During TDP2021 I noticed that the front friction brake was not working correctly – only the rear brakes…and those were also really bad.
Since there is near to no information about TWIKE brakes and the different variants, I thought it would make sense to write about this vital part of the vehicle in a short entry.
For context, there are three types of friction-based brake setups in TWIKEs (which typically get used very little):
- Split brake systems – legs brake back tyres via a back pedal setup, left hand brakes front wheel
Very limited ability to brake with the front wheel as the hand cannot build up the required pressure
- Integral brake system (via pedals, TWIKE active setup)
Superior braking via back pedal brake acting on both front and back wheels
- Integral brake system (via pedal, TWIKE Easy setup)
Superior braking via a traditional pedal as a TWIKE Easy does not have any pedaling setup
TW560 has the integral brake system and the front brake had taken on some air and stopped working.
I have felt for a while, that this is something I should be able to do myself – and started researching how to do this.
There are two ways to bleed the brakes – manual and with a specialized tool.
The manual method only requires an 8-sized wrench, a receptacle for the braking fluid that was pushed through and some DOT4 braking fluid – it requires also two people.
You position one person below the TWIKE, locate the brake caliper and the small rubber cap for the bleeding nipple. Remove this rubber cap and position the receptacle below the nipple.
Get the other person to sit in the TWIKE and have them remove the small cap of the braking fluid container.
Now get the other person sitting in the TWIKE to press the brake. Now open the bleeding nipple and let the pressure push the brake fluid out. The person has to keep the pressure up until the person below the TWIKE tightens the nipple again. Now you get the person in the TWIKE to press the brake again and you start over.
Typically, it will take a few cycles before there will be one or two ‘bubbling’ cycles when the air is flushed out of the system.
The person in the TWIKE will typically not feel the brake pressure collapse during the first few cycles. As soon as the system is flushed, the brake should push through to max smoothly when the pressure is released through the nipple.
Make sure there is always enough brake fluid in the container – getting air into the system through that container is the best way to have much more work 🙂
(As a disclaimer, the manual method only works if the braking system hasn’t taken on too much air. As the front brake line, unlike with motorbikes, first heads up and then down again, air can be trapped at the top and will not be pushed downwards if there is too much of it there. In such cases, the air just gets compressed, nothing more. For such cases, either you get yourself a tool like the one below or just visit any motorbike mechanic, as they will have the required negative pressure compressor …and the experience how to bleed such brakes.)
At a garage, typically, they have compressed air and have a gadget that creates negative pressure from it.
Without this luxury, there are simple hand-powered devices that are able to create enough negative pressure to bleed smaller braking systems such as my TWIKE’s.
After assembling the tool and starting to pump, the nipple can be opened and the brake fluid will start flowing slowly at the start and eventually the air will be pulled out of the system.
With this tool it is even more important to make sure that the container above is always full! The tool can pull rather large amounts of fluid in a short period.
After this, the front brake will be very responsive again! The rear brake system can only be bled using a more professional setup. A future entry will be dedicated to this process.