What chemical would you soak a master cyl in?

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Dana67Dart

Dana67Dart

The parts you don't add don't cause you no trouble
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I have a master cyl that was well sealed for 40 plus years.

The inside of the reservoirs are not rusty but is kind of solid with dried brake fluid.

Right now I'm just trying to get the crusty solid gunk out.

Chemical thoughts


PXL_20231218_061102036.jpg
 
i'd soak it in pinesol 50/50 with water for a day or two to get the brake fluid crusties out and then throw it in some evapo rust.
 
i would initially soak it in brake fluid...
any old crap, that half bottle of dot 3 you opened 2 years ago..

see if that un crusts what has crusted up

then do some of the other things...

Dave
 
HOT soapy water. Like with Dawn in it. Brake fluid is water soluble.
 
this is very true, well water is absorbed easily in it, they mix well certainly

but we don't know if "what it turns into" when left to its own devices for 30 years is water soluble.... :)

very much of a "i can clean my carb in petrol" suggestion from me

Dave
 
Same deal going on here, stuck valve....
Soaking in all sorts....parts washer, MMO, stuck valve is going to be fun....
..
 
4spdragtop said:
Same deal going on here, stuck valve....
Soaking in all sorts....parts washer, MMO, stuck valve is going to be fun....
..
Click to expand...
Some thoughts on this................

Pumping grease in through the front outlet might press it out?

Weld a tap to a rod, thread it into the valve and use a slide hammer weight to pull it out??
 
Man, when it comes to brakes, don’t mess around. Get a new or rebuilt one from a source that knows what to do.
 
Plan on a rebuild kit and cylinder hone and use CRC Brakleen chlorinated solvent.
 
Lol, I can "do" things....maybe not fixem, but I can "do" them lol.
I was going to try that next Troy.
CFD244 said:
Some thoughts on this................

Pumping grease in through the front outlet might press it out?

Weld a tap to a rod, thread it into the valve and use a slide hammer weight to pull it out??
Click to expand...

Heywodja said:
Man, when it comes to brakes, don’t mess around. Get a new or rebuilt one from a source that knows what to do.
Click to expand...
 
Here's how I look at brakes. Yall are dead right not to mess around. However, I would rather have a factory "rebuilt by me" master cylinder, wheel cylinder or caliper than some junk butt chinkesium casting. These old factory castings are just fine as long as they don't have deep pits in the bores.
 
In the small side is part of the rubber gasket for the lid, see the writing in there?

See those spacer looking things in the ports, those are factory on a 1967 mopar. Reuse them.

First take the piston out, unscrew the spacers, take the fittings out of the ports, use your favorite solvent to get it clean, then evaporust to get the rust out. Now rebuild it.

evaporust doesn’t remove goop, and it lasts much longer if you use it on clean metal.
 
413 said:
In the small side is part of the rubber gasket for the lid, see the writing in there
Click to expand...
Note the writing is a mirror image.

It's an impression in the solid of the bottom of the bellows in the lid.

The rubber is good and still playable
 
I have been tumbling stuff in Hot Water, Stainless Steel Pins, dish and Lemi-Shine (mild acid)
If to large to fit in my tumbler just soak in Hot Water, Lemi-Shine and Dish Soap over night. Real Rusty gets longer. Yes the water gets cold but starts out hot.
Or like stated ultrasonic for more gental
 
Dana67Dart said:
I have a master cyl that was well sealed for 40 plus years.

The inside of the reservoirs are not rusty but is kind of solid with dried brake fluid.

Right now I'm just trying to get the crusty solid gunk out.

Chemical thoughts


View attachment 1716179807
Click to expand...
I assume you're planning to rebuild it. I'd start by pulling it apart and hone the cylinder to see if it's rebuildable. If badly pitted and you just have to reuse it for some reason, have it stainless sleeved, rebuild it, and then use DOT 5 fluid from now on. If it's not badly pitted, soak in Evaporust, rebuild kit, and DOT 5.
 
Bewy said:
Donate it to your favourite junk pile.
Click to expand...

Maybe, but only after digging into it to see what's really there.
Let's face it, same could've been said about many of our cars twenty years ago.
 
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