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Installing Four-Wheel Disc Brakes On A Tri-Five Chevy - Drummed OutFrom the February, 2012 issue of Rod & Custom By Kev Elliott Photography by Jason Scudellari
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Hot rodding is all about going fast, though it’d be foolish to increase performance without increasing braking capacity. If you’ve experienced brake fade or simply not been able to bring a car to a stop once you’ve made performance upgrades, you’ll appreciate the importance of improving the “whoa” as well as the “go”. Of course, in recent years, braking and handling have become much hotter topics, as performance has become measured not just in straight line quarter-mile times but on autocross circuits and with the popularity of Pro Touring–style cars. You wanna drive your car? Well, that’s what they’re for in our opinion, so it makes sense to upgrade the braking system as well as the engine. You’ll likely remember this... You’ll likely remember this shot from last month’s suspension install. The CPP 2-inch drop spindles came fully assembled with rotors, calipers, and hoses. These are CPP’s newer drop spindles, which don’t feature integral caliper brackets, though the earlier modular versions do. The newer style doesn’t limit the size of rotors that can be used. There’s not much that can beat four-wheel disc brakes, and there’s not much that can beat a bolt-in upgrade kit, which is exactly what Classic Performance Products can provide for a number of classic cars, as well as trucks. So after we lowered the ’55 Chevy wagon last month, we set about installing just such a kit, prior to owner Paul Gauvry upgrading the motor and trans. Note the emphasis on prior! There’s not much point doing it afterward is there? You already saw the disc brakes going on the front, as CPP supplied their drop spindles and brakes pre-assembled. It saves you work and time, and saves them answering technical queries on the phone! So with the front brakes already installed during the suspension swap, we’ll concentrate on showing how you can add rear discs to a stock ’55 Chevy rearend. It’s a true bolt-in swap, as was the suspension, and is easily accomplished in a few hours. The new master cylinder and booster even attaches to the stock brake pedal.  Seeing as the front brakes...  Seeing as the front brakes are supplied fully assembled, any installation problems are virtually eliminated. However, before fitting the brakes and spindles we felt it wise to ensure there were no clearance problems with our wheels. As the wagon has already been updated to 15-inchers, we were in the clear.  With the spindles installed...  With the spindles installed as shown last month, all we had to do was hook up the stainless braided brake hose, shown here still tucked between the rotor and spindle to prevent damage during installation, and ensure the hose won’t contact any moving suspension parts, including the springs. Note we chose the optional cross-drilled rotors.  Converting the stock ’55 Chevy...  Converting the stock ’55 Chevy rearend to disc brakes was a little more involved than the frontend upgrade! With the wagon on the rack, the brake drums were removed.  Though we’ve probably all...  Though we’ve probably all used needle-nosed pliers to remove the brake shoe clips and springs, a dedicated tool is available for this purpose. This one’s from Snap-on, and eliminates the possibility of losing the retaining clips once the slot in them aligns with the end of the spring pin, which is removed through the backing plate once the springs are released.  With the retaining clips and...  With the retaining clips and springs removed, the remainder of the drum internals—springs, shoes, and adjusters—can be removed.  Though we’d advise removing...  Though we’d advise removing the axle shafts and using a press to remove the studs, they can be removed using a dead blow hammer at this stage.  New, longer studs (supplied)...  New, longer studs (supplied) can then be installed, here using an air ratchet to pull them into place. Note a couple of washers are used between the nut and the faceplate of the shaft. The studs have to be pulled or pressed into place as the section of the stud that locates in the shaft has knurled ridges to retain it.  With the new studs installed,...  With the new studs installed, we could move onto removing the shafts, as the backing plates had to be removed, and are held in place by the bearing retainer plate on the shaft (arrow).  The retainer plate is secured...  The retainer plate is secured with four bolts through a flange on the end of the axle housing. The nut on each was removed using an air ratchet.  The axle shaft could then...  The axle shaft could then be removed from the housing, the retainer plate and bearing coming with it. On post-’65 GM cars and ’63 trucks, the shafts are held in place by a C-clip in the center of the rearend, not by the four-bolt flange and plate, though CPP offers kits for these too.  Once the brake line was removed...  Once the brake line was removed from the slave cylinder, and the emergency brake cable disconnected, the backing plate was removed.  Here’s what you’ll be faced...  Here’s what you’ll be faced with now, with 50-plus years of crud and grime covering the ends of the axle housing!  After cleanup, the new caliper...  After cleanup, the new caliper bracket and spacer were located on four new bolts through the flange that held the backing plate and retainer plate.  This backing plate shim (replacing...  This backing plate shim (replacing the thickness of the backing plate now it’s no longer used) locates on the retaining bolts.  While the shafts were removed,...  While the shafts were removed, the bearings and seals were inspected. Deemed OK, the shafts were re-installed, with RTV in the freshly cleaned bearing housings.  Thick and thin shims are included...  Thick and thin shims are included in the kit, fitting between the caliper bracket and the spacer, and should be installed as required to center the caliper over the rotor. They weren’t needed in our application. The retaining plate nuts and bolts were then tightened.  The rotor was installed next,...  The rotor was installed next, using a couple of lug nuts to keep it from moving.  The caliper was then bolted...  The caliper was then bolted in place, with the bleed screw toward the top. Once the bolts were tightened, it was checked to ensure it was centrally located on the rotor. Shims can be added if not.  The brake hoses were loosely...  The brake hoses were loosely installed using crush washers on each side of the banjo bolt.  These clamps secure the brake...  These clamps secure the brake hose tab to the rearend housing, with a new section of hard line plumbed into the existing lines. Once the flexible hose end was located and clamped, the banjo bolts on the caliper could be tightened.  Four-wheel disc brakes will...  Four-wheel disc brakes will require a new master cylinder, as well as a booster; this assembly was also supplied by CPP. It includes a combination valve.  With the master cylinder and...  With the master cylinder and combination valve removed, the booster was bolted to the existing studs on the firewall, and connected to the brake pedal.  It’s always advisable to bench...  It’s always advisable to bench bleed a new master cylinder. Clamped in a vise, and with plastic tubing leading from the outlets back into the reservoir, a socket extension bar was used to operate the master cylinder.  Bench bleeding will remove...  Bench bleeding will remove air bubbles from the internal passageways of the master cylinder, meaning you won’t be attempting to push air through the cylinder, as well as there being fewer bubbles when bleeding the system properly. Note the bubbles visible in the tubing and fluid at the top of the picture.  With plugs in the outlets...  With plugs in the outlets to prevent loss of fluid, the master cylinder was installed on the booster, the plugs then removed to install the combination valve. Obviously a little fluid will escape at this time so use a rag to prevent damage to paint on the inner fender.  The brake lines to the front...  The brake lines to the front and rear of the wagon were connected next. Obviously, a dedicated brake-fitting wrench would be advisable here, though that’s not so important when working with new fittings!  We won’t go into detail on...  We won’t go into detail on bleeding the system, as that’s covered in every workshop manual, plus we figure if you’re undertaking this type of work, you’re already comfortable with the procedure! All that remains to complete the brake system on this wagon is to install new e-brake cables. CPP can supply these too, designed to fit the stock brackets using stock-style C-clips.  Fitting the new cables to...  Fitting the new cables to the calipers is simple, this arm having a slot to locate the cable end. Connect the other end of the cable to the e-brake mechanism, and adjust to suit.
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