Topic: For anyone who doubts the effectiveness of brake fluid

[eigenvector]

Don't get me started.  The frickin' master cylinder cover leaked overnight.  I can't believe how utterly clean the drip line is - like bare metal, even ate through the decals.

I'm gonna have to throw some paint on that, any paint to keep the metal from rusting, but that tank needs to be redone now.  Sucks too, the inside of the tank is in excellent condition and until now the outside was just a bit dirty with a few spots of cancer rust.

[calj737]

Best paint stripper known to man  Not so nice to the environment either... 

[eigenvector]

I wish they'd just go back to mineral oil, at least that wouldn't destroy everything it touches.

Christ I'm angry about that.

[dusterdude]

Dot 5 boys and girls.

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[slikwilli420]

Dot 5 boys and girls.

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Other considerations than just switching such as seal compatibility. Better off just having a master that doesn't leak.

[ekpent]

 Bummer- kind of like a kick in the ole' balls !

[754]

I think 4 works in ours, not sure how bad it is for paint..

[MikeSimon]

DOT4 is as bad as DOT3 or DOT5a for paint. They are all glycol based fluids. Only DOT5 is paint-safe, because it is silicone based. It has other significant drawbacks, however, and I do not use DOT5 in any of my vehicles. Just make sure, you don't spill or leak any brake fluid and if you work on an open system, have a spray bottle with water handy.

[dusterdude]

Dont be scared of dot 5,ive had it in my panhead brakes for 20 or so years.no problems at all.

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[jaytee-nz]

+1 on the DOT 5, used if for years without issue - but don't want to turn this in to a dreaded oil thread !

[PeWe]

Not leaking MC must be first. A leak can suddenly change to no brakes at all. If MC restore kit feels as much job, order a new MC from DSS for almost same price as the Honda restore kit. I did that work fine with dual brakes.

[eigenvector]

Absolutely the master cylinder needs to be fixed, and I believe it has been.  the issue I think is that the cap has a steel plate that provides stiffness to it.  Trouble is the plate rusts and of course rust bulges and pits to form places where fluid can leak out.  I scrapped off the rust, but it's only a matter of time.  I'm not a fan of this style of master cylinder at all, someone mentioned that the master off of a CB750 from 78 to 82 will fit and are supposed to be more reliable.

[calj737]

Absolutely the master cylinder needs to be fixed, and I believe it has been.  the issue I think is that the cap has a steel plate that provides stiffness to it.  Trouble is the plate rusts and of course rust bulges and pits to form places where fluid can leak out.  I scrapped off the rust, but it's only a matter of time.  I'm not a fan of this style of master cylinder at all, someone mentioned that the master off of a CB750 from 78 to 82 will fit and are supposed to be more reliable.

Is the metal plate outside and above, or underneath? If the MC body is aluminum, I'd scrap the metal plate, or have it powder coated to protect it fully. Brake fluid won't bother PC.

[MikeSimon]

Brake fluid won't bother PC.

Common myth! Brake fluid will also attack powder coats. Just not as quick as regular paint. I see powder coated brake calipers dulled by brake fluid, even partially stripped all the time.

[calj737]

Common myth! Brake fluid will also attack powder coats. Just not as quick as regular paint. I see powder coated brake calipers dulled by brake fluid, even partially stripped all the time.

I doubt those calipers you've seen "powder coated" were actually. Far more likely that they were anodized bodies, and the anodizing was eroded. Certainly cheap anodizing will fade under the sun light; in fact look at SOHC switch bodies and calipers. Proof enough.

The reason manufacturers use powder coating on calipers (when they actually are) is because it is VERY indifferent to brake fluid.

[MikeSimon]

Funny how you know what others did or saw. 
I had some of these calipers powdercoated myself. I have an interest in a business that paints, medium blasts, vapor blasts and powder coats. Most powder is urethane based and thus the same as paint. PC is just a tad more resistant to brake fluid, but not "indifferent". Ask any powder coater if he will give you a "warranty" against brake fluid damage.

[eigenvector]

Well in any case I won't deal with it anymore.  I ordered a replacement from 4into1 - same bore size, less complicated design.