We
are restoring the US-style brake master cylinder for the Magnette Mk.
III. The difference between the US and rest-of-world style is
the addition of a large seperate tank. The US and UK cylinders
are identical in all other respects and even use the same rebuild
kit.
This
is an overview of all the parts of the brake master. Again, the US
version has this additional tank, pipe, and bracket shown. It was
originally painted black with a blue "Girling" sticker. I have not
been able to locate a sticker for it. I have chosen to powder coat
the tank rather than paint it because the powder coat is more
resistant to brake fluid.
Here
is the US style tank, before sand blasting.
I
chose to shot blast the can because of the curves around the cap.
There was also a great deal of hardened "something" around the inside
edge. It is surely a blend of evaporated brake fluid, paint, and the
remnents of the rubber seal under the cap.
Whether
you end up painting or powder coating your can, it is best to put a
wire hanger on the inside and hang the can from a wire when applying
the finish to avoid contact marks from touching the ground or your
fingers.
Here
I am preheating the can, just to get the chill off in the below
freezing garage.
Here
I've powdered it.
And
now its done.
The
cap gets a similiar treatment, but I de-rusted it on the the wire
wheel. I prefer to use the wire wheel whenever possible because I
don't have to have the compressor running to use it!
Here
is it, completely de-rusted and paint free. It wouldnt' look like
this for long though if we didn't give ti a protective
coating.
Here
is the cap, done. I have powder coated it because 1) you do not have
to prime, 2) you can powder coat in freezing weather, 4) it dries in
about two minutes rather than a half hour, and 4) powder coat is
resistant to brake fluid because it is not paint, it is plastic
powder melted to look like paint.
Here
is the actual brake master. UK versions look slightly different, with
an interagal fluid resevoir. Boy does it look ugly!
The
master cylinder is easily taken apart by removing the circlip on the
inside of the cylinder orifice. The remaining components are removed
(in this case) by plunging them back into the cylinder body to break
them loose, and then banging them on the workbench to get them out. A
professional would use compressed air I guess, but nobody is really
reading this anyway are they?
Here
are all the insides, all layed out.
The
body needed work. I removed all the rust and scale on the wire wheel.
The cylinder would soon however become ugly again if you didn't
atleast shellac it. I have, in this picture, plugged the threaded
ends with high temp silicone plugs for powder coating. You can plug
them with masking tape if you are only spray painting.
"Clear"
powder coating goes on dry in a white color. But once it is heated
and cured, it turns clear.
From
my manual: Lift the the thimble leaf over the shouldered end of the
plunger. Depress the plunger return spring to allow the valve stem to
slide through the elongated hole of the thimble and release the
spring tension. Remove the thimble, spring, and valve complete;
detach the vavle spacer, taking care of the spacer spring washer
located under the valve head. Remove the seal from the valve head.
Assembly is mainly a reversal of the dismantling procudre, but note:
Make sure that the flat side of the valve seal is correctly seated on
the valve head. Locte the spring washer with the somded side against
the underside of the vavle head. Parts Key: 5- Valve Seal, 6- Valve
Stem, 7- Curved Washer, 8- Valve Spacer, 9- Spring, 10- "Thimble",
11- Plunger Seal, 12- Plunger, 13- Some plungers have a space for
this additional seal.
Here
it is, all done and on my desk.
This page, like all pages, are copyright John Elwood. All Rights Reserved.