Aluminium bellows coupling D5,1 – the connection that takes out play and misalignment
A bellows coupling is an inconspicuous part with a clear task: it connects two shaft ends so that the torque is transmitted cleanly, but small axial misalignments do not get through to the bearing. The folded bellows in the middle absorbs exactly this inaccuracy. As long as it is healthy, you notice nothing of it. When it is tired, you notice immediately.
This coupling is made of aluminium and designed for a bore of 5,1 millimetres. The manufacturer lists it under part number C.1.549. It is supplied as a single part, without shaft and without counterpart.
When it is due
The adjustment feels soft or suddenly has free travel before anything happens. A faint cracking or rattling can be heard when turning. The bellows shows a crack or is dented at one fold. Or one of the clamping screws has dug into the aluminium and no longer holds reliably.
At a glance
| Type |
Bellows coupling |
| Installation point |
between two shaft ends inside the machine |
| Fits |
La Marzocco assemblies with this coupling. Send us the serial number and we will check the fit. |
| Scope of delivery |
one bellows coupling |
| Part number |
C.1.549 |
| Version |
Aluminium, bore 5,1 mm |
| Installation |
Installation by a specialist recommended |
| Brand |
La Marzocco |
Important for installation
The coupling sits inside the machine, where you inevitably work next to live components. That is why there are no step-by-step instructions here. The machine must be disconnected from the power and cooled down, and the alignment of the shafts must be right after installation, otherwise the bellows constantly works against a misalignment. This is a job for a specialist.
Who it is for
For service technicians and workshops that want to get an adjustment free of play again instead of replacing a whole assembly. And for businesses that like to keep a small part of this kind in stock, because otherwise a failure costs a whole service appointment.
What goes with it
The full selection is available in Accessories and spare parts for La Marzocco and in Original spare parts. If you are working on a grinder, you will find suitable parts in Accessories and spare parts for coffee grinders. And when the machine is open, machine and grinder cleaning belongs on the list too.
Workshop tip from Bern and Zurich
Our own routine, not a manufacturer's specification: before removal, we mark the position of both shafts with a felt-tip pen. On installation, everything is then back the way it was, and you notice immediately if something has twisted. After that we always pull a test shot with Nutty Delight, because it reliably shows whether the setting is right again. If you like it sweeter, take Cozy Chocolate; if you want punch, Very Nutty. Everything else in our coffee beans.
Returns excluded
Spare parts are excluded from exchange and return. They are procured to order and cannot be resold after being installed or test-fitted on the machine. So before ordering, check the model, year of manufacture and serial number of your machine – or drop us a line and we will clarify the fit together. Your rights in the event of defective goods remain unaffected.
Frequently asked questions
How can I tell that the coupling is defective?
Free travel is typical: you turn, and only after a small distance does something happen. This is often accompanied by a cracking noise and visible cracks or dents in the bellows.
What bore does the coupling have?
5,1 millimetres. The manufacturer lists it under C.1.549. If that does not match your shaft, it is the wrong item – write to us and we will find the right one.
Is a second coupling or a shaft included?
No. A single bellows coupling is supplied. Shafts, bearings and counterparts are separate items.
Can I install it myself?
We recommend a specialist. The part sits inside the machine next to live components, and the shafts have to be precisely aligned after installation.
Can I look at the part in your showroom?
Yes. We are in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b. Let us know shortly beforehand and we will have the part ready.
Questions about the fit? Write to us with the model and serial number at [email protected]. We deliver across Switzerland and to Liechtenstein in 2-4 working days.
