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Years ago I had another 66 that I put a 68 disc setup onto and I was always sorry there was no 14" wheel that fit which would have allowed me to keep my car looking original.

I'm not making that mistake this time. I'll drive it with drum brakes before I convert to 15" wheels. I drove my 427 4 speed drum braked B body for almost 9 years in the 80's and somehow survived.
 

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Drum brakes are better than disc brakes. You don't need a power assist to hold your foot on the brake pedal as drum brakes are self activating. It takes a strong spring to pull them off the drum once they have stopped as the bind up.

The only problem with a drum brake is they are lighter than a disk brake. Sounds like a good thing with less un-sprung weight, but brakes work by friction converting mechanical energy into heat and with less mass they are not as good at absorbing heat as a big heavy rotor. If you look at a pick-up truck the disc brake caliper is basically the same, only the rotor is thicker by an eighth of an inch so there is more metal there to heat up. It is a disc brake's rotors ability to absorb a lot of heat as well as radiate that heat by way of a greater surface area that allows a disc brake car to stop repeatedly from a high speed without fading. After getting as thick as a truck brake, the Corvette started growing the rotor in diameter as well to include even more metal in the heat sink. So in brakes bigger is better.

The factory went to disc brakes not because they were better (they were originally sold with out power assist and did customers ever complain). They sold disc brakes on cars because they are cheaper to make and cheaper to install on the assembly line. The reason only the Corvette came with four wheel disc brakes for the longest time was because there has to be a tiny drum brake inside the rotor hub to allow for an emergency brake and a parking brake. Newer cars have a second mechanically operated caliper attached to the axle to act as an e-brake and parking brake, but because there is no power assist and they have to be constantly adjusted to account for wear they rarely ever work after the first 10,000 miles or so.

On my Camaros and Novas that I used to build as street cars that could compete in a drag race or a road race competitively I used the larger 11 inch rear drums in place of the factory supplied 9 inch drums. (GM rear axle flanges on cars all share the same bolt pattern so any car brake can be bolted on in place of any other). With the Impala the larger rear drums off of a pick-up truck won't work on an Impala because heavier trucks use a live axle (that big hub you see sticking out of the wheel on circle track race cars) and generally six or more wheel studs. So that trick won't work for you.

You can go wider if not larger in diameter so you can order the rear brakes off of a station wagon or cop car (that is why in parts books all parts have a disclaimer saying non-police or wagon because the parts are different on those vehicles). Also older cars before computer designed parts where built bigger because there was more of a safety factor built in. So old Buick brakes that had aluminum fined steel drums where wider than newer drums. But you have to buy the backing plates as well and I don't think they are reproduced.

Big Dave
 

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Big Dave is correct. The drum brakes ARE better ...unless your Impala is a road race car, which it probably isn't.
I speak from experience. I did the front disc conversion from CPP on my '64 only to find out that each wheel was now moved out about 5/8". Not much? Wrong. The additional track width upset the steering geometry enough to significantly increase the turning radius AND tire scrub when making tighter turns AND the stopping itself wasn't one bit better. In fact, I noticed a slight increase in pedal pressure to get the same braking as with the OEM drums. The only advantage to converting to discs is that it is easier to replace disc brake pads than it is to replace drum brake shoes.
The whole experience was a total waste of money and time. After living with the conversion for a couple of years, I finally reinstalled the power drum brakes and was surprised(reminded) of how well they worked and how well the car(once again) tracked and steered.
 

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From personal experience if you do any real world driving drum brakes are not better. on my 67 I installed CPP 0 offset disc brake conversion and the car stops MUCH better, also the brakes don't get hot and loose stopping power after you brake once. Trying to stop a behemoth of a car with drum brakes was ok once, but the drums would get hot especially going down hill, and it was scary cause drum brakes would barely grip.

To be able to run 14's and hubcaps I've bought G body 14" wheels for $50 each on ebay, 6mm spacer $19 for 2 and they clear just fine.

CPP 0 offset kit doesn't push the wheels out at all and it comes with longer studs so 6mm spacer is not a problem.


 

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Hello again....lots of questions in restoraing 65 Impala. Added dics brakes to front. Used cpp two yrs ago on another 65 Impala. Could not maintain enough vacumn (only12'') this was with a stock solid cam on 425hp 396.

Added extra vacumn canister and electric pump...still took extreme pressure on pedal to stop. Took the system off and back to drum brakes. Want to try again on the next 65 Impala and add disc to front....again but have heard about ''Hydroboost''. I don't know how involved it is. Any ideas would be appreciated.

Back in 1965 many BB cars came from the factory with power disc brakes. Many of these cars had solid lifter camshafts that would not produce 15-18'' of vacumn as required. So....how did they get buy back in the day with power disc brakes? thanks for help and advise ....Elmo
 

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Howdy...not sure how to use this great Impala form. Keep coming back to where I last visited to see results.

Question: Where can I send stainless trim parts and moldings to be straightened and polished. Maybe someplace close to Montana. Thanks Elmo
 

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Hyrdoboost just uses the power steering pump to add pressure to power brakes instead of Vacuum booster from engine vacuum.

My old 85-87 BMWs use Hydroboost for braking. I believe most GM guys use the Hydro boost from a 90s Chevy Astro Van.

Just google GM Hydroboost.

Forums are great tools, use a PC or laptop to view instead of a phone, makes life easier.

If you go to the index below you can add questions in the correct topic.

https://www.impalas.net/forums/

https://www.impalas.net/forums/8-restoration-corner/
 

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Drum brakes operate on 750 psi. Disc brakes require two to four times that amount of line pressure to work.

Any GM diesel powered vehicle will use a HydraBoost because diesels do not have any manifold vacuum. If you have no manifold vacuum because you have a cam too big for the street you will need a HydraBoost to have power assist brakes. I prefer manual brakes, and manual steering (Saginaw 525, Corvair or a Vega gear box) on my race cars.

Big Dave
 

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C3 Corvette Brakes are a direct bolt on swap. This opens the door for stock C3 4 piston brakes, or anything the aftermarket has to offer. The best part is everything is available from local parts stores if you happen to need parts in a pinch.

To convert, you'll need C3 spindles, and a set of brackets for the rear. Here's a picture of the back brakes I mocked up to see how they fit.
29444


And the front spindles installed.
29445
 
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