Hydraulic Coupler Challenges

LarryBud

Active member

Equipment
L3130
Dec 5, 2020
241
127
43
Cleveland, MO
I installed a Summit 3rd Function and have a MTL Grapple ( awesome btw ).

When I change it out with the bucket, I generally have challenges but after some struggle I can generally get them connected. Today, I dropped the bucket and hooked up the grapple. After shutting the tractor, I worked all three function in an attempt to relieve the pressure. I could install the female link from the grapple but could not get the male coupler to hook up.

I repeated the pressure relief routine, no joy. I unhooked the lines from the valve no good. Finally, I assumed a damaged fitting. I removed the fittings from each respective hose.... snapped together slick as can be. I hooked it up and was good to go.

I never want to go through this again. Suggestions? I'll switch out couplers if I need to. It was a huge frustration and downtime.
 

mcfarmall

Well-known member

Equipment
Kubota M5660SUHD, Farmall C
Sep 11, 2013
1,382
1,649
113
Kalamazoo, MI
You have pressure build-up in the lines on the grapple. You relieved it when you removed and reinstalled the couplers. There are commercially available solutions to depress the center check valve to make hookup easier. Here's something I built.
Made one for each hose on the grapple.
20210404_162437.jpg
 
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LarryBud

Active member

Equipment
L3130
Dec 5, 2020
241
127
43
Cleveland, MO
OK. I figured that out after doing some additional reading. Originally, it didn't dawn on me that the grapple side would have the pressure. I just assumed it would be on the tractor / pump side of things. Live and learn.

I also read that you can put a rag on it and depress the ball for the male end. It will be messy. Will that help on on the female side as well? One looped system or does the cylinder stop the pressure and I have it on both sides?

Thanks.
 

DustyRusty

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Equipment
2020 BX23S, BX2822 Snowblower, Curtis Deluxe Cab,
Nov 8, 2015
5,183
3,843
113
North East CT
When you want to release the pressure on the 3rd function valve, you need the key in the on position, and then while pushing each button, move the joystick in all directions to release all the pressure in all the lines. This is the method that I have found works well for me with my BX23S with the LandPride 3rd function valve with flat-faced couplers.
 
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PaulR

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Equipment
BX 23S -- 100 hours seat time so far
Aug 3, 2020
581
457
63
Hadley, MA
When you want to release the pressure on the 3rd function valve, you need the key in the on position, and then while pushing each button, move the joystick in all directions to release all the pressure in all the lines. This is the method that I have found works well for me with my BX23S with the LandPride 3rd function valve with flat-faced couplers.
YOU ARE MY HERO if this works.
Newbie grapple owner here, I always had one side no matter what I did had pressure and was a B!@# to press on. I assumed I had a bad fitting from the dealer. I will be trying the key on position tip, thank you!!
 

DustyRusty

Well-known member

Equipment
2020 BX23S, BX2822 Snowblower, Curtis Deluxe Cab,
Nov 8, 2015
5,183
3,843
113
North East CT
Today, I attempted to install my grapple, and I used my own advice to release the pressure in the lines. It didn't work! I fought with it the mandatory 5 minutes, and then broke out my wrenches and loosened one coupler. I found that one of the couplers is a Summit brand and the opposite end was what came with the 3rd function valve. With the female coupler in one hand and the hose with the male coupler in the other hand, I still had difficulty putting them together. The hose female coupler was a 1/4" thread, and the tractor side is 3/8" thread so I couldn't change it today. I think that it is the slightest difference between brands even though they are supposed to be built to a standard, or the metal shrunk over the winter! I am going to get another Summit branded coupler and see if it makes a difference. Eventually, I did get them connected.
 

ayak

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Lifetime Member

Equipment
L3301 HST
Feb 16, 2018
574
746
93
WV
Before shutting off, I’ll raise my 3-point a little, the front (grapple) a little (curled slightly in), and both lids of the grapple also ‘open’. I then turn off the tractor and lower and work everything (including the joystick dump motion) with the grapple lids themselves being last. This seems to relieve all pressure back to the tank-I can even hear the fluid returning. Since doing it like this, I’ve yet to have any pressure on either side of the grapple that would later prevent me from hooking back up later, but I also don’t typically have any hoses sitting in the sun heating up.
 

minthral

Active member

Equipment
Kubota L47
Nov 22, 2021
189
92
28
NC
Well it's getting hotter and my grapple has the same problem. I spent a good 30+ min trying to connect it with no luck... Basically I unhooked it cold then it got hot and pressure built up. Normally a 'love tap' using wrench and hammer works for my backhoe, but that didn't help.

I tried to hit connector pin with rag+hammer to relieve pressure. Some oil did squirt out a few times, but apparently still not enough to relieve pressure and I didn't want to keep wacking it. Got fed up with fooling with it and decided to do something else.

Hoping it will connect early morning when it cools off.

I like the idea of the quick connect valve posted... I'm going to get some next time as this is a huge pain in arse and wasted time when you're trying to get stuff done. I spent a long time trying to connect my backhoe due to the same issue...
 

LarryBud

Active member

Equipment
L3130
Dec 5, 2020
241
127
43
Cleveland, MO
Well it's getting hotter and my grapple has the same problem. I spent a good 30+ min trying to connect it with no luck... Basically I unhooked it cold then it got hot and pressure built up. Normally a 'love tap' using wrench and hammer works for my backhoe, but that didn't help.

I tried to hit connector pin with rag+hammer to relieve pressure. Some oil did squirt out a few times, but apparently still not enough to relieve pressure and I didn't want to keep wacking it. Got fed up with fooling with it and decided to do something else.

Hoping it will connect early morning when it cools off.

I like the idea of the quick connect valve posted... I'm going to get some next time as this is a huge pain in arse and wasted time when you're trying to get stuff done. I spent a long time trying to connect my backhoe due to the same issue...
There must be some type of in-line relief valve. Even if it spits out fluid. I'd be happy to get a bucket or a rag and deal with the mess.

It seems like I only have trouble when I'm on a timeline...... Which is usually when I'm hooking up the grapple.
 

LarryBud

Active member

Equipment
L3130
Dec 5, 2020
241
127
43
Cleveland, MO
You have pressure build-up in the lines on the grapple. You relieved it when you removed and reinstalled the couplers. There are commercially available solutions to depress the center check valve to make hookup easier. Here's something I built.
Made one for each hose on the grapple. View attachment 78051
McFarmall,

Is this just a shut off cock? Shut down the line, hook it up, then, open the line back up and away you go?

If so, how does it work for you?
 
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mcfarmall

Well-known member

Equipment
Kubota M5660SUHD, Farmall C
Sep 11, 2013
1,382
1,649
113
Kalamazoo, MI
McFarmall,

Is this just a shut off cock? Shut down the line, hook it up, then, open the line back up and away you go?

If so, how does it work for you?
It's just a ¼" ball valve and a sintered bronze pneumatic "muffler" attached to a male and female flat face coupler. I click those onto the grapple hoses with the ball valves closed. When I use the grapple again, I just crack the ball valves to relieve the pressure in the grapple hoses. I depressurize the third functions in the usual manner, then hook up the grapple hoses to the tractor. This has worked great for me so far.
 

LarryBud

Active member

Equipment
L3130
Dec 5, 2020
241
127
43
Cleveland, MO
It's just a ¼" ball valve and a sintered bronze pneumatic "muffler" attached to a male and female flat face coupler. I click those onto the grapple hoses with the ball valves closed. When I use the grapple again, I just crack the ball valves to relieve the pressure in the grapple hoses. I depressurize the third functions in the usual manner, then hook up the grapple hoses to the tractor. This has worked great for me so far.
OK. I'm tracking now. You click these in when the grapple is not in use, then, relieve the pressure from the grapple lines prior to hooking up again. Nice.
 

mcfarmall

Well-known member

Equipment
Kubota M5660SUHD, Farmall C
Sep 11, 2013
1,382
1,649
113
Kalamazoo, MI
OK. I'm tracking now. You click these in when the grapple is not in use, then, relieve the pressure from the grapple lines prior to hooking up again. Nice.
I leave the depressurizing couplers on the whole time the grapple is parked. They live on the grapple when it's parked.
 
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DeepWoods

Active member

Equipment
B2650HSDC Woodland Mills WC68 Wood Chipper
Apr 10, 2019
326
247
43
Bigfork Minnesota
Or you can do what I did, and make your own depressurization tool like the one in the link below. Took care of all my problems with the hoses getting pressurized from the hot sun.