125-200cc How to tell if brake master cylinder seal is a goner

Shed time today. Top end on 165 done, greased front brake pins, linkage, shock n swingarm. Went to grease rear brake pins n nuthin at the pedal! Havnt ridden the bike for 3-4 months. I've tried bleeding it normally n reverse but won't build pressure! Banjos look ok n hose too. I'm assuming the seal inside the master cylinder has crapped out? Sound feasible? Havnt had much to do with brakes how do I check?

Got clear fluid cumin out(no air) nipple wen cracked under pressure n fluid level in MC drops every bleed. ???

try prying the pads apart in the caliper to see if the piston has seized .

Roger that will try giv it a crack. Nah not suckin air wen bleedin via nipple(pedal down crack nipple then tighten again before releasing pedal). Took MC off n held it up high to make sure no air in line n pumped sum fluid reverse with a syringe. Pure fluid no bubbles. I'll report back after prying piston hopefully sumthn easy like that. Cheers boys

Pistons not seized. Pried em apart but not even any pressure to push them in at all

Take the master cyl apart and inspect the seals and you should find the problem if it has one. One thing you should check before you do that is make sure your brake pedal has some free play. If the master cyl piston doesn't travel all the way back to the stop it wont uncover the small hole that relieves the pressure and allows it to get a new charge of fluid to pressurize the brakes.

Yeh tried it with free play maxed in n out n in the middle Doug. How do these MCs cum apart? Never dun one before looks like a circlip in the bottom?

Youtube is your friend, padwan!! If ya done a front master cylinder, the rear is much easier!!


View: https://www.youtube.com/watch?v=WnBfkJiRCjU

That looks exactly like my bikes MC!

U did good OMG.
U did real good.

Is the above MC off the 09 ktm 530exc stil the standard rear MC? If not wat year did it run to? Tryin to figure out crossover as no listing for Italian husky

Watched vid n caught the part number 18-1028 so will check it out. Looks easy enough!

Check your seals on the mc piston and blocked orifices, no resistance at pedal indicates air in system would try sucking oil through from caliper bleed using a syringe to apply vacuum whilst pumping t the brake lever, make sure you put teflon around the thread of the bleed screw to seal it on the threads, dont appy too much suction and clear tube from bleed screw to syringe use g clamps to compress caliper.

I tried it all(vacuum, reverse, normal, pushin piston back) multiple times think the MC seal is shot so wanna confirm before ordering. 18-1028 is for berg 70 degree engines n other ktms up to 12 by the look of it

Mx store .com.au all balls rear rebuild kit $33 should be 13mm same as ktm upto 2009 or so.husqvarna same as early ktm.10850511 part number of master cylinder complete.

Italian Husky's and KTM pretty much shared the same Brembo components...that MC looks the same as l have on my 13 FE350!!

Yeh there's a coupla different versions that's all. Late 90s thru to mid 00s then another up to 12/13 then current models ktm/husky. My vast powers of deduction lead me to believe the middle one would be correct one, the early one for the bigger caliper(like on wr300) n the third one for latest gen ktm/husky. Im jus gonna order it-$22AU del from oem cycles in the US. $10 more here?!!

I'm sure Stefan from R&D would help ya...you'll get the proper Brembo kit?
No part numbers on your MC?

At work mate so can't check. Proper brembo kit cost a shite load I'd imagine. All balls kit cums with everythin including piston apparently. For $23 worth a shot!

Ok so jus whacked new MC kit thru n stil no go. Reverse bled, no air bubbles so must be piston seal. Puttin the MC kit thru was easy enough but I gotta buy sum reverse circlip pliers!

With free play adjusted I can see the piston pulse but it won't cum out

these 3 little notches r all I could find wrong with the piston seals in MC. Was really hopin it was my issue but seems not!