72 brake pedal & booster questions

[Bryan_Tenn]

I've been lurking here for months & just want to say what a great forum for 67-72 info.

I bought a 72 a few months ago & my plans are to make a shop truck out of it. I own a lawn & garden repair/small engine business & I want something I'm not afraid to get a scratch on, just a reliable truck to throw mowers in & haul my trailer. I used to restore first gen Mustangs but had gotten out of working on old Fords for a few years & this has been a lot of fun, & frustrating too LOL!

Anyway, I just got spindles, rotors, & proportioning valve from a 74 that doesn't have power brakes. I've read & read on here but still confused as to what pedal I need for power brakes.

I plan on getting a power booster & MC from a 74-75??? Do I need to change my brake pedal? I know I need to find brackets for the booster as this 74 is not power, which year do I need to find a donor booster for the core & brackets?

Thanks so much for your help

[ultraranger]

I used a dual-diaphragm booster/brackets from a '75 F-350 in my '69 F-100. The booster has a straight input rod and was a direct connection to my '69 brake pedal. You'll also need the hard plastic tube that goes between the firewall and the back of the booster.

I turned the wrecking yard donor booster in on a newly rebuilt booster.

http://m.oreillyauto.com/mt/www.oreilly ... &ppt=C0066

[sargentrs]

Hey Steve! I see you used a newer M/C with that booster. Got a link to which one that is or what make/model it's for? Would look good on my build when I get there. Thanks and my apologies for the hijack!

[Bryan_Tenn]

well, I just went & got a booster, MC, rod, & the plastic sleeve the rod rides in off of a 79 2WD. I hope it all will work

[ultraranger]

well, I just went & got a booster, MC, rod, & the plastic sleeve the rod rides in off of a 79 2WD. I hope it all will work

Is the booster input rod round or flat?

[Bryan_Tenn]

the rod itself is round, its flat of course where it hooks to the pedal. I havent taken it apart so I cant see what it looks like in the back of the MC. But the rod is round, & it turns down & is flat where it mounts to the brake pedal

[ultraranger]

Hey Steve! I see you used a newer M/C with that booster. Got a link to which one that is or what make/model it's for? Would look good on my build when I get there. Thanks and my apologies for the hijack!

The '75 F-350 booster had a MC on it with a 1-1/4" bore, when I got the booster from the wrecking yard donor. It was for the larger front disc rotors and twin piston calipers of the 1-ton truck.

I put the booster on not very long after I bought my '69 F-100 nearly 4 years ago. Up until recently, I was running the booster with my stock 4 wheel drums. When I first put the booster on, I installed a 1.00" bore conventional style cast iron MC.

A little over a month ago, I began swapping out the front drums/beams for the front discs/beams from a '77 F-100. --I'm also installing a power steering pump/brackets, Saginaw PS gear box, tilt column from a '78 F-150 and a front sway bar from a '78 F-250 CS.

While I was removing old brake components, I noticed the conventional MC, I had just put on less than 4 years ago, already had a crusty layer of rust around the rim where the lid seals to the MC. This means every time the lid is lifted off to check the brake fluid level, or to bleed the brakes out, little pieces of rust flakes will fall down into the MC reservoirs and will eventually end up in the brake valve and in the calipers/wheel cylinders.

This isn't the first time I've used a modern MC in an older Ford application. Modern MCs have several advantages over the older conventional cast iron MC design;

They are much lighter due to their aluminum body casting and plastic reservoirs.

The aluminum body and plastic reservoir doesn't rust. This means the outside stays looking better for much longer than an iron MC. The main advantage is the inside doesn't rust either --this greatly helps to keep rust contaminants out of the brake fluid and out of the brake system components.

The top doesn't have to be taken off the modern MC to be able to see how much brake fluid is inside it. The more a MC top is taken off, the more dirt, rust or contaminants gets into the MC, --and eventually the rest of the brake system.

The other big problem, with having to remove the lid to see how much fluid is inside the MC, is the introduction of air to the brake fluid. DOT 3, 4 and 5.1 brake fluid is hygroscopic (it attracts and absorbs moisture from the air). This is very bad for the life expectancy of the brake fluid --which under normal circumstances should be changed out for fresh brake fluid every 18-24 months.

The less you have to remove the lid of the MC, the better off you (and your brake system) are. These are the primary reasons why you don't see the old conventional style cast iron MCs on modern vehicles anymore.

The newer style MC I've replace my old MC with is for a 1995 Ford Explorer. It has a 1.062" (1-1/16") bore diameter. The ports are for metric bubble flare fittings. The primary side (port closest to the booster) is 10 mm x 1.0 . The secondary fitting is 12 mm x 1.0 .

I purchased the new (not rebuilt) MC from NAPA (I don't do rebuilt brake MCs). Its part number is M3246.

This Explorer MC is designed for 4-wheel disc brakes. For now, it'll be run with rear drums but eventually, I plan to install rear discs.

Steve

[Bryan_Tenn]

the MC looks good & I agree 100% with all the advantages you listed.

Is there one that uses standard fittings like the old style? Just wondering if you checked all that out & this was the easiest. I dont guess its that big of a deal to cut & put metric fittings on one end though.

Looks awesome

I'm using 74 spindles so I guess I need 74 calipers. Since Im attempting to use a 79 booster bracket what booster & MC do I need? Are they all the same for 73-79 F150 2WD front disc rear drum?

[sargentrs]

Thanks for the info Steve! Adding that to my wish list.

[ultraranger]

the rod itself is round, its flat of course where it hooks to the pedal. I havent taken it apart so I cant see what it looks like in the back of the MC. But the rod is round, & it turns down & is flat where it mounts to the brake pedal

Sorry, I guess I didn't do a very good job of being more precise in my question about the booster you have obtained.

There were several styles of boosters available in the Bumpside trucks ('67-'72). No Bumpside F-100 came from the factory with front disc brakes. Front discs only became optionally available on F-250s and F-350s beginning in 1968.

Any F-100 through F-350 was optionally available with a booster but, F-100 would have only been with all wheel drums.

The '67 is an odd-ball year for the brake booster. It's only compatible with a '67 (well, unless you also swapped the '67's pedal(s) and pedal hanger into a later model pickup).

If you find a booster in a Bumpside, it's usually the smaller diameter single diaphragm unit but, there were some dual-diaphragm boosters. Any of the Bumpside boosters from '68-'72 should bolt into any '68-'72 model and connect directly to the pin on the brake pedal.

Beginning in '73, F-100s came standard with front disc brakes, as did all the F-250s and F-350s. Not all had brake boosters though.

There were various booster designs and various brake pedals that were used. Not all Dentside ('73-'79) boosters are directly compatible with '68-'72 brake pedals. Some Dentside brake boosters will also require swapping the Dentside pedals and pedal hanger into a Bumpside truck to be able to use the booster.

Most booster input rods are cylindrical and connect directly from the brake pedal pin to the back of the booster. Some rods are connected to a cantilever/bell crank mechanism and then another rod runs from the bell crank to the back of the booster.

Evidently, the Dentside trucks had at least two different bell crank booster versions. I believe, if I remember correctly, HIO Silver has a bell crank booster from a '75 in his Bumpside. I believe he said the flat input rod on it was a direct connection to the pin of his stock brake pedal.

I have a bell crank style booster from a '78/'79 F-150 with the longer flat input rod. In its current configuration, the flat input rod is too long to connect to the pedal pin of a '68-'72 model truck. --it would require modification to the input rod or, switching to the correct Dentside pedal/pedal hanger.

This is what the 11" single diaphragm (high-mount) '78/'79 Dentside bell crank booster looks like that I have. Notice the flat input rod to the bell crank mechanism.



The Dentside boosters with the round input rods can have round eyelets, where it attaches to the pedal pin or, it can have a triangular eyelet. The triangular version is designed for a Dentside with cruise control.

Dentside booster with round input rod and 'triangular' eyelet for cruise control shown in the following link.

http://m.oreillyauto.com/mt/www.oreilly ... &ppt=C0066

Dentside dual-diaphragm booster with round input rod and round eyelet (not for cruise control). --this is the exact booster I have on my F-100.

http://m.oreillyauto.com/mt/www.oreilly ... &ppt=C0066

[ultraranger]

Thanks for the info Steve! Adding that to my wish list.

I forgot to mention.....

There are two versions of the '95 Explorer MC. One version is designed for cruise control, the other version is without. The version I have is without --although I will eventually have CC but, controlled off a cancelling switch mounted to the brake pedal but, that's another story.

There's a 'rhino' horn at the front of the '95 Explorer MC. On this style MC, designed for CC, the 'horn' will be drilled and tapped for a pressure switch to screw into. On this style MC w/o CC, the boss is there but isn't drilled or tapped for the pressure switch.

'95 Explorer MC w/o CC. (I got my MC from NAPA but O'Reilly's had better photos to illustrate the differences).

http://m.oreillyauto.com/mt/www.oreilly ... _v_thumb=3

'95 Explorer MC w/CC.

http://m.oreillyauto.com/mt/www.oreilly ... _v_thumb=2

[sargentrs]

Got it! Thanks for pointing that out.

[ultraranger]

the MC looks good & I agree 100% with all the advantages you listed.

Is there one that uses standard fittings like the old style? Just wondering if you checked all that out & this was the easiest. I dont guess its that big of a deal to cut & put metric fittings on one end though.

Looks awesome

I'm using 74 spindles so I guess I need 74 calipers. Since Im attempting to use a 79 booster bracket what booster & MC do I need? Are they all the same for 73-79 F150 2WD front disc rear drum?

....You might wanna get a drink and a sammich before reading this. This is a long post....

As I had mentioned earlier in this thread, this isn't the first time I've used a modern MC in an older Ford application.

In late 2003/early 2004, I was designing some adapter brackets to adapt '94-'04 SN95 Mustang V6/GT rear disc brake assemblies onto the older Ford 8 & 9-inch small bearing rear end housings of the '65-'73 Mustangs. During this time (2003/2004), I was extensively searching the internet to try and find a MC designed for 4-wheel disc brakes to use with this conversion.

About the only thing I could come up with was references and photos of people using either the Corvette cast iron 4-wheel disc MCs or, references/photos of people using the Mopar 4-wheel disc MC with alumium body and black plastic reservoir.

I didn't want to use either one of these choices. I wanted a Ford solution. After a lot of searching and coming up with nothing I wanted to use, it finally dawned on me that it only made sense to use the MC that was specifically designed for the rear brakes I was adapting --the MC for an SN95 V6 Mustang.

At the time (2004), a friend of mine had a '65 Mustang fastback and agreed to let me use his car as a test platform to install the rear discs (and SN95 V6 MC)
and test them out afterwards.

At that time ('04), there was absolutely zero information or photos on the internet of anyone using this MC in a vintage Ford application. I've been a Mustang owner for much longer than I've owned a Bumpside --although the first vehicle I learned to drive, in the very early '80s, was my dad's '68 F-100 Ranger.

After I had the machine shop produce the conversion brackets, I installed them on my friend's '65 fastback, installed the modern MC, got everything hooked up and tested out the brakes. Everything went well and afterwards, I posted the information and my photos on various Mustang sites that I'm a member of (on the Mustang forums, I go by the board name, 'ultrastang').

These are some of the photos I posted at Mustang sites, back in '04, when I did this conversion.



















Today, you can search early model Mustang forums for a modern 4-wheel disc MC and you will find many people making reference to the SN95 Mustang MC but, prior to 10 years ago, before I had posted these pictures, no one was talking about using this MC in an early Mustang.

The '94-'98 Mustang V6 MC has a bore diameter of 1-1/16". the ports exit on the right and are metric --10mm and 12mm. The '99-'04 Mustang V6 has a bore diameter of 1.00". Unlike the GT/Cobra MC, the Mustang V6 reservoir mounts, more or less, level. All the '94-'04 V6 Mustangs used vacuum boosters. From '94-'95, The GT and Cobra Mustangs used a vacuum booster. Beginning in '96 ('96-'04) the SN95 Mustang GTs, Cobras, '01 Bullitt Mustangs and '03/'04 Mach 1s had hydroboost brakes. Their MCs will not work on a vacuum brake booster.

Comparison of a '94-'04 SN95 V6 reservoir on the left and a '94-'04 GT/Cobra reservoir on the right. --notice the downward slope of the Cobra reservoir. This won't keep the MC from working but, to me, it just doesn't look right when installed in an older vehicle. --It messes with my sense of symmetry.




I've also used a '95 Ford Windstar 4-wheel disc MC. This application I installed in a friend's '65 Mustang. 1-1/16" bore, (2) 10mm bubble flare fittings. (1) 3/8"-24 inverted flare fitting sticking out the bottom, front, of the MC. --I capped that port off with an inverted flare plug.






Side by side comparison of '95 Explorer MC (on left) and '95 Windstar MC (on right) --both 1-1/16" bore.







The Windstar MC is 8-1/8" in overall length. The Exlorer MC is 7-1/2". This isn't a problem for an old F-series truck but does matter in an older Mustang, where the drivers side shock tower is a concern for clearance.


For the lack of a better term, the 'down spouts' coming out the bottom of the plastic reservoir have the same center-to-center distance on the SN95 V6 reservoir, SN95 GT/Cobra reservoir, the Explorer reservoir and the Windstar MC. This means that their reservoirs can be interchanged between MCs.


The MC bore diameter plays an important role in the effectiveness and ease in being able to apply the brakes and to get the vehicle to stop. A small bore MC will have more output pressure but move a lesser amount of brake fluid. Pedal travel will also be longer and the pedal will feel less firm.

A large bore MC will have less output pressure but it will move more fluid volume. It will give a very firm pedal and far less pedal travel but, it may be difficult to apply the brakes and to get the vehicle to stop, if the bore is too large.

Generally, it's best to have a 1.00" bore diameter --particularly for manual brakes --a 15/16" or 1.00" bore generally works best. The 1.00" bore is also generally a good choice if you have a brake booster with a single diaphragm.

If you have a more powerful dual-diaphragm booster, it's easier to get away with running a slightly larger 1-1/16" bore MC.


All the Mustang MCs have ports on the right side. A '93 Cobra will have a 15/16" bore and the sloping reservoir.

A '94/'95 Cobra MC will have a sloping reservoir and a 1.00" bore.

The '94-'98 SN95 V6 Mustang MC will have a more level reservoir and a 1-1/16" bore.

The '99-'04 SN95 V6 Mustang MC will have a level reservoir and a 1.00" bore.

The '95 Explorer MC will have a level reservoir (same reservoir as used on the V6 Mustang), 1-1/16" bore and ports on the left.

The '95 Windstar MC will have a very large, level reservoir, 1-1/16" bore and ports on the left.


You could also use a '93 Ford Ranger MC (designed for discs front/drums rear). It has ports on the left and a 1.00" bore but, the reservoir slopes like the Cobra MC.

All the other MCs I mentioned were designed for 4-wheel disc brakes and, I don't know of any modern Ford MCs that have SAE ports for the brake line fittings. that's not really a show stopper though as you can see from my photos of my truck I installed it with that configuration with no problem --Metric bubble flare on the MC end and SAE inverted double flare fittings on the other end of the tubes coming off the Explorer MC into the brake valve.


In reference to Dentside calipers; The '73-'79 F-100 and the '75-'79 F-150 single piston calipers are the same. You don't have to have calipers just specific to a '74 for your application.

Steve

[Bryan_Tenn]

ok ultraranger, thanks for explaining.

The booster I got off the 79 doesn't look like the one you have in the pic. It has a round rod and turns down & flat at the end to hook to the brake pedal

[Bryan_Tenn]

http://www.oreillyauto.com/site/c/detai ... ke+booster#

I'm still trying to figure out how to post pics here. Im used to doing it from my computer, not from a web address, anyway I dont know if this pic is gonna show up or not, but on OR's website the booster I have looks like this one. its for a 79 non cruise #50-3717

I said it curved down & hooked in the pic its curvrd up, same thing, my mistake, it moves

Anyway, will this type booster fit my brake pedal set-up? If not I need to know what will, I REALLY dont want to change out pedal assemblies. I read one of the articles on here & it sounded like a real PITA!

I plan on using the bracket & rod off this booster & using it as a core. Do I also need the plate it mounts to on the firewall? I assume I do, I will get it tomorrow. Theres a junkyard down the road from me, actually a collision shop, Ive known the guy all my life & he lets me get stuff cheap. I was very lucky that he had this, it was the only 70's Ford truck in his boneyard