Four Wheel Disc Advice and Recommendations

[Machspeed 219]

I have a 69 Mach 1 with OEM power disc brake system of front discs and rear drums. I'll be needing to replace and/or rebuild what I have, this to include the master cylinder and booster. As such, was thinking that I might just upgrade a bit and go with a four wheel disc set up. I will be keeping with 15" Ford factory Magnum 500's. I believe the rear are 8" while the front are 7", not sure on the offset.  I'm not going to be road racing the car and frankly, it's just that if I need to replace all this, I might as well upgrade a bit. Moreover, I do prefer discs over drums. If I go with a four wheel disc set up, what changes will need to be incorporated to run it? The other thing is, I'm converting my car over from an FMX auto to a TKO-600 so things need to fit.  Advice on parts or a kit would be most appreciated. 

Thanks,

John 

[JayEstes 172]

Here is my not-so-popular take:  If you can rebuild and adjust the back  drums and mash the parking brake and lock them up, what more braking power do you really need in the back?  I hate drums brakes more than your average guy, but I've got my front discs dialed-in for almost no pedal, solid feel and back brakes adjusted carefully to provide maximum assist without dragging.  I've got more brakes than I need.... however, I've just a driver, not road racing.  The road racing is the biggest differentiator - but are 4 wheel disc really required?  If you don't have more weight in the back than my stock car, how can you get much grip back there?  The ass end of these cars weighs next to nothing, and I don't feel like rear-disc is required.  

[Machspeed 219]

I know Jay, and I've thought about what you said prior to posting. I've never really been disappointed with the factory equipped brakes, it's just that I need to replace everything. My booster, which I will keep, needs to be rebuilt. The MC, wheel cylinders, calipers, rotors, drums, all need to be replaced and/or rebuilt. If I've got to do that, I might as well look into a slight upgrade and discs are not that much more than drums from what I'm finding. The conversion appears to be easy, though I'm a bit uncertain about changes needed for the MC. Thanks!   

[lanky 44]

Every car I've converted from drums to discs, braking power has nothing to do with it. It improves the braking feel, and allows much better braking balance IMO. We all know how much easier servicing discs are too.

Slightly off topic, but I just converted my dd's rear brakes to disc since the drums were warped. Huge improvement even under normal driving conditions (Toyota Solara).

[Machspeed 219]

15 minutes ago, lanky said:

Every car I've converted from drums to discs, braking power has nothing to do with it. It improves the braking feel, and allows much better braking balance IMO. We all know how much easier servicing discs are too.

Slightly off topic, but I just converted my dd's rear brakes to disc since the drums were warped. Huge improvement even under normal driving conditions (Toyota Solara).

Details please? What did you go with and how much did you change out to make the conversion?  

[cavboy78 28]

Opentracker sells a rear disc kit that is easy to install. I have it on my 66 and works great. Mustang Steve has rear disc options as well if you want to use a late model mustang set-up, but i think they all require a 17" wheel for clearance. 

[Rich Ackermann 174]

On 4/15/2020 at 11:19 AM, Machspeed said:

I have a 69 Mach 1 with OEM power disc brake system of front discs and rear drums. I'll be needing to replace and/or rebuild what I have, this to include the master cylinder and booster. As such, was thinking that I might just upgrade a bit and go with a four wheel disc set up. I will be keeping with 15" Ford factory Magnum 500's. I believe the rear are 8" while the front are 7", not sure on the offset.  I'm not going to be road racing the car and frankly, it's just that if I need to replace all this, I might as well upgrade a bit. Moreover, I do prefer discs over drums. If I go with a four wheel disc set up, what changes will need to be incorporated to run it? The other thing is, I'm converting my car over from an FMX auto to a TKO-600 so things need to fit.  Advice on parts or a kit would be most appreciated. 

Thanks,

John 

Hi, I converted my 70 from all drum to all disc. Have not driven the car, so I can only speak to the conversion and installation.

I bought the whole thing from CPP and the brake lines from inline tube.. I used Granada front spindles/disc. The install was straight forward. The Granada flex lines required a adapter to connect to the stock hard line. The 69 disc/spindle not as strong as the stock 70-73 or the Granada units. Both will require changing the outer tierod ends and the Granada hub diameter is larger (70mm) and will not fit stock wheels. The 70-73 stock setup will connect to the hard lines without an adapter like the Granada brakes and works with 14" wheels. Converting the rear complicates things a little more. These kits commonly use a GM Eldorado rear brake caliper. It comes with brackets to adapt them to a Ford 8" or 9". Depending on rotor size they require a 15" or larger wheel. They typically require cutting the drum hard brake lines to connect to the flex lines in the kit. If you have stainless steel lines, you need hydraulic equipment to re-flare them after cutting. I chose not to use the flex lines and avoided needing to cut the lines and just had to bend them. The big challenge for me was what proportioning valve to used. If you stay with a disc/drum setup, a stock 70 valve and stock brake lines will work fine, but if going all disc a GM PV4 valve is needed. With this valve there will be master cylinder lines, brake line, brake light switch, and valve mounting modifications, as well as line adpters needed. Also, the parking brake cables will need to be modified or partially replaced with a Lokar type kit. So rear disc brakes are a nice upgrade but cost, and installation effort is greater than staying with a stock rear drum setup. The cheapest and easiest is disc/drum for all the reasons stated above. 

One additional comment, you mentioned converting to a Tko or tremec 600, if you also convert to a hydraulic clutch, i believe a small (7"-8") brake booster is needed for clearance reasons.

[Machspeed 219]

Thank you gentlemen! After looking at things and evaluating the use of my car, am thinking I'm going to stick with the stock setup.  

[barnett468 418]

1 hour ago, Machspeed said:

Thank you gentlemen! After looking at things and evaluating the use of my car, am thinking I'm going to stick with the stock setup.  

If you want to improve on the stock setup, you can run EBC Green Stuff pads, and shoes if they make them.

If you drive it hard occasionally, ENDLESS RF650 brake fluid will give you the firmest pedal feel without fade.

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[Machspeed 219]

The problem I have with replacing the OEM parts is that most of them are made in China. And, what pisses me off is that one really has to look to find out the origin of the product. Looking at replacing it all with Raybestos through Rock Auto. Thoughts/comments please?  

[barnett468 418]

30 minutes ago, Machspeed said:

The problem I have with replacing the OEM parts is that most of them are made in China. And, what pisses me off is that one really has to look to find out the origin of the product. Looking at replacing it all with Raybestos through Rock Auto. Thoughts/comments please?  

Most aftermarket discs are now made in China, including, some, if not all Raybestos rotors. EBC pads and discs are  made in England.

 

[Machspeed 219]

Thanks Barnett! Say, I wonder if you might know.... I believe my car came with 1.75" wide rear shoes. I do see however that 2" is available, as are the drums. If my car came with 1.75" shoes and drum, would there be a problem in going to 2" shoes and 2" drum?

Thanks,

John

[stangman69 17]

On 4/17/2020 at 8:59 AM, Rich Ackermann said:

Hi, I converted my 70 from all drum to all disc. Have not driven the car, so I can only speak to the conversion and installation.

I bought the whole thing from CPP and the brake lines from inline tube.. I used Granada front spindles/disc. The install was straight forward. The Granada flex lines required a adapter to connect to the stock hard line. The 69 disc/spindle not as strong as the stock 70-73 or the Granada units. Both will require changing the outer tierod ends and the Granada hub diameter is larger (70mm) and will not fit stock wheels. The 70-73 stock setup will connect to the hard lines without an adapter like the Granada brakes and works with 14" wheels. Converting the rear complicates things a little more. These kits commonly use a GM Eldorado rear brake caliper. It comes with brackets to adapt them to a Ford 8" or 9". Depending on rotor size they require a 15" or larger wheel. They typically require cutting the drum hard brake lines to connect to the flex lines in the kit. If you have stainless steel lines, you need hydraulic equipment to re-flare them after cutting. I chose not to use the flex lines and avoided needing to cut the lines and just had to bend them. The big challenge for me was what proportioning valve to used. If you stay with a disc/drum setup, a stock 70 valve and stock brake lines will work fine, but if going all disc a GM PV4 valve is needed. With this valve there will be master cylinder lines, brake line, brake light switch, and valve mounting modifications, as well as line adpters needed. Also, the parking brake cables will need to be modified or partially replaced with a Lokar type kit. So rear disc brakes are a nice upgrade but cost, and installation effort is greater than staying with a stock rear drum setup. The cheapest and easiest is disc/drum for all the reasons stated above. 

One additional comment, you mentioned converting to a Tko or tremec 600, if you also convert to a hydraulic clutch, i believe a small (7"-8") brake booster is needed for clearance reasons.

@Rich Ackermann - would I not be able to retain the factory proportioning valve and add an adjustable block to the rear line?  That's what I've done and while I don't have any road time yet, I'm at a perfect time to fix my mistake if what I've done won't work...

Thanks,

Nate