[danK]

I replaced my front caliper's piston. Ordered the kit from Balle Racing (great service, price, everything!)
http://www.balleracing.com/Hayes_Caliper_Piston.htm
Everything went in perfectly.

I replaced my front and rear pads at the same time. Now here's the problem:

Even after bleeding the front, there is no power. Lever goes to the grip almost all the way. Yesterday with worn out pads I had better modulation and feel.

So I have rebled 3 times tonight (I've been bleeding this Hayes setup for the past year so I know how to do it), and the front is crap. The rear is good. I even went out to burn the pads. Still crappy front.

Is there something wrong with the part where the hose hooks back on to the front caliper?
There is no air coming out of the hose when I bleed it but it feels as if there is a big air bubble.

So, anyone know what's up with my front brake since replacing the piston?
Thanks!

 

[Dougal]

How's the bleed nipple looking?

I had trouble bleeding a mates HFX-9's, turned out to be sucking air around the nipple. A little teflon thread tape cured it nicely.

I've also heard of MC wearing out over time. It's not something I'd normally associate with changing the pads though.

 

[VT no 1 2 or 3]

Rebleed again- there is air in there and it does not have to be very much. I once had to bleed a system four times to get the air out- I had to use all the tricks to get it right- Taping the bleed screw, Tapping the caliper to dislodge any air inside, Changing the orientation of the caliper and lever several times to get to that little trapped bubble.. Other tip- don't just push the fluid through, let the bleed bottle suck a little fluid out and some air bubbles will come with it.

 

[danK]

Rebleed again- there is air in there and it does not have to be very much. I once had to bleed a system four times to get the air out- I had to use all the tricks to get it right- Taping the bleed screw, Tapping the caliper to dislodge any air inside, Changing the orientation of the caliper and lever several times to get to that little trapped bubble.. Other tip- don't just push the fluid through, let the bleed bottle suck a little fluid out and some air bubbles will come with it.

The tips are great! I will attack the bleeding again with these notes in mind.
Thanks!

 

[uofabill]

A couple more tips,

The tips are great! I will attack the bleeding again with these notes in mind.
Thanks!

Flick or pump the lever towards the end of the bleed process.
I like a large syringe better than the plastic bottle to push fluid through the system. You can get one where vet supplies are sold or maybe a drug store. Mine holds 35 cc I think, they're cheap, less than $1 if I remember right. It will give you much better control and more power. You can suck fluid back much easier.
The Hayes instructions say to pump some fluid into the system and stop and count to five. That seems to help. Seems to me that going slow with the whole process works the best.
I like to suck fluid back out of the caliper at the start rather than in the middle or end of the process.
Tap both caliper and the lever/master cylinder.
I agree, sounds like there is still air in there somewhere.
Good luck.

 

[Wombat]

I replaced my front caliper's piston. Ordered the kit from Balle Racing (great service, price, everything!)
http://www.balleracing.com/Hayes_Caliper_Piston.htm
Everything went in perfectly.
Thanks!

You might be having trouble getting the air out of the master cylinder. Something I use to do on cars was "bleed" the mc before connecting the lines to the wheel cylinders. This was done by simply pushing the mc's piston in and keeping it there while the lines were connected. This should be straightforward for a bike by just holding the lever down (with the reseviour full of fluid). If you have the brake hose full of fluid when you connect it, it might also simplify the process for you.

Good luck

Wombat

 

[danK]

I stayed up for hours bleeding and re-bleeding the front. Still bad. Just to "make sure" I remembered how to bleed a brake, I did the rear and it's perfect. The front just won't do anything ever since I replaced the piston and o-ring. There has to be a leak somewhere, and I think it started when I took the caliper off the hose and replaced the parts.

Anyone want to tell me not to use gasket seal on the surface of the two caliper halves? I'm taking it all apart and starting over, and I'm hoping making an almost-microscopic gasket will take care of any leaks down in the caliper.

 

[jamisxtrspeeder]

I stayed up for hours bleeding and re-bleeding the front. Still bad. Just to "make sure" I remembered how to bleed a brake, I did the rear and it's perfect. The front just won't do anything ever since I replaced the piston and o-ring. There has to be a leak somewhere, and I think it started when I took the caliper off the hose and replaced the parts.

Anyone want to tell me not to use gasket seal on the surface of the two caliper halves? I'm taking it all apart and starting over, and I'm hoping making an almost-microscopic gasket will take care of any leaks down in the caliper.

I currently run the G1 calipers and every so often i change the fluid so a little trick i have come up with works for me.
Put the bike upside down overnight,this way any air in the system will go into the caliper.The next day,turn the bike back over and hook up a bleeding bottle and open the nipple and then pull the brake lever a little.The air in the caliper will go into the bottle but you have to hold the bottle upside down so the bubbles go all the way to the top.Then take out the bleeding screw in the lever and push the new fluid back into the caliper until full.close the nipple on the caliper and squeeze the lever a few times to make sure it worked.

 

[danK]

I currently run the G1 calipers and every so often i change the fluid so a little trick i have come up with works for me.
Put the bike upside down overnight,this way any air in the system will go into the caliper.The next day,turn the bike back over and hook up a bleeding bottle and open the nipple and then pull the brake lever a little.The air in the caliper will go into the bottle but you have to hold the bottle upside down so the bubbles go all the way to the top.Then take out the bleeding screw in the lever and push the new fluid back into the caliper until full.close the nipple on the caliper and squeeze the lever a few times to make sure it worked.

Thanks for the tip. One question:
Do I close the nipple AND then put the bleed screw back in before pulling the lever a few times to make sure it worked?
Sorry if this is obvious and I"m not getting it; was up all night bleeding brakes. Ugh.

 

[jamisxtrspeeder]

Thanks for the tip. One question:
Do I close the nipple AND then put the bleed screw back in before pulling the lever a few times to make sure it worked?
Sorry if this is obvious and I"m not getting it; was up all night bleeding brakes. Ugh.

Yeah,just close the nipple on the caliper before you squeeze the lever,you don't have to put the screw back in the lever and you shouldn't because when you squeeze the lever the fluid level in the master cyclinder will drop a little and you will have to add some more fluid to top it off.there shouldn't be any fluid coming out of the screw hole on the lever,but that little hose and adaptor will keep things clean if it does.good luck man,i have had issues like this before but luckily i manage a shop and have a lot of resources.

 

[Dougal]

I stayed up for hours bleeding and re-bleeding the front. Still bad. Just to "make sure" I remembered how to bleed a brake, I did the rear and it's perfect. The front just won't do anything ever since I replaced the piston and o-ring. There has to be a leak somewhere, and I think it started when I took the caliper off the hose and replaced the parts.

Anyone want to tell me not to use gasket seal on the surface of the two caliper halves? I'm taking it all apart and starting over, and I'm hoping making an almost-microscopic gasket will take care of any leaks down in the caliper.

I'd certainly want to split the caliper again and check the transfer port O-ring. Gasket seal may work well. I'd rather have the oring doing it's job properly though. Hayes run up to 2000psi line pressure and if the fluid can leak into a bigger area between the halves then you've got a lot more force pushing them apart than usual.

 

[danK]

I'd certainly want to split the caliper again and check the transfer port O-ring. Gasket seal may work well. I'd rather have the oring doing it's job properly though. Hayes run up to 2000psi line pressure and if the fluid can leak into a bigger area between the halves then you've got a lot more force pushing them apart than usual.

I split the caliper and cleaned everything again. The o ring is perfect. I rebled both ends, again, and the rear is incredibly perfect, and the front is now about so-so. I have tried everything. The bike is upside down for the night so we'll go for round 17 tomorrow.

I am so close to getting Avid Juicys (like they're perfect, 'eh).