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Old 10-15-2012, 12:01 AM   #1
robbor
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improving drum brakes?

Does anyone know if there is any easy swap to improve manual drum brakes on a 69? I was wondering about possibly increasing the mechanical/hydraulic advantage by switching the bore size of master cyl or wheel cyls?
id like to swap to power disks but not right now

Last edited by fine69; 10-15-2012 at 04:29 PM.
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Old 10-15-2012, 12:16 AM   #2
SS Tim
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Re: improving drumb brakes?

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Originally Posted by robbor View Post
Does anyone know if there is any easy swap to improve manual drumb brakes on a 69? I was wondering about possibly increasing the mechanical/hydraulic advantage by switching the bore size of master cyl or wheel cyls?
id like to swap to power disks but not right now
If there was anything to be really gained I'd think the factory would have done it. The first thing to do is make sure your system is functioning properly. New cylinders, shoes, springs and hoses would be a good start on often overlooked parts. Just because something works does not mean its right. The drums need to be round, within limits and properly adjusted as well. A power booster is a great add on and was offered as a dealer installed option.
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Old 10-15-2012, 12:21 PM   #3
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Re: improving drumb brakes?

I agree with the above.I would recommend doing that then add a power booster.I have read a couple of articles about drilling the brake drums but have never seen it or tried it.They do warn that if done improperly the drums are junk.
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Old 10-15-2012, 01:31 PM   #4
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Re: improving drumb brakes?

Some half-ton C-10's had bigger brakes, meaning that the shoes were 2.75 inches wide, compared with the others that were only 2-inches wide. Wider drums, and wider shoes....more stopping power. Add in a power brake booster and you'd have more stopping power.

But I get what you're asking...bigger bores to move more brake fluid to exert more force. The fact that you can't compress a liquid is what makes a hydraulic brake work. Get some air in the system and your brakes don't work, or work as well as they should.

Keeping them cool helps. It's something that racers have known for years when they would duct cooler air to the back side of the brakes.
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Old 10-15-2012, 07:26 PM   #5
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Re: improving drumb brakes?

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Some half-ton C-10's had bigger brakes, meaning that the shoes were 2.75 inches wide, compared with the others that were only 2-inches wide. Wider drums, and wider shoes....more stopping power. Add in a power brake booster and you'd have more stopping power.

But I get what you're asking...bigger bores to move more brake fluid to exert more force. The fact that you can't compress a liquid is what makes a hydraulic brake work. Get some air in the system and your brakes don't work, or work as well as they should.

Keeping them cool helps. It's something that racers have known for years when they would duct cooler air to the back side of the brakes.
The 1/2 ton pickups w/ the wider shoes, are as commom as hens teeth...however the wider shoes ARE what's installed on suburbans/carryalls.

The power booster helps, but NOT enough. I've read a thread here debating the use of drum brakes vs. disc.

Several ACTUALLY stated the there was little difference......I strongly disagree.....

IF, IF you want to stop your pickup and actually feel safe driving it, you need to just forget about the drum setup and convert to disc..... I'm sure Moser engineering could whip up a sep of 5 lug axles to fit your stock rear end. They are currently advertising C-clip axles for $260.00/pair. I don't know if a custom order would be more, but this would take care of the "out back" issue, doing a conversion. The stock single piston caliper type disc setup is a VERY good braking system, you don't need the flavor of the month latest exotic 6 piston caliper setup that's advertised......

Properly installed drum brakes in new condition, w/ all parts in working order, are a poor excuse compared to a stock disc setup...

Just my opinion, and my experience...
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Old 10-15-2012, 09:48 PM   #6
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Re: improving drumb brakes?

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Originally Posted by 68Gold/white View Post
The power booster helps, but NOT enough. I've read a thread here debating the use of drum brakes vs. disc.

Several ACTUALLY stated the there was little difference......I strongly disagree.....

Properly installed drum brakes in new condition, w/ all parts in working order, are a poor excuse compared to a stock disc setup...

Just my opinion, and my experience...
Full agreement here. I have completely replaced the manual drum set up on my '69 c-10. It stops very well yet it has the typical limitations. Drums will always be susceptible to fade since heat is trapped inside the drum. Not to mention drums flex somewhat due to the shoes pushing outward. Not so with disk set ups.

Then there is the rain factor. Water enters the drum, stays in there and reduces friction. Usually pulling the car to the left into oncoming traffic since the passenger side is where most puddles lie. This was the source of many head on accidents back in the day. Smart front drum brake owners learn to ride the brakes slightly after a puddle to dry them out so you won't get pulled to one side or the other when the brakes are truly needed.
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Old 10-15-2012, 04:57 PM   #7
Eddie H.
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Re: improving drum brakes?

By far, the cheapest and best improvement you can make to manual drum brakes is adding a vacuum booster.
I added a junkyard booster to a 69 GMC , the difference was like night and day for a total investment of $40.
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Old 10-15-2012, 07:03 PM   #8
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Re: improving drum brakes?

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By far, the cheapest and best improvement you can make to manual drum brakes is adding a vacuum booster.
I added a junkyard booster to a 69 GMC , the difference was like night and day for a total investment of $40.
X2... I did the same on my 69 Chevy and my 68 GMC.

Do a complete brake job on the truck if everything is original. Use quality parts not cheap junk. Safety being the #1 consideration. Don't cheap out on brake shoes. They make a lot of difference in the stopping ability.

I replaced all three rubber lines, all brake cylinders,master cylinder, used all new sprinkg kits, had the drums turned and the difference is amazing.
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Old 10-15-2012, 07:57 PM   #9
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Re: improving drum brakes?

I have a 70 C10 with Manual Drum Brakes and I'm on a seriously tight budget. I'm going to go through my brakes and replace everything I can on my next paycheck. I'd like to add a booster to my setup but I'm wondering what parts besides the booster are necessary.
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Old 10-15-2012, 09:37 PM   #10
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Re: improving drum brakes?

Just to reiterate, make sure you go through and check/replace basics. I've run the drums on mine for years and they always stop. There are benefits to disc for sure, but the drums will work for you. I too want to upgrade to a nice set of disc brakes, but in no way does that mean that drums are bad. A couple things that people often forget, adjust them, often people don't adjust the rears and end up just using the fronts. adjust everything and you'll likely notice a difference. I recently swapped to a different tire size for something that was a little taller and slightly narrower. I noticed a difference in braking simply from losing width in the tires.
Also just had to replace a reman M/C that lasted about 3 years. it slowly went bad and the brakes noticeably changed along with the m/c. Check everything, the parts are cheap enough, wheel cylinders, etc. If you can get a booster in there, do it. Good luck.
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