Bleeding rear brake!!!
 

My S4r has same rear brake as the 748/9** series i think maybe only diff posistion of master cylinder and disc maybe bigger.

Its finally got to point where it wont actually bite now where as before it was getting further and further away until it bit.

As the caliper is underslung haynes says to take off caliper to put nipple pointing upwards, only the 2 bolts are not easy access with out taking off sprockert or risk using just allen keys and rounding them off!!

Got as one way bleed kit still air in system! need one which sucks fluid thru now i guess? or risk taking off caliper.

Any other suggestions?

I just had bike serviced end of April it was bad then on travel but they didnt touch it cause it not on the schedule fot 12 month service, bit peeved after paying all that out to and who ever test rode it must have noticed it to!

Many thanks

Yikes,

It looks like this is some sort of Virus spreading, done a total of 30k miles on 99X series bikes with no probs then last week me back brake goes awol, this site is riddled with similar posts about back brakes that have packed up.................

Ray.

Thanks Ray

I sure hope its not totalled in winter I used it a lot and for slow speed around town. On my 748s it was fine for the 18 months I had the bike to.

I think also when new it just wasnt bled well as it always went down to far i just compensated by extending the push rod on master cylinder.

A vacum suck bleed kit is £35 maybe have to invest in one of them, do they do Ezi bleed for bikes? all the ones motoman had were for cars.

You have to take off the calliper, and turn it right way up. Thats the way it was designed. I doubt sucking it out will have enough flow to compensate for the speed at which air rises to the top of brake fluid.
What service did you have done. Because at 10000km/2 yr the fluids should have been changed. If not, best you be asking yourself how come there is air getting in there. Are your pads still Ok? Are you boiling the brake fluid from too much back brake use? Is one pad jammed on and heating it up. I think you need to seriously look at it, as you have a problem.

Even after using a Mityvac and taking the caliper off and lifting it I had to take my bike to a local bike shop for him to use his compressed air bleeder which runs at about 120psi and even then it took about four attempts to get it bled.Like a brick now !!

Thanks for replies guys in the end had to take off wheel then caliper and turn it up so nipple upwards worked a treat! Still a tiny bit of air in there but now bites real well.

It was the 12 month service they did, and I see why now why they didnt do it out of courtesy as even for them would not be that quick to do. Though one of the 2 tech's that test rode it must have noticed how bad it was.

Its just over a year old and the back brake was never very good i just think it wasnt done well from new not bled well.

Speed bleeders

It will still go soft again but at least the process is faster

:frog: Hi Lee, you mentioned you had adjusted the pushrod if it dosnt have any free play the caliper wont self adjust as the pads wear, this could have caused the problem in the first place.
Brian

Thanks Brian, I meant i had lengthened the rod that goes in to the master cylinder to take up the sponginess, the pads back off still and are hardly worn at 3000 miles.

Maybe we talking about different parts lol

Cheers

Lee

He's talking about the same pushrod. If there's no free play, when things get hot, your back brake will come on on its own.
Happened to me just after I got my S4R, on my way to Louigi for him to service it and have a look at the rear brake, and set fire to the caliper and rear hose before I got there.

No, you're talking about the same part...If the length of the pushrod that goes into the master cylinder is adjusted too much you might also not allow the fluid to return into the master cylinder and your brakes will start to pump themselves on getting tighter with each succesive prod. I've seen rear brakes that start rubbing enough to turn the disc blue and grind the pad right to the metal.

Snap Bunny

I have a calliper here that some guy paid no attention too here. It pumped it self up, wore the pads down, cocked the piston and let fluid all over the disk which then caught fire. Expensive.

Been checking my disc after riding and its just a tad warm and the bike rolls easy enough so the brake is not on, on its own.

When the brake is applied it backs off after it is realesed, still will keep an eye on it dont want flames!

Cheers

Lee