Front brakes weak

[goldfish]

So I just noticed this starting to happen a few weeks ago, my brakes just got really weak. To the point where I was riding at my track at home and went into a corner the same way I always do but instead of stopping and making the corner I plowed through it and had to lock up the rear and slide the rear end around to avoid a fence.

I got new front brake pads and bled the lines. After that the brakes started off the same as before. However 2-3 hard brakes into corners it started getting better (could pull the lever in an inch or so and lock the tires up) but then after 10-12 times of hard braking they started softening up again.

By soft I mean I am pulling the lever in till it hits my fingers on the grip before I get any sort of stopping power..and even then to get anywhere close to the stopping power I had a month ago I have to lift fingers up and pull the lever all the way till it touches the grip. No matter how far the lever is pulled the tires will not lock up and I take WAY to long to stop.

Any ideas?

[mjc400ex]

Are your rotors worn out?
Or, maybe your lever is worn down and is not hitting the piston far enough in to get the correct amount of force.

[goldfish]

Originally posted by mjc400ex
Are your rotors worn out?
Or, maybe your lever is worn down and is not hitting the piston far enough in to get the correct amount of force.

How long do those take to wear out? The bike only has probably 60 hours on it at most.

[jaybee240]

do you have stainless braided lines??? Could always be a pin hole in the line. I know mine started doing that i thought that it was the master cylinder so I bought a new one bled them put new pads on and still the same thing so my next thing will be stainless braided lines

[goldfish]

Originally posted by jaybee240
do you have stainless braided lines??? Could always be a pin hole in the line. I know mine started doing that i thought that it was the master cylinder so I bought a new one bled them put new pads on and still the same thing so my next thing will be stainless braided lines

No I am still running everything stock. I am considering switching to the steel braided lines, or upgrading to YFZ450 or 450R front brake setups.

All three are comparable money wise so it's a tough call deciding which is my best bet to resolving the issue..

[Dirtjunkie85]

I had similar problems. I pulled the lever and it would just fade out. I rode forvever with pretty much no front brake. I thought it was the master cylinder and just never did the rebuild but i just broke my lever so i upgraded to an ASV and my front brake is working now so maybe it just wasnt pressin the pin in all the way... It won't quite lock up but i've got a whole heck of a lot more brakes than i used to have

[jaybee240]

If you get the yfz calipers figured out let me know cause I would like to run them myself also how do you like the back brake upgrade

[goldfish]

Originally posted by Dirtjunkie85
I had similar problems. I pulled the lever and it would just fade out. I rode forvever with pretty much no front brake. I thought it was the master cylinder and just never did the rebuild but i just broke my lever so i upgraded to an ASV and my front brake is working now so maybe it just wasnt pressin the pin in all the way... It won't quite lock up but i've got a whole heck of a lot more brakes than i used to have

But does that explain how after I installed the pads it was nice and tight, and stopped really good for 20 mins before fading out again?



Originally posted by jaybee240
If you get the yfz calipers figured out let me know cause I would like to run them myself also how do you like the back brake upgrade

I will definitely let you know about the YFZ calipers if I go that route. It's actually what I'm leaning more towards now because from what I've read they are a direct bolt up. I don't have any rear brake upgrades.

[jaybee240]

The YFZ or the Rs are a direct bolt up

[goldfish]

Originally posted by jaybee240
The YFZ or the Rs are a direct bolt up

From what I've gathered to do the R swap you need the spindles as well? Is this not true?

[Wheelie]

The R calipers require the use of 06-up spindles. Do a search under my name for a complete write up and information on the R front and rear brake swap.

[honda400ex2003]

450 brake swap info

front
06-up Spindles
450R calipers and Master Cylinder
450R brake hoses

http://www.exriders.com/vbb/showthread.php?s=&threadid=365496&highlight=450r+brakes


is what i have found and i think that may be quoted from wheelie at one time or another with a search from the past that i had done to find out what was needed. I have the info to do both fronts and backs saved for a later date as i plan to do them one day. steve

[CJM]

Probably have a pinhole leak in the lines. Course the master could be bad too and letting air in the seal.

The fact that it starts off fine and then goes to heck, to me means there is leak somewhere. If you keep pressing the brake lever over and over while moving does it firm a bit? If it does you have a leak usually, as oyur adding enough pressure by pumping it.

I went with braided steel lines, they stop the quad so much better :)

[00.400ex#55]

Go with ss lines and a yfz master cylinder. Your problem is likely just a worn out master. I wouldn't bother changing the calipers they work rather well.

[goldfish]

Originally posted by Wheelie
The R calipers require the use of 06-up spindles. Do a search under my name for a complete write up and information on the R front and rear brake swap.

Your write-up was actually where I got the idea and info to do the 450r swap!




Originally posted by CJM
Probably have a pinhole leak in the lines. Course the master could be bad too and letting air in the seal.

The fact that it starts off fine and then goes to heck, to me means there is leak somewhere. If you keep pressing the brake lever over and over while moving does it firm a bit? If it does you have a leak usually, as oyur adding enough pressure by pumping it.

I went with braided steel lines, they stop the quad so much better :)


Well it only "got better" right after doing the pads and bleeding the lines. It then slowly deteriorated back to not stopping well.

I guess I'm going to go ahead and order some SS lines today and see if that does the trick, I'll be sure to update the thread with results.

Thanks for everyone's input

[togup]

could be the diaphram in the bottom of the master cylinder or the brake line bulging due to broken reinforcing cords in the line kinda like what old air lines do.When the line bulges the hydraulic pressure drops which in turn translates to brake loss .

[TRXRacer1]

Brand new the stock lines SUCK. Always switch to SS lines before anything else.

[F-16Guy]

I had similar issues with spongy brakes until I installed my stainless lines. With new lines and a good bleeding, they are very firm and powerful. Try new lines before you go through the trouble and expense of a conversion.

[fearlessfred]

Originally posted by F-16Guy
I had similar issues with spongy brakes until I installed my stainless lines. With new lines and a good bleeding, they are very firm and powerful. Try new lines before you go through the trouble and expense of a conversion.

i agree.and if that does not fix it and u still need to rebuild the master cylinder ,in the end your braking will be better for having used the stainless lines

[goldfish]

I ordered SS lines and they are due in on monday. I might get a chance to install them one night this week, if not then next weekend. I'll be sure to post results after the install!

[CJM]

Good luck with it.

May want to invest in a vacuum brake bleeder. I replaced my lines and calipers this past summer and had a HELL of a time getting them to bleed all the air out, went thru half a bottle (large ones) of fluid before I said eff it and reused it (was brand new anyways at that point!).

[goldfish]

Well I got the SS lines installed saturday. The bike stopped on a dime, I could lock the fronts up no problem. I rode for about 15 mins, and by the end I couldn't lock the tires up anymore, the lever was getting soft. WTF?

I was really pissed off at this point so I just parked it and didn't bother with it until last night. Went out for a ride, brakes were strangely quite strong again. I only rode for 5-10 minutes because it was hot as hell but I'm still confused by this.

:confused: