Cobra Front Brakes with rear drum viability?

[Jaym14]

Like the title says......

I'm still piecing together my cobra/5 lug swap parts and was wondering how viable it would be to install the fronts and swap the rear drums out later since I already have all the front components. I would imagine this would provide vast improvement over stock fox brakes because most of the braking is done with the fronts anyway.

If I did this, the set up would be as follows:

94 Spindles
94 GT M/C & Booster
M.M. adj. Prop Valve
M.M. Brake Prop Valve Eliminator kit, 1987-93
M.M. 94 GT M/C adapter
M.M. front braided lines
Front Cobra 10 anniversary calipers
Cobra front 13" Rotors
Stock Rear 5 lug Drums
5 lug fox length axles

Would I need any other parts? Would there be any issues using the rear drums with the newer 94 booster and M/C?

This would be a good option for me for the time being b/c I would save some $$$ on holding off on purchasing the rest of the stuff I need for the rears. Plus I could run 15" rims on the rear for trips to the track and I wont have to touch the E-Brake for the time being either.

What do you guys think???

 

[93 LX]

i have seen stangs with cobra/drum combos. I am sure you will have huge brake dive but it should stop!

 

[Jaym14]

I am sure you will have huge brake dive but it should stop!

I was thinking the same thing!! I think if I play with the prop valve enough I should be able to even in out somewhat.

 

[Beasty306GT]

youll be fine...lot of the conversions still have drums in the rear

 

[trbkrb]

The only issue I can see with swapping out the MC & PV is the potential lack of residual pressure for the drum brakes. They can release due to the spring tension and will not engage enough to be useful if they don't have the residual pressure preloading them.

That said, I put in my 94 MC in a couple of months before swapping my system to 5 lugs, and didn't experience adverse braking that I noticed. All I swapped was the MC, I left the stock PV alone until I swapped the rears.

One of the guys on Corral (or here) his name is nosmatt I think, ran Cobra fronts with drum rears and stock MC, PV and booster for several years. His brakes were Ok to him.

Good luck on it!

 

[Jaym14]

So maybe I should run the front cobras and rear drums with the 94 mc & booster but leave the stock prop valve until I finally swap the rear to disc?

 

[stang&2Birds]

So maybe I should run the front cobras and rear drums with the 94 mc & booster but leave the stock prop valve until I finally swap the rear to disc?

A few things:

1) You want/must have a prop valve that is designed for rear drum brakes. That means either an 87-93 prop valve, or a pre-87 prop valve.

1A) To keep the stock 87-93 prop valve, you'd have to do the 87-93 front brake line mod. The pre-87 prop valve and MC setup isn't screwed up like the 87-93 prop valve.


2) Either way, if you have 13" rotors up front, you'll have the problem of not enough proportional pressure going to the rear wheels for optimal braking.


A lot will depend on your exact tire, suspension, spring, shocks, mods, setup, etc.

If you run 275s in the back, and 225s in the front, you may have the front lock up before the rear. That's bad and dangerous!

A stiff suspension will be better. A soft one (4 cyl springs) will be worse.
Stiffer shocks will be better. Soft OEM Monroe's will be worse.
Having alum heads and a battery in the back will be better (more proportional weight in the rear).
Having a 3-core rad in the front will be bad (more front weight from more water).
And, so on!

So, please be careful about broad statements on how well something will work.

If I had to make a wild *ss guess, I'd say that as long as the front and rear tires are the same, and you do not have 4 cyl springs, you should see braking improvement and the mod will "likely be safe".

Good Luck!

 

[Jaym14]

A few things:

1) You want/must have a prop valve that is designed for rear drum brakes. That means either an 87-93 prop valve, or a pre-87 prop valve.

1A) To keep the stock 87-93 prop valve, you'd have to do the 87-93 front brake line mod. The pre-87 prop valve and MC setup isn't screwed up like the 87-93 prop valve.


2) Either way, if you have 13" rotors up front, you'll have the problem of not enough proportional pressure going to the rear wheels for optimal braking.


A lot will depend on your exact tire, suspension, spring, shocks, mods, setup, etc.

If you run 275s in the back, and 225s in the front, you may have the front lock up before the rear. That's bad and dangerous!

A stiff suspension will be better. A soft one (4 cyl springs) will be worse.
Stiffer shocks will be better. Soft OEM Monroe's will be worse.
Having alum heads and a battery in the back will be better (more proportional weight in the rear).
Having a 3-core rad in the front will be bad (more front weight from more water).
And, so on!

So, please be careful about broad statements on how well something will work.

If I had to make a wild *ss guess, I'd say that as long as the front and rear tires are the same, and you do not have 4 cyl springs, you should see braking improvement and the mod will "likely be safe".

Good Luck!

Thanks for the Reply!

I started this thread to explore the viability of completing the swap in 2 stages with the ultimate goal being a complete cobra brake system. Your post definitely provides some food for thought. My car currently has a stock (v8) suspension with the exception of some Lakewood rear uppers. I'm currently running draglites with M.T. 275's in the rear and skinnys up front. Once I swap to five lug I plan on running wide tires all around (still have not selected which rims yet though buy they will be 17x9s). As would be expected, my brakes are currently scary (with lots of one wheel peels when the front passenger side locks up) and the skinnys dont help.