Short answer
There is one logic to the order when fitting an attachment: mechanical connection first, hydraulic connection second, and on removal the reverse. The reason is safety. An attachment with hoses connected but pins not fitted swings on the only thing holding it, the hose, and ruins both hose and fitting. On removal, if the circuit is left pressurised, oil sprays when the coupling is opened. The sequence below is built to remove both risks and applies to every attachment; with a quick coupler some steps shorten, but the logic does not change.
Fitting, step by step
- 1
Prepare the ground and the attachment
The attachment should stand on firm, level ground where it cannot topple. Clean the bracket faces and the pin bores; leftover mud stops a pin from seating fully.
- 2
Line the bracket up
Bring the machine to the attachment and line the bracket up with the boom end. Do not force it: if the bores do not line up, reposition the machine rather than driving the pin home with a hammer.
- 3
Fit the pins and secure them
Set the pins in place and fit the retainers, whether circlip, plate or bolt. With a quick coupler, confirm by eye that the safety lock has closed and follow the coupler’s own procedure.
- 4
Release the pressure in the circuit
Before opening any coupling, release residual pressure in the machine’s auxiliary circuit. Trying to connect against pressure is both difficult and damaging to the coupling faces.
- 5
Connect the hoses the right way round
Do not mix supply and return. A breaker connected the wrong way round either does not run at all or strains its internals. Connect clean: a coupling that has touched the ground is wiped before it goes on.
- 6
Check the hose routing
Make sure the hose is neither stretched nor rubbing at any point through the full boom movement. Work the boom end to end and watch. A rubbing mark shows up not on the first day but months later, as a burst.
- 7
Do the first greasing
Grease with the tool pressed up before any work begins. With an automatic system, confirm the cartridge is full and the pump is running.
- 8
Run it off load and listen
Run it briefly without setting into material and look for excessive hose movement, leaks or an uneven rhythm. If the shaking continues, see the hose vibration guide.
Removal: the mirror image, with two differences
Removal is fitting in reverse: hydraulics first, mechanics second. Two points need extra care.
First, couplings are capped the moment they come off. An open coupling takes dust into its mouth and that dust goes straight into the hydraulic system at the next fitting. Where there is no cap, a clean cloth and tape will do, but the habit of capping is the cheapest protection there is.
Second, no pin comes out before the attachment is on the ground. Hanging in the air, a pin is already bound by the load on it; forcing it out is both dangerous and damaging to the bore. Let the attachment settle, let the load come off, then take the pin.
The five most common mistakes on site
- Forcing the pin instead of moving the machine when the bores do not line up. That single move is what ruins a bore.
- Fitting a coupling that touched the ground without wiping it. The next address of that dust is the piston surface.
- Leaving the hose routing untested through full boom movement. A stretched hose lengthens before it bursts and starts weeping at the fitting.
- Skipping the first greasing after fitting. A breaker started dry marks its bushing in the first hours.
- Setting the attachment down on ground where it can topple. A toppled attachment usually damages the tool or a hose fitting.
One rule with a quick coupler: confirm by eye
From inside the cab, a quick coupler safety lock can look closed when it is not. Getting out and confirming by eye that it has actually engaged, before lifting the attachment, is the one step no warning system replaces. The coupler’s own manual asks for that confirmation every time.
Do and don’t
Do
- Complete the mechanical connection before the hydraulic one; reverse it on removal.
- Cap couplings the moment they come off; with no caps, wrap them in a clean cloth.
- Clean the bracket faces and pin bores before fitting.
- Work the boom through its full movement after fitting and watch the hose routing.
- Do the first greasing before work starts, with the tool pressed up.
Don't
- Do not drive pins with a hammer; set the alignment with the machine.
- Do not open or connect a coupling against pressure.
- Do not remove an attachment while it hangs in the air.
- Do not disconnect hoses without marking them; unmarked hoses go back the wrong way next time.
- Do not balance a removed attachment on its tool; set it down where it cannot fall sideways.
The first hours after fitting
The first hours of a newly fitted attachment set up the months that follow. What you are looking for in those hours is not performance but consistency: does the sound stay the same, do the fittings stay dry, is the housing running hotter than it should.
Heat matters most, because it is the shared symptom of both wrong hydraulic settings and insufficient greasing. If the housing is too hot to touch, work stops and the cause is separated.
On a breaker fresh from overhaul or with new parts fitted, this period is also a run-in; working at full load without pause in the first hours prevents a new bushing and seal from bedding in.
What HKM uses
SolidLube: the first greasing stops being a step you can forget
The automatic lubrication station mounted on the breaker meters grease during the blow itself. Missing the first greasing after fitting, or forgetting it during the day, stops being a risk that rests on the operator’s memory.
Look at the automatic lubrication station(solid-lube.com)