Dodgy M/C ??

The Rig · Derestricted Danger Joined: 29 Oct 2008 Karma :

pushed the brake pistons all the way back in and now cant get them out while bleeding them.
i have split the calipers to clean the pots up etc,so they are not stuck but fluid is coming out the bleed nipples with no air,the pistons have moved out but just seem to pulsate when i pull the lever,the lever comes all the way back to the bar still.

fecked m/c ???

lonner · Spanner Monkey Joined: 09 Jan 2009 Karma :

how old is the bike as unlikely if its under 10yr old but is possible.

if the brakes worked before its unlikely to be the m.c

you usually get leakage at the leaver if the m.c seals have perished.

so i think you need to bleed the brakes a bit more. Thumbs Up

BanditsHigh · Worse than a woman Joined: 21 Mar 2005 Karma :

If you have not taken the pistons out .... DOH, just reread the post ... I've included another of my posts (you may want to check the other brake bleeding posts)..

Hope you get it sorted.

binge · Emo Kiddy Joined: 03 Jul 2004 Karma :

Pressure bleeding is the way forward. And its simple to do with general household and garden shed products if you use your imagination.

I can bleed front and rear brakes on my pit bike in about 10 minutes using some clear hose, A fairy liquid bottle and a tyre valve.

Ben

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

Sure you've put the right fluid in?

Same thing happened to mine when I put ATF in instead of brake fluid, corroded the seals. Had to rebuild the entire m/c and calliper Embarassed

Borg · Derestricted Danger Joined: 24 Jul 2006 Karma :

or have you used synthetic fluid DOT 5 and mixed it with DOT 4, That will turn to jell and swell the seals

timjim · Trackday Trickster Joined: 31 Aug 2006 Karma :

Have you tried "back bleeding" the brakes,??attach a tube and syringe to the open caliperbleed screw and squirt fresh brake fluid into the screw..the air moves to the highest point (reservoir) and pushes the air out of the system.If youve ben bleeding the system for a while the fluid can also get aerated..pull the lever in with the bleed screws done up,tie the lever in with an elastic band or lenghth of string and leave for half an hour or so and let the fluid settle.

The Rig · Derestricted Danger Joined: 29 Oct 2008 Karma :

cheers for replies guys.

i`ll try the back bleeding method, same fluid as usual DOT4.

on each caliper, 2 of the pots (one side) are out as far as they can be and the pads are onto the discs, its the other 2 on each caliper that dont seem to be coming out as far as they shpuld to put the pads onto the disc, if i pull the lever in and watch the pots they extract but then get sucked back in and dont stay out so the lever travels all the way to bar each time.

very weird

BanditsHigh · Worse than a woman Joined: 21 Mar 2005 Karma :

Any piccies?

Are your discs ok?

The pistons shoudl come out and then retract slightly when you release the lever ... sounds as though you have quite a lot of air in the system.

What's the setup (single to splitter to double, two singles, single down and one over mudguard)?

The Rig · Derestricted Danger Joined: 29 Oct 2008 Karma :

discs are good.

the pots arent coming out enough,the gap is about 2-3mm on each caliper.

the setup is single line from m/c, into a spliter under the headstock then a single line to each caliper.

its an 87 gsxr 750
cheers

BanditsHigh · Worse than a woman Joined: 21 Mar 2005 Karma :

Hmm, sounds like original brake lines ... may be they are past it, see if they bulge at any point when applying brake pressure as another check Thumbs Up