Running out of ideas

[wildpudding]

Having some difficulties with the front brakes on my project bike, mainly getting them bled properly.

Done a search and tried reverse bleeding with a syringe, pumping the pistons out then pushing them back in with a g-clamp, holding lever on over-night and just before tried priming the master cyclinder, but still no go. There is pressure there, just its spongy and the pads are far too close to the disc, ie they are rubbing and make turning the wheel difficult.

I changed the pads over and had disconnected the lines, and they are assembled back properly. Any ideas to sort this out would be appreciated.

Cheers,

Stefan

[imdying]

If you're sure the pistons aren't sticking (which is extremely common, a strip and clean is the only way to fix that), then try having the master cylinder lower than the calipers, with the hoses running up. Air goes up

What you describe is commonly sticking pistsons though...

[The Pastor]

give the brakes a good overhaul, remeber to get a seal kit!! also try running alot of brake fluid throgh the system, i.e open the bleed nipple and pour in the fluid till it come out a steady streem, I bleed my nipples (hehe that makes me laugh...) for ages and ages, then i just let them go for ages and a BIG air lock came out! good luck!

[wildpudding]

Hmmm, sticky pistons....would that explain the sponginess in the lever? I did take the callipers apart to clean, though left the pistons in the bores. Might be worth a try, cause don't really have much else to try!

Cheers
Stefan

[MSTRS:Me]

You def need to pop the pistons out. Use very clean, lint-free cloths and swab out the bores/pistons. You also must not use any cleaner/solvent in here - use new brake fluid only. Pay particular attention to the condition of the seals on the pistons - might pay to fit new ones, just to be sure. Lubricate them with new brake fluid to facilitate refitting in the bores.

[PLUG]

Hmmmm tough one ... remove m/c fluid cover ... good sized screwdriver & wedge/wiggle between pad & disc, & rotate screwdriver ... should push piston back ... keep an eye on the m/c fulid ... either air bubbles or fluid will flow back into m/c ... if no movement in piston, service calaper

get your syringe, plunger pushed rite in ... connect it to bleed nipple with the shortest bit of hose you can ... open bleed nipple 1/2-1 turn & SLOWLY pull plunger out ... you should get some air/fluid, keep an eye on m/c fulid level ... repeat until you have a firm leaver feel ... if nothing, have a look around the back of m/c - where pushrod from hand lever works on m/c piston ... maybe some shit in there stopping the piston comming right back & uncovering the fulid return port in m/c ...

[Motu]

Clamp the hoses....work your way back until you find where the lost travel is.

[imdying]

Clamp the hoses....work your way back until you find where the lost travel is.

Yep, I'd do that. Find some hose clamps (like plastic pliers generally) or be pretty careful about how you do it. Don't wanna damage the the hose with your manky old vice grips

[wildpudding]

Clamp the hoses....work your way back until you find where the lost travel is.

Thats a great idea, cheers I'll try that too

Stefan