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Power brakes vs. disc

Mac2Night

Bronco Guru
Joined
Aug 10, 2005
Messages
2,199
So I have a question about power brakes vs. disc. I have a '73 with new drums all the way around and stock tires, but as we all know, stopping is still underwhelming with drums. I have enough funds to add a power brake set up on it (which I have been told really helps with the whole system) or instead put disc on WITHOUT a booster.

What are your thoughts and experiences with these options?
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,761
Loc.
Conway, AR
I ran 4 wheel power drums for about 10 years.......Just added the booster and was off and running

The booster amplifies any out of adjustment you might have. I was running 32's with 2.5SL and had my share of OH $%&# moments when getting on them hard.

I had to adjust them often and drove in a very defensive manner but it worked and stopped better.

I have disc now and they're 100% better than the power drums.

Tim
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
I think disc is more important so the Bronco stops straight. Drum brakes don't stop straight in a panic stop unless the brake adjustment is perfect and kept that way. Just doesnt happen in real life. What good is power brakes that slam you into the car next to you. I wouldn't waste my money on Vacuum power brakes anyway. Start thinking hydroboost. Driving the Bronco 35mph on the street is no big deal which you choose but a panic stop at 70 mph on the highway you'll be looking for all the brakes you can get.

Vacuum drum brakes on stock tires will be OK as long as you stick to stock size tires and hang on to the steering wheel when you slam on the brakes. Stock tires are the saving grace.
 

spap

Bronco Guru
Joined
Jan 2, 2010
Messages
2,606
Go with the disks brakes, I will be an amazing difference
My first bronco was a 76 stock disk brakes without a booster and it did really well with 33s
You can always add a booster to it later
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,918
Go with the disks brakes, it will be an amazing difference
My first bronco was a 76 stock disk brakes without a booster and it did really well with 33s
You can always add a booster to it later

This/\/\/\
 

doghows72

Bronco Guru
Joined
Jan 5, 2005
Messages
2,036
I would do the disc first. I've got my hydro boost all ready to go but a friend told me to go do a panic stop and see what happens. Sure enough off to the ditch I was headed. Now he said multiply that by ten with a power booster!!
I'm saving for discs now.
 

pcf_mark

Bronco Guru
Joined
Jun 11, 2010
Messages
3,647
Discs. The proper master cylinder will give you better feel and power too.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
Do the disc mod.
While power drum brakes can be made to work well, drums in the front can pull if not installed correctly.
Proper shoe arc is necessary to eliminate this. You can't just throw on a set of shoes on the front and expect it to stop straight.
I don't even know of a auto part store with a shoe arcing machine anymore.

And like pcf_mark said^^^
Get the correct master cylinder for your calipers. The pistons in the calipers are way bigger than those in a wheel cylinder.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
It's not enough to adjust the drum brakes exactly right but keeping them adjusted exactly right.

One of the other members here said he was under his Bronco adjusting the drum brakes every week.
 

SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,830
Loc.
Hawthorne ca
I had both for a while. My 72 had non power with front disc and our 66 had power 4 wheel drums. Hands down the 66 stopped quicker /better but would lock up real easy. Both were running 33s. Now both are 4 wheel disc with hydroboost. Got tired of blowing boosters. If going power I would spent the extra couple bucks for hydro.
 

Apogee

Contributor
Bronco Guru
Joined
Nov 26, 2005
Messages
6,221
...Get the correct master cylinder for your calipers. The pistons in the calipers are way bigger than those in a wheel cylinder.

That statement implies that you need a bigger master cylinder because you have a bigger piston area, however that's not necessarily the case. The factory EB's used 1" bore MC's regardless of the brake configuration, drum/drum or disc/drum, manual or power.

A stock EB front wheel cylinder has a 1.125" piston diameter (~1 sq in effective area), whereas the standard front Ford caliper has a 2.875" piston diameter (6.49 sq in effective area). While certainly a huge difference, so is the difference in what they travel in order to actuate the brakes. Every .010" stroke of the caliper piston equates to about .065" stroke of the wheel cylinder, and most drum brakes I've worked on required more than 1/16" of stroke, whereas the Ford calipers are probably right around .010" to .012" stroke based on the square seal design.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,761
Loc.
Conway, AR
One of the other members here said he was under his Bronco adjusting the drum brakes every week.

I think that was me on another thread....lol Maybe not every weekend but once a month for sure...I was under there all the time.

The proper master cylinder will give you better feel and power too.

I run the stock MC and H-block on my Ford disc setup off a 79 Bronco and it will put you through the windshield if needed. Running 32's

Tim
 

76 bronco J

Bronco Guru
Joined
Oct 20, 2005
Messages
1,480
>>>> remember also that any hub deep water makes drum brakes pretty much disappear ..... I really like the the feel of non power assist disc brakes ,but I only have 30 inch tires.... on the master cylinder, make sure there's no residual pressure valve in the port going to the front brakes .... lots of new aftermarkets don't have them, but check anyway.....
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
That statement implies that you need a bigger master cylinder because you have a bigger piston area, however that's not necessarily the case. The factory EB's used 1" bore MC's regardless of the brake configuration, drum/drum or disc/drum, manual or power.

A stock EB front wheel cylinder has a 1.125" piston diameter (~1 sq in effective area), whereas the standard front Ford caliper has a 2.875" piston diameter (6.49 sq in effective area). While certainly a huge difference, so is the difference in what they travel in order to actuate the brakes. Every .010" stroke of the caliper piston equates to about .065" stroke of the wheel cylinder, and most drum brakes I've worked on required more than 1/16" of stroke, whereas the Ford calipers are probably right around .010" to .012" stroke based on the square seal design.

In my experience, the drum brake master cylinder has smaller pistons and provides more pressure. However, it doesn't move enough fluid for the caliper.
Also, the drum brake master cylinder has a residual valve built in that can cause the brakes to drag when used on disc brakes.
Another difference in the two master cylinders is the size of the disc brake reservoir. As disc brakes wear, more reserve is needed than with drum brakes.
Better to just get a disc brake master cylinder.
 

SavageBurro

Sr. Member
Joined
Aug 12, 2013
Messages
589
If you only have funds for disc or power.... definitely do disc!

I think I have about $160 into my hydroboost and it works amazing ($30 for astrovan booster; $30 for mc; and $100 for hoses and fittings). You will have to get a new mc with disc anyway... so marginal additional cost for the booster is about 130 bucks.

I've run stock drum drum; power drum drum; vac power disc drum; and now hydroboost disc drum (1 ton stuff) and hands down the best feel, control and stopping power in all conditions is the hydroboost disc drum setup. (I will eventually do disc in rear too but to save weight more than anything).

Stock drum drum just about killed me and my family numerous times when playing in the snow years ago. Scary when all 4 drums get packed with ice.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
49,465
It's not enough to adjust the drum brakes exactly right but keeping them adjusted exactly right.
One of the other members here said he was under his Bronco adjusting the drum brakes every week.

I think that was me on another thread....lol Maybe not every weekend but once a month for sure...I was under there all the time.

Haha, me too Timmy. Probably seen posts from both of us. Although I very often was literally under there at least once a week (sometimes more often if things weren't perfect) trying to keep them dialed in just right.
Paid off many times when mine was the only one of our group that would stop straight. But realistically how many of us can do that? Or even know to do that? With so many new EB owners having never driven an older car or truck and having no idea how they're supposed to work, or that they need constant "adult supervision" to keep from killing you, I bet there are many that wouldn't know a brake spoon from a screwdriver. Not that you can't use both of course, but you get the point.
Even I can't do that stuff all the time anymore. No time or inclination, but since I swapped to discs long ago, have never had to do it for the fronts at least.
With rear discs going on at some point, I'll never have to tweak the rears again either.
Can't wait!

The biggest reason I went with discs in the first place was brake fade. One full load and a steep hill too many, and I was ready for the next step. Luckily lived to upgrade!

So in case you couldn't tell Mac, I say discs first too. I won't claim you'll see massive power increases until you add boost, but you'll drive safer and have less maintenance in your future. And those are both good things.

Paul
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,918
Front discs made me willing to slam on the brakes. Prior to that while I had front drums I would always hit the brake with modulation and steering manipulation in mind, haha....
Doing 75 mph on our toll roads here in O'Town the other day and had to slam on the brakes. The back brakes locked up just a little, but not scary. Stopped in a very straight line and I wasn't really scared at all. Used to not be that way....That kind of stop with 4 wheel drum could of ended very badly...

Just front discs were a really big difference since having four wheel drums.
I presently have non-power 4 wheel disc. Remarkable braking. So linear. So confidence inspiring compared to 4 wheel drums. It's a different vehicle.
 

pcf_mark

Bronco Guru
Joined
Jun 11, 2010
Messages
3,647
Also the correct master cylinder will include the residual pressure valves for your set up (I think 10 psi for drum and 2 psi for disc) in the ports of the master cylinder.

Discs are all the rage - since 1965.
 

Skiddy

Bronco Guru
Joined
Oct 8, 2003
Messages
11,567
I ran non power disc/drums for a long time not bad at all, until I did a bunch of trails then my leg would get tired.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,761
Loc.
Conway, AR
Also the correct master cylinder will include the residual pressure valves for your set up (I think 10 psi for drum and 2 psi for disc) in the ports of the master cylinder.

Discs are all the rage - since 1965.

The last 2 drum/drum MC's didn't have RPV's in either port..........Odd but true

Tim
 
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