Poor stoping power ...

[Toxxin]

Hey hi there !
Im new on this forum and i just got a 2003 400ex
but the front brake giving me headache
i read all the brake thread to resolve my problem but no luck



Here what ive done so far

brand new pad
freshly rebuild master cilynder
100% bubble free brake line
nothing wrong with the oem brake line no leak or anything
no leak from the caliper piston
cleaned and lubed slider pin in caliper
rotor seem ok..

but im still able to pull the lever to the grip: /

what now ??

[CJM]

I found I had the same issue where you could pull the lever to the grip with ease after I put on new calipers and replaced with stainless lines.

I had to take my brake vac and work for about an hour continually bleeding fluid out of each side, then I left the cap off the master for awhile and it was good. I literally went thru a bottle of brake fluid.

[guenther]

I ended up pumping the lever to get it built up firm and strapping it to the grip as tight as possible with the cover off the reservoir. Do this about 5 or 6 times continually over the course of a couple days and this might do the trick. It will help the bubbles work out slowly. I know you said you have no bubbles at all but that's what I though too. I bled and bled and bled and bled......... and went through 2 bottles of fluid. After using this method my brakes work great. When I first grab the lever hard, it will stop quickly but not send me over the bars. If I pump it quickly again, I will go flying. I'm very happy with where they are right now.

[Toxxin]

i did try straping the lever to the grip 3 time over 2 night
i tried the reverse bleeding, pushing fluid from the bleeder to the master cilynder

the only thing i did not try is a vaccum bleeder...
i started reclycling my fluid after the 3rd bottle

:confused:

i will try to ziptie the lever to the grip again tonight

[guenther]

You might want to try the vacuum bleeder or pop for steel braided lines. The oem lines bulging is the only thing I can think of if everything was replaced with new parts or rebuilt correctly. Maybe someone smarter than me with brakes has something to add.

[CJM]

Originally posted by guenther
You might want to try the vacuum bleeder or pop for steel braided lines. The oem lines bulging is the only thing I can think of if everything was replaced with new parts or rebuilt correctly. Maybe someone smarter than me with brakes has something to add.

I would agree, I found that no matter what after replacing the calipers that I kept getting mushy lever.

Sprung for the stainless lines and better but not great. The vacuum bleeder was the only thing that worked and like i said took a long time.

The main issue is you dont have enough fluid to pump to get the air out to easy. the reservoir holds maybe a shotglass worth of fluid and that isnt enough to force the air out imho like a cars master cylinder which is probably 10x the size would.

[Toxxin]

well i will try to borrow a vac bleeder somewhere then if it fail im gonna try some braided lines from Rocky Mountain the Tusk one
any feedback on the tusk brake lines ?
they are the only lines i found for the 400ex that dont cost an ''arm'' to ship (Canada)

Or can i piece a custom kit together with russell fitting and line ??
i can get russell for almost nothing what size banjo bolt 400ex use ??

[CJM]

Im not sure what size banjo it is, probably m12 or m10 thread on 1.0 or 1.5 thread pitch.

My kit I got on ebay for 50 bucks or so had the double banjo bolt which eliminates the stupid split on the frame. Think they are american star.

[TRXRacer1]

I think I paid $100 off ebay when I did mine but those stock lines suck and need to go if you want good performance.

[Toxxin]

i tried my friend 2005 450r and his braking power is awsome even on stock rubber line i cant get the lever anywhere near the grip ... i know the caliper are different but oem line stay the same no?

[TRXRacer1]

Originally posted by Toxxin
i tried my friend 2005 450r and his braking power is awsome even on stock rubber line i cant get the lever anywhere near the grip ... i know the caliper are different but oem line stay the same no? Nope, not all rubber lines are made equally. You have air or something going on too but even if you waste your time working it out you'll still have crappy 400ex lines that bulge. Night and day difference from stock to SS.

[06typeS]

Did you pull apart you calipers and clean the pistons and check the seals?


If the seals are starting to go the brakes will never get firm