• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Disc/Disc Master Cylinder for Bronco II


speedysprocket

Active Member
Joined
Dec 22, 2008
Messages
33
Reaction score
2
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
So I put Mustang discs on the rear of my 85 Bronco II without changing the master cylinder and they're definitely not working as hard as the fronts. With a lot of hard braking around the block, front rotors will be about 220 degrees while rears around 110.
I know there's no proportioning valve to change.
I also know discs and drums work on different principles- drums cylinders use a small volume of high pressure while disc calipers move a lot of volume at a lower pressure.
So what disc/disc master cylinder bolts up? I looked at the Mustang and Explorer ones, but they seem to have metric flare nut threads while the stock is SAE. Is the only and best option to run the Mustang and change the brake lines, or is another master cylinder hiding out there somewhere?
Thanks!
 


dirtcowboy

Well-Known Member
V8 Engine Swap
Solid Axle Swap
Joined
Mar 18, 2008
Messages
336
Reaction score
7
Location
NW Montana
Vehicle Year
1985,1986(2),19
Make / Model
FORD
Engine Size
2.9, 4.6, 4.0, 6.8, 5.0x4
Transmission
Automatic
I used an F-350 master, made my own lines. Brakes all day, every day and twice on Sundays!
 

BlackBII

Ranger Custom
Article Contributor
OTOTM Winner
TRS Banner 2010-2011
Truck of Month
Joined
Aug 14, 2007
Messages
7,913
Reaction score
1,012
Location
UT
Vehicle Year
1989
Make / Model
Ford
Engine Type
4.0 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
5
Tire Size
33

adsm08

Senior Master Grease Monkey
Supporting Member
Article Contributor
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
34,623
Reaction score
3,629
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
I used a 95 non-ABS Explorer master and just got the proper line adapter.
 

lvwill

Well-Known Member
Joined
Sep 15, 2013
Messages
430
Reaction score
143
Location
Las Vegas Nv.
Vehicle Year
2020
Make / Model
ford
Engine Type
2.3 EcoBoost
Engine Size
2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
2WD
Tire Size
265/65/17
I used a 96 explorer master and it bolted right up. Had to adjust the pushrod a little shorter but that's it.
On a 92 ranger.
 

dirtcowboy

Well-Known Member
V8 Engine Swap
Solid Axle Swap
Joined
Mar 18, 2008
Messages
336
Reaction score
7
Location
NW Montana
Vehicle Year
1985,1986(2),19
Make / Model
FORD
Engine Size
2.9, 4.6, 4.0, 6.8, 5.0x4
Transmission
Automatic
I will get pics and part #,s tomorrow.
 

dirtcowboy

Well-Known Member
V8 Engine Swap
Solid Axle Swap
Joined
Mar 18, 2008
Messages
336
Reaction score
7
Location
NW Montana
Vehicle Year
1985,1986(2),19
Make / Model
FORD
Engine Size
2.9, 4.6, 4.0, 6.8, 5.0x4
Transmission
Automatic
This is the brake master cylinder for an '86 Ford F-350 that I used on my BII. I compared it to an AC Delco unit my local NAPA had on the shelf, they were the same. The MC has 1 1/8" piston bore, moving lot's more fluid. Cammeddrz posted this setup before, and I copied his idea. http://www.therangerstation.com/forums/showthread.php?t=89225 Read this post as it also describes switching the brake lines on the MC. I also had a Wilwood prop valve but I haven't needed to use it.

BYPASS THE RABS CRAP!!!!! BYPASS THE RABS CRAP!!!!!

I also had to grind the MC a bit to make the bolt holes wider, I used a simple carbide bit and my electric drill, it took about 2 minutes to do.

https://www.amazon.com/Dorman-M39445-Brake-Master-Cylinder/dp/B001PYNY6C/ref=sr_1_1?ie=UTF8&qid=1525626972&sr=8-1&keywords=1986+ford+f-350+master+cylinder

Installed pic


The lines pictured were made with the cheap crap, they are a cool green now.

I originally bought bulk brake line from Amazon, but I couldn't get it to flare properly. After further inspection I found that the tubing was produced with the fluid transport port about 1.5 RCH to one side, making it impossible to get a proper flare, so I trashed it. NAPA has some 3/16 brake line that has a cool dark green finish. I needed 10' 2" of line. I bought a 72" and a 51" piece, with a brass union and it worked out great, at a cost of about $16.00.

Like I said, brakes for days!

Oh, yeah, HE'S OUT OF THE GARAGE!!!!!

 
Last edited:

speedysprocket

Active Member
Joined
Dec 22, 2008
Messages
33
Reaction score
2
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
I saw there are some new OEM Ford Explorer ones on eBay that appear to even include the proportioning valve at pretty reasonable prices. I might just grab one of those and then figure out the lines.
 

speedysprocket

Active Member
Joined
Dec 22, 2008
Messages
33
Reaction score
2
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
I bought a 97 explorer master cylinder on eBay with the proportioning valve. Looks like the front is a DIN flare and the rear valve is an SAE double flare? Can anyone confirm and the thread sizes?
 

speedysprocket

Active Member
Joined
Dec 22, 2008
Messages
33
Reaction score
2
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
Well put the 1995-97 master cylinder in. Pedal is nice and hard, but I still have to stand on it to get the truck to stop, and I still can’t lock a tire up. I hear them working hard like they’re about to skid, but they don’t. Is there a stronger booster that could be helping me? Or is this just Bronco II fate for stock front brakes with 33” tires?
 

speedysprocket

Active Member
Joined
Dec 22, 2008
Messages
33
Reaction score
2
Vehicle Year
1985
Make / Model
Ford
Transmission
Manual
For anyone interested, I pulled the booster out of a 1998 explorer sport. It’s both a larger diameter and longer than stock Bronco II.
To fit, I had to elongate the firewall/pedal box holes, cut the push rod and weld the stock one on because the explorer was too short, and grind down the steering joint tabs that were hitting the larger booster.
The result was maybe slightly better braking, but with noticeably less effort.
I think the only thing that would improve more are better pads, maybe like EBC.
 

85_Ranger4x4

Forum Staff Member
TRS Event Staff
TRS Forum Moderator
Article Contributor
V8 Engine Swap
OTOTM Winner
TRS Banner 2010-2011
TRS 20th Anniversary
VAGABOND
TRS Event Participant
Joined
Aug 7, 2007
Messages
33,164
Reaction score
20,096
Location
SW Iowa
Vehicle Year
1985
Make / Model
Ford
Engine Type
V8
Engine Size
5.0
Transmission
Manual
What benefit do you get from a larger bore master cylinder?
Moves more fluid for altered braking setups.

I put an Explorer 8.8 in with disk brakes and the stock MC was fine. I upgraded to ‘95 twin piston calipers (D35 swap mainly) and whoosh... nobody home. So I went to a ‘85 full-size MC and all was well.
 

lvwill

Well-Known Member
Joined
Sep 15, 2013
Messages
430
Reaction score
143
Location
Las Vegas Nv.
Vehicle Year
2020
Make / Model
ford
Engine Type
2.3 EcoBoost
Engine Size
2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
2WD
Tire Size
265/65/17
When I swapped the rear to disk brakes I also installed the master cylinder for a 97 explorer. Rear disk brakes require more fluid flow than drum brakes. This was on a 92 ranger 4x4. The only thing I had to alter is shortening the pushrod on the booster.
 

Sponsored Ad


Sponsored Ad

Staff online

Today's birthdays

TRS Events

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Rick W
October Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

25th Anniversary Merch

Follow TRS On Instagram

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top