Drum Brake to Disc Brake Conversion 1968

Q: Drum Brake to Disc Brake Conversion 1968

My 1968 firebird has drums all the way around, and I would like to step up to disc brakes ( at least in the front) without ‘Breaking’ the bank. I have thought about going to the local junkyards and looking. I read the FAQ, but I have only ever messed with drums and don’t know exactly what I need. Would you folks be willing to describe what I need to pick up off of the various doner cars? I plan on running 15 inch wheels, if clearence is a problem.

Also, I haven’t ever been to a junkyard. Any thoughts on what I need to bring? 🙂

A: To do a drum to disk conversion, you need the following:

-Disk brake calipers (use these as an exchange core for getting rebuilt units)
-Caliper brackets
-Brake backing plates/dust shields
-Disk brake spindles
-Front brake hard lines (sometimes the used stuff is pretty corroded. Might have to spring for new stuff)
-Master cylinder for disk applications (and booster if applicable) (use this as a core, or exchange you drum unit for a rebuild disk item. Most counter clerks can’t tell the difference)
-Disk brake proportioning valve
-Front brake flex lines and brackets (plan on buying new hoses. Don’t risk your life on used hoses of unknown reliability)
-Disk rotors (often worn beyond further machining, expect to buy new ones.

Some 14 inch wheels can clear the standard GM single piston brake caliper. I ran 14×7 Ralley 2s for a couple of months before switching to 15″ wheels. No problems.

Where can you find these parts:

1969-72 GM A-body cars (Chevelle, LeMans/GTO,Skylark,Cutlass) 1968-74 GM X-body cars (Nova,Ventura,Apollo,Omega) 1969 GM F-body

Earlier versions of these cars had a 4 piston caliper that is prone to rust, and parts are expensive.

You have not been to a salvage yard….Astounding!

There are two basic types of junkyards/auto recycling centers. The first is the full service type. You just go in to the office, tell them what you are looking for, and they pull it off the car. They may let you wander around a bit, but they do the work. Some of the better places already have the parts pulled and are sitting in a warehouse waiting for a buyer.

The second type is the self serve. Pick-Your-Part is the biggest chain here on the left coast. You bring your tools, pay the 2 dollar fee, and go hunting. You are also expected to remove the parts yourself, though it seems that the writers of Hot Rod and Car Craft seem to be able to get the hired help to do this for them.

If you go the self serve places, bring your coveralls, gloves, hand cleaner, and some band aids. You should also bring a spring compressor, since you will most likely have to pull the spindles off the car by removing the front springs. A big breaker bar and some good penetrating oil are also a must.

Once you get it home, you will need to evaluate the parts and see what needs replacing or reconditioning. You can find a machine shop to hot tank and/or beadblast the hard parts for you, or just clean them yourself. It’s always better to work with clean parts. Buy new bearings and seals, get some fresh brake fluid. The Ford Heavy Duty fluid is recognized as the best around of the DOT 3 type, and is reasonably priced. It has the highest boiling point next to the silicone stuff. New pads are also a must. Try and stay with high quality brand name products.

Used kits can be bought from places such as Firebird( and Camaro) Specialties for $350. They sell a kit with new or rebuilt parts for $795. I found that this is less expensive than buying used parts and replacing the above listed unuseable parts with new or rebuilt. Your call. I went the used part route, then compared my expenses to the cost of a new kit. I spent more, but got very anal on some of the stuff I did.

Alternative sources for used parts would be swap meets and some of the used Pontiac parts dealers found on the web or in publications such as “High Performance Pontiac” or “Pontiac Enthusiast”.

You may find that once you take the front end apart, you may want to do some additional work. Change the ball joints, replace worn tie rods and bushings, etc. It’ll snowball for certain.

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