Cycling UK Forum

I have a friend who has a Vanmoof bike. The rear brake is very spongy and I assume needs bleeding. I only have cable operated rim brakes on my bikes and looking online I can not seem to find specific instructions for these brakes. I do know that they work with mineral oil not DOT fluid.

If I buy a universal brake bleed kit like this
https://www.sjscycles.co.uk/tools/oxfor ... bleed-kit/
I assume one of the fittings will work. Is it just a matter of trial and error to see which one screws in?

I have posted below pictures of the brakes. I assume the torx head screws outlined are the brake bleed points?

Any advice gratefully received

Steve Underside view of brake lever Rear brake caliper Top view of brake lever reservoir

Steve O'C wrote: ↑1 Aug 2023, 8:57amI assume the torx head screws outlined are the brake bleed points?

That's definitely the case for the caliper one. As you say, you'll need to find the adaptor with the right thread to screw into it so you can connect up the bleed hose. Can't help much with that, other than pointing towards this kit which a bloke on Reddit claims had the right adaptor for his Vanmoof: https://www.amazon.com/gp/product/B0784 ... =UTF8&th=1 Not cheap, and you will probably find one of the many cheapo universal brake bleed kits on eBay/Amazon have probably got the right adaptor in there.

As for the one under the reservoir, that looked a bit odd to me, as I'm used to bleeding brakes through the top of the reservoir, either by taking off the cap and pouring fluid in directly, or via attaching a funnel to a port in the cap. However, it looks like the Vanmoof system has to be bled by sucking the fluid up from the top (rather than pulling it down to the caliper) in which case, that torx screw is probably the bleed point. Again, you'll need the right adaptor to screw in and connect the syringe to. I've never bled this sort of system before, but here's a YouTube video of a similar type being bled:

Sounds like a way to spoil a friendship

here's a YouTube video of a similar type being bled

Thanks

Sounds like a way to spoil a friendship

Well its not working at the moment so how much worse can I make it

Going forward I think this is probably the least of his problems. The bike also has a fancy electronic control system with LEDs built in to the down tube. Now that Vanmoof have gone bust when they need fixing I doubt any parts will be available

Bleed should be fairly straightforward, doubt there is anything a universal kit could not repair. Opening up the reservoir should identify Dot vs Mineral Oil. Google appears to think the latter.

If it's reservoir only and doesn't take a funnel, make sure you just go slow and take out the access till the air bubbles are out. But I'd want to know why it needs bleeding likely a leak somewhere, most commonly where the hose meets the caliper/lever and has been pulled out.

Make sure you take the pads out, and wheel/disc.

This is the sort of job that by the time you have brought the kit, oil etc etc. Your better off taking to the bike shop. They will have it done in 5mins and spot any likely leaks.