I've f%$#& had it with brakes

[J_C]

These farking bastiges. Yesterday I pulled the calipers, swapped out the piston seals (hadn't replaced them previously), put in new pads, put them on the bike. I was bleeding and started to build pressure. MC was feeling greater than it ever had, engaging quickly, slight bit of sponge.

I decided to bleed the MC to see if anything was trapped. I pumped up the brakes as hard as I could, cracked the banjo and PFFFFFFFT! out came a fine mist. I did it one more time and PFFFFFT!

Everything going great? Nope. No pressure. None. I can't build pressure worth a crap after bleeding at the MC.

I have no leaks. I continue to dump fluid through the system and out the calipers. I've removed the mc and tried pumping it vertically. I've removed the lever and pushed the piston manually with a screwdriver. I've removed the brake line from the mc and bled it using my thumb over the opening for the banjo bolt. I've tried leaving it with the lever pulled in overnight.

I've just about lost my friggin mind.


The ONLY thing I can think is that somehow the MC banjo bolt washers (which have some type of rubber inner gasket with the washer ring on the outside) have become compromised and are letting air in without allowing fluid out. Is this even possible?!?

[TheCafeKid]

These farking bastiges. Yesterday I pulled the calipers, swapped out the piston seals (hadn't replaced them previously), put in new pads, put them on the bike. I was bleeding and started to build pressure. MC was feeling greater than it ever had, engaging quickly, slight bit of sponge.

I decided to bleed the MC to see if anything was trapped. I pumped up the brakes as hard as I could, cracked the banjo and PFFFFFFFT! out came a fine mist. I did it one more time and PFFFFFT!

Everything going great? Nope. No pressure. None. I can't build pressure worth a crap after bleeding at the MC.

I have no leaks. I continue to dump fluid through the system and out the calipers. I've removed the mc and tried pumping it vertically. I've removed the lever and pushed the piston manually with a screwdriver. I've removed the brake line from the mc and bled it using my thumb over the opening for the banjo bolt. I've tried leaving it with the lever pulled in overnight.

I've just about lost my friggin mind.


The ONLY thing I can think is that somehow the MC banjo bolt washers (which have some type of rubber inner gasket with the washer ring on the outside) have become compromised and are letting air in without allowing fluid out. Is this even possible?!?

Deep breath. Teflon tape....give it a shot. It might be coming in thru the bleeders...Teflon tape...Go...

[J_C]

Breathes in attempt to achieve zen like state

Thanks TCK. If I remove the bleeders will I have a large mess on my hands? (I'm assuming yes.) I will try it.

In case that dosn't work, can anyone think of what may have happened to the MC banjo bolt?

[don_gibb6512]

It's a piston with an O-ring. Pull the piston, change the O-ring and try again. Try this MC bleeding method the next time: slap the lever against the grip several times fast with the cover off the MC. Wait a few seconds and then repeat. Do this a WHOLE BUNCH OF TIMES. It sucks but it works, eventually. Then go through the standard bleed process at the bleeder on the caliper and it should be ok. Anyone who doesn't hate bleeding brakes hasn't had a bad experience with it yet. Good luck. We feel for you.

And one more thing, change the washers at the banjo bolt. They might look ok but that's deceiving. Use new ones. You'd be surprised.

[Nessism]

Hey Jeff,

We had that same problem when we bled your brakes last time, remember? To get the air out we opened the bleeder on the right hand disc and pumped really quickly which forced the air down into the caliper and out. Was a real pain as I recall but we got it.

If you continue to have problems maybe we can hook up this weekend - I'm free.

Ed

[J_C]

Don, thanks for the input. It's a new (4 months) aftermarket MC, so the oring should be fine. If it comes to it I'll take it apart. As for the slapping method, funny enough I just found that today by accident. Glad to see it actually does work (and that my problem isn't totally unheard of)

Ed, I do remember (and it WAS a pain ). Perhaps I'm just not doing it quickly enough between cracking and pumping. I'm doing all this without an "assistant" (she's taking finals) so maybe I'll need to get creative. Will try again. Thank you. FYI, my caliper pin seemed greaseless again, so I went out, bought some, and greased the crap out of it.

[TheCafeKid]

Don, thanks for the input. It's a new (4 months) aftermarket MC, so the oring should be fine. If it comes to it I'll take it apart. As for the slapping method, funny enough I just found that today by accident. Glad to see it actually does work (and that my problem isn't totally unheard of)

Ed, I do remember (and it WAS a pain ). Perhaps I'm just not doing it quickly enough between cracking and pumping. I'm doing all this without an "assistant" (she's taking finals) so maybe I'll need to get creative. Will try again. Thank you. FYI, my caliper pin seemed greaseless again, so I went out, bought some, and greased the crap out of it.

Oi, go to AutoZone or the like and get ya one of them thar MityVac wannabes. 25 bucks and makes life SOOO much easier

[J_C]

Oi, go to AutoZone or the like and get ya one of them thar MityVac wannabes. 25 bucks and makes life SOOO much easier

Im extremely tempted. May head down if this doesnt work. Will try the above methods and get back to you all soon.

[J_C]

ok I tried the above. Stopped when I ran out of brake fluid (used .5L). Will need to head to autozone to get more.

I gotta tell you guys.... this is the third time I've had this brake system apart, and I've never seen anything like this...

I'm still getting tiny clouds of microscopic air bubbles, but no big bubbles or anything coming out. Moto shops are closed for the day I think, so no hope of trying new washers this evening. I was able to obtain some pressure in the system by tapping the brake lever very fast, just hard enough so it'd go a half inch of travel each tap. I have it tied off now... hopefully some of the bubbles will come up.

At this point I'm assuming there is air trapped in the system, or being allowed in the system. Unless anyone has any other ideas.

[J_C]

M/C is the culprit. It's having a problem. After re-bench bleeding, I got it to behave correctly, but it's still requiring a double pump for a firm feel. I'm thinking that, for whatever reason, the 14mm piston isn't pushing enough fluid. I'm swapping for the old 5/8" tomorrow to be sure. Thanks all for the help.

[TheCafeKid]

M/C is the culprit. It's having a problem. After re-bench bleeding, I got it to behave correctly, but it's still requiring a double pump for a firm feel. I'm thinking that, for whatever reason, the 14mm piston isn't pushing enough fluid. I'm swapping for the old 5/8" tomorrow to be sure. Thanks all for the help.

You have OEM brake lines? Mine is stock, and sometimes when hot requires a double pull to get really good feel on it. I attribute this to swelling of the old rubber lines. Will be swapping to stainless very soon.

[J_C]

tck, they are stock, but they're also new (2 years old, only 2000 miles use). I can visibly see them flex when I pull in. Stainless would be a great mod, and one I'd like to do, I just dont really have the money to spend

[TheCafeKid]

tck, they are stock, but they're also new (2 years old, only 2000 miles use). I can visibly see them flex when I pull in. Stainless would be a great mod, and one I'd like to do, I just dont really have the money to spend

Goodridge lines from Z1 arent that pricey. I think my REAR assemly cost me all of 25 bucks and that was for the line and all new banjos and bolts. In your case, I would ditch the splitter up front, and simply run two lines (one to each caliper) with a double length banjo bolt. Common mod here on the board. From what i HEAR, it makes bleeding MUCH simpler.

[salty_monk]

hehe - Jeff sounds like fun.... Between Ed & I we're sure to be able to sort you out. I can't believe many people on here have more brake parts in their garage than me at this moment in time

[J_C]

Goodridge lines from Z1 arent that pricey. I think my REAR assemly cost me all of 25 bucks and that was for the line and all new banjos and bolts. In your case, I would ditch the splitter up front, and simply run two lines (one to each caliper) with a double length banjo bolt. Common mod here on the board. From what i HEAR, it makes bleeding MUCH simpler.

I believe it, its a pain in the rear to make sure that splitter is air free. I'll price out the goodrich lines + hardware and post back. How does the routing work with the double lines?