FYI FORD - MustangSteve's Ford Mustang Forum
The Internet's Most Knowledgeable Classic Mustang Information
IF YOU HAVE A QUESTION ABOUT CLASSIC FORD MUSTANGS, YOU HAVE COME TO THE RIGHT PLACE!
MustangSteve has over 30 years of Mustang experience, having owned 30 of them and restored several others. With the help of other Mustangers, this site is dedicated to helping anyone wanting to restore or modify their Mustang.... THERE ARE NO DUMB QUESTIONS!!!!!
Visit MustangSteve's web site to view some of my work and find details for:
FYIFORD Contributors' PICTURES - Power Brake Retrofit Kits for 65-66 Stangs - Classic Mustang FAQ's by MustangSteve - How to wire in a Duraspark Ignition - Mustang Ride Height Pictures and Descriptions - Steel Bushings to fit Granada Spindles to Mustang Tie Rods - Visit my EBAY store MustangSteve Performance - How to Install Granada Disc Brakes MustangSteve's Disc Brake Swap Page - FYIFORD Acronyms for guide to all the acronyms used on this page - FYIFORD Important information and upcoming events

You are not logged in. Would you like to login or register?

12/17/2018 10:59 AM  #1


More Brake confusion?!

My sons car is a 66 289 Automatic non power Drums all the way around.
Budget is tight.  We are looking into several options and hoping to eventually end up with disk conversion up front.
For now we are trying to get the car driveable. I would like to convert to a dual bowl MC at least. We recently were offered a Powerbrake MC setup from a local mustanger, but he says it is for a 6 cylinder.
Questions: What is the different between 66 cylinder and v8?  Automatic and Standard? Zbar linkage I assume?
When and why do you use the 15/16 bore vs a 1 inch bore? Proportioning valve is only needed for Disk and drum combinations, right?
Eventually the plan will be CSRP kit and MS power brake kit, until then we are trying to get some type of MC on to just find out what other issues the car has.  I hate to buy another single bowl just to get it moving as it would be nice if the MC we pick up could be used as we continue to upgrade.
Thanks for any help and sorry about all of the questions.
 

 

12/18/2018 3:46 PM  #2


Re: More Brake confusion?!

IMO already contemplating a swap from drum/drum to power disc/drum I would just buy a new stock master cylinder and get the brakes working.  With a tight budget there's no reason to spend the money twice.  Also, going to non-stock parts can cause issues you didn't have before.  IMO its better to get it working and then modify it, so you know what caused the problem.  A single bowl master is all of $40.

The power boosters are the same between 6 and 8 cylinder cars, assuming stock parts.

In a drum/drum system all the car has is a distribution block.  There is no proportioning needed.  A disc/drum car needs a proportioning valve to keep the rear brakes from prematurely locking up and sending you into a skid under heavy braking.  The factory valves were in the rear brake line by the rear axle until, IIRC, the '70 model year when Ford went to a combination valve that combined the distribution block and proportioning valve into one piece which was under the hood. 

Master cylinder bore size is going to depend on the system you are using.  Disc systems use a larger bore because the bore size equates to how much fluid the master moves and a caliper needs more fluid than a wheel cylinder.  Why you typically find power boosters on disc cars is because moving the larger bore master requires more effort.  All things being equal a 1" bore master seems to be what was used in all stock applications for my '67, which had a factory dual circuit design. 

 

12/18/2018 4:05 PM  #3


Re: More Brake confusion?!

I will add............15/16" bore works for NON-power assist MC's.(front disc/rear drum)
Maverick MC is 15/16" bore  for their manual  front disc/rear drum set-up.....works for your application. Mustang steve has the special fittings that will work. A good idea to change out the complete front and rear brake lines IF they are original.  Lotsa cruddy stuff in those lines after 60 years.
6sally6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

12/18/2018 4:27 PM  #4


Re: More Brake confusion?!

Thanks guys.  I really appreciate the complete and detailed information. I agree TKO, its likely best just to grab a 40 dollar single bowl and see where any other issues might be lurking, then purchase the conversion kit and all the other associated parts to complete the job.
 

     Thread Starter
 

12/18/2018 5:42 PM  #5


Re: More Brake confusion?!

If your plans include new front drums. When I did my 66 years back I noticed the catalogs listed only 1 drum for all 65 to 73 drums no matter if it was a small block or a big block. Small block cars used a 2.25" wide shoe while big blocks used a 2.50" wide shoe. So I used 2.50" wide big block shoes on the front of my 66. They really worked great. The factory drums were not finned. The aftermarket drums are finned. Between the wider shoes and finned drums it was a very effective! That set up worked so well, when I went to disc I really didn't notice any improvement.


I'm not a complete idiot.....pieces are missing. Tom
 

12/18/2018 5:46 PM  #6


Re: More Brake confusion?!

Other than the issues with repeated stops, and wet weather driving, drum brakes work just fine. My brother's 69 Mach 1 428scj has 4 wheel manual brakes, and it will stop as quickly as my 13" Cobra 4 wheel disc 69. Go with the new master cylinder and be done.


Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
 

12/20/2018 6:04 AM  #7


Re: More Brake confusion?!

Old tech is neat, but there's a reason OEMs went to disc/drum, and then disc/disc.  Today you cannot find a new vehicle that uses drum brakes for anything but the parking brake located inside the back of a disc. 

The braking on my car going from drum/drum to power disc/drum was night and day. 

If like mot people you are used to how a new vehicle stops you're going to find drum/drum brakes somewhat unnerving to drive.  That first stop usually isn't a big deal, but every stop thereafter takes longer and longer.

 

12/20/2018 1:47 PM  #8


Re: More Brake confusion?!

Qstang wrote:

Thanks guys.  I really appreciate the complete and detailed information. I agree TKO, its likely best just to grab a 40 dollar single bowl and see where any other issues might be lurking, then purchase the conversion kit and all the other associated parts to complete the job.
 

I agree.  my single pot disk/drum mc  lasted 400,000 miles and over 20 years.  It will be easier to plumb too.  Disk mc's are different than drum mc, so be sure to get the correct one.
 


Original owner - 351w,T-5, 4whl disks, power R&P
 

12/20/2018 2:46 PM  #9


Re: More Brake confusion?!

IMO the biggest problem with drums these days is that the asbestos issue put the end to properly arced shoes and it is nearly impossible to make a set of drums work as they were designed to do.  Back when I had a 97 F150 with rear drums (last year before all discs) I designed a setup for my table saw that would properly arc shoes.  Never got it built...just lived with crappy rear brakes until I bought the '13.

BB


 

Last edited by Bullet Bob (12/20/2018 2:49 PM)


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

12/20/2018 4:09 PM  #10


Re: More Brake confusion?!

My opinion:  Do it right, one time. 

If you are not going to drive very far, you could use a 70 MC for disc/drum on a drum/drum manual setup, but there might be some slight drag of the front drums.  Maybe that would be a good way to get you off TDC and install the discs at the same time.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

Board footera


REMEMBER!!! When posting a question about your Mustang or other Ford on this forum, BE SURE to tell us what it is, what year, engine, etc so we have enough information to go on.