Brake bleeding woes

[Pebbles167]

Anyone have any experience with bleeding really stubborn brakes?

Dads CB1300 failed it's MOT on rear brake binding. Caliper was sound but the piston was a looking a bit of a mess and not retracting, so replaced it along with the seals and refitted the caliper.

Attempted to bleed the brakes the old fashioned loosen/tighten way but there is absolutely no pressure on the pedal now, and cannot seem to get anywhere no matter where I put fluid. I've tried reverse bleeding, vaccum bleeding, moving the caliper about, purging at the master cylinder but still nothing.

Obviously there is a load of air in the system somewhere, but my fear is that me being somewhat unfamiliar with ABS on bikes, I've allowed air to make its way into the pump or something, which looking online seems like it may need Honda software to sort. It's worth noting that this is the 2007 model, so predates Hondas combined ABS so at least that's one fewer thing to worry about.

I'm about 20 miles away from Fowlers Bristol, and wondering whether I'd be better off just throwing it in there, and accepting having my pants pulled down for a job that I've done a hundred times on bikes without issue. My own fault for going at it gung ho I guess.

Any advice appreciated!

Edited by Pebbles167 on Sunday 21st June 23:04

[BarryMissioner]

Are they not linked on CB1300? I remember helping my mate with linked brakes on his Blackbird and there was a process to follow that I think involved a secondary bleed point. Search bleeding Honda linked brakes.

[the cueball]

My ‘98 Pan European has the combined ABS brakes.

There is a specific bleeding procedure you have to follow to get the best of it.

It’s a bit of a fiddle, and extra work… but just something you have to work through.

From memory it’s something like:

Front brake circuit bleeders:
Left upper
Right upper
Rear front

Rear brake circuit bleeders:
PCV
Rear rear
Right lower
Left lower

Final bleed
Left upper
Right upper

[Biker9090]

Honda linked and Honda linked are not the same.

E.g. the VFR800 and Deauville had incredibly complicated brake systems to bleed. Yet the VFR1200F had a relatively simple one.

Are you sure you haven't pushed the piston in back too far? See if you can get it to come out and check for pressure. This exact thing happened on my VFR1200F and I was pulling my hair out trying to understand it.

[OutInTheShed]

I've always managed with a syringe on the bleed nipple.
If you can pull fluid right through the system, it should sort itself out.
If you tie the brake lever on/down, the MC should shut of the flow from the reservoir, then a syringe on the bleed should be able to generate some vacuum.
If you can feel you're pulling against firm vacuum, the amount of air in the system is not huge.

If the bleed nipple thread is slack, it will let air in and you won't get far. I've resorted to ptfe tape on the thread before now.

I'm not familiar with the internals of ABS modulators, but my limited experience is that they sometimes sort themselves out overnight!
As far as my knowledge goes, there are a couple of solenoid valves and a pump motor, for some units there are 'shade tree mechanic' get arounds for operating these to bleed the system. I'd be wary of that unless you had specific info for the bike model. There was some stuff on one of the Ducati forums, I would look for similar on a forum relevant to the Honda model in question.

[InitialDave]

I've sometimes been able to resolve weird bleeding issues by using a big syringe full of fluid and a tube on the bleed nipple to push fluid back through the system, as is common practice for bleeding some mountain bike brakes.

[s p a c e m a n]

I'm another advocate of pushing it up from the bottom using a syringe, sometimes I take master cylinders/calipers off and spin them about a bit to get stubborn bubbles out too.

Edited by s p a c e m a n on Monday 22 June 14:23

[Marquezs Stabilisers]

Have you tried doing it with the engine, or at least the ignition, on, to potentially power the pump?

[Biker9090]

The only "manual" way to activate those pumps (as far as I was ever able to work out) is to go along and stamp on the rear and then go over a speedbump and pull hard on the front brake lever.

They're not like the BMW/Triumph etc where you can just plug the bike into a code reader.

[Pebbles167]

Thanks for all the suggestions everyone. Tried a few more times with various methods (including the ones you've all mentioned) but to no avail. It's possible that in the time it took me to disassemble and reassemble, one of the hoses got blocked or the master cylinder failed, but who knows?

Either way the bike has well and truly defeated me and so I stuck it in the local bike dealer, who despite being a Husqvarna dealer and not Honda, are confident they can fix it.