Just a tad fed up now!

Been on me hols and got nothing but grief from the missus. Got home and my lost master cylinder arrived today. Excitedly, I fitted it, reverse bled the brake - nothing! Got my little orange self bleed pipe out, pumped away till no bubbles and there was some pressure, whoopy! Fiddled with my carb cables, started the engine (no tank) bike started to edge forward. Squeezed brake - nothing - not a sausage, what is going on? New master cylinder, new pipes, new copper washers, empty bank balance! and fudge all brakes!

I think at this point you need someone else to take over… (?)

Or a bullet in the brain!I have never had problems bleeding brakes on any vehicle before - don’t understand what’s up.

front or back ?
Are you sure the calipers are free

Is the brake pedal getting full movement, on my bike there is a bolt and lock nut under the pivot for the brake pedal to adjust it’s height, might be winding that down to allow the pedal to drop all the way and re testing

Also loosen the rear brake light switch a touch and pump the pedal to expel any air from behind the switch

Sorry, I thought you all would know! I’ve been posting for ages about this.It is the front brake, linked system.I had no problems with the linked front/rear brakes.I will check pistons, but all was working fine before I replaced the top section of hose because I was sticking Cali bars on. Venhill hose.Now left with elastic bands on lever.

jmee542013-08-20 17:43:02

I would take the pipe off the caliper put it in a jar with some brake fluid and then pump the handle
if the level in the jar rises then the master is actually pumping it down there ie the hose and banjo are clear
are you certain the calliper piston is free

Ex smokingbiker2013-08-20 19:17:43


Then logically there MUST be a problem either with that hose OR it’s fittings assuming NOTHING else was altered.

Hydraulics are logical THIS problem MUST be an air leak … rather than keep throwing money at it get it to a hydraulic specialist it is obviously beyond your current capability to sort it. they could also have checked the old Mast cyl and possibly repaired it … It is impossible to diagnose this on line and needs someone there LOOKING at it.

It did occur to me too, viz all this kicked off with the new hose being put on. Can’t be a coincidence. I agree that we’re trying to fault-find this from a distance… and failing…

Put new hoses on my V50 a few days ago. Tightened the banjo bolts on the calipers and started to bleed. Nothing, then suddenly loads of fluid everywhere, there was not enough bend on the pipe out of the banjo to miss the fork mounting for the caliper. Had to take a file to the mounting casting to get clearance and allow the banjo to tighten up properly.Worth checking.

The new master cylinder is pumping fluid. I’ll try replacing the old hose, even though it is too short and see what happens. I agree there must be air in the system somewhere, but I can find no leaking fluid anywhere. I am going to replace the bleed nipple also, just in case.I will not be beaten by by a bloody brake line! Whilst the bike is immobile I can’t get it to anyone else anyway.

is the brake lever goinghard or moving right back ?
I had a simialir fault on a BMW the hose was breaking internally and swelling
also check the union in case its blocked
if you have had a pipe fail bits of rubber may be in the systems
check the vent in the master cylinder is clear and drawing fluid in, these often block on cylinders left unused
it will be soemthing stupid
go awya have a beer or a big cake and forget about it
the brain will then idle and resolve it for you

Have you tried pumping the lever many times to get everything back in place? It should firm up after a while.

I once bought some new hel brake lines and could not seem to get any fluid out of the caliper via the bleed nipple, turns out when the ends were made, the hole in the fitting was blocked, it actually looked like there was no hole, but I picked at it with a small screwdriver and a little disc fell out, worked ok after that!

I use a vacuum bleeder on my bikes, and have never had any real problems bleeding the brakes, it has the benefit in that your not moving the piston in the master cylinder further than it usually travels, when I replaced the metal brake pipe on my lemon, it took 2 mins to bleed to a solid pedal,

Mine is the type that works off a compressor.ianboydsnr2013-08-21 09:46:39

I wonder if the Venhill hose is holding onto some trapped air. (?) By the sound of it I’m guessing it’s got a top hose, a ‘junction block’ on a fork yoke with brake switch attached, and then a bottom hose?

There are no blockages. The lever goes semi hard (!) but there is still a fair bit of travel. I left it for a while and then went to move the bike and - no brake.The brake lines are all braided. There is a union on the forks where top hose, brake witch and bottom hose attach. I have reverse bled and bled normally. I will try from scratch again.Where do you reckon the most likely air pocket is?New nipples to try.I will check caliper pistons.I will try old hose.

Definitely suggests air then if after you leave it it’s gone soft again. Can’t think what else would do that

When I had problems with the front brake I took the lot off the bike , easy to do and get it on the bench you do NOT have to take a disc off as long as you put something thick enough between the pads.

THAT way you can easily have everything on the same level.

See if there are leaks, sometimes they really are difficult to see.

As a guess it points to the hose if everything worked beforehand always go back. on the bench it is seconds to swap put the hose

Before using new bleed nipple CHECK carefully the shape of the base of it.

Over the years I have had

  1. mast cyl rebuild
  2. leaking bleed nipples due to the seating
  3. very unusual but leak of air BUT no fluid from a banjo
  4. leaking at the union where it all meets on mine between the yokes where the brake light switch plugs in, it was leaking in air from the switch

the only joints are top banjo into the mast cyl
the 2 + brake light switchc on the joint
the caliper

not that much to check out…save your self time and hassle get it all off the bike onto the bench mate, put kitchen roll under each joint it will show up any leak, once it is all together and filled that is

Hope you get it sorted buddy

It is alot easier to fault the front brake as opposed to the linked ones.

DEEP BREATH take time , do it all logically one step at a time IF it Is the hose complain alot, as this has cost you time money and a master cyl

IF the old hose works at least you have found the culprit, and it IS very unusual

I tend to use PTFE tape on all threads it helps only need 1 wrap around to seal it all up.

I’m glad I got the single hose version with just 2 banjos! Is a lot simpler. If you’re wondering, the fr. brake switch functions as master cyl. ‘banjo bolt’.

That is one thing I have changed! My brake switch was on the master cylinder and there was a duff one, unused on the union between the forks. I bought a new one and placed it on the union and removed the one on the master cylinder.Maybe the switch on the union is somehow trapping air.Yep removing the lot to the bench seems a good idea and will definitely be my next move. That is when I am allowed to.Life single would be so much more pleasant, but we joint own the house, we both have workshops - pottery and glass studio and finding somewhere to relocate on half the capital would be impossible. Having said that I am getting to the stage where I don’t care anymore.