no brake pressure

[KX925]

  Okay i'm hoping someone can help me,I have a 1991 KX500 and i took it apart for the winter, i took the brake lines off and hung them up, now when i put them back on, i'm getting pressure in the rear but no pressure at all in the front, they worked fine when i took it apart, i've bled them about a million times even tried zip tying the lever overnight, nothing, i'm getting fluid to the caliper because when i open the bleed nut fluid comes out but the front brake will not build pressure, is it something easy i'm missing this is very frustrating. would it be the front caliper? the master cylinder? can someone PLEASE help me i'm begging you, it's nice enough to go riding and my poor beast is sitting in the garage, thank you in advance.

[maddoggy]

sounds like something dried out in the master. take it apart and look at the seals. i'll bet you find the problem. when you leave brake components disassembled for long periods of time orings and seals dry out and crack.

[Friar-Tuck]

KX 9,
 I think I would remove the caliper and push (collapse) the pistons in the caliper completely.  Remove the cap from the master cyl and see if you get any air bubbles.  I'm wondering if you have air in the brake cyl, and squeezing the lever is just compressing the air in the caliper and not pushing them against your rotor.
   The other thing this may accomplish is force any air out from the master.  
  Wrap some rags around the master when you remove the top, and be mindful if you squeeze the pistons in the caliper too hard/fast it will shoot up and out of the master.
   Tuck\o/  

[KX925]

ok thanks you guys i'll try both thank you again.

[Friar-Tuck]

 Good luck,
It is a pretty simple system so eliminating one part of the equation at a time should reveal the culprit.
  Mad Dog also brings up an excellent point about the seals drying up with no fluid in them.
  Tuck\o/

[KX925]

well i took the caliper and blew some air into it the pistons opened and closed so i put it back on the bike and same thing....nothing, so i'll take apart the master cylinder and see what happens....this is very frustrating.

[cbxracer30]

You need to check into a Mityvac brake bleeder or a similar product that push fluid back up through the system , they work great and save alot of headaches. Most auto parts stores have something similar , it attaches to the bleeder at the caliper and pumps fluid and air back up the lines. CBX

[DoldGuy]

KX925,

It sounds like you need to bleed the Master Cylinder first. Remove the brake line at the M/C (keep the line up to keep most of the fluid in) & with Many rags around remove the M/C cap, next cover  the hole where the banjo bolt goes with your finger & pump the lever a couple of times & hold in, remove your finger, continue to pull on the lever, hold lever & cover again with finger. After 5-6 times you will start to have "Feel" at the lever, re attach brake line & bleed ((I like using the Mity Vac).

Hope this helps & keep us posted!

DoldGuy

[Hillclimb#42]

The mighty vac is great. Everyone should own one.

[Roostmad1]

Okay i'm hoping someone can help me,I have a 1991 KX500 and i took it apart for the winter, i took the brake lines off and hung them up, now when i put them back on, i'm getting pressure in the rear but no pressure at all in the front, they worked fine when i took it apart, i've bled them about a million times even tried zip tying the lever overnight, nothing, i'm getting fluid to the caliper because when i open the bleed nut fluid comes out but the front brake will not build pressure, is it something easy i'm missing this is very frustrating. would it be the front caliper? the master cylinder? can someone PLEASE help me i'm begging you, it's nice enough to go riding and my poor beast is sitting in the garage, thank you in advance.

ive had the same problem with bleeding the KX and kdx front brake,what we ended up doing was losen of the front brake line where it bolts to the master cylinder and held a rag around it and bleed it from there first then tightened it back up and then the front brake bleed up no problem down as normal at the caliper,worked for us goodluck

[alward25]

Have you tried reverse bleeding the system? You might have in air bubble in the MC that does not want to work out.
Good luck

[riproost]

I had a problem bleeding after disassembly onthe front brake of my '90 K5. Tried several times with no luck so I got a master cyl. rebuild kit and still no luck. Then I removed the master cyl. and mounted it to a spare set of bars clamped to a bike stand and attached the front hose to the rear caliper and instantly got pressure.
Then I mounted the hose back on the front caliper and instantly got pressure...still using bike stand and hose somewhat horzontal.
Mounted the master cyl. back on the bike and done deal.
Wondering if the hose being horizontal heped?
Seemed to help.
Anybody?

RipRoost

[KX925]

I took my master cylinder apart and one of the seals feels a little softer than the other, so i'm going to try a rebuild kit. i'll keep everyone posted and thanks again for the ideas.

[KX925]

ok if anyone lives in the mid michigan area around lansing,st johns let me know, i bought a rebuild kit and still nothing this is pissing me off to no end, if you live close by let me know, maybe i can bring my bike by or you can come to my house, i'm at my wits end someone please help i would definitely appreciate it. thank you again.

[KX925]

well had someone look at it looks like it could be the caliper, they said the caliper is no good. i dont know