Need Brake advice for a MrkIII for a newly bought roadster

[the shadow]

Hey all, I'm not a new member been one since 2012 but a long time lurker and 30+ year cobra enthusiast waiting for my time to buy a cobra. I was going to build one originally but with time and age I decided better to find one done before I cant enjoy the thrill of owning one. Anyway I just picked up a MrkIII that was built in the early 2000's runs great looks great and has no cosmetic issues. It has a 5.0 power train with mild engine mods & stock EFI, mustang doner brakes etc under it. It has things I want to change but I want to drive it first before tearing it apart. eventually I want to do a 5 lug conversion F/R, remove the stock EFI for traditional looking carb type efi and brake upgrades. I don't like is the manual brakes so I've already decided to do a power brake upgrade 1st. I've searched the multitude of threads that show the booster installs over the last 25 years etc. my question is besides the booster/MC/spacer install up front what else do I have to factor into doing to complete the switch down stream of that? Do I have to change out the stock doner calipers/brakes right away to larger or can I utilize them till I decide to upgrade later. Not looking to track this car its just a cruiser for an older guy so I don't want to go down the "race parts" rabbit hole. I just want proven off the shelf up grade advice or links to get power brakes on an older MrkIII running build. Maybe one of you have done just that and can advise me on what to buy or not buy.

Thanks in advance and sorry for bringing up the ever repeating "brake booster up grade " question.

218258

[johnnybgoode]

You should be able to pretty much just add the booster/master and modify the pedal back to stock or replace with stock. Maybe upgrade the pads while you are at it. You will need to make sure you use a master that is compatible with rear drums if that's what's on the car.

Whitby Motor Cars makes a very nice complete kit to add power to the brakes and can probably help you make sure you have all the correct/compatible components.

Nice car BTW. Scott

https://www.whitbymotorcars.com/product/power-brake-kit/

[Flip Smiley]

My 1st stop for the brake and 5 lug upgrades would be North Race cars & Richard Oben. Richard has been involved with Factory Five from day one and is one of the site sponsors here. I used North Race cars and Richard for the changes you are interested in last year and am very happy with the results.
Best of luck with your projects.

[tnt_motorsports]

Hey all, I'm not a new member been one since 2012 but a long time lurker and 30+ year cobra enthusiast waiting for my time to buy a cobra. I was going to build one originally but with time and age I decided better to find one done before I cant enjoy the thrill of owning one. Anyway I just picked up a MrkIII that was built in the early 2000's runs great looks great and has no cosmetic issues. It has a 5.0 power train with mild engine mods & stock EFI, mustang doner brakes etc under it. It has things I want to change but I want to drive it first before tearing it apart. eventually I want to do a 5 lug conversion F/R, remove the stock EFI for traditional looking carb type efi and brake upgrades. I don't like is the manual brakes so I've already decided to do a power brake upgrade 1st. I've searched the multitude of threads that show the booster installs over the last 25 years etc. my question is besides the booster/MC/spacer install up front what else do I have to factor into doing to complete the switch down stream of that? Do I have to change out the stock doner calipers/brakes right away to larger or can I utilize them till I decide to upgrade later. Not looking to track this car its just a cruiser for an older guy so I don't want to go down the "race parts" rabbit hole. I just want proven off the shelf up grade advice or links to get power brakes on an older MrkIII running build. Maybe one of you have done just that and can advise me on what to buy or not buy.

Thanks in advance and sorry for bringing up the ever repeating "brake booster up grade " question.

218258

I am working on an MK3 as well. I have put power brakes in on the advice of many including Mike Everson. My car is not done yet, but excited for this set up. No fluid inside the car is certainly a bonus.

I bought the booster and M/C off of Amazon. I am using the SN95 dual piston from calipers on the FFR hubs and the single piston rear calipers.

https://www.amazon.com/dp/B0B4ZZ3R3K?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_6

https://www.amazon.com/dp/B0B3RN72T2?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_6

[David Williamson]

When I built my Mkll in 2004 I used a 93 GT donor car. With a limited budget I did the 5 lug conversion but kept the stock Mustang brakes. I have power and I removed the rear brake limiter and it works great. I have thought about doing an upgrade but for a street car it is really just cosmetic.
Ford sold a 5 lug conversion that gave you axles and drums drilled for 5 lug, not sure if it is still available? On the front just get some Lincon Mk7 rotors, they are identical to the Mustang except 5 lug. To remove the rear limiter you neeed a plug Ford Racing part #M-2450-A again not sure it is still available
David W

[Jeff Kleiner]

Question before you go any farther is whether the brake pedal was modified to change the leverage ratio. If not that may explain why you’re not happy with the brake performance. If it has had the modification done you’ll have to change it back if you install power brakes.

Jeff

[CraigS]

I just looked for a pic of the rear brake limiter but only have this.
218289
These were used on the front heavy Mustang to keep the rear brakes from locking. Since the FFR is slightly rear heavy it isn't needed so it can be removed. It is usually mounted within a foot of the MC in the rear brake line.

[the shadow]

All great info, this is why I like this community they help each other out. I am anxious to get into this project and will have more info on my exact set up in a couple days. At the rate of sounding stupid, Jeff what is the brake pedal modification for leverage and why would or wouldn't it be done. Since I didn't build this car nor did the seller I have no manuals so Im not aware of what was recommended in the original kit etc. If I know what to look for I can surely check the pedal assembly and be able to reply to your question better. It does have the factory distribution block under the master cylinder now (see pic)
Just so you know my complaint on the brakes, they work and stop the car but there is no pedal movement its rock hard? Ive had manual brakes before and you could still feel the pedal, 1st time I pushed the brake pedal on the test drive I thought I was pushing my foot against the firewall behind the pedal (solid). I could also smell the front brake pads after driving it, I assumed it was because the car had not been driven and was sitting, after reading the replies and searching the links provided Im thinking the front brakes are doing all the work?
with out taking anything apart yet and as far as I know the brakes are doner mustang brake set up front disc and rear drum (all 4 lug) I will keep you guys informed and may message a few of you for more advise. I may tackle this issue at the same time I do the 5 lug conversion in the winter. Maybe I will get lucky and can do some simple mods to make the "fall weather" driving better like gutting the distribution block and new pads or the brake pedal mod (if not done)

218290

[Norm B]

Here is a picture of the proportioning valve in the diagram Craig posted. If it’s there and not modified as per the diagram then, you at the very least want to do that. If you plan to convert to rear discs then it has to be removed and either be replaced by a modified sn95 or a T fitting for the front brakes. The rear axles have to be changed either way.

Norm

[the shadow]

I did notice that the brake pedal is shorter then the clutch and in a few old posts I've seen members asking other members to check and see if the pedal's are the same length or distance off the floor. I suppose this means the pedal has been modified for leverage? I will know better when I can get under the dash and see plus take pics. but hares a shot looking into the floor from outside.
218293 218293

[Jim Doak]

Regarding the brake pedal mod: When using a Mustang pedal box and manual brakes, you cut 1.5" out of the pedal between the pivot point (mounting bolt) and the stud that connects the push rod to the master cylinder, then re-weld the two halves back together. This increases the mechanical advantage when pushing the brake pedal. Otherwise, if you're using power brakes, you leave the pedal as-is, since no additional mechanical advantage is necessary.

I have a PDF of FFR's base kit assembly manual. It's for a Mark 4, but there's some information that'll be useful to you. If you PM me your email address, I'll try emailing it to you. (It's a pretty big file.)

[Derald Rice]

An alternative to cutting and welding the brake arm is to use the Maximum motorsports
conversion kit for 79-93 Mustangs....

https://www.maximummotorsports.com/Manual-Brake-Pedal-Kit-1979-93-P678.aspx


EDIT: : To level the clutch pedal to the brake pedal MM had another kit for that purpose.....

https://www.maximummotorsports.com/Clutch-Pedal-Height-Adjuster-C163.aspx

[Jeff Kleiner]

I did notice that the brake pedal is shorter then the clutch and in a few old posts I've seen members asking other members to check and see if the pedal's are the same length or distance off the floor. I suppose this means the pedal has been modified for leverage? I will know better when I can get under the dash and see plus take pics. but hares a shot looking into the floor from outside.
218293 218293

We're not talking about the brake pedal's height relative to the clutch pedal. The pedal modification changes the distance between the pedal's pivot point and the master cylinder activation point resulting in a better mechanical advantage when the brake booster is omitted. After modifying (which can be done either by cutting and then rewelding the pedal between these two points or by relocating the upper pivot bushing) the distance between the two should be approximately 2.25"

https://thefactoryfiveforum.com/attachment.php?attachmentid=218296&d=1756747904

See if you can get up under the dash and measure what you have.


If the modification is not done the result is that "the pedal is rock hard" and takes a bunch of effort to stop the car. Hmmmmm...sound familiar?

By the way, your interior photo shows that the car is a Mk1, not a Mk3. The giveaways are the door hinges, flat passenger side floor and shape of the trans tunnel.

Jeff

218296

[CraigS]

Another option is better brake pads. The pedal mod coupled w/ Hawk HP+ on the rear and HPS or HPS5.0 on the front gives a pretty good system w/ reasonable effort. The HP+ do dust so use this.
https://www.armorall.com/intl/product/shield-brake-dust-repellent/

[weendoggy]

Hey Jeff, he could have a "tweener" MKI/MKII. My late, I early II had those stinking hinges. I could be persuaded to think otherwise, but then what fun is that. :rolleyes: The other give-away is the space between the door and seat.

[weendoggy]

Another option is better brake pads. The pedal mod coupled w/ Hawk HP+ on the rear and HPS or HPS5.0 on the front gives a pretty good system w/ reasonable effort. The HP+ do dust so use this.
https://www.armorall.com/intl/product/shield-brake-dust-repellent/

Agree, better pads make a huge difference. I've been running Carbotech XP10/XP8 in mine for years. The Armorall product does work well keeping dust at bay. If you worry about dusting, take a look at all the daily drivers front wheels next time you're out and about. Like anything else, you have to clean them.

[CraigS]

Thanks weendoggy, I should have mentioned that there are other pads that will work but that my personal experience is w/ the Hawks that I mentioned.

[the shadow]

Ok sorry about the long delay in the pic's and info but here's what I found.

the center to center measurement on the pivot points is 3.5" and not 2.25"? the pedal looks to be in the upper mounting position near the top of the mounting bracket (see pic)? the stock proportioning valve doesn't look to be modified/gutted (still has stock -cap see pic). so I think that is the problem with my rock hard brakes, Let me know if you guys agree with my deduction on the issue.

I am thankful to you guys for helping me find this issue I dont know how this car was driven for 10,000 miles like this!

218618

218600

[Norm B]

Doesn’t look like the pedal was modified. That’s bad and good news at the same time. The bad is your current braking is awful/dangerous and needs to be fixed. The good news is, one of the difficult steps in converting an already built car to power brakes, is already done should you choose to do that.
I would highly recommend a power brake mod. It’s a game changer.

[the shadow]

I guess I need to consider adding the power brake booster. How much would I need to change or ad if I were to keep the stock front disc brakes and rear drums. I know I'd need to ad the booster,spacer plate. Modify the 3/4 cross tube. Would I need a different master cylinder?

[jts359]

Hi , do a search to power brake retro fit MK2 on 8-12-2020, After trying new pads and master cylinders this is what I did and I could not be happier with my stopping power, I did it with the engine out of the car and I did have to get another braker pedal , Ed

[jts359]

Hi , do a search to power brake retro fit MK2 on 8-12-2020, Post #3 After trying new pads and master cylinders this is what I did and I could not be happier with my stopping power, I did it with the engine out of the car and I did have to get another braker pedal , Ed

[the shadow]

After reading dozens of brake upgrade posts I think it's having to be easier to do the power brake upgrade then take apart the brake pedal assembly. Since it's already unmodified. I just need to find out what proportioning valve I need to use since I'm keeping the disc/drum set up?

[Jeff Kleiner]

Shadow,
If you keep the drums you'll use the same master cylinder. Ditch the distribution block. You need to use a Fox Mustang brake booster. You'll have to cut the 3/4" square chassis tube and then replace the removed portion with a section of tube below or beside it or by using Whitby's bolt together piece, cut a larger hole in the front wall of the footbox and cut/modify the front wheel splash panel for master cylinder clearance.

Jeff

[the shadow]

Shadow,
If you keep the drums you'll use the same master cylinder. Ditch the distribution block. You need to use a Fox Mustang brake booster. You'll have to cut the 3/4" square chassis tube and then replace the removed portion with a section of tube below or beside it or by using Whitby's bolt together piece, cut a larger hole in the front wall of the footbox and cut/modify the front wheel splash panel for master cylinder clearance.

Jeff

stupid question jeff, if I ditch the stock distribution block can I tie the existing lines together with an inline coupler ?

[CraigS]

Yes you can. One other option is gut the valve. There used to be a solid plug you could install to cap off the valve section but I haven't ever actually seen one. What I did was remove the existing cap which has a small (1/16"?) hole. I got small cap bolt and nylock nut w/ 2 aluminum washers. Drilled that small hole out to clear the bolt, put a washer on the bolt and pushed it through from the inside. Put washer and nylock nut on the end and tightened. The aluminum washers were soft enough to seal brake pressure.
https://www.mscdirect.com/product/details/05520077
It was long ago and memory faded but I think it was in the 6/32 or 8/32 size. Whichever would allow the head diameter to fit inside the cap.

[Jeff Kleiner]

stupid question jeff, if I ditch the stock distribution block can I tie the existing lines together with an inline coupler ?

Yes, rear to and from the block can be coupled. There are two outputs from the master cylinder into and from the block; one for each front wheel. The in and out for each will also get joined. In the end you'll probably find it cleaner and easier to remake some lines because the master cylinder will be moving forward several inches.

Jeff