[greenreese]

Last week at Diablo my front brake had no power, so I bled it, cleaned the pads and rotor and still, no power. Once I got home, I installed new goodridge lines front and rear, also new pads and a new rotor in the front. Back brake is a Hayes Purple with the G1 caliper and it worked fine before the new hose and works even better now. Front brake is a Hayes Mag with the older square lever blade. Both these brakes are used, so I have no idea about their life.
First bleed on the front brake produced a spongy feel. Second, third, fourth and fifth... all produced the same results.
So I did some more research, talked to a few people, and went down today to try again. First I inspected the brake, no leeks, both pistons seem to move,no paint chipping or wetness near the pinhole on the back of the lever body,no nothing. I just bled it at least 6 more times. Still feels like garbage. I made sure to pump the lever, get all the air out of the bottlehose and bleedscrew first, did everything.
I might try ripping apart another Mag I have and switching the levers and then rebleeding it again. Depending on the results, it should tell me if the problem is in the MC or caliper. But that would take a while and the other brake works perfectly so I don't exactly want to go taking it all apart if I can avoid it.

Suggestions?

 

[greenreese]

And I know someone will say it(Brian), so go right ahead, but I don't want them.

 

[manwithgun]

Try swapping the master(lever) and re-bleed. Also, tapping the caliper, hose, and master (with bleed nut wrench) while bleeding will usually flush a few extra bubbles... A dramatic failure is most likely a seal rather than a bubble. good luck.

 

[Zutroy]

Also make sure that little adjustment screw isen't all the way in, I always back mine out all the way before i bleed the system.

 

[greenreese]

The adjustment screw shouldn't make any difference, it just spins.

I have done everything possible as far as tapping and shaking the line, and there is so many bleeds into it, I can't imagine there is still a bubble in there.
I need to shorten the line on my other brake anyway, so I guess I will just try that.

 

[SilentJ]

How crappy does it feel? Is it just a little soft or can you damn near get the lever to the bar?

I've had a similar problem with some Purple hayes. I bled one of them many times and they were still pretty soft.

Are you just pushing the fluid through from the caliper to the MC? I set my bleed up vertically like this:

catch bottle
|
|about 1.5 feet
|
MC
|
|however high this is
|
Caliper

It allows me to let the fluid flow back from the MC to the caliper which ALWAYS loosens up some more bubbles regardless of how good the I think I may have gotten the 1 way bleed. (I cant even remember exactly how Hayes suggests to do the bleed) Having the hose run up to the catch bottle puts a little pressure (about a whopping 1/2 psi) back onto the system which can make the disconnection procedure potentially messy, but I seem to get rock hard bleeds using this method whenever I use it.

Swapping MC's would be a good way to see what's fubar, but I hate disconnecting the hose from the little barb thingy. :mumble:

 

[dhtahoe]

The adjustment screw shouldn't make any difference, it just spins.

I have done everything possible as far as tapping and shaking the line, and there is so many bleeds into it, I can't imagine there is still a bubble in there.
I need to shorten the line on my other brake anyway, so I guess I will just try that.

But it does. Also try a bench bleed. Take the brake off put the caliper on the ground and the line strait up in the air with the lever blade aiming at the ceiling. Try a different bleed bottle. I think you can never squeeze stock bottle hard enough to get ALL the air out of a back brake. Swiched to a syringe and NEVER had that issue again. It was always the back too... same thing you explain here. Hate those damn bottles.

 

[TtotheJ]

I don't get why people hate tearing their brakes apart all the way, its not that hard and is the best way to ensure all the parts in the brake are in good shape. I haven't worked on the purples but the mags are simple and pretty easy. I did this on my front brake only to discover that the stock hose had a constriction in it, so definitely check all your hose and connectors along with all the internal seals and parts.

Also a hint for getting the G2 calipers apart: Hayes says to use a compressed air gun to get the pistons out of the calipers. I didn't have a air compressor but found that the brake line fits in my presta bike pump tightly and I could just connect the hose to one half of the caliper, plug the fluid port with my finger and use the pump to force the piston out. Just be careful cause when that piston comes out it shoots like a bullit, do it some place where there's no glass you can break.

 

[buildyourown]

Start with the caliper, as these are easier to rip apart than the levers. Pull the pads, and squeeze the lever. The slave cylinders should drop out. You'll be surprised how much debris can be trapped in there. I clean everything with brake-cleen and re-assemble using brake fluid as lube. Also, be sure to remove and clean the hose fitting and bleed fittings from the caliper.

 

[Jm_]

Well, I have a phantom hayes problem too. My rear brake has gone to "nothing" a few times now. I've re-hosed it twice, and rebled it about 3 times. Each time it slowly fails and I can never find any leaking fluid. Fluid is leaking out SOMEWHERE, but it's not obvious. It doesn't appear to be around the caliper, there's no wetness and nothing ever gets on the pads or rotors on this one. It's not leaking at the hose interfaces, at least it doesn't appear to be. It may be micro-leaking somewhere in the master cylinder, but even that is speculation. I don't want to install a new master cylinder just to find out that it's not the problem. Very frustrating when you can't track these things down.

So I did what brian hcm1 always does, I bought hopes.

 

[Brian HCM#1]

So I did what brian hcm1 always does, I bought hopes.

And a wise choice at that, now to get you to buy an Avy DHS

 

[Brian HCM#1]

And I know someone will say it(Brian), so go right ahead, but I don't want them.

You know you do, admitting you want Hopes is the first step

 

[greenreese]

I installed the lever from my other brake, and put three or four bleeds into it. Checked the whole system again and cleaned it all up. It has a slight bit more power, with amazing modulation and yet, still feels like total crap. Still not nearly enough power and the feel is still soft, but the modulation is kind of neat... huh. So it has to be the caliper. I did notice that the pistons are a little kooky. Time to pop the caliper apart and have a look.

And yes, it is fun too shoot the pistons.

edit- oh yeah, I did get tired of that little bottle, so I took a stans cap and stuck it on a huge rubbing alcohol bottle.

 

[teamkranzelbike]

possibly bad o ring in the m/c. causing it to bypas the valving and not sending the fluid down the hose.I took a good fall and my brake was fine until i fearhered it and it would come all the way in, took it off, held my finger over the cartrige fitting pulled it real slow and it came right in no fluid shot out. put in a new cartrige and everything was back to normal. took the cartrige apart and there was a tore o ring. replaced the innerds and it fixed it. keeping it as a back up.

 

[JRogers]

Well, you seem to be well on your way to solving this problem. The only advice I have has already been offered but it's important: use a syringe. I have a good amount of experience bleeding and working on Hayes and that's the best way to get a consistent, full bleed. The Hayes people (given their kit and instructions) must not like this, but it's the best way.

 

[phlegm]

I'm just stabbing in the dark here, but your pads might be contaminated in spite of what you've said. try popping them in the oven @ 450f+ for 30 min.

 

[greenreese]

I'm just stabbing in the dark here, but your pads might be contaminated in spite of what you've said. try popping them in the oven @ 450f+ for 30 min.

No, it isn't the pads, I have tried two pairs with the same results. I picked up a new transfer port seal, two new pistons and seals, and also new lever pivot bushings. I am going to stop and grab yet another bottle of brake fluid, split the caliper in two and go at it again.

I have a syringe too, so I will test a few bleeding methods to see what works best.

The good thing about having the elusive problem is that I have learned so much in the process. Although I do get annoyed with all the bubbles in my soda.

 

[dhmtbj]

No, it isn't the pads, I have tried two pairs with the same results. I picked up a new transfer port seal, two new pistons and seals, and also new lever pivot bushings. I am going to stop and grab yet another bottle of brake fluid, split the caliper in two and go at it again.

I have a syringe too, so I will test a few bleeding methods to see what works best.

The good thing about having the elusive problem is that I have learned so much in the process. Although I do get annoyed with all the bubbles in my soda.

I think I've been having same problem with the mags on my imperial...feels ok but no power at all...had ricky rebleed and got new pads but it still hasno power...quite weird...

 

[greenreese]

I think I've been having same problem with the mags on my imperial...feels ok but no power at all...had ricky rebleed and got new pads but it still hasno power...quite weird...

Have a look at your pistons, do they seem crooked or really far out from the caliper halfs? Mine seem to seat awkward and not want to stay in when I reset them. I am hoping this is the problem and I should be able to find out once I have some time to get back to the bike.

 

[Brian HCM#1]

This will fix ALL Hayes problems.............

 

[greenreese]

This will fix ALL Hayes problems.............

Haven't you seen that Death Star picture.....

 

[Jm_]

This will fix ALL Hayes problems.............

He's right. Trust your feelings, you know it to be true.

 

[Cooter Brown]

I just bled my Mags last nite, I don't use a bottle though, get a big syringe from an agriculture supply/vet store and push the new fluid thru the system that way. It's always worked well for me