2004 400ex rear brakes

[az300]

I melted of my rear brake line last week riding my 2004 400ex. I put on the new brakeline and the rear brakes still aren't working when I press the brake. What do I still need to do?

[REDRIDDER]

did you bleed the brake line system?

[JOEX]

Just wondering... how did you melt the brake line?

[az300]

How do you bleed the brakeline?

I melted the brakeline on my new pipe didn't realize the breakline was so close to the exhaust. I went to the dealer and got a line for 05' 400ex becuase it is metal the first few inches which is under the pipe.

[JOEX]

Originally posted by az300
How do you bleed the brakeline?

1. Remove the reservoir cover
2. Add fluid to the fill line if needed
3. Press brake lever & hold
4. Loosen & retighten bleeder valve on the caliper
5. Release brake lever

Repeat steps 2-5 until you get firm pressure.
Top off reservoir & replace cap.

[REDRIDDER]

Get your buddy and have one of you pump the foot pedal until pressure builds up (it may not depending on the severity of air in the line) and the other at the rear brake caliper, their is a bleeder on it.It will have a rubber nipple on it take it off and once you have pumped the foot pedal a few times hold the pedal down while you use a box end wrench to open the bleeder a little.A little air will come out followed by brake fluid repeat this process until you get a straight stream of brake fluid.Also be sure to always have fluid in the reservoir.

[az300]

Thanks for all your help, I'll get right on this so I wont be riding the trails with just front brakes again out of control.

[REDRIDDER]

no problem that's why were here.

[az300]

So I did like you guys said and kept bleeding the line until the nipple at the bottom only had a steady stream(5-6 cycles). I pushed down the brake and the pads still wont move. I took the caliper off of the disk brake to see if the break pads were moving and they aren't. I took the pads out of the caliper and I had to hit the pin with a rubber mallet to get it to move. How do I know if possible my caliper is bad.

[MO-EX-RIDER]

are you pads shot? and if you remove your pads you can see the caliper piston move outward when the pedal is pressed..if it doesnt move then there is a problem :eek2: :eek2:

[az300]

My pedal still bottoms out and caliper piston doesn't move out.

[JOEX]

Originally posted by az300
My pedal still bottoms out and caliper piston doesn't move out.
May need to rebuild the master cylinder.

[az300]

How do I tell if it is the master cylinder that is bad or the caliper. Is it easy to rebuild or better to just buy new.

[JOEX]

Originally posted by az300
How do I tell if it is the master cylinder that is bad or the caliper. Is it easy to rebuild or better to just buy new.
Mine had similar symtoms and after rebuilding the master cylinder it worked great. But it would probably be a good idea to do both since the fluid may have gotten hot enough to damage the seals at both ends.

They are both fairly easy to rebuild and much cheaper. Get a repair manual if you don't have one already;)

[az300]

could you walk me through the process of the rebuild and what I will need.

[az300]

I was missing one of the lower bolts to the master cylinder so when I was riding it slipped back making me think the master cylinder was bad. So I put the bolt back in after bleeding the bikes went out for a ride and the brakes worked like brand new. Went to ride two days later and the rear brake pedal went all the way down with no response. Checked all over can't find a leak, rebuilt master cylinder holds for a day or two. Can you rebuild the caliper or do I need to breakdown and get a new one?

[JOEX]

Originally posted by az300
I was missing one of the lower bolts to the master cylinder so when I was riding it slipped back making me think the master cylinder was bad. So I put the bolt back in after bleeding the bikes went out for a ride and the brakes worked like brand new. Went to ride two days later and the rear brake pedal went all the way down with no response. Checked all over can't find a leak, rebuilt master cylinder holds for a day or two. Can you rebuild the caliper or do I need to breakdown and get a new one?
The caliper can be rebuilt as long as the bore isn't worn or damaged. The kit consists of two seals (o-rings basically) that go in the caliper. The o-ring that goes on parking brake side isn't included in the kit but it can be found at an auto parts store.

[az300]

I was looking at the caliper trying to take it apart and the allen nut seems to be siezed (feels like I will brake it off) if I get it apart, the rebuild kit will only be two o-rings. If so I could probably get all pieces at auto parts store?

[JOEX]

Originally posted by az300
I was looking at the caliper trying to take it apart and the allen nut seems to be siezed (feels like I will brake it off) if I get it apart, the rebuild kit will only be two o-rings. If so I could probably get all pieces at auto parts store?
Sorry, didn't mean to imply they were o-rings, they just resemble them.

I suppose it's possible to find them at a parts store but I have my doubts. The seals have a square profile rather than a round profile like o-rings. If you cut them and look at the end you would see something like this [] instead of this O.

[choco]

Originally posted by az300
I was looking at the caliper trying to take it apart and the allen nut seems to be siezed (feels like I will brake it off) if I get it apart, the rebuild kit will only be two o-rings. If so I could probably get all pieces at auto parts store?

I have an 06, that allen nut is hard as helk on mine, I try with all my might and it just dont budge.

[az300]

I'm having the same problem, kinda gave up and just riding with front brakes, makes it interesting when you ride trails in 4th and 5th gear though.

[prnstr4life]

i got a similar concern, no air in line, fresh fluid, good pads, ebrake blockoff, and no pressure

pedal bottoms out

wish i knew what to do

[choco]

Prnstr4life you and me havin same prob brotha, im gonna keep working at it till I figure it out, and be back to update ya'll.

[prnstr4life]

i am going to clal honda tomorrow about seals for caliper and master cylinder...i think its the caliper since it all happened when i put pads on it and did the parking brake block off

[JOEX]

I just came up with a theory... but it could very well be wrong...

If you needed to push the caliper piston back with a c-clamp to get new pads to fit i'm wondering if doing that forced brake fluid past the seals in the master cylinder. I would also suppose leaving the reservoir cap on while using the c-clamp caused or worsened the seal failure.

Any thoughts?

[choco]

well the cord that connects to the caliper which the fluid passes through, I disconnected and got oil everywhere, thani pushed the clamp back manually. Does that decline your theory or still keeps it into play. All the oil came out that was in it. Than I pushed the piston out, so i could get the pads in. The piston was a bit stubborn but didnt require a clamp of any kind.

[choco]

Originally posted by prnstr4life
i am going to clal honda tomorrow about seals for caliper and master cylinder...i think its the caliper since it all happened when i put pads on it and did the parking brake block off

Forward the info to hear if you find any of it helpful, thx.

[choco]

S.O.S.

[JOEX]

Originally posted by choco
well the cord that connects to the caliper which the fluid passes through, I disconnected and got oil everywhere, thani pushed the clamp back manually. Does that decline your theory or still keeps it into play. All the oil came out that was in it. Than I pushed the piston out, so i could get the pads in. The piston was a bit stubborn but didnt require a clamp of any kind.
If you pushed the piston back with the brakeline disconnected means my theory doesn't apply but it doesn't disprove it.

Have the pins the pads slide on been cleaned?

[choco]

Yea there clean have rust on them, should i take teh pads out that press on the pedal and see if the piston moves?

How do i rebuild the cylinder? push it out all the way and replace teh insides?

[prnstr4life]

they have the master cylinder kit for $40 and the caliper one is $10. they dont have the caliper seals in stock right now though. we dont really have any other honda dealers close enough. i dont think i have ever had to force it it got a good squeeze with big channel locks. when i messed with the adjustmetn on the master cylinder i got a little less travel with the pedal but didnt get to test drive it since it was still strapped to the trailer

[JOEX]

Originally posted by choco
Yea there clean have rust on them, should i take teh pads out that press on the pedal and see if the piston moves?

How do i rebuild the cylinder? push it out all the way and replace teh insides?
You should be able to tell if the piston is moving without removing the caliper, it may take two people unless your arms a real long or have some ingenuity;)

A repair manual will be a great help for rebuilding. Remove the unit, take it apart & install new parts. It's not hard if you pay attention to the sequence of parts, the only trouble I had was getting the rubber boot folded correctly:p

[choco]

Originally posted by JOEX
You should be able to tell if the piston is moving without removing the caliper, it may take two people unless your arms a real long or have some ingenuity;)

A repair manual will be a great help for rebuilding. Remove the unit, take it apart & install new parts. It's not hard if you pay attention to the sequence of parts, the only trouble I had was getting the rubber boot folded correctly:p

Lol by ingenuity do you mean looking at the piston and using my moms golf club to pump the pedal?

Yea it's not budging, theres a hole inside the cylinder(behind the piston) where the intake brake fluid comes in, I tried bleeding it through there by covering the hole with my finger/thumb, than pumping a few times, tried it atleast 6 times. It's not getting very much fluid through. The Baja bolt that's connected to the caliper it bleeds okay. So Do you think isolated the problem? The fluid gets to the baja bolt on the caliper but doesnt get in the cylinder(behind the piston) to push it out.


Fyi I always keep the fluid above lower and everything bleeds fine except in behind the piston.

[JOEX]

Originally posted by choco
Lol by ingenuity do you mean looking at the piston and using my moms golf club to pump the pedal?

Yea it's not budging, theres a hole inside the cylinder(behind the piston) where the intake brake fluid comes in, I tried bleeding it through there by covering the hole with my finger/thumb, than pumping a few times, tried it atleast 6 times. It's not getting very much fluid through. The Baja bolt that's connected to the caliper it bleeds okay. So Do you think isolated the problem? The fluid gets to the baja bolt on the caliper but doesnt get in the cylinder(behind the piston) to push it out.


Fyi I always keep the fluid above lower and everything bleeds fine except in behind the piston.
LOL @ golf club:p

I've never bled individual parts of the brake system so I don't know about isolating the problem. I've done the whole system a few times with no problems.

Your sig says it's an '06 so i'm leaning towards something wasn't done correctly rather than a mechanical failure unless you ride in some fairly extream conditions...

[choco]

They where working before just a bit chunky i figured because there was barely any of the pads left. Well Ill probaley take it in monday and hopefully get it ack before august long weekend.