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Discussion Starter · #1 ·
Mark III, donor build, stock front discs with rear drum, stock master cylinder. The questions:
1. Do I use the distribution block or straight to front/rear brakes from M/C
2. If the above is true, do I plug one of the front brake outlets from the M/C
3. Is there a switch in the distribution block that needs to be used and if so...for what
4. Can anyone link me to some really good detailed pics
5. Do I need to modify the M/C
So many questions. I just finished the Mott Build School (super helpful but they're doing the MK4 complete kit so no donor M/C) and the detail around the use of the '89 mustang donor M/C, distribution block and proportioning was not super clear. Any help i get is appreciated and I know the info is on this site somewhere, but my searches are coming up empty.
 

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It was recommended to me (and I listened) to ditch the distribution block.
The M/C does not need to be modified.
The front port goes to the rear brakes, The rear port goes to the front brakes.
Some guys run the brake line across the x-member, I chose to go low, across the chassis brace.

Hope these help:




 

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Discussion Starter · #3 ·
Quick question - I was going to go without brake boost, but your pictures show that you are putting that in. Did you have any frame clearance issues or is that not the stock Mustang booster (if that's the correct name for it) and are you using rear drums?
Holy crap is your brake line routing ever clean....I only hope mine looks that good>
 

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Not a waxer
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I don't use the distribution block. With the 3 port master from '89 you can do one of two things. First of all understand that the bottom and rearmost ports are for the front wheels, go into the same chamber and will have equal pressure. One option is to plug the bottom and then add a "T" to split to each front caliper. The other option is to plumb the bottom port to one front wheel and the rearmost port to the other. That is how I did my Mk3 shown here:



Yes the chassis and front bulkhead need some minor modifications to use the Fox Mustang booster. If you check the early posts of my Mk4 build thread linked below you'll find some details (a Mk3 is essentially identical in this area) of how I did it. Remember, if you use the booster you will not modify the brake pedal but if you change over to manual the pedal must be reworked.

Good luck,
Jeff
 

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FFCobra Craftsman
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Whatever you do, throw the mustang prop valve in the trash. It was used on a quite nose heavy car and hurts performance on the rear heavy FFR. As far as the two MC holes to the front brakes goes- I think you will find that there are two different diameter holes in the MC. At least that is the way the Mustangs were.Not sure why. As mentioned above you can do the front brakes either of two ways. I would go w/ whatever is easiest w/ what lines you already own. I can't remember for sure but this may include the rubber hoses to the two front wheels. If the chassis end of those hoses are different and you have two different diameter holes in the MC, it may be easiest to run the different diameter hard lines the whole way.
 

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Yes, stock Mustang booster.
I cut the frame at the front of the footbox, inserted a piece of square tubing inside of it and bolted it to the side of the 3/4 tubing inside of the footbox. It clears the booster and the only thing you see from the engine compartment is 1 bolt (painted black). It does distort the F-Panel just a little and I'm sure I'll need to adjust the Ear panel, but no biggie.
From everything I read, the Power Brakes are highly desirable.
 

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Just Pluggin Along
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Mark III, donor build, stock front discs with rear drum, stock master cylinder. The questions:
1. Do I use the distribution block or straight to front/rear brakes from M/C
2. If the above is true, do I plug one of the front brake outlets from the M/C
3. Is there a switch in the distribution block that needs to be used and if so...for what
4. Can anyone link me to some really good detailed pics
5. Do I need to modify the M/C
1 & 2. See my picture from my MKII. I used the distribtution block, but you should gut the internals if you do it this way. I was doing a donor the first time and trying to keep costs down.

I also used the donor booster assembly, which is one of the best mods I did. Even in the MKIV it requires some opening of the footbox to accomodate the booster, but it should fit. You will need to cut the 3/4" bar, but Whitby's sells that dogleg piece you can see in my picture. They also sell spacers for the booster to clear the steering shaft bearing that is in the bottom of the footbox.



3. No
4. See picture
5. No
 

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Here is a slightly different approach.

No distribution block. I brought both lines forward to keep them cool, and away from the headers. The rear line travels down the outside of the front X-member, then all the way back on the 4 inch frame rail.



Front line on the x-brace



No MC mods are required.

Don't waste time with the donor / manual approach to the rear brakes. I copied Mark at Breeze instead. Mount the line to the frame. Use stainless lines (also from breeze) to connect the calipers.

 

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Actual builder now!
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Hi: just reviving this thread since I am at the same point in my build. There doesn't seem to be a consensus on whether or not the donor distribution block needs to be used. Does it? Does it matter at all? is it simply a way of one line into 2?
I have a MKIV with 88 donor front rotors and rear drums.

Also I have heard a lot of talk about proportioning valves to lessen rear brake bias. Is this really a big problem?

Thanks

Steve
 

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Senior Charter Member
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I gutted the proportioning part of my valve and using frt disc and rear drum have almost perfect equalization. Thats according to the brake skid machine when I went through state inspection. The only reason I left the valve in the system is it has a shuttle valve that if you have a failure on either end of the system it blocks that side off so you don't empty the fluid reservoir . Am I ever going to need that function?? probably not, but it had nice neat factory plumbing between it and the master so I kept it.
 

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FFCobra Craftsman
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On my MkI w/ mustang brakes and rear drums I gutted the prop function of the valve. That definately helped the brakes. Its wasn't a fix but it did help. I left the valve in position mainly because it was easier than removing it and needing to redo some of the lines.
 

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DJ: Since you are new to the forum (judging by the number of posts only) I think this might help with your build. All kinds of info can be found here. I found this on the forum after my car was done and I was having problems with braking. Here's what you do;
go to google or use the link below then enter the following:
site ffcars.com: then what you wish to like
site ffcars.com: prop valve for drum brakes or pinion angle, SAI mod, bumpsteer etc. It was a great source of info for me.
HTH
CB
 
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