[IanfromOz]

Hi guys,

This my first post on this CF Moto site.  I have become the de facto mechanic for my female neighbour's CFORCE 550 (CF500 AU 6L). The handlebar master cylinder was damaged in a minor crash recently.  I fitted a new master cylinder and replaced the front brake pads.  OK, all I have to do now is flush out the old brake fluid and bleed the brakes.  (Oh, you poor simple fool Ian...)

So, I've now read 8 or 9 posts describing in detail what a PITA it is to bleed CF Moto brakes.  And I've found the Dealer bulletin descripting how to do it.  To no avail.  Nothing I've tried, including pressure bleeding both the front and rear systems, has resulted in any operating pressure on either brake lever.  Applying pressure to the foot brake master cyl, I was able to get flow out of the rear-most nipples on the front calipers, but nothing out of the rear caliper.  Applying pressure to the handlebar brake master cyl, flow comes from the front-most nipples in the front calipers.  This seems opposite to what the parts list shows for which system connects to the rear/front connections of the front calipers.

From my reading of the parts diagram, the front and rear hydraulic systems should be completely separate (apart from both systems acting on the front calipers via separate cylinders in the calipers).  Is this true?  Because I've noticed that when operating the foot brake pedal, fluid wells up in the handlebar master cylinder.  Can't be sure if it also happens in reverse, i.e. handlebar lever pushing back into rear system master cyl.  In any case,  perhaps this is why I cannot generate any operating pressure, if the fluid escapes back to the opposite master cylinder?

By the way, throughout all these attempts, I've tried every combination of levels released and/or held in the operating position.

Is there some interconnection between the front and rear system that I'm missing?  Any help would be much appreciated, as this thing is doing my head in at the moment!

[NMKawierider]

There are two types of systems used. both are a royal pain to bleed conventional...like most of these are. The most effective way to to reverse or back bleed them. That's from the calipers to the masters. And yes yours is the toughest with two chambers in the front calipers. What makes it even tougher is that there are check valves I believe mid system or on the masters of the "all brake" system that prevents fluid from one master going to the other...as you are saying it is. Sounds like an issue with that check system.

[IanfromOz]

Hi NMK,
Thanks for your suggestions. Today I experimented with blocking off various fluid hoses, banjo fittings and caliper ports by substituting a plain bolt for the banjo bolt (M10 x 1.25 x 20mm). I think I now have rear brakes, but there are more combinations to try next. I'll keep you informed of progress and any useful things learned.
But it's too hot here this afternoon (35 C / 95F) too continue and the sun is blazing in under my west facing awning where the quad is parked. Maybe time for a beer?

[NMKawierider]

Hi NMK,
Thanks for your suggestions. Today I experimented with blocking off various fluid hoses, banjo fittings and caliper ports by substituting a plain bolt for the banjo bolt (M10 x 1.25 x 20mm). I think I now have rear brakes, but there are more combinations to try next. I'll keep you informed of progress and any useful things learned.
But it's too hot here this afternoon (35 C / 95F) too continue and the sun is blazing in under my west facing awning where the quad is parked. Maybe time for a beer?

We up here don't always remember that as we roll into fall and winter, below the equator is moving into their spring and summer. Amazing how much difference a little tilt makes. Yeah...it might just be beer-30...for everyone   

[IanfromOz]

Hi all,
After only(?) two months I'm back with news of my neighbour's CFORCE 550 brake repairs.  And at last - Success!
A 240km round trip by the owner to the CF Moto dealer confirmed that the front left caliper was faulty - but they had none in stock.  They arrived by post a few weeks later and I fitted them and, without too much trouble, was able to get a firm handlebar lever and foot brake pedal.  And then dismantle the faulty caliper and see exactly what the problem was.
I've written up the entire process with diagrams, photos and sketches (.pdf file attached).  Hopefully this information may be of use to other owners/fixers.
Ian

[NMKawierider]

Thanks for reporting back.

[murdo]

Thanks for that Ian. If ever I have trouble I will check the seals first.