Hi All,

Few weeks ago at a trial I lost my rear brakes. Had a quick look at the fluid (full) and then took the caliper off and had a look, there's no pressure on the foot brake and the cylinders weren't pushing out.

Got back home and bled the system out fully, still having the same problems, anyone got any ideas what I can try next?

Cheers

Andy

Is the plunger in the master cylinder moving in and out when you press and release the pedal?

Yeah I can see it moving in and out freely, I'm getting some friction onto the disc so if you pull the wheel round by hand you can stop it, but if you get on it, there's not much there to stop you. I recently changed the rear pads, but that was before they stopped working.

Edited January 10, 200620 yr by arturner51

Make sure you have some play on the plunger rod that comes out of your master cylinder.

Did you fall off in the trial because if the bike was say, upside down the air at the top of the resevoir can sometimes get in the hoses,and even though you bled it the air can take a lot of persuasion to work its way out and wil not show straight away at the bleed nipple.This happened to mine once when I had the airbox off and had moved the resevoir to make things easier and it was hanging upside down.The problem was not apparent until I took it out the following weekend.I would search the forums for advice on bleeding the rear brake as it can be a pain in the neck sometimes.

Surprisingly I didn't fall off at that trial, however I did come off big style the trial before buy it landed on the side of the chain not the caliper.

Next door neighbour put a lorry brake bleeding kit on it (he's a lorry mechanic) which ran off my car battery, so I assume that thing had enough power to bleed it forcefully enough.

Do you reckon I should try a new master cylinder on it? How much are they roughly?

OK...this may be too obvious...but make sure you haven't bent your brake pedal and it's hitting something before it gets full travel.

Yeah checked that too, the pedal's got full movement, it goes all the way down with little pressure by hand

Spoken to Lampkins who suggested a new Rear Master Cylinder, so I've ordered one and I'll see if it rectifies my problem!

Andy

This worked for my old montesa after trying to bleed it for hours and hours:

Tip the bike up 45 degrees ( front wheel up the wall)and bleed it.

Then tip it 45degrees ( back wheel up the wall) and bleed it.This is not a wind up

Spoken to Lampkins who suggested a new Rear Master Cylinder, so I've ordered one and I'll see if it rectifies my problem!

Andy

<{POST_SNAPBACK}>

Have trials parts now gone the way of auto parts?

Can you no longer buy the rubber bits to freshen up a master cylinder?

Spoken to Lampkins who suggested a new Rear Master Cylinder, so I've ordered one and I'll see if it rectifies my problem!

Andy

<{POST_SNAPBACK}>

Have trials parts now gone the way of auto parts?

Can you no longer buy the rubber bits to freshen up a master cylinder?

<{POST_SNAPBACK}>

I dunno, they never mentioned, I'm a bit of a noob to fixing my own bike but I'm having a crack at it, they relieved me of about

Nightmare, spent ages trying to get this working today, replaced the rear master

cylinder which has made no difference (

Edited January 14, 200620 yr by arturner51

Try bleeding just the master.

Disconnect the hose, put your finger over the hole, and pump the pedal. Air and fluid will push past your finger (don't run it out of fluid).

Keep the pedal depressed while you hook the hose up again.

Now you can back fill/bleed with a syringe.

Make sure you have some play on the plunger rod that comes out of your master cylinder.

<{POST_SNAPBACK}>

Sorry to bring it up again but have you checked there is play in the rod. No play gives the symptoms you describe.

Also check that there isn't any play in the pivot for the brake lever. It needs to push squarely towards the master cylinder.

Mark T