Brembo rear Master cylinder woes

[sfcpiet]

Yes those rear drums work fantastic on the rear but up front????????????

They just require proper linings and careful set up, then they're just as good as any of their contemporaries.

piet

 

[78jotadave]

I'm finally getting around to installing the master cylinder kit, and I have a question. The kit comes with a small packet of Brembo grease. Is this for use on the piston's O rings, or is it exclusively for metal-to-metal pivot points? Thanks

 

[TeddyG]

The Brembo grease for the O rings- when assembled, the pistons should glide back and forth when pressed. Make sure the interior of the caliper is clean- with the lines connected and pucks and old seals in place,
dunk the caliper in a pail of soapy dish soap and scrub the inside caliper w a toothbrush. Examine the exposed pistons for any rust or dirt build up that can cause them to hold up in the bores.

 

[Tippie]

The grease is for all the o-rings, including the square section piston ones. Do not fit old chromed steel pistons today, replace with the alloy coated ones as Piet mentioned. I always use a smidge of copper grease or similar on the bolts joining the caliper halves.

 

[nick7]

Ain't the modern ones Teflon coated?

 

[sfcpiet]

Coat all rubber bits with it upon assembly. It is not suitable as metal-metal lube.

Ain't the modern ones Teflon coated?

The modern stuff is anodised alloy, as opposed to the old chromed steel stuff.

piet

 

[nick7]

 

[sfcpiet]

Scratch one and find out.

piet

 

[78jotadave]

I'm going to vent...FUCK, this is a challenge. What should have been a simple master cylinder rebuild has become a journey of discovery and frustration. With the help of Forum members, the M/C was identified as a 12mm piece, thanks.
So I ordered the part and fitted it and to date, I was unable to build up pressure in the braking system even after trying every trick I know. I removed the M/C, disassembled it, and compared the new 12mm piston with the old one. Well what do you know they are both 12mm pistons (actual 12.7mm) but as can be seen in the photos they are of different lengths, why is that, did Brembo make different-length pistons? The pictures show that the working part of the piston is longer, the seals are spaced further apart, and the grooves too. It was suggested the M/C could be from a Laverda 500, do they also utilize a different piston length/kit?
If anyone has come across this, any help will be appreciated.

 

[The Sock]

Any chance you could carefully remove the seals from the new piston, fit them to the original and reassemble?

 

[Vince]

I had similar on my Pantah with homemade rear sets, I gave up after 3 days of also using all the tricks, back bleeding etc. Took it to the pros and they found an extra washer that didn't allow that tiny port to be exposed. Charged me $400 and forgot to tighten the cliper mount bolts. It fell off while riding home and thankfully didn't jam in the wheel.

 

[78jotadave]

Any chance you could carefully remove the seals from the new piston, fit them to the original and reassemble?

Great minds think alike, that was my next move, fingers crossed.

 

[1200ts]

I can't find any other bike but the Laverda 500 that used this master cylinder.

 

[ozijotati]

Ducati Pantah’s used the same master cylinder, probably just as rare as the Laverda item
Tom

 

[lavgert]

Stein-Dinse offers a replacement:

Laverda Fußbremszylinder PS 12, schräg, schwarz

Laverda Fußbremszylinder PS 12, schräg, schwarz

www.stein-dinse.com

Ciao, Gert