rear brake problem

hi, i have a problem with my back brake on my gen 2 , i have fitted some rear sets by sato racing along with a master cylinder from a ktm ( same as rsv4 ) .

when they were all fitted a couple of months ago after a bit of a ,mare getting it all bled satisfactorily ( plenty of pedal pressure etc ) , all seemed well with the world apart from **** weather so a road test was outta the question . did 80 odd miles the other week end and the back brake is crap if you stomp hard on the brake pedal it just keeps going plenty of resistance but not solid like it should be , brake efficiency is piss poor too

do you chaps out there think there is still air in the system or has the internal seal in the m/cyl given up the ghost and has an internal leak .had this problem on an old mini my missus had yrs ago , that turned out to be an internal leak under pressure

seal kits for brembo gear seems very had to get hold of unlike stuff for old mini,s HELP ME PLEASE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:banghead:banghead:banghead

i would bank on air trapped in the caliper mate :yes take the caliper off and bleed it upside down then refit and bleed again :thumbup

Mate, these brakes are a ******* to bleed, and everything you've posted indicates a bit more air left in the system. just like Brooksy has said.
When you have 10 mins to spare, give Griff a call, and buy another bleed nipple that will fit on the master cylinder...the highest point in the system.
All the pesky air finds it's way up there, and once you've installed it makes bleeding a piece of piss.

Here's a pic of mine fella...good luck



Oh yeah....don't forget to let us know how you get on :thumbup

Had the same problem on ma orange (it's got the same setup with the m/c in the vertical position).

I sooked and blew the system from the caliper end,,,,,all to no avail.

Eventually got it sorted by cracking open the banjo connection to the top of the m/c as shown in Tifas pic.

Looking at the pic I reckon that a bleed nipple in that position would be a definite plus and more than likely fix the problem for good.

I concur with the others,...sounds like some air trapped in the somewhere.
Dont know what you are using to bleed the system,but the best tool I have is a simple 50ml syringe with a short length of rubber pipe.I fill it with brake fluid and then gently pump the fluid backwards from the caliper up to the master cyl reservoir.Works every time for me.

cheers guys for responses.

i tried the reverse bleed method , still no change . i was on the verge of buying a vacuum bleed tool , but decided to re fit the original equipment master cyl and remote res and re bleed . hey presto fully working rear brake . one happy bunny !!!

so now i have a "for spares only " rsv4 / ktm rear master cyl with knackered seals .

just got to find a satisfactory place for the reservoir !!

Happy days.