Brake master cylinder kits has any one fitted any
my lever comes right back to the bars and when i took the cover off the top up tank it squerts fluid into the tank just wondered if there was such a thing and if they work ?
I have fitted many kits to master cylinders but mostly cars. Kits are available through "bikebusiness" on line company. In general as long as the bore of the cylinder is not badly worn then it can be repaired. I dont want to state the obvious but I take it You have tried replacing brake fluid and re bleeding system also checking callipers are moving freely.
Neal, the only kit I will use is a O.E. one. Even then I'm never totally happy about fitting a repair kit to master cylinders, they are made of Aluminium & if more than just a few years old, the bore will have increased in size slightly.
Front brakes are termed a critical item on a bike mate !!!!
My advise, bottom line, fit a new master cylinder unless the reason for excess lever movement is found elsewhere !!!!
cheers guys must admit i was wondering if the bore may be a factor in the equasion .
pads are new braided lines and new fluid Wacko so i can only see it being around piston area
OH well ebay here i come again
If the master cyl is leaking you should still be able to get a 'lever' but it will receed to the bar slowly.
If you can't get a 'lever' then the prob could be else where like a sticking piston in the caliper or just an air lock.
Don't jump to conclusions and spend a load of money to find out it was something else.
Beware Ebay it could be worse than the one you've got allready. Seal kit and inspection or new cyl. I've had good results from resleveing in stainless and lasts very well!
Don't know if you have tryed but if you can get pistons fully extended then re compress this could expell any air back to the res mate had same prob on his bike and that cured it just air lock in system Watch for over flow onto paintwork have soapy water to hand
have fitted master cyl kits from m&p no problem, but unless you have high mileage above 60,000 it probably isn't that! as yamahama said check if pistons sticking, make sure properly bled, try rapidly pumping lever up to get pressure and tying back overnight and gently tap all system from bottom up to top to bring bubbles up [ like burping a baby] no comments please! What I had on ZZR calipers was wear on piston seal grooves so that when you got pressure up then released, pistons withdrew too far from discs so then lever came back to bar trying to get them back to disc face, that was around 55k and 10 winters of salt/cleaning out crap from seal ring grooves. I have not looked at what make bike you got, best of luck.
thanks harry, just clamped all the pistons right back and no improvement, hope its just an air lock, will try back bleeding them at weekend. Had same problem with a yam xs750 years ago turn out to be internel wall damage in a brake hose, you could see a bleb when you pulled the lever,so if the bleed dont work it be a close look at the hoses. triumph 900 trident sprint, done 50k.
Weirdoraptor In: Brough, E. Yorks
Posts: 2087
Karma:
Sometimes you can get an air lock at the banjo that goes to the master cylinder. It depends, if your handlebars are slightly "dropped" you probably have a high point (and a bubble trap) at that bolt. You may just have to crack that banjo bolt while back bleeding to get the air to move.
I had to do this today on my lad's thundercat and it made a big difference to the feel of the lever. Like you Neal, i'd fitted new pads, braided hoses and new fluid.
I've had similar problems with my ZZR 600 (in fact both of them!) and after cleaning the pistons, fitting new seals, fitting braided hoses, found I still had too much lever travel.
So... got a large syringe, and force-bled the brakes, actively sucking the fluid through the pipes (i.e. negative pressure at the caliper end from the syringe).
Surprising how much air you can get out of "bled" lines that way :-)
I use a syringe the opposite way Mr P and blow the fluid back up from the wheel cylinder to the master cylinder, works for me, i also use a banjo bolt with a bleed nipple in it on the brake lever
To all the advice given on this thread Many thanks
i have found the problem thought id say what it was
it did indeed turn out to be ( sticking brake pistons ) popped em out abit gave them a good clean and honestly i cant believe the diffrence it has made , suprised me too as i really didnt think it make lever travle further back so big thanks guys ive learned some thing new ! .
Oh and GT sorry i never got round to ringing you mate but if I bump into you i'll buy you pint or coffee bud
Caliper pistons is item 4 in my list of things to check Neal !!
You'll bump into me coz you'll take me to the pub when I hunt ya down.
Well done for sorrting it mate !!
Whealy, next time you strip and clean the pistons try putting some 'Castrol red rubber grease' on the seals. Its a castor oil based grease that doesn't react with the brake fluid, or cause problems with the caliper seals. Its hard to get hold of but, if you go on the Morris Minor clubs web site, you can get some on there. You don't need much just a smear but it works wonders. I struggled for months with a similar problem with my old Thundercats brakes when I did a complete rebuild. But just a few hours work and a dab of grease the problem was solved
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