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Rear brake replacement

panteramatt

Sr. Member
Joined
Mar 11, 2011
Messages
651
Seems like I got a leak coming from my wifes 74 and the brake performance isnt good. Im not going the hydroboost route for a while so dont ask. So, do I just replace everything with a new drum kit for around $150 or do I go disc setup for a lot more? Will I notice a performance difference? I know maintanence will be a lot easier. Is there a drum upgrade available?
 

B RON CO

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Bronco Guru
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Jun 29, 2016
Messages
2,412
Loc.
Statesville, NC
Hi, where do you see the leak? Did you check the brake fluid level? Front disc brakes work pretty good. Good luck
 

Bajabrewer

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Bronco Guru
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Jan 28, 2012
Messages
1,435
I'd have to say it depends on how you use your Bronco. Sunday cruiser around town that doesn't see the highway then well adjusted drums will be fine. If you drive it a little harder/longer trips, wheeling, some highway I would want disc up front. I'm putting Disc on my 66 right now so I can keep up with traffic & it needed new brakes anyway so it was a good time to upgrade. Drums work well when properly adjusted & maintained but for my time & money I like disc.
 
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panteramatt

Sr. Member
Joined
Mar 11, 2011
Messages
651
Ok so Im almost positive its a leaking cylinder and yes the fluid level drops to the rear only. Its just a cruiser but wouldnt mind a little more brake performance. Im not going to remove anything til I have all new parts in hand as Im sure they need to be replaced anyway.
 
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panteramatt

Sr. Member
Joined
Mar 11, 2011
Messages
651
I moved the bronco only using front wheel drive when I was replacing the driveshaft. I noticed the brakes would hardly stop the bronco at all when in front wheel drive. Im thinking the rear brakes are hardly doing anything and I already did the chevy front disc upgrade
 

Apogee

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Bronco Guru
Joined
Nov 26, 2005
Messages
6,033
I'd rebuild the drums and be done with it. As you said, it's a cruiser and the drums work well when properly maintained, plus they have an excellent parking brake. While I'm a huge fan of disc brakes in general, you're opening a whole new can of worms going that route and significantly more money.
 

edgeoffroad04

Full Member
Joined
Aug 12, 2004
Messages
218
If you had problems stopping the Bronco while moving it around at low speeds, I'd recommend bleeding the fronts. If what I understand your saying the rears are leaking. Majority of your braking should come from the front. Rears I've always have been told provide support and stability when braking.
 

B RON CO

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Jun 29, 2016
Messages
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Loc.
Statesville, NC
Hi, so you already have gm disc brakes up front. Did you do the necessary grinding for caliper clearance?
I would not put disc brakes on the rear. And I wouldn't buy parts until I knew what is needed.
Fix what needs it and get a good solid brake pedal. Post pictures of the before and after. Good luck
 

DirtDonk

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Bronco Guru
Joined
Nov 3, 2003
Messages
47,344
Seems like I got a leak coming from my wifes 74 and the brake performance isnt good.

Those could be related, or not. But only a thorough going through will tell you for sure.
It can be gear oil back there too, but since you say the fluid level goes down, that's a pretty good indicator of the wheel/slave cylinder.
Easy fix.

Im not going the hydroboost route for a while so dont ask.

So non-power assist at all right now? I had manual brakes and thought they stopped really well. Was glad too, because as nice as boosted brakes are, I prefer simplicity.
The fact that it was cheaper didn't escape me either, but that wasn't the driving force.

So, do I just replace everything with a new drum kit for around $150 or do I go disc setup for a lot more?

Depends.
Disc brakes are not necessarily more powerful unless you up-size them. I waited until I needed new drums too, before I went with discs. Up until then it was just too easy to replace the normal service items like shoes, and then renew the old cylinders with a $4 kit.
You can buy a whole kit with drums of course, but until you open up the old ones for inspection you can't know what's needed. And speaking of that, don't forget to factor new rear wheel bearings into that mix. If it's never been done, then now's the time.

Will I notice a performance difference?
I know maintanence will be a lot easier. Is there a drum upgrade available?

Again, depends.
Does this '74 have big brakes, or small? Are they in good shape with good quality shoes? Are the drums worn beyond their service life, or are they still good? Lots of things can make disc's "better" but it's not automatic.

As for a drum upgrade, that depends on what you have now. But big or small, you can install a larger diameter slave cylinder for more power-per-pound of pedal pressure. But it's a crapshoot whether it'll be a good improvement or will be too much.
I did the larger wheel cylinder thing when I went to disc up front while keeping my H-block instead of a prop valve, and it seemed to balance well. I had the big drum brakes though, so your results may vary if you have the smaller rear brakes.

Because it's not that much work, if you're doing your own work anyway it's a good idea to give it a quick inspection to see what you're in for. Maybe you don't need new wheel bearings. Maybe you only need new wheel cylinders and you're done. Maybe you need it all after all.
But you'll only know once you look.

Paul
 

Jfryjfry

Sr. Member
Joined
Aug 28, 2017
Messages
502
Your brakes work the same regardless of what driveshaft isn’t installed. The brakes are on the hub/wheel, not on the transfer case.

Drums in the rear will be just fine. New/good wheel cylinders, good shoes that match good drums, properly adjusted.

And of course unobstructed lines that are properly bled.
 
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panteramatt

Sr. Member
Joined
Mar 11, 2011
Messages
651
Those could be related, or not. But only a thorough going through will tell you for sure.
It can be gear oil back there too, but since you say the fluid level goes down, that's a pretty good indicator of the wheel/slave cylinder.
Easy fix.



So non-power assist at all right now? I had manual brakes and thought they stopped really well. Was glad too, because as nice as boosted brakes are, I prefer simplicity.
The fact that it was cheaper didn't escape me either, but that wasn't the driving force.



Depends.
Disc brakes are not necessarily more powerful unless you up-size them. I waited until I needed new drums too, before I went with discs. Up until then it was just too easy to replace the normal service items like shoes, and then renew the old cylinders with a $4 kit.
You can buy a whole kit with drums of course, but until you open up the old ones for inspection you can't know what's needed. And speaking of that, don't forget to factor new rear wheel bearings into that mix. If it's never been done, then now's the time.



Again, depends.
Does this '74 have big brakes, or small? Are they in good shape with good quality shoes? Are the drums worn beyond their service life, or are they still good? Lots of things can make disc's "better" but it's not automatic.

As for a drum upgrade, that depends on what you have now. But big or small, you can install a larger diameter slave cylinder for more power-per-pound of pedal pressure. But it's a crapshoot whether it'll be a good improvement or will be too much.
I did the larger wheel cylinder thing when I went to disc up front while keeping my H-block instead of a prop valve, and it seemed to balance well. I had the big drum brakes though, so your results may vary if you have the smaller rear brakes.

Because it's not that much work, if you're doing your own work anyway it's a good idea to give it a quick inspection to see what you're in for. Maybe you don't need new wheel bearings. Maybe you only need new wheel cylinders and you're done. Maybe you need it all after all.
But you'll only know once you look.

Paul

Thanx Paul. Its a power boosted system though you guys. You got a number for the wheel bearings? Also how do you check to see what size drums are on there now?
 

billh1289

Contributor
Full Member
Joined
Jul 2, 2006
Messages
471
Loc.
Jackson, NJ
Thanx Paul. Its a power boosted system though you guys. You got a number for the wheel bearings? Also how do you check to see what size drums are on there now?

Assuming that rear is original there were 2 possible size bearings (small or big). There should be a number stamped on the back of the backing plate that as far as I know will accurately identify the bearing size. Worked for mine anyway. For the size of the drum just take it off and measure the inside diameter. Where are you in south Jersey?
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,344
The brakes are different widths and diameters, but a '74 could have had an oddball size too. For other years if you have the big brakes you have the big bearing, and small brakes meant small bearing.
But a '74 can have the small brakes and big bearing, making it a "medium duty" setup. Just a nickname given it by us out here in the real world. But as was said, there are only the two sizes of bearing at least.

If you look at the backside of the brakes and don't find any numbers, look at the axle tube itself. if it's straight all the way to the backing plate and bolting flange, it's a small bearing. If it's got a small bulge about a 1/2" before the end, it's a big bearing.
Or at least it should be!

Here's some more info that that effect: https://www.wildhorses4x4.com/category/bronco_rear_axle
Sorry the pics are not active and can't be enlarged. thought we had that corrected...

If you don't know, these sealed bearings have a life expectancy of about 125 to 150 thousand miles before they self-destruct. Both sizes, but especially the small version.
So the recommendation is that by 100k miles it's time to start planning their replacement. Mine large bearings were dry, loose and hard to turn at 90k so while somewhat consistent, it's not unheard of for them to die an early death.
Be extra careful with the wife's EB obviously, but if it's got more than 100k on it, and you don't know the history of the rear bearings, be sure get some new ones in there.
It's a classic case of "cheap insurance" when it comes to Broncos.

Paul
 

gr8scott

Contributor
Bronco Guru
Joined
Jul 1, 2011
Messages
1,823
Here's my '74 with 10" drums and large bearings. Kind of hard to see with all the mud and grime. Recently did a Set 20 bearing and seal change.
It has the "Torino" bolt pattern with 3/8" bolts.
 

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