Inline Tube - Master Cylinder Rebuild
Inline Tube - Master Cylinder Rebuild
Today it is hard to decide to rebuild or buy new.
Rebuilding is time consuming, messy and may still result in a leaky part. On
some cars and trucks it is the only solution since limited master cylinders are
available. Rebuilding requires some common tools ( Snap ring pliers) and a parts
cleaner unit or a sand blast cabinet. If you want a show quality part you will
have to send out the cap and the straps to be plated. If the unit is in good
shape and the cylinder wall is not deteriorated it will be a easy rebuild. If
the unit is rusty and pitted you could be in for a long day. The bleeders could
be rusted in place, the inside piston while riding smooth may not want to come
past where the cylinder wall is a bit rough. All this is compounded when a
bleeder breaks off or other issues arise. Once you get the unit apart you may
find the cylinder wall to have small pits and this is bad news. While a few pits
are ok, heavy pits under the seals will help the fluid travel past the seals and
cause the rebuilt unit to leak again. If the cylinder wall is bad, then it may
need to be sleeved and this costs more than the new unit. So you ask at this
point why rebuild it? You do it for the ultimate matching numbers show car. The
original unit will have the manufacture logo, part number, and date code. If you
want the car to be factory concourse correct rebuilding is the only solution. If
you are not concerned with these numbers don't waste your time. The new
unit will have the exact shape and performance as the original with the
bleeders. These new units are very hard to tell from the originals but will not
have the part numbers and date codes. The new unit is ready to bolt on so you
will save a few hours of time.
Since rebuilding is not to
common any more the rebuild kit is slightly cheaper than a new unit. With the
rebuild kit running around $30.00 and the new unit $70.00 but once you factor in
your Saturday of time the clear winner is the new part, in a few hours you can
be driving the car again. By following the steps below you can
rebuild your component just like an experienced mechanic. Inline Tube offers all
the pieces of the rebuild from the rubber seals to complete master cylinders ready to
bolt onto your classic.
This is an original Delco 1
1/8" bore master cylinder and
features the Delco logo, part number, date code. The 1 1/8" bore is
standard on most disc brake master cylinders. In order to take apart the master
there is a spring clip on the back side that must be removed with snap ring
pliers. Once the ring is removed push the piston in a few times until it pops
out. Once it pops out, pull out the back assembly, then the front assembly. If
the assembly will not come out you may need close the system and apply air
pressure to the front port, this will pressurize the master and force the
pistons out. If this does not work the lining of the master is corroded and the
back of the piston will have to be drilled and a large easy out used to remove
the piston. The rebuild kit will have a new rear piston so do not worry about
destroying it. To remove the bleeders place a socket or a line wench on the
bleeder so you do not round them off. If they do not want to come loose apply
heat and try again if you round off the bleeder vise grips is your next move. If
the bleeder breaks off not only is your ego hurt but the master is most likely
in bad shape. The next step is to center drill the bleeder then drill with a
5/16" drill and re-tap the hole with a 5/16-24 tap. Do not drill too deep or
your rebuild will be over.
Once the master is taken apart, inspect the bore, and the seats of
the master. If the bore is pitted and rusty most likely once rebuilt, the master
has a good change of leaking. If the brake line seats are destroyed again your
rebuild is looking grim. You can remove the seats with an easy out, but finding
new seats will be difficult. We bead blasted our housing, which took a
while to get it back to a bare casting. We plated the master with the
Palmetto Enterprises gray phosphate kit. Heat the solution in a stainless pot to
200 degrees, drop in the parts, when they stop bubbling take them out and spray
down with WD-40. The spray will turn to oil with the heat and once it cools wipe
the part clean.
Once part is clean of all oil, tape off a few areas
and shoot with black paint or if you like the cast iron look you can leave it
plated and skip the painting step. From the factory primer was never used on
these parts so the black paint is applied over the bare casting.
From the factory this is exactly how the casting looked. All the machining
was done after the black paint was applied. So any machined surface would be
bare metal. To get this look you can tape off these areas and spray silver paint
to duplicate this look. If you choose to sand or grind these areas and leave
them bare they will rust in record time. We flattened the top of the master
since it was a bit rough we wanted to make sure the cap sealed like new.
With all the pieces back from the being plated at Bob's boosters we are
ready for the rebuilding. The cap is gold zinc while the straps are silver, the
bleeders are new from inline tube in gold zinc. In the first photo our original
internal assembly is laid out above the rebuild kit. The rebuild kit has a new
rear piston and seals assembled and the seals for the front are provided but no
new front piston is in the kit so we will have to reuse it. The seals quickly
come off the front piston and the new ones install back on the same. Pay close
attention to the direction of the seals so remove one at a time and reinstall in
the same direction.
Here are all the parts ready for final assembly. Before installing the new
bleeders it is a good idea to run a tap into the bleeder hole, this will clean
and recondition the threads the tap is a 5/16-24. After tapping, blow out the
hole with air to remove any metal shavings. Install the bleeders and the cover
bail straps.
Before installing the internals coat the seals and the cylinder wall with
brake fluid, this will provide a slick surface and the assembly will slip right
into place. Install the front piston then the rear piston.
Now that all the internal assemblies are back in place the snap ring needs to
be installed. Hold the snap ring in place and with the pliers ready to go push
the piston in and the snap ring will snap into place. Make sure it is securely
in place and move on to installing the bolt in the front bowl.
The finished master cylinder looks factory fresh. When your ready to install the master
cylinder on the car it is a great idea to bench bleed the master. To bleed the
master, clamp it in a vise, fill it with fluid, crack the bleeders, and with a
screw driver push the piston in several times the full length. When bleeding is
finished
remove the cap and connect clear hose to the bleeders draining back into the
master. Lots of air will be coming through the bleeders but at some point this
will change to all fluid. Be careful not to get fluid on the paint because the
fluid will eat it away.
The black master is our rebuild and the cast lighter part is the Inline Tube
reproduction. The only difference is the date code on the bleeder side and the
part number on the other side. If you are not concerned with numbers this is the
way to go instead of spending a day in the garage you can spend a day driving
the car.
Sources:
Inline Tube - Brake & Fuel Lines,
Rebuild Kits, Brake Hardware, Disc Brake Conversions,
15066 Technology Drive
Shelby Twp, MI 48315
586 532 1338
Palmetto Enterprises - Grey Phosphate Plating
2311 A Old Parker Road
Greenville, SC 29609
PH (864) 246 3836
Bob’s Boosters - Silver, Gold, Black Zinc Plating
East Point, MI
PH (586) 774 8883
