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GM Rear Drum to Disc Brake Swap

Stock Rear Brakes Giving You Fits? Stock rear brakes giving you fits? We show you how to get big brakes for 10- and 12- bolt axles.

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Foot to the floor for 100 feet when you brake for that bus full of nuns? Upgrade when we show you that putting disc brakes on the rear of a GM car is actually very easy. Watch as we swap out the drums on our '86 Caprice and swap in a set of discs from a '94 Caprice police car. The good news is that these tricks will work for any GM C-clip-style 10- or 12-bolt axle on nearly every GM car.

Reality Check
You're probably thinking, "That was too easy," and you're right. Yes, mechanically, the job is simple. You can swap drums for discs in a couple of hours as long as you do your research ahead of time. However, a lot of things can go wrong if you don't.

The axlehousing dimensions are the same on all '77-'96 Chevrolet B-bodies (Chevrolet Caprice and impala) are nearly identical under their sheetmetal, and virtually all parts are interchangeable among those model years. We can swap the whole thing into our '86 Caprice, and in doing so, we'll be upgrading from our puny 7.5-inch 10-bolt to a much stronger 8.5- inch unit with limited slip. The rear discs are just a bonus.

Truthfully, we planned to swap axle assemblies all along. The point of the exercise at the beginning of the article was to demonstrate how quickly you could get mired down in the multitude of variables involved in a rear disc brake swap.

Have you ever wondered why there are so many aftermarket companies offering brake upgrade kits? Or why most car builders or restorers, guys who have no fear of building engines and transmissions, will run aftermarket braking systems on their cars? Well, neither did we until we started researching for this article. We quickly discovered that trying to cobble together a brake system involves a lot of trial-fitting until you get the combination right. Fine if you've got the time and funds.

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Car Craft