1969 Fairlane brake upgrade

[69Cobra428]

It's the bore size that counts. The size of the reservoirs makes no difference.

I'm going to go back to your 1st post and say that the OEM Ford front discs aren't really all that hot for a 500hp ride. Heck, no muscle cars of the era (and I drove most all of them) had brakes worth a darn except for a few (4 wheel disc Vettes, Boss 302's, Z-28's). Point is you may still need to upgrade the fronts to bigger and better rotors/calipers even with rear discs. Try your changes now and then decide on rear discs....and then maybe better fronts. I did on my '70 Mach 1 and although it was all quite pricey, the car now stops like an SCCA racer.

Well I’ve already got the rear discs on there

[machoneman]

It's the bore size that counts. The size of the reservoirs makes no difference.

I'm going to go back to your 1st post and say that the OEM Ford front discs aren't really all that hot for a 500hp ride. Heck, no muscle cars of the era (and I drove most all of them) had brakes worth a darn except for a few (4 wheel disc Vettes, Boss 302's, Z-28's). Point is you may still need to upgrade the fronts to bigger and better rotors/calipers even with rear discs. Try your changes now and then decide on rear discs....and then maybe better fronts. I did on my '70 Mach 1 and although it was all quite pricey, the car now stops like an SCCA racer.

Well I’ve already got the rear discs on there

Missed that. Great. One other thing, if you stick with the OEM front discs, note that most off-the-shelf pads are hard (like in way too hard) for long life. You many wanted to investigate softer pads for better street braking. Porterfield, Performance Friction, Hawk and other aftermarket brake pad makers offer a wide range of soft to hard pads.   

https://www.porterfield-brakes.com/

https://pfcbrakes.com/products/brake-pads

[69Cobra428]

It's the bore size that counts. The size of the reservoirs makes no difference.

I'm going to go back to your 1st post and say that the OEM Ford front discs aren't really all that hot for a 500hp ride. Heck, no muscle cars of the era (and I drove most all of them) had brakes worth a darn except for a few (4 wheel disc Vettes, Boss 302's, Z-28's). Point is you may still need to upgrade the fronts to bigger and better rotors/calipers even with rear discs. Try your changes now and then decide on rear discs....and then maybe better fronts. I did on my '70 Mach 1 and although it was all quite pricey, the car now stops like an SCCA racer.

Well I’ve already got the rear discs on there

Missed that. Great. One other thing, if you stick with the OEM front discs, note that most off-the-shelf pads are hard (like in way too hard) for long life. You many wanted to investigate softer pads for better street braking. Porterfield, Performance Friction, Hawk and other aftermarket brake pad makers offer a wide range of soft to hard pads.   

https://www.porterfield-brakes.com/

https://pfcbrakes.com/products/brake-pads

Thanks for that info. I will look into those.

I’m not sure why the rest of my post didn’t show but I mentioned that I will make some adjustments to the push rod and see how it works. I’m hoping it will work for the summer and then I will look into a new master and maybe some bigger front discs as next winters project

[machoneman]

Be careful with the pushrod adjustment as if it's set too tight (long) it will put pressure on the master's piston and cause brake drag.

[SReist]

Rear disc brake conversions are sometimes very tough to bleed. Especially the ones with the parking brake incorporated into the caliper. The bleeder screw my not be positioned at the
high point. You may have to remove the caliper and tilt it. These kits are typically a mismatch of factory parts. Hope this helps, Steve

[TomP]

Just a sec… you have a disc drum master but using disc all around? There is a residual valve in the master for those rear drums.  Use a four wheel disc master , like Explorers and 94 and newer Mustangs have.

I am just not a power brake guy and the Hydroboost even less but those are not as critical for bore size as manual brakes are.  Too big a bore with manual and you will need both feet to push the pedal.

I am curious what I am seeing in JimComet's picture. It looks like the stock motor mount perch area but a rear steer rack and tube upper control arms with a coilover. Does that still use the original lower arms and spindles?

That Stratus master is compact!

[Falcon67]

It's the bore size that counts. The size of the reservoirs makes no difference.

I'm going to go back to your 1st post and say that the OEM Ford front discs aren't really all that hot for a 500hp ride. Heck, no muscle cars of the era (and I drove most all of them) had brakes worth a darn except for a few (4 wheel disc Vettes, Boss 302's, Z-28's). Point is you may still need to upgrade the fronts to bigger and better rotors/calipers even with rear discs. Try your changes now and then decide on rear discs....and then maybe better fronts. I did on my '70 Mach 1 and although it was all quite pricey, the car now stops like an SCCA racer.

If you are using the 70s single piston calipers, the reservoir makes a difference.  For sure a drum/drum master is short on volume in the rear chamber to safely (in my mind) operate the big piston front units.  I run single piston front (75 Comet), drum rear, disk/drum (76 Maverick) manual master with a 15/16 bore and organic front pads.  I have not changed or wore out a set of pads or shoes since a freshened them in 2004.  No problem stopping a 3250 lb race car from 90+ MPH on the track, stops fine on the street.  Holds fine in the burnout box.  To add to that, I bracket race which means I'm on the brakes either riding or punching at 90~95 MPH in the lights when running the finish line.  I might look into upgraded disks on the corners if the car got over, say, 100~110 MPH in the 1/8 mile.  I'd have no issue running 6.80s,90s or so in the 1/8 on the stock system.  Passes - I have no idea in the last 16 years, but between 2003 and 2005 when I was saving ET slips, I tossed out 2200 or so slips.

Also note that most of the braking - 70% or so - is handled by the fronts, so the rear isn't all that busy most times. Running SCCA or some such track racing is different.  On the street, meh.  If you like 'em, run 'em.

Multi-piston calipers likely don't need much master volume.  The dragster weighs 1650 lbs with driver and runs 126 in the 1/8.  The braking system is two 4 piston calipers and a bitty 7/8" bore master cylinder.  There's more volume in a coke can.
 

[machoneman]

Rear disc brake conversions are sometimes very tough to bleed. Especially the ones with the parking brake incorporated into the caliper. The bleeder screw my not be positioned at the
high point. You may have to remove the caliper and tilt it. These kits are typically a mismatch of factory parts. Hope this helps, Steve

Trick I learned long ago from a Formula III racer. Pop off the caliper, pads included, and stuff a cut-down 2X4 or other other chunk of wood about the thickness of the rotor between the pads. Hold up or wire up the caliper with the bleeder facing up. Have your helper push the brake pedal until all air is cleared. Tighten the bleeder, yank the wood and re-install the caliper. Move onto the next wheel and repeat.

Works every time!