Tubo wrote:

Many of the Ford cars Master cylinder are sold as being disc/drum or disc/disc. I'd always taken for granted that Ford evs drum brake. I do know some disc/drum master cylinders (T-Bird & Mk VIII as examples) become disc/disc, with removaal of a restrictor inline with the rear brakes.

Tubo

Thanks for your reply, Corky. I had previously stated that there is a difference in master cylinders with regards to the type of brakes being used. What I'm asking is, is there any such thing as a drum brake booster or a disc brake booster?
 

hmartin025 wrote:

Not in my opinion!
Howard

I'm not squabbling with the guy on the subject. That discussion is over with anyway. I would just like to see a definitive answer if such a thing exists.
 

ultrastang wrote:

Tubo wrote:

Many of the Ford cars Master cylinder are sold as being disc/drum or disc/disc. I'd always taken for granted that Ford evs drum brake. I do know some disc/drum master cylinders (T-Bird & Mk VIII as examples) become disc/disc, with removaal of a restrictor inline with the rear brakes.

Tubo

Thanks for your reply, Corky. I had previously stated that there is a difference in master cylinders with regards to the type of brakes being used. What I'm asking is, is there any such thing as a drum brake booster or a disc brake booster?
 

Just so Ultrastang.
AFIK booster wise Brake pedal pin would be the difference for me too.

Tubo
 

The following is from childhood memories.   My father had a 1967 Ford Falcon six cylinder car that had 4 wheel drum brakes AND power brakes.   I remember as a boy the brake booster went out.  My dad stopped at the autoparts store and got a remanufactured brake booster and we went home and I watched him put it on.   He started getting a bit upset and said a few words that a 9 or so year old boy shouldnt hear, and then he went inside and made a couple of phone calls and then the next door neighbor, who is now 83 took us back to the autoparts store to exchange it for another.   I was there, and I still remember this.   He told them the rod was TOO short.   I remember the counter man telling him that the difference in the rod length was the master cylinder bore size, and he had the right one in stock and we went back home happy.  

 

Tubo wrote:

ultrastang wrote:

Tubo wrote:

Many of the Ford cars Master cylinder are sold as being disc/drum or disc/disc. I'd always taken for granted that Ford evs drum brake. I do know some disc/drum master cylinders (T-Bird & Mk VIII as examples) become disc/disc, with removaal of a restrictor inline with the rear brakes.

Tubo

Thanks for your reply, Corky. I had previously stated that there is a difference in master cylinders with regards to the type of brakes being used. What I'm asking is, is there any such thing as a drum brake booster or a disc brake booster?
 

Just so Ultrastang.
AFIK booster wise Brake pedal pin would be the difference for me too.

Tubo
 

Input rod lengths can be different. Some are straight, some are curved, some have adjustable length input rods, some have round eyelets where the pedal pin attaches, some Dentside ('73-'79) trucks had sort of a triangular shape around the eyelet on the input rod specific to a truck that came with cruise control. Some boosters have adjustable output rods. Some dont --although I think all Bump or Dentside trucks, that had boosters, all came with adjustable output rods (but some Fox boosters don't have adjustable output rods, just as an example).

No pre-'73 model F-100 ever came from the factory with front disc brakes. The first Ford trucks to get optional front disc brakes was the 1968 Ford F-250s. Boosters were factory optional on any '67-'72 F-100 but, it would have been on a truck with all wheel drums. '67 was an odd - ball year in the 5th generation trucks and the optional booster for it is one of the odd, one year only, items on them. They do not interchange with the '68-'72 model brake pedals/hanger supports.

Ford lists around 11 different brake pedal part numbers and nearly 100 different part numbers for brake boosters. I'm fairly certain that there are around a half dozen booster designs I've seen on these trucks but not anywhere close to actually being 100 completely different designs (at least not outwardly). The guy I referenced from the other forum listed three different Ford part numbers for various boosters that he felt proved the boosters were different ("calibrated" to the specific brake design).
 
Any of us that have been around Fords very long are all too familiar with the fact that Ford was constantly changing part numbers. I'm not so certain the the change of part numbers indicates that something specifically inside the booster is somehow 'calibrated' to a particular brake type. My thought is the number changes applies more to the application it was used on rather than an actual change inside the booster. A booster put on an F-100 may have a different part number than a booster installed on an F-250. The booster may not physically be different, only the application is different thus, generating a different part number even though no actual change to the booster itself. (This is my theory, mind you).

With this train of thought, I checked out the Oreilly website last night. I searched for a booster for a '68 F-100 (that would have been a truck with all wheel drums). It came back with a part number of 54-73515. I next searched for a booster for a '68 F-250. This scenario could be either for all wheel drums or discs front/drums rear. The number that came up was 54-73515. Hey! That looks like the same number as the one that came up for the F-100!

The description mentioned the booster was a 9" diameter unit, single diaphragm with an adjustable input rod. It made absolutely no distinction of the booster application being specific to an all drum brake system or to one with discs front/drums rear. So, does this support my theory that boosters are not specific to brake type or, is it a lack of information on their part? Again, it goes back to needing an (engineering) explanation as to whether a booster is merely a force multiplier or if there is any fact that they are somehow 'calibrated' to a particular brake system; drum/drum, disc/drum or disc/disc?

My line of thinking, is that clearly, all drum brake cars require a longer pedal stroke than disc/drum cars.   Maybe the factory once built boosters to specific car lines/options contained in those car lines, and that somewhere along the line rebuilders got the idea to add adjustable input rods as a way to condesnse their part #s and overhead, and it became commonplace. Maybe an OLD Hollander manual, or a retired old timer that once worked at Cardone could shed some light.   Some of these parts have probably been through the remanufacturing process several times over the course of 50+ years.   

As far as the function of the booster itself, I think you are very correct that it serves one function.   I think the only differences would be in pedal travel length, whether that be by pedal ratio, car options (drums or discs) and master cylinder/wheel cylinder bore sizes, would be the biggest reasons for different part #s

GPatrick wrote:

...A-1 Cardone does list two different Bendix boosters/part numbers =12px 54-73507 vs. 54-73011 for a 1968 Ford Custom with 289 for drum/drum and disk/drum (a random test).  
.

Thanks for your reply, Gary, and the effort you put into looking up the various information you provided. I see an immediate problem with the information above from the source that printed it. The problem is, "289." In '68,  there were only 3 engine options for the 5th generation pickups; 240 & 300 inline sixes or a 352 big-block. For 1968 to 1969-1/2, engine options were; 240, 300, 360 or 390. 1969-1/2 was the first year a small block was available in a 5th generation truck. That engine was the 302. The 289 was already out of production by that time. From 1969-1/2 to '72, engine choices were; 240, 300, 302, 360 or 390.

The erroneous information the site provided on engine size also makes me wonder how inaccurate its other information is?

I realize the misinformation is not your fault. You're just providing the information that was listed and again, thanks for your time and effort.
 
EDIT

Doh! I thought you were referencing information on Ford trucks.  After re - reading what you posted, I see you were talking about a '68 Ford Custom ( a car ). My mistake. .... back to our regularly scheduled program, already in progress.....

Last edited by ultrastang (5/06/2014 5:26 PM)

Sometimes Rock Auto "rocks"  I have done a fair amount of research there when there seems to be conflicting part number information.  It has been surprisingly accurate and often provides links where actual dimensions and details are shown rather than "this part fits the following vehicles".  I haven't looked up the difference in the part numbers at Cardone yet.

I will have my own booster project on my new truck I'm afraid - not much boost but possibly the original booster from 1970.  My truck learning curve is steep.

True74yamaha wrote:

If there was such a difference why don't we put it to the test. Use a 65 mustangs drum brake booster and then a 67 disc drum booster and side by side differences and internals. I dought there's a difference but there could be. Because disc brakes are by far superior to drums couldn't you have a stronger booster on drum brake cars than you do on disc brake cars?

I understand what you're getting at but that particular comparison would be an apples to oranges deal. I'm not certain of the '65/'66 booster diameter but would guess it to be either 7" or 8" in diameter. I'm fairly certain that the stock '65/'66 Bendix booster was a single diaphragm unit.

The '67 Bendix booster was 8" in diameter and had dual-diaphragms. Dual diaphragms have twice the surface area of a comparable sized booster with only a single diaphragm and has greater output force potential than a single diaphragm unit.

So, the comparison of those two choices really wouldn't yield the results of what I'm wanting to know.
 

That or look at other car on the fox chassis that had power drums all the way around. Then compare it to a svo mustang which have all around power discs.

I could be wrong but didn't some of the Fairmont's have all drums?

True74yamaha wrote:

I could be wrong but didn't some of the Fairmont's have all drums?

 
Fairmont/Fairmont Futura & the Mercury Zephyr were Fox chassis vehicles. For a time, the T-bird & Cougars were on a Fox platform. All Fox platforms had front disc brakes.