Non power disk brakes???

[scgamecock]

My 72 Mach has front disk brakes but a manual master cylinder with no booster.  Does this sound right or did someone put a disk brake setup on but never completed the process of full power disk brakes???  It seems odd that manual disk brakes would have come from the factory.  They work fine but if this was an incomplete half a$$ job I would rather finish it.

Also, just below the master cylinder there is an opening in the firewall to the cabin.  It 'appears' that there is a plate missing to cover that opening.  Is this correct and if so do any of you have pictures of the plate and where I can get a replacement?

Thanks

Wade

 

[turtle5353]

I don't think they ever came from factory with manual disc brakes but im not 100% sure. I am running manual disc brakes in my car and it works fine. Im sure power disc would be nicer but for the last 6 years or so mine has been fine with manual discs. I have 4 wheel disc brakes in my car and I have the parts up in the garage to convert to full power disc brakes, just haven't got that far yet!!

 

[Jeff73Mach1]

May have been done to deal with a large cam and low vacuum. Be aware manual pedal and power pedal are different. Not having a power brake booster doesn't affect braking power, just pedal feel. Different pedals do make a difference as to leverage and length of travel- MC bore must be matched to the system Manual usually uses a smaller bore than power as a result of the longer pedal travel.

Hopefully my edit improves readability and clarity on the subject of my opinion, which should not be taken as fact, or relied upon in any way, unless you want to

 

[Stanglover]

Wade, if that cover plate is missing, my guess is that at some point either the original power booster failed and was removed, or someone attempted to add a booster to a disc brake conversion and gave up on it. It is not a job for the feint of heart!. One way to tell is the push-rod pin location. If that is high up and inline with the master cylinder, then either the brakes were always manual or the pedal arm was replaced which is quite a bit of work. To add a booster, you would need to relocate that pin 2" lower on the arm.

Do you have a Marti Report for your car or a copy of the factory invoice or build sheet? Those items should tell you what it was born with as far as brakes are concerned. Nothing really wrong with non power discs, I ran an SSBC front brake conversion with no booster for 5 years before eventually adding a factory booster. There are loads of post on this subject. I have posted about my power booster addition as well.

Let us know what you find.

Geoff.

 

[Stanglover]

May have been done to deal with a large cam and low vacuum.  Be aware manual pedal and power pedal are different.  Doesn't affect braking power, just pedal feel

 Jeff, I don't think it would work if the pin was 2" lower as on a power brake pedal arm. The angle would be too acute to push the M/C piston, assuming the M/C is located were it should be for non-power brakes.

 

[secluff]

Wade, sounds as though a conversion was started but never completed. Manual disc brakes were never offered on the 71-73 Mustang. Manual drum were standard with power disc brakes as an option. Never understood that since the 70-71 Torino had a power drum brake option and the Torino and  Mustang shared the same front end architecture and brake components. Ford did offer a dealer installed kit that included everything necessary to convert manual drum to power.

 

[scgamecock]

I have a MARTI report but it was the $18 one. It lists the trim, color, number built engine and transmission but nothing on brakes. The dash is completely out right now so if the pedal was never swapped this is probably the best time to do it.

It would be just a pedal swap and add a break booster and master cylinder???

 

[boilermaster]

scgamecock,

Don't forget to change out the brake light switch to match the brake pedal used.

There is a difference.

                                     Boilermaster

 

[secluff]

Wade, have you looked to see if the buck tag is still on your car? If it is still there you need to look at the second line and see if there is a "PB" present. If so, then your car left Detroit with power disc brakes. If the tag is missing and you don't have the build sheet, it would help if you had the deluxe Marti report. If you ordered your standard report in the past year you can upgrade to the deluxe for $28. It would sure make it easier for you to determine what you need to do and change to get your brakes like you want.

As Jeff posted, with disc brakes and no booster, it's possible someone removed the booster because of a "Big Stick" in the engine (on old school term people my age used) and fixed the low vacuum/no brakes problem. Or someone started the brake conversion and ran out of patience, money, or interest. Like others have posted, there are numerous items that are different such as the brake pedal, differential valve, brake switch, etc that you may not have to change.

Keep us posted and let us know if you need any help or more info.

 

[Jeff73Mach1]

Alteration of the pedal or the MC location is not a big deal for someone that builds a hot rod.

No, it didn't come from the factory that way. No it is not correct. No I don't recommend it in general and yes I will likely do some version of this mod myself in the future. It just didn't make the list for this year's projects.

 

[Tnfastbk]

I have had four wheel manual disc brakes on my car from the time we put it together.  No it did not come that way but is the way I chose to go as Jeff eluded to by my cam/engine build choice. The brakes work extremely well. But also my car is a driver not a concourse correct trailer queen that has been restored to factory specs. So it really boils down to what you want for your car and what works best for you.

 

[Stanglover]

So were are you on this upgrade, change over etc?.

As I've already done this as a conversion, I found a few pictures of my firewall that shows the original M/C position  and with the cover plate removed. By the way, this plate needs to be cut to suit the opening and reinstalled as it has spacers welded in place that are necessary when putting it all back together. If it is not put in the whole bracket, booster position and even the column will be out slightly. I recommend a new rubber seal as well on the steering column. I tend to go overkill on stuff like this, so I used a sealant called Automotive Goop, which is NOT a silicone to ensure no leaks. If you have not removed the column, I strongly suggest you do, it's not hard, but extra long socket extensions are very useful!

Here are a few pictures which I hope you find useful.

They loaded in reverse order, but you get the "picture". The pedal arm shows the top original non power pin location and the new position for the booster. Sorry, but for what ever reason, I did not take a picture of the new booster in place, least ways, I can't find it.

 Also, note the distribution block. This is the non-power drum brake version and can be used as a connector for the front brakes. I used a separate rear brake adjustable valve which can be seen just to the rear, supplied with the SSBC kit I installed. This set-up give excellent control over the rear brake bias.

Geoff.

 

[imusa76]

Here is the Pedal difference between Manual and Power, I did the Power Disc conversion 3 week ago, I originally had 4 wheel Manual Drum.

The all Black pedal is the Power brake (the pin is lower 2.5"), the pedal with the rust is the manual (Pin is 2.5" higher), I used the same brake light switch, it worked just fine.

To convert from manual to power is not a big deal at all.



https image

 

[scgamecock]

Thanks guys!! I havent worked on the car in a while. Life in general always seems to limit your time. These pics really help. Since the entire dash is alr3ady out it just makes sense to go ahead and change the pedal and put a new boot and rag joint on the column.

Is that pedal pretty easy to find used?

WW