Quick release hydraulic couplings - leaking when connected - hydraulic expert required!

X344chap

Member
Mixed Farmer
Location
Central Scotland
Hi - 2 of the the quick release couplings on the back of the tractor (IH 685) are dripping steadily when they are connected, but dry when not. I can see a rubber o-ring inside the connector which i suspect has become hardened or deformed over time.

Can i just pull the o-ring out with a pick and replace it - or does the fitting need to come off and be disassembled? Are the o-rings a standard size for the quick release connectors on the back of older tractors?

Many Thanks
 

milkloss

Member
Livestock Farmer
Location
East Sussex
Hi - 2 of the the quick release couplings on the back of the tractor (IH 685) are dripping steadily when they are connected, but dry when not. I can see a rubber o-ring inside the connector which i suspect has become hardened or deformed over time.

Can i just pull the o-ring out with a pick and replace it - or does the fitting need to come off and be disassembled? Are the o-rings a standard size for the quick release connectors on the back of older tractors?

Many Thanks
Yes, pick it out, measure and order a bag from bearing boys or whoever. I can’t remember what size they are and need some myself so if anyone knows I would appreciate a shout.

There is, or should be, a white nylon backing ring next to the o ring. I’m not really sure of it’s purpose but without it the o ring will move about and get chips out of it when you push the plugs in. I don’t know the size of those either sadly.
You can just use o rings without and if you have a decent sized bag of spares then you won’t worry about the white part.
 

traineefarmer

Member
Location
Mid Norfolk
The nylon back-up ring is to prevent the O-ring extruding out of the coupling when under full pressure. The clearance between male and female parts of the coupling is too great for an O-ring alone.

You don't have to replace the back-up ring if it is undamaged, but it should definitely be in place.
 

milkloss

Member
Livestock Farmer
Location
East Sussex
The nylon back-up ring is to prevent the O-ring extruding out of the coupling when under full pressure. The clearance between male and female parts of the coupling is too great for an O-ring alone.

You don't have to replace the back-up ring if it is undamaged, but it should definitely be in place.
Interesting, presumably the back up ring should be away from the pressure?
 

spin cycle

Member
Location
north norfolk
Hi - 2 of the the quick release couplings on the back of the tractor (IH 685) are dripping steadily when they are connected, but dry when not. I can see a rubber o-ring inside the connector which i suspect has become hardened or deformed over time.

Can i just pull the o-ring out with a pick and replace it - or does the fitting need to come off and be disassembled? Are the o-rings a standard size for the quick release connectors on the back of older tractors?

Many Thanks
can just undo couplings and buy new ones :)
 

X344chap

Member
Mixed Farmer
Location
Central Scotland
Yep, O-ring on pressure side.
So the probe goes through the nylon backing ring first and the rubber o-ring is closest to the tractor and not the implement?

Does anyone have a note of the correct size? I can never understand the sizing of hydraulics - are the standard ones on the back of most tractors 3/8 " ones - or is that the size of the rubber hydraulic hose and the actual fittings are larger?
 

milkloss

Member
Livestock Farmer
Location
East Sussex
So the probe goes through the nylon backing ring first and the rubber o-ring is closest to the tractor and not the implement?

Does anyone have a note of the correct size? I can never understand the sizing of hydraulics - are the standard ones on the back of most tractors 3/8 " ones - or is that the size of the rubber hydraulic hose and the actual fittings are larger?
Correct on the rings going by the post above.
Tractor will be 1/2 inch, don’t understand the sizing myself, I think it’s loosely based on the recommended size of pipe.
 

traineefarmer

Member
Location
Mid Norfolk
The o-rings will need to be matched at a store or measured and compared to a chart to get the part number. Despite the male probes all being the same size, I've come across dozens of different sized o-rings within the female couplers depending on how they are made internally. The back-up ring will be matched to the o-ring size.
 

X344chap

Member
Mixed Farmer
Location
Central Scotland

DrWazzock

Member
Location
Lincolnshire
There a so many different sizes of O ring that if possible, it's best to try and identify it from a workshop manual or dealers parts list and even to to pay the dealers premium for half a dozen of the right size. Failing that, go to the shop and try comparing it with what they have got there in their boxes.

The biggest part of the job is finding the right size. Slightly wrong and chances are it will leak or snag when you push the connector in.
 

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