Bleeding Magura Clara/Julie Discs

[digdug]

I'm having some difficulty with the bleeding process on Cannondale OE Magura Claras on my F700, mostly because the thread on the backside of the Clara calipers is not M6 but something else, that actually fits a ball pump needle. Does anyone know if this an M7 or M7.7 thread or something else like a NPT thread? I can't find anything anywhere about this thread being anything other than an M6, which includes the Clara/Julie manual from Magura. It's very wrong, and I'm very irritated.

I'm stumped, and now have half of my brakes without proper fluid. Any insight to my dilemma?



Doug


Photo for a quick preview...

 

[Bullpup]

The inside as shown is the static side of the calliper I.e. only the outside has the piston that moves. The inside is adjusted by an Allen key so the pad just doesn’t touch the disc. The outside needs a special magura adapter to bleed the brakes.

 

[digdug]

The picture isn't for reference, it wasn't really for any reason other than I liked the photo.

I understand how these calipers work, as I have taken them completely apart to figure out why the bleeders aren't working as the manual states. The issue as described is that the thread on the outside of the caliper inlet that the bleed fitting is supposed to thread into is NOT a M6 like every other Magura caliper ever made, it's more like a Schrader valve M7.7 x 0.794 pitch, which makes no sense—even worse, I can't find any fitting even remotely close to what all of the brake bleed kits come with to bleed these brakes.

I can't be the only person to experience this issue. What does anyone else do with a Magura Clara besides throw them away? I'm starting to look for other braking options circa 2001 at this point...

 

[digdug]

Soooo... not the answer I was looking for from Magura:

The proprietary bleed fitting for this age of brake is no longer available unfortunately; but by using just the tip of one of our medical grade syringes, you will be able to bleed the brake.

Really not thrilled about that, quite honestly. I know these are 20-year old brakes, but that leaves me pretty weak options for getting a proper bleed on these. I guess I will be forcing it and making a mess tonight.

 

[digdug]

For anyone searching this group sometime in the future, Magura not only doesn't have the fittings needed to bleed these brakes correctly, but they also don't have any idea what the fitting threads should be. It's VERY close to an M7.7 x .794 pitch thread, which is a Schrader air valve. Not much help as there are no male fittings like that anywhere to be found.

They also recommended just sticking a hose in the caliper and forcing brake fluid through that way. Easily the dumbest recommendation from a manufacturer for making their products work that I have encountered. Don't do it. It spills mineral oil all over the frame, caliper, rotor, wheel, tire, floor, down your arm and everywhere else.

A lot of 4, 6 and 12 letter words were spilled, too. I officially hate Magura Claras.

So yeah, my next project is to figure out what other brakes will fit around these OE 160mm 4-bolt rear rotors. Any recommendations? Hope Mini Monos seem to fit the bill as a direct bolt-on, but not very common here in the US. I'm open to ideas, I just don't want these Maguras on my bike anymore.

 

[Bullpup]

Have you got a photo of the actual callipers and bleed screws / port?

 

[digdug]

Yup, I did tear the rear caliper one more time last night after my most recent post, and something that didn't happen before is that the small set screw inside the piston position adjustment M5 was able to be completely removed, which wasn't possible before. It loosened with a 2mm Allen wrench, that would make it an M4 set screw—even smaller than the outside thread of the piston adjustment. So it looks like the fluid could be filled with either an M4 fitting or the Schrader-type thread with the piston moved all the way in past the bleed hole. Either way, not an easy answer at the moment.

I managed to get most of the air out of the line last night, and even after making a complete mess, it now has a better-than-it-was but less-than-ideal lever feel to it.

It's entirely possible that I'm an idiot and I'm missing something completely obvious. I'm not a "good enough" type of person, and this is bugging me. I'm open to ideas if anyone has any. At this point, the rear brake is functional and about 80% of what the front brake is, but still squishy. I'm sure there is still air in the system. I'd love to know how to get it bled properly.

Oh, and I'm convinced that after all of that mess last night that Magura Royal Blood is just blue unscented baby oil.

 

[digdug]

Quick idiot follow-up: I just found M4 x 4mm pressure fittings on Amazon for like $8 USD. I just ordered a handful, I'll report back once I have them. This might fix the issue... we'll see, but I'm optimistic.

 

[hamster]

I solved this in the past by taking a plastic syringe, running the tip through an M4 die and screwing the syringe directly into the caliper.

 

[digdug]

Now THAT is an awesome idea! Thanks!

I think I might even have an M4 die.