1940s Dodge Truck Brake & Clutch Pedal Conversion - Hang Time

Like many great classics,...        read full caption Like many great classics, our Dodge came with through-the-floor pedals similar to these. But the old setup had to go to make room for the Mopar 360/727 combo. We wanted to get rid of the old single-reservoir under-floor brake master cylinder anyway, and we thought power brakes would be the logical swap.

Fans of clean firewalls are...        read full caption Fans of clean firewalls are probably disgusted by our first idea. We trial-fitted a power-brake booster and pedal from a ’72 Dodge pickup. Besides being ugly, this approach requires a lot of under-dash fabrication to hang the pedal. Full Tilt’s Clay Mullis suggested Wilwood’s swing-mount rig instead.

Fans of clean firewalls are...        read full caption Fans of clean firewalls are probably disgusted by our first idea. We trial-fitted a power-brake booster and pedal from a ’72 Dodge pickup. Besides being ugly, this approach requires a lot of under-dash fabrication to hang the pedal. Full Tilt’s Clay Mullis suggested Wilwood’s swing-mount rig instead.

The beauty of Wilwood’s...        read full caption The beauty of Wilwood’s swing-mount setup is flexibility. One assembly supports both master cylinders and pedals. The rig we chose bolts to the firewall and has upper struts to allow it to hang or be reinforced from above. Other Wilwood rigs bolt to the floor, and master cylinders can be mounted in the cab or in the engine bay.

Wilwood’s swing-mount...        read full caption Wilwood’s swing-mount pedal was developed for racing, so it’s small and lightweight but very potent and high-tech. Compare it with the Dodge power unit above it. Carbon-composite material surrounds the Wilwood master cylinders’ precision aluminum bores and reservoirs. The pedal and mount are aluminum.

The Wilwood system isn’t...        read full caption The Wilwood system isn’t power-assisted, but it’s made to stop racers quickly with no worry about losing brakes if the engine dies. No proportioning valve is needed, because the master-cylinder bores differ in size for front and rear, and the assembly includes a balance bar (arrow) to fine-tune the front-to-rear brake bias.

Mullis dumped the ’72...        read full caption Mullis dumped the ’72 booster, then marked a workable position for the Wilwood pedal. He had to consider foot clearance around the steering column and gas pedal, provide for a comfortable pedal height, and allow enough clearance for the master cylinders in the engine bay.

Thin, flimsy firewalls can...        read full caption Thin, flimsy firewalls can pose a problem for pedal mounting. Mullis chose to install a 3/16-inch reinforcing plate. He plasma-cut a hole large enough to allow plenty of mounting room and to take advantage of existing firewall reinforcing ribs. Then he double-checked the mounting clearances from inside.

Mullis used the pedal itself...        read full caption Mullis used the pedal itself to mark the holes for the master-cylinder piston boots. This Wilwood setup puts the master cylinders in the engine bay. Wilwood also offers versions that mount the master cylinders inside the cab. The welded-on rod (foreground) compensates for unevenness due to firewall ribs.

Even after marking with the...        read full caption Even after marking with the pedal itself, Mullis made a template to help ensure that he cut the piston-boot holes the right size and spacing. Mullis stresses protecting wiring and other flammable components when you weld or cut in or near your truck.

With the pedal and master-cylinder...        read full caption With the pedal and master-cylinder assembly bolted to the 3/16 reinforcing plate, Mullis tack-welded the plate into position from inside the firewall. Then he removed the pedal assembly and welded the plate from inside so the bead wouldn’t show from the outside.

Mullis used silicone to fill...        read full caption Mullis used silicone to fill the gaps between the mounting plate and the firewall, then he painted it to match the firewall. Wilwood recommended a 1-inch-bore master cylinder for the front disc brakes and a 7/8-inch bore for the rear drums. External reservoir dimensions are identical for both units, so they come size-labeled.

Because of the stout mounting...        read full caption Because of the stout mounting plate, we didn’t need to use the swing-mount pedal’s top-mount bar. Four nylon-locking nuts and Allen bolts sandwich the plate between the pedal assembly and the master cylinders. Access to the balance bar is quick and easy if brake biasing is needed.

Of course, replacing a single...        read full caption Of course, replacing a single under-floor master cylinder with dual firewall-mount units requires some new brake plumbing. Besides, no one trusted any of the Dodge’s original lines. Luckily, Classic Tube is a one-call source for all brake-plumbing needs.

Classic Tube offers pre-bent...        read full caption Classic Tube offers pre-bent tubing kits for many trucks but not our old Dodge, unfortunately. Even so, the company’s experts asked a few questions and then calculated the right size and amount of tubing we’d need. Classic Tube also supplied the necessary tube bender, flaring tool, fittings, tube wrenches, and bleeding kit.

Mullis recommends running...        read full caption Mullis recommends running brake lines following the most direct route while keeping them away from potential abrasion, pinching, or other damage. Following the original routing isn’t always possible given suspension modifications. He cuts the line a little longer than his measurement, then trims it back for the final fit.

Double-flaring is the only...        read full caption Double-flaring is the only recommended technique for brake-line work. Single-flare fittings too often leak. Classic Tube can supply the proper tool. The only hard part about using the flaring tool is remembering to slide the fitting on first.

Both Classic Tube and Mullis...        read full caption Both Classic Tube and Mullis urged the use of proper tube wrenches (supplied by Classic Tube) for tightening the brass fittings. Regular box-end wrenches are too prone to rounding off the fittings’ soft corners.

Order a little extra brake...        read full caption Order a little extra brake line if you don’t have experience making several precise bends in a short length such as this. Mullis made it look easy, but he’s had lots of practice. Here he marks a section of line for cutting to plumb in the brake-light sending unit.

Bench bleeding is Wilwood’s...        read full caption Bench bleeding is Wilwood’s preferred last step before final master-cylinder installation. In this case, Mullis achieved the same effect by adding brake fluid while a helper pumped the piston until all the air was expelled from the piston outlet (behind forefinger). Then he attached the fitting.

Classic Tube’s brake...        read full caption Classic Tube’s brake bleeding kit makes the task much easier, even for one person. But our Dana 60 rear axle’s left wheel cylinder leaked (yep, from the same ’72 donor as the brake booster). Wilwood offers all sorts of disc brake components. Hmm .

The Wilwood swing-mount pedal...        read full caption The Wilwood swing-mount pedal has a 7:1 pedal ratio. Coupled with the big-bore master cylinders, that amounts to lots of race-proven stopping power with normal pedal effort. All in all, the conversion was an easy deal. And a clutch/brake dual-pedal installation works just the same. CCT

Your classic truck’s up-through-the-floor brake and clutch pedals can cause major headaches when you swap in a modern engine and transmission. Pedal-travel arcs, under-floor mounts, and linkages have the most amazing habit of being in exactly the wrong place for clearance and for routing to modern components. And even if clearance and linkages aren’t problematic, only the most hard-line purists would say they actually like all the clatter, wind whistle, and even water splashes common to through-the-floor pedals at today’s cruise speeds.

There are safety issues, too, whether you swap in a pumped-up engine or keep the original. Early non-power-assist systems simply aren’t trustworthy enough to handle the stresses of braking at modern highway speeds. And most pre-’60s brake systems are single-reservoir designs. If there’s a failure in the master cylinder, in just one of the wheel cylinders, or in any brake line, you’re out of brakes, period. So upgrading to a dual-reservoir brake system is a top priority.

You have a number of good choices when you decide to upgrade clutch and brake pedals and master cylinders. We followed along as Clay Mullis of Full Tilt Street Rods installed one of the best: Wilwood’s swing-mount brake pedal and composite dual master cylinders. Wilwood offers a similar setup with both hydraulic clutch and brake pedals. We didn’t need the two-pedal rig because we swapped a TorqueFlite 727 automatic tranny as well as a Mopar 360 V-8 into the ’40s Dodge shown here. Mullis also replaced the ancient brake lines with new goods from Classic Tube. Of course, Mullis’ problem-solving processes for our Dodge apply to just about any through-the-floor conversion.