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A New Rearend And All-Wheel Discs - Brake-DownFrom the October, 2012 issue of Rod & Custom By Kev Elliott
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You may remember I mentioned a couple of months back, when I unveiled the new plans for my modified project, that I decided to use four-wheel disc brakes rather than early Ford drums. Since my plans include street use as well as lakes racing, I also wanted to incorporate an emergency brake. It just so happens that Wilwood Engineering not only manufactures a vented disc brake kit that bolts right up to an early Ford spindle, but also offers a similar setup for 8- and 9-inch Ford rearends that include an emergency brake. [1] When Currie Enterprises... [1] When Currie Enterprises built the 8-inch rearend for this project, I asked them to install the SO-CAL Speed Shop cast spring hangers to the axle tubes prior to welding the bearing housings in place, and weld the hangers on at the same time. Though I have an 8-inch axle, it is a Currie Enterprises item and has the bigger 9-inch bearings and housing ends, so I needed a kit for a 9-inch. Of course I forgot that the first time and had to reorder. Duh! Wilwood makes rotors in various diameters, as well as solid, vented, and cross-drilled, but I selected the Dynalite Pro Series vented and drilled option for front and rear, after speaking with the guys at Wilwood who advised that it’d be ideal for my application. The rear rotors measure 12.19 inches in diameter, with the front coming in at 11 inches. I’ll also use Wilwood master cylinders, as I’m using the company’s through-firewall pedal assembly. This has a balance bar to adjust front to rear brake bias, so you’ll see three cylinders used rather than two. However, before I could install the brakes, I had to swap out the old Mercury rearend for the Currie 8-inch. It had been sitting on the floor of the shop for a couple months since picking it up from Currie, and embarrassingly, the nice bare metal surface had started to acquire surface rust. It’s nothing that can’t be cleaned prior to paint, however, though it doesn’t look great right now. Sorry Currie!  [2] The Model A spring from...  [2] The Model A spring from Speedway Motors previously mounted a Mercury rearend, so I had the hangers installed the same distance apart. I fabricated a temporary spring spreader from some all-thread and nuts, two lengths of tubing, and a couple 2-inch lengths of angle iron welded to the ends.  [3] The chassis has a 3-degree...  [3] The chassis has a 3-degree rake, so the spring hangers were welded 3 degrees from horizontal, meaning the shackles would be perpendicular to the hangers and the spring, with no bind.  [4] The pinion angle was set...  [4] The pinion angle was set at 0 degrees, the same as the transmission. As there’s no carburetor on my Zetec four-banger, there’s no need to mount it angled down toward the rear.  [5] The rearend set in its...  [5] The rearend set in its final position. Prior to installing the brakes I temporarily welded the rearend housing to the chassis to keep it from moving, as the upper suspension links will likely mount to the rollcage, and that’s not been made yet!  [6] With the rearend in the...  [6] With the rearend in the chassis, I could install the brakes. Wilwood discs and calipers will be used at each corner, with Dynalite Pro Series 12.19-inch-diameter discs at the rear. The first job was to remove the axles. Note I’d had long wheel studs installed at Currie Enterprises.  [7] Just one of the many options...  [7] Just one of the many options offered by Wilwood is this rear disc assembly with an integral emergency brake. It’s designed for the caliper to mount vertically at the rear, but in my attempt to tuck the rear wheels in nearer the body, I had the rearend made 54 inches wide instead of 55. The extra 1/2 inch on each side would have allowed the calipers (or more specifically the flex hoses) to clear the spring hanger. Hmm …  [8] My initial thought was...  [8] My initial thought was to “clock” the caliper mounts at a different location on what is essentially the backing plate. The threaded holes looked like they’d align …  [9] … but they didn’t quite,...  [9] … but they didn’t quite, so I re-applied thread locker and put the caliper mount back to the original location.  [10] The solution was to swap...  [10] The solution was to swap the assemblies side for side, and top to bottom, so the caliper would now be in front of the axle, similar to many modern cars, such as the Mustang. The emergency brake cable now exits toward the rear.  [11] With the axles reinstalled,...  [11] With the axles reinstalled, the Wilwood-supplied U-shaped bearing retainers were fitted before the bearings were seated. Ensure the open side faces up, and the lip faces toward the bearing.  [12] With the bearing seated,...  [12] With the bearing seated, the bearing retainer was bolted down in the same way as a regular retainer, using the bolts in the housing flange, accessed through the end of the driveshaft.  [13] These rings are also...  [13] These rings are also supplied, and fit in the center of the disc to centrally locate it on the driveshaft.  [14] With a couple of wheel...  [14] With a couple of wheel nuts holding the disc in place, the caliper was bolted to its bracket.  [15] The caliper has to be...  [15] The caliper has to be located centrally over the disc. It’s hard to see, but this one is located slightly outboard of center.  [16] The solution? To install...  [16] The solution? To install one or more of the 0.032-inch shims supplied between the caliper and the mounting bracket (arrow). With the caliper centered over the disc, thread locker could now be applied to the mounting bolt threads, the bolts torque to 30 ft-lb. Wilwood advises installing safety wires to prevent the bolts from coming loose, in addition to thread locker, though as the whole car will come apart again prior to final assembly; I omitted this step for now.  [17] Wilwood can also supply...  [17] Wilwood can also supply emergency brake cables (and braided stainless hose). Here’s how they hook up to the bracketry on the rear brakes. Now I just have to mount an e-brake lever, once the cage and floor are done!  [18] Here are all the parts...  [18] Here are all the parts for Wilwood’s Dynalite Pro Series kit to fit early Ford front spindles, including aluminum hubs. The vented discs are 11-inch diameter.  [19] The first order of business...  [19] The first order of business was to install the 1/2-inch-diameter wheel studs, which are threaded, not pressed into place. The hubs are pre-drilled and tapped for Ford and Chevy bolt patterns.  [20] New bearings and seals...  [20] New bearings and seals are supplied, though as I’m at the dry build stage right now, these weren’t packed with grease, and in fact the seals will not be installed until final assembly.  [21] The discs bolt to these...  [21] The discs bolt to these rotor hats using star bolts, which in turn bolt to the hub. For the same reason as no grease was used in the bearings, no thread locker was used at this time, though it’s highly advised prior to road use.  [22] The caliper mounting...  [22] The caliper mounting bracket is actually a full circular aluminum plate, the same diameter as the brake disc, which bolts to the spindle, using hardware supplied. Our Speedway Motors steering arm replaced the upper pair of bolts though.  [23] One small modification...  [23] One small modification I had to make was to trim the ends of the threads on the steering arm for clearance. I’m sure these discs are rarely used with this type of steering (more often Vega-style cross steering would be used), and the Speedway arm is fine when used with drum brakes. Either way, it was hardly a huge problem!  [24] The finished front brake...  [24] The finished front brake install. I’m assuming basic knowledge of bearing installation, locknuts and cotter pins, and fitment of brake pads here of course! All it needs now are braided hoses and brake fittings.  [25] Of course, any brakes...  [25] Of course, any brakes require master cylinders to make ’em work. Wilwood supplied a pair of 3/4-inch bore units for the brakes, as the pedal assembly has a balance bar, plus a 7/8-inch bore cylinder for the clutch. Each cylinder has four setup options, with one of two reservoirs either mounted on the cylinder or remotely. All fittings as hoses are included.  [26] With the pedal assembly...  [26] With the pedal assembly mounted on the inside of the firewall, as well as to the rollcage structure, I cut three 1 1/2-inch holes in the firewall for the master cylinder pushrods to pass through. I elected to mount the smaller reservoirs on the cylinders, though they have to be removed to access the upper mounting stud.  [27] Here are all three master...  [27] Here are all three master cylinders mounted to the firewall. The studs pass through the sheetmetal and locate in the pedal assembly bracket.  [28] Here’s what it looks...  [28] Here’s what it looks like on the inside of the body. You can clearly see the balance bar (arrow), which allows the bias between front and rear brakes to be easily adjusted. I still have to mount this side of the bracket. Next step, bend and install the brake lines and braided hoses and the system will be complete.
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