Hot Break Master

[guest1406]

Hi all,

For my project ive attempted to clean the bars up as much as possible, to do so i have acquired a remote master cylinder.

The best place I can think of to place it would be on the frame under the tank. However I am worried that the brake fluid may get hot from the engine. I did think to paint it heat protective paint or BBQ paint, would this be effective enough? Or any other suggestions?

Thanks all,

Mackenzie

[themoudie]

Aye Mackenzie,
I would share your concerns at heating brake fluid unecessarily. Would it fit behind the head light or in this sort of area, in the draft, but tucked out of harms way?

My regards, Bill.

[johnr]

every aircooled bmw boxer built between abut 1971 and 1982 had a cable operated hydraulic master cylinder on the frame under the petrol tank and they never seemed to take any harm. im amazed that you should worry about the half cupful of flamable brake fluid near your hot engine yet seem unconcerned about the steel tank containing 4 gallons of petrol sat on top of it,,,,,, i think it could be pretty safely left to its own devices,,,,

[Steve H]

Where was the remote reservoir originally mounted. Brake fluid has to withstand high temperatures in calipers so heat from the engine should not be an issue. My only concern would be differential expansion rates between the body and the plunger, causing it to seize if too hot. It might makes sense to put a heat shield below it. Painting it black will make it soak up more heat.

[beeman]

BMWs did have their front master cylinder tucked under the tank. However both cylinders were sticking out the side so heat wasn't an issue.

[johnr]

youre kidding arent you. bmw engines get stinking hot regardless of the pots sticking out the sides. the crank cases are too hot to touch in normal use. the bm ones were sat on top of the frame tube under the front of the tank, they were only secured with a large version of a jubilee clip that went round the frame tube and round the steel body of the master cylinder, passing between the cylinder and the plastic reservoir sat on top. they did get hot too, but didnt take any harm.

[guest1406]

Thanks all for you replies and input.

Bill, being a very 'clean' bike with 'less is more' there is a lot of open space, however under the tank is best place I think.

John thanks, put 'steel tank containing 4 gallons of petrol sat on top of it' into perspective!

So Steve, dont paint it black?

I am now a lot less concerned about the heat, however now may as small heat shield for it

Mackenzie

[beeman]

Your right Johnr wish I engaged brain, I was just thinking of exhausts etc being the hottest part of the bike and heat rising. As Mackenzie says there is a big tank of petrol on top of most bikes engines without much problems.
Bill does have a point that heating brake fluid may not be the best idea but I don't suppose it has ever really been researched. Master cylinders I think are probably put where they are for convenience and cost for the manufacturer.
I have noticed that the reservoir is usually above the master cylinder, I presume to eliminate air getting into the system, could be wrong though. Would this be a problem if below tank. Its a bit early in the day to think this through and work beckons. 

[johnr]

no, the bmw system was based on bmws vanity in that as car builders they wanted everything hidden away, so the master cylinder was under the tank and was operated by a cable to a cable brake lever on the bars, the pipes from the master cylinder exited from the sides running down to the front calipers. the twin disk ones had twin pipes and a larger bore, the single disk ones had a smaller piston and just the one connection. either way, they were both utterly shite. bmw themselves realised this and later bikes had a megura master cylinder on the bars where normal bikes had had them for 20 years,,,,

[guest1406]

Problem solved!!!

c o c kneycustoms.blogspot.co.uk/2013/07/brake-master-mounted.html

Small resivour simply mounts onto the tank bolt.

Mackenzie