, then mark the jaw position. If it still backs off, look at cylinder/check valve. If it holds but has too much clearance, the problem is wear/geometry, not pressure.

For going direct, a 100-to-110 front mismatch usually means new bosses/bushings or a properly machined sleeve arrangement, not just a loose sleeve. The front pin takes a lot of curl load, so I would want full-width support in the boss and correct pin hardness/grease path. If the coupler frame is not cracked, rebuilding the jaw pivot/cylinder side may still be cheaper than modifying every bucket.

 

[dewbee]

So I think I had a few problems, I pulled out the cartage inside the pressure control valve and it was in 2 piece (suppose to be one). And the seals were ruff. Since it was in 2 pieces, I ordered a new Danfoss 4SK303S3

Pulled the cylinder apart and the piston seal was missing a big section and the inner o-ring was shot. Geith wanted over $400 plus I had to pay shipping from Geith to a dealer and from a dealer to me and several weeks turn around time. I wasn't ok with paying that much so I measured the seals and made my own kit for around $40 shipped to me overnight.


MKPD-80X64.5X6.3 piston seal
MWRB-80X12.6X3.3-SC wear ring
MOR-50X3-90D inner piston oring
MUUL-50X60X10 U Seal
MCWN-50X56X5 wipper seal
Reused the oring and backup ring on the outside of the glad since it was perfectly fine.

Got it put together and its all working good for now. Thanks for everyone's help.