Brake bleeding

[RUDDY]

Got round to putting some fluid in the rear brake today, thought it would be a simple bleed, not a chance.

During the rebuild it had new cylinder, new piston kit, new hose, new caliper seals and piston.

Now I've cracked the nipple and pumped, nothing.
Faffed about with the nipple and pumped, nothing.
Cracked the banjo on top of the cylinder, nothing.
Had the cylinder back off for a looking over, looks ok.

Is it just air locking, does the fluid need to be sucked through to get it going, seem to remember a similar problem on a new TR7 hydraulic clutch.

Any words of wisdom ?

Cheers, Paul

[Hinckley]

I just did mine - totally dry system.

Try loosening the banjo at the master cylinder to help get the fluid moving through, then once the fluid comes through nip it up and use a syringe and some tube to help pull it through.

Air gets trapped everywhere, with air in the master cylinder it doesn't move enough fluid through quick enough to stop the air returning back up the pipe work.

Sucking it through speeds things up - quicker with two doing it - but can be done alone easy enough - just takes time.

[z1bman]

remove the banjo bolt from the cylinder & put your finger over the hole & pump the lever & you should feel some pressure / fluid. yes it will make it easier to bleed if you have a syringe

[RUDDY]

Cheers guys, I did try removing the banjo from the top of the cylinder, pumping the pedal didn't give a great amount of pressure and the fluid in the reservoir didn't drop at all, fluid doesn't appear to be getting into or out of the cylinder.

Did I mention stepping on my plastic syringe and snapping the end off it ....bastard

Cheers, Paul

[z1bman]

there is i tiny air bleed hole in the bottom of the cylinder is this clear?

[RUDDY]

there is i tiny air bleed hole in the bottom of the cylinder is this clear?

Can't say I've noticed it, will check that tomorrow though.

[ADRIAN H]

I had to prime the master cylinder on my bike after I fitted new seals to my z100A2 master cylinder.

[RUDDY]

Well, still no rear brake, bought a small hand vac pump, no help, tried bleeding the cyl off the bike , no different.

I have a feeling its one of two things both down to the pattern piston, either the seals aren't right or the piston is too long and covering the fluid port, I seem to recall the pattern piston being slightly longer than the old original.

The worst thing being, after I'd got all the components built up and on the bike, and believing all it needed was bleeding, I binned the old parts.

So, tomorrow I'm gonna check that and see if it is too long, if so I'll be after another piston which I believe genuine are NLA, I've even compared my ZRX cyl to see if one of those would fit.

It's never plain sailing

[oldzed]

If its a screw cap on the resevoir you could ask one of the local garages if they can pressure bleed it.

we use one of these in work cos you can connect it to a tyre to supply pressure.
http://www.amazon.co.uk/Sealey-VS0205-A ... B001K4GA1S

just a thought

[RUDDY]

And here lies the problem, the photo shows the piston at its lowest point, the pattern part piston is too long, the top seal at rest is above the top fluid port, fluid can never get to the pressure side of the system.

So I need a shorter, original piston.

Anyone got an old m/cyl with piston laying about ?

Checking my ZRX cylinder this morning I don't think using one of those is a goer, although the mounting hole centres are the same and the piston bore etc, the ZRX one is cast slightly different so it wouldn't fit due to the ELR's cast foot peg carriers getting in the way.

Thanks for the help guys.

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[needaz1100r]

It's all good fun isn't it.