1967 - 1975 Mopar Brake Tube Tee Rebuild

This document describes how to rebuild the 1967 - 1975 Mopar brake tube tee using a new seal and spring kit available from Muscle Car Research LLC.  Tools needed:

  • 5/16" or 1/2" socket or box wrench
  • 5/8" box wrench
  • 9/16" brake line fitting
  • Liquid ammonia
  • Clean brake fluid
  • .45 caliber bore brush
  • Ball peen hammer
  • Rubbing alcohol

The rebuild kit provided by Muscle Car Research LLC includes the following parts:

  • Springs
  • Spring cup o-ring seals
  • Switch o-ring seal
Arrange your valve, tools, and rebuild kit on a clean work surface. Let's get started! The first step is to inspect the tee and make sure that the exterior is undamaged. Check the port threads for damage. Make sure the body is securely attached to the mounting bracket. A loose mounting bracket can be tightened up by lightly tapping the brass mounting tab with a ball peen hammer. If any of the brass port threads are stripped or damaged you're better off finding another tee. If your tee passes the exterior inspection you're ready to disassemble it and inspect the internal parts.
 
Disassemble the valve as described in our 1967 - 1975 Mopar Brake Tube Tee Autopsy article. Soak the metal parts for a few hours in a container of liquid ammonia. Ammonia does a great job of softening tarnish on brass, but be careful of the smell! Remove the parts, flush with water, and polish with steel wool. Clean the bore of the valve with the bore brush and make sure that the bore is perfectly clean - any dirty residue that lingers in here can cause a leak! Finish cleaning the parts using alcohol and cotton swabs.
 
The bracket can be cleaned with a wire wheel or by bead blasting. Rinse with alcohol when finished. Lay out the clean parts and your rebuild kit.

Install the new o-ring seals on the switch and spring cups. It helps to lubricate the seals with clean brake fluid.

Note the orientation of the plug, spring, spring cup, plunger, spring cup, spring, and seat. 

Install the spring cup and spring into the "plug" end of the tee. Install the plug, and be careful not to use too much force - the brass hex head is soft and can be stripped with steel tools.

Drop the plunger into the tee from the other open end of the tee. You should be able to see the thin, middle portion of the plunger through the switch port. If the ends of the plunger are visible you somehow screwed the plug in too far! Back it off and make sure the plunger is properly aligned.

Install the spring cup, spring, and seat in the other end of the tee. The seat will be loose because it needs to be pressed back into place. Press the seat into place using a brake line fitting.

Screw the switch into the body of the tee - and you're done!

​Now you can reinstall the tee in the car and reconnect the brake lines to the tee. Start each line by hand as best you can to ensure that the fittings are threading in straight and smooth. Be careful - it's easy to cross-thread the fittings and damage the soft brass threads. Tighten each fitting with a flare nut wrench. You may need to tighten, loosen, and retighten each fitting multiple times to obtain a leak-free seal. Add brake fluid, bleed the brakes, and check for leaks.

The bracket used on this tee was originally plated with a zinc dichromate or yellow cadmium finish. If you're rebuilding the tee for use on a concours show car you will want to remove the bracket from the tee by carefully reforming the staked brass tab that holds the bracket in place. After plating, the bracket can be reinstalled by restaking the brass tab with a ball peen hammer.