The JB Hendrix pin quick coupler on my Cat 325B is getting real sloppy where it connects to the dipper. Pins have lots of wiggle and noise which drives me nuts. I'd like to re-bush the grabber but am wondering for the price and hassle if I should just purchase a nice used Cat Pin Grabber (there's one locally for sale). The other reason I'm considering the Cat is because it allows me more range of pin spacing as opposed to my JB Hendrix which is only the C-linkage family. But...I don't know if the Cat pin grabbers use only pilot pressure like my JB or if it needs the high pressure. I thought I read somewhere Cat was high pressure or a mixture of both which would mean I would have to replumb it a bit. I searched for that post but couldn't find it. Anyone know if there is a rule of thumb for psi on the Cat Pin Grabbers?
I looked up a random data sheet for a pin grabber on a 315 and it was 3626 psi.
The Cat Pin Grabber operates off bucket cylinder extend pressure (curl). The JBHendrix coupler fit only one pin spread by three side surrounding of the link pin. Therefore, lower cylinder pressure is required to maintain lock. The Pin Grabber only surrounds one side (top) and therefore requires much greater pressure to maintain lock. Setting aside liability issues of mix and match components on a device such a coupler, I believe that simply changing the pilot pressure input on your current coupler control valve to be from the bucket cylinder extend circuit would work. I just found a NOS JBHendrix cylinder on my shelf from when I had a fleet of them. Pretty sure it's from an S linkage 322B.
Okay- that makes sense to me as I can easily see how the JBHendrix has much more "grab" by the 3 sides of the frame holding the pin as opposed to the Cat that only uses the one side (the bottom of the frame) to hold the pin in conjunction with the wedge/gripper. No worries on the liability. It's a ranch machine for clearing cedar and it's just me operating it with no one else around. As far as using the bucket cylinder extend circuit, it seems pretty straight forward to just move the input from a pilot port to the bucket extend circuit. I'll have to go study it next time I'm out at the ranch to see where all the ports are located for the various circuits and make sure I understand it. I also attached the JBHendrix user manual which shows the JBHendrix control valve to be rated up to 5k psi (pg 13) so that should be good. No idea on what those hoses are rated so that's another thing I need to check.
The hose could be rated 6k psi Cat OEM hoses, and they'd still disassemble when using the heel of the bucket to pound/ tamp. I've have them fail well under 1000hrs. Tamping with the heel (or reverse bucket digging (shovel style) on a JBHendrix drives the link pin into the coupler frame, BUT, on a multi grab coupler, the link pin solely pushes against the lock cylinder. We've disassembled hoses, footballed the cylinders, and even ripped the saddle mounts apart that retain the cylinder. Used like you own it, and you may not encounter these issues