If it isn’t one thing, it’s definitely another when it comes to modifying suspension, changing wheel offsets, etc. But, more often than not, there’s always a fix for those “things.”
In this particular situation, the 14×8 reverse-offset Tru-Ray spokes on our ’68 Impala rubbed the fender lip — something you’re typically stuck with, as the addition of aftermarket disc brakes generally moves the wheels outward. Well, this isn’t a typical situation, as Classic Performance Products (CPP) has their original-offset kit for full-size ’65-’68 Chevrolets (6568WBK-SO), which brings the wheel mounting surface back into the stock location. This, ultimately, provides some needed clearance for the 5.20-14 Premium Sports bias-plies.
Using a separate brake rotor, or hat, and hub, CPP is able to narrow the track width 1 1/2 inches overall (3/4-inch on each side). Ultimately that sucks the wheels back in where they were when the Impala rolled out of the factory in the ’60s with drum brakes (actually, a bit narrower). Same 1-inch thick, 11-inch diameter rotors; same big-bore GM calipers; same superior stopping power, but without the tire rub.
Whether installing a complete kit from bare spindles out (as we initially did) or swapping rotors and calipers out, the CPP kits are as straightforward as you’re going to find. And they work. In last month’s issue we added rear brakes, now here’s part two with the front discs installed.
1. Minus the caliper bracket portion, which had already been incorporated when the first set of CPP disc brakes were installed, here’s what it took to bring the ’68 Impala’s wheels back in 3/4 inch on each side — and not sacrifice brake performance whatsoever. CPP’s original-offset disc brake kit (6568WBK-SO).
2-3. For comparison purposes only (the spindle applications vary), here’s a side view profile of a standard GM-type rotor (top) and the narrower separate hat/hub combo (bottom).
4. Once the previous rotors and calipers had been removed, the existing mounting bracket hardware was re-torqued, as it will be reused.
5. CPP’s aluminum hubs are available with either 1/2- or 7/16-inch wheel studs (our stock application uses the latter, in 5×4.75 bolt pattern), which must be installed by the customer. Use red Loctite on the last five threads (nearest the bolt head shoulder) as well as the threads in the hubs.
6-7. Included with the hubs is an instruction sheet for wheel mounting guidelines — as for wheel studs, once installed, torque down each to 90 lb-ft. Notice we’ve set one of the rotors in a vise (using rubber pads to avoid damaging brake surface) to aid in the torquing.
8. Hand-pack the wheel bearings with high-temp disc brake grease (liberally), adding grease to the hub races as well.
9. With a seal installation tool or similar (block of wood or aluminum), carefully install the rear dust seal with the inner wheel bearing in place.
10. Verify both inner and outer bearings fit spindle snug. Any marring or excess wear on the spindle shaft should be addressed.
11-12. While spinning the hub, set the bearing preload. Carefully tighten the axle nut until the bearings are seated (no more than 12 lb-ft); untighten just enough so nut is loose, then tighten by hand. If cotter pin hole does not line up, back off nut (not tighten) to the closest hole.
13. Use a couple lug nuts to keep the rotor from moving around while you install the caliper.
14. With the guide pins removed and their inner bushings bottomed out against the caliper body, set caliper onto rotor with both brake pads installed, making sure the bleed screw is on “top” of the caliper.
15. Ensure the rubber O-rings in the outer guide pin holes do not get pushed out when inserting and tightening the pins to secure the caliper onto the bracket.
16. Install supplied braided stainless flex line — banjo will direct the line up toward the fenderwell. Connect to the existing hard line, or…
17. …Install new hardline, as we did using a pre-bent stainless crossover supplied by Inline Tube.
18-19. The proof’s in the “putting,” that is, putting the wheels and tires back on to verify our regained clearance with the narrow-hub CPP brake kit.
20. And there you have it, 5.20s no longer contact the inner fenders. Success…without a bit of performance sacrificed.
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