Author Topic: FS -- Dual circuit master cylinder mounting kits for late 30s to 1949 Cadillacs  (Read 227 times)

Well, after much work and some unavoidable delays, I have finally gotten back into production of the mounting kit for mounting a dual circuit master cylinder in place of the single circuit master for (late)1930s to 1949 Cadillac's.  My kit doesn't fit the big chassis cars with the triangular mounting flange for the master.  Instead, it fits the two-lug masters that were more or less ubiquitous for many years. The kit mounts without drilling any holes in the body or chassis and requires no welding either.  So the installation is 100% reversible if a future owner of the car wants to revert to the single master and leave no trace of the dual set-up. 

I sold 50 of these kits previously, was out of stock for a while, and now am shipping them again.  The first 5 of this second batch of 50 were shipped this week.   I had been content not to have to deal with all of the details of making and assembling these kits, but there was so much demand within the CLC for these kits that I felt compelled to make them again.  So I am selling them through the Forum and am not advertising them elsewhere (my hope is that they all go to CLC'ers).

$270 including shipping within the US.  The kit includes all of the special doo-dads needed for the installation.  Master cylinder itself is to be purchased separately from commercial sources.
Art Gardner

1955 S60 Fleetwood sedan

Offline G Pennington

  • Posts: 93
    • CLC Member
      CLC Member #17677
  • Name: G Pennington
Art,  Which master cylinder does your kit use?  Does it require new/modified brake lines?

Gary Pennington
   1953 6267X CC
   1941 6267D CC

My kit works with the Wilwood 260-7563 dual master.

The stock brake lines remain intact and are connected with the dual master with some specialty fittings and two short pieces of special brake line, all of which I supply in the kit.
Art Gardner

1955 S60 Fleetwood sedan

There are lots of folks who have already used these kits and can attest to the quality and design.  If you want one, don't wait.  When these 50 are gone, I probably won't make them again.
Art Gardner

1955 S60 Fleetwood sedan

Here is how they are installed:

A qualified mechanic should be involved in the installation of the master cylinder and the plumbing of the lines to ensure that it is done safely and properly.  Essentially, you remove the old master, leaving the original brake lines on the car (assuming that they are in good shape).  Install the bracket, install the new master on the bracket, connect the lines with the special fittings and adapter lines I provide, and bleed the system.  NO DRILLING.

Your car already has a main rear line and a main front line coming into the big three-way brass fitting on the front of your master.  So you just plumb it up so that the main front line goes to the output port for the front (which is the rear-most port on the dual master) and the main rear line goes to the output port for the rear (positioned at the front of the dual master).  To make the connection to the existing rear brake line, you can use a short 90 degree brass elbow (included in the kit).  For the brake light switch and the existing front brake line, you would use a special T-fitting (also included with the kit), with inverted flare connections on two of the outlets of the T and a tapered pipe fitting in the third one (for the tapered pipe threads on the brake light switch).  This relocates the brake switch to be a little lower on the car, so you may need to extend the brake light switch wires a tad.  It sounds a lot more complicated to describe than it is to plumb!  Don’t use Teflon tape on any of the fittings -- don't do this as Teflon tape is not resistant to brake fluid and just makes a mess.   
The new push rod that is actuated by the stock pedal arm is a special length for this installation (I provide that in the kit, along with a new jamb nut). 
The custom-engineered bracket fits a 49 frame like a glove and provides proper clearance for ease of installation.  The bracket is powder-coated for long-lasting protection.  It mounts the new Wilwood master in the stock location, so you use the stock pedal assembly.  The brake fluid reservoir lines to the master are simply routed conveniently away from anything that might chafe or interfere with the rubber lines.  The reservoirs can be mounted to an optional bracket that gets secured to the inner fender using the inner fender's existing fastener holes. 

My kit is fairly complete.  It includes two short bits of adapter steel brake line that adapt the larger existing brake lines (1/4”) to the smaller ports (3/16”) of the Wilwood master cylinder.  These short lines will need to be bent to connect up.  The bracket mounts to the frame and the brake pedal arm mounting bracket, using one Grade-8  7/16-20x1-1/4 bolt (and nut and washers) and a pair of GR-8 fine threaded 5/16 bolts (longer than the stock bolts to accommodate the added thickness of the new bracket). 

Note how the new big mounting bolt is oriented to face away from the frame, extending through the hole in the brake pedal arm mounting bracket toward the middle of the car, securing the forward part of the new bracket.  The forward hole on the brake pedal mounting arm is not used anymore (previously, it secured the forward lug of the original master).  The rearward part of the new bracket is secured to the frame using the longer 5/16” fine thread bolts.

In the photo, the master has brass adapters screwed into the 3/16” ports to accommodate 1/4” lines.  I have now switched to the included special adapter lines in the kit, which eliminates the male/female adapters that would go into the ports, thereby minimizing the number of fluid connections and minimizing the chances for leaks. 

In the photo, note the brass elbow just below the master, between the ports.  This is the connection of the car’s main rear brake line to the forward port.  The short adapter line will need to be bent into a generally U-shape to make this connection (and this is more easily done with the thinner 3/16 adapter line, rather than the ¼” line shown in the photo).

Note also that the adapter line for the front brakes (the rear-most port in the photo) descends in the space between the forward edge of the new bracket and the jog in the factory brake pedal arm mounting bracket. Take care to route this to clear the bolts, as shown.  It doesn’t need to be bent into this sharp of an L-shape.  To connect the existing front brake line, simply bend it down some until it connects with the brass Tee.  Only use the middle port of the Tee for the brake light switch!  It is the only port in the Tee that is threaded for a 1/8 tapered pipe thread (which is what is on the brake light switch).

The bleeders are pointed toward the brake pedal arm side of the master.  If these seem too close to the pedal swing, one can remove the bleeders and grind off the nipple portion of the bleeder screws and then reinstall.

Master must be thoroughly bench-bled before installation.  Pre-fill the lines, if you can, to make it easier to bleed the system. If you are redoing the wheel cylinders and/or brake lines at the same time, take care to fill the cylinders and lines beforehand.  It is difficult to bleed a system if the entire system is filled with air.

« Last Edit: November 06, 2017, 06:47:57 AM by Art Gardner CLC 23021 »
Art Gardner

1955 S60 Fleetwood sedan

Reminder -- I am back in stock with these kits.  Get 'em while they last...
Art Gardner

1955 S60 Fleetwood sedan