Hitachi zx35u - new thumb and needs couplers

[MinnesotaDave]

Got a thumb on order and need couplers. I'm guessing this is a very common question for people - which ones do I buy?

I did some online searching and came up with these numbers for the ones possibly on the machine.
(need some to hook to them)

KV13884, sub for 4486229
KV13885, sub for 4486230

Also found listed:
AT312877

Does that help narrow down what I would buy to plug into them? Thanks in advance

I'm very much a novice to excavators...been using my old WD Allis Chalmers since the 90's for everything.
Got tons of work done with that tractor, but it's amazing how fast and versatile this excavator and the Bobcat 873 are in comparison.

Oh, the thumb is a 27" hydraulic: https://linvilleindustries.com/produ...backhoe-thumb/

[thegary]

Thats a very good price for a hydraulic thumb. I can't help you on the couplers

[ronsii]

Can't help you on the couplers normally I'd just buy a set and change out what's on the machine... especially if their some odd ball ones you might post up pics of the ones on the machine along with measurements...

One thing I'd definitely do is check and reset the thumb pressure relief to <2500 (or less)to match that cylinder as the machine can do >3500PSI

[12V71]

For that setup you can probably use standard ag type 1/2" pioneer couplers. Is the machine pre-plumbed? I like to stay away from pipe threads for that stuff and use O-ring boss fittings on the hose ends that connect to the coupler halves. If you do go pipe threads, Loctite 567 pipe sealer is the stuff. I've used it on drill rigs that had some heavy pressure spikes and it holds up well and you can still unscrew the fittings.

[ronsii]

Oh... forgot to add earlier... on a thumb like you're getting you really don't need quick-couplers.... anyways... unless you're planning on getting more attachments like a hoepac, woodsplitter, breaker,mower,etc... if you do put QC's on it then don't use them for a year or two they will probably be stuck/rusted on and won't come off quick anyways

[12V71]

Oh... forgot to add earlier... on a thumb like you're getting you really don't need quick-couplers.... anyways... unless you're planning on getting more attachments like a hoepac, woodsplitter, breaker,mower,etc... if you do put QC's on it then don't use them for a year or two they will probably be stuck/rusted on and won't come off quick anyways

True.... Especially those flatface types. I hate them.

[BluCllrPlt]

Can’t help with the connectors but wanted to comment that you’ll wonder how you ever did without the thumb. I’ve had them on excavators and have one now on my Kubota backhoe.

[John T]

True.... Especially those flatface types. I hate them.

Agree.
Kubota uses them (along with a quick disconnect gizmo)

leaked like crazy...

removed quik disconn. and replaced them with 4 individual pioneers... PERFECT !

[MinnesotaDave]

Can't help you on the couplers normally I'd just buy a set and change out what's on the machine... especially if their some odd ball ones you might post up pics of the ones on the machine along with measurements...

One thing I'd definitely do is check and reset the thumb pressure relief to <2500 (or less)to match that cylinder as the machine can do >3500PSI

Ah, I'll definitely have to look at that. I tend to run machines until the pressure relief kicks in...I mean that's how you find the max lift capacity right?
I don't know where that pressure adjustment is, but it should be something that can be found with a little looking around.

For that setup you can probably use standard ag type 1/2" pioneer couplers. Is the machine pre-plumbed? I like to stay away from pipe threads for that stuff and use O-ring boss fittings on the hose ends that connect to the coupler halves. If you do go pipe threads, Loctite 567 pipe sealer is the stuff. I've used it on drill rigs that had some heavy pressure spikes and it holds up well and you can still unscrew the fittings.

It is pre-plumbed and I'll have to get sweetie to send me some pics, it's up at her place.
The regular pipe dope I use does not seem to be good with high pressure.
It didn't even seal the pressure washer wand handle - getting soaked is irritating....

Can’t help with the connectors but wanted to comment that you’ll wonder how you ever did without the thumb. I’ve had them on excavators and have one now on my Kubota backhoe.

I bet you're right. Only used it a few days and was irritated by not having one...
Heck, after a couple days I wonder how I got along all these years without the excavator... LOL
Every time I fire it up it saves me hours (or days) of work with my old tractor and hand tools.

Agree.
Kubota uses them (along with a quick disconnect gizmo)

leaked like crazy...

removed quik disconn. and replaced them with 4 individual pioneers... PERFECT !

I looked up 1/2" pioneers, they look to be cheaper to buy all 4 parts than it will be to buy just the 2 ends I need.
I wonder if the ends of the pre-plumbed pipes are just NPT or some weird o-ring connection.

[M J D]

. This is the best stuff I've ever used for pipe threads. Even on angled fittings that you can't always get tight enough it never fails to seal. Pretty pricey but it's a one and done deal.

[M J D]

The permatex # is 5454O , which works equally as well.

[John T]

I looked up 1/2" pioneers, they look to be cheaper to buy all 4 parts than it will be to buy just the 2 ends I need.
I wonder if the ends of the pre-plumbed pipes are just NPT or some weird o-ring connection.

If you have a Parker store nearby, They will have anything you need.

my pioneers were 1/4 NPT same as snow plow stuff... I had to also get adapters to go to Flare fittings...

yours may be diff sizes, but Parker will have it.

.

[John T]

Funny though... Out back, the backhoe fittings are flat faced and they work fine....

[farmersammm]

All, and I mean ALL my hydraulic threaded connections get the Teflon Tape treatment. Because...............ya might wanna take them apart one day.

[ronsii]

all, and i mean all my hydraulic threaded connections get the teflon tape treatment. Because...............ya might wanna take them apart one day.

why????

[farmersammm]

Tape can get a bad rap because of faulty installation procedures. 4-5 wraps, and tighten her down WITH LESS THAN A 6 FOOT BREAKER BAR Make sure you wrap the tape in the opposite direction of the thread. A taped joint doesn't require excessive torque to seal perfectly.

[farmersammm]

why????

I can hardly count the number of times I've dealt with an old piece of equipment that the previous owner had slobbered pipe dope on the threads. Takes an Act of God to get it loose

[farmersammm]

Might I want to get this apart sometime in the future?

You betcha I put it together 20yrs ago with tape, and it was a snap to get it apart again for the rebuild. Plus, ya don't have all that hardened crud floating around in your cylinder from the pipe dope that ya slathered on the threads.

[ronsii]

Pro tip: If you leave them a bit loose the oil leak will prevent the threads from seizing

[farmersammm]

Pro tip: If you leave them a bit loose the oil leak will prevent the threads from seizing

ROFL

[Lis2323]

True.... Especially those flatface types. I hate them.

Yup. HATE HATE HATE


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[Lis2323]

Pro tip: If you leave them a bit loose the oil leak will prevent the threads from seizing

Also good for finding your way home from
deep in the woods. Much better than bread crumbs if there are birds around.

Oops sorry Dave. My vote would be no couplers unless you plan on other attachments.


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[12V71]

I can hardly count the number of times I've dealt with an old piece of equipment that the previous owner had slobbered pipe dope on the threads. Takes an Act of God to get it loose

And I can hardly count the number of times I've had to trace out a sliver of tape plugging a tiny orifice that's keeping a quarter million dollar piece of equipment from working. Most good sealers will dissolve in the system and not cause a problem. Most every hydraulics manual for Caterpillar, etc. says DO NOT USE TAPE. I been there and seen that.
Rebuilt a very expensive Cat loader transmission over a plugged .030 orifice, it wasn't getting full clutch engagement pressure and we all know what that leads to. Stupid part was that some idiot used tape on a bunch of O-ring boss fitting that didn't even need it.

[farmersammm]

And I can hardly count the number of times I've had to trace out a sliver of tape plugging a tiny orifice that's keeping a quarter million dollar piece of equipment from working. Most good sealers will dissolve in the system and not cause a problem. Most every hydraulics manual for Caterpillar, etc. says DO NOT USE TAPE. I been there and seen that.
Rebuilt a very expensive Cat loader transmission over a plugged .030 orifice, it wasn't getting full clutch engagement pressure and we all know what that leads to. Stupid part was that some idiot used tape on a bunch of O-ring boss fitting that didn't even need it.

The trick is to wind the tape short of the end of the thread so that it pushes back up the thread as it's tightened. I guess I've been lucky.

Dunno why anybody would use tape on ORB fittings (shrug) it's only for NPT stuff.

[12V71]

Yup. HATE HATE HATE


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I have a couple of customers with New Holland telehandlers with those things for attachments up front, hay squeeze/spears with grapples. When their guys go to change attachments they tend to beat on the sleeves to uncouple them because there is no way to relieve the trapped pressure in the lines. I've showed them how to crack a swivel fitting and just release a few drops of oil but I guess caveman tactics work better. Or even better they get out Mr. screwdriver and try to beat on the center pin (that doesn't move) and nick everything up.