Manual Brake Coversion - Pros And Cons?

[Fordfreak93]

I'm looking for some feedback from those who have done this conversion. I'm wanting to do the conversion to prevent any issues I may have with vacuum because of my camshaft and to clean things up in the bay. I'm running a manual steering rack so the hydroboost conversion is off the table. Here are some of my questions:

Are manual brakes ok for a car that will be driven on the street?
Can you tell me how the pedal feel is?
How are panic stops?
Was it a pain swapping in the new pedal?
Do you regret converting to manual brakes?
Anything else you can share? Thanks in advance...

 

[billison]

I’ve never converted one but I’ve driven one. The difference was huge. That said, upgrading the brakes will offset a lot of that

 

[revhead347]

I have manual brakes. I did it for the same reason, had a big cam, and the power brakes were unreliable. I had two dedicated vacuum cannisters, and a dedicated vacuum gauge so I could monitor how much vacuum I had for braking at all times, and the power brakes still didn't work. As for converting to manual brakes, it kind of depends what you want out of the car, how big your brakes are, and how old your knees are. So I tried the manual master cylinder on the stock brakes first, and I can say flat out IT DOES NOT WORK. You need bigger front brakes with a manual brake master cylinder.

I run an Aerospace street kit with stock rear brakes. I was not willing to sacrifice my parking brake to have Aerospace all around. I drive it on the street all the time. The Aerospace brakes are a pretty good size PITA to install. The pedal was no problem. You have to pull the pedal assembly out, and drill a hole in the pedal arm for a knew mounting point for the master cylinder rod. Bad news is, the brake light switch is integrated into the factory armature on a Mustang, and it won't work with the manual brake setup. Aerospace recommended using a pressure activated switch on a T with the brake lines. I figured that was one more thing to leak, so I made a little bracket and put a stoplight switch in there from a Camaro.

As far as driveability, it's honestly not that bad, unless you are switching between your Mustang and a Focus RS like I am. You really have to push with manual brakes; they work fine, but it's not what you are used to. Then you get in the RS, forget it has power brakes, and nearly kill yourself. Not kidding, that thing stops so hard it'll make you puke. Panic stops are fine. It works fine with my ABS. No real complaints.

I probably would have done something else if I had to do it over again. I want a car that is a little more in line with my old fart knees. I have a ripping hard clutch (SPEC 4+) on top of the manual brakes. I think the car is a little hard to drive for a car that really isn't that fast. Your other options are a vacuum pump, or a hydroboost system off a 4.6L Fox chassis. I've heard of people getting an electric vacuum pump off of a 2002 Cobra R, even for non Mustangs. They used to be under $200, not sure what they go for now.

Kurt

 

[90sickfox]

I had manual brakes on a 87 with a big block 460. It was terrible to drive on the street. My set up was not done correctly ( like everything else on the car ) used a spacer plate and the stock master cylinder with 4 cylinder brakes. It stopped OK at the track, but every time someone's brake lights would come on my sphincter would pucker up. I can remember plowing through a few intersections and past a few turns.

If you're going to do it....spend money and do it right.

 

[General karthief]

If you're going to do it....spend money and do it right.

Keep the power brakes unless it's a track car. Consult your cam grinder about a cam that can work with power brakes.
Unless of course if it's a track car then you can deal with it

 

[revhead347]

If you're going to do it....spend money and do it right.

Keep the power brakes unless it's a track car. Consult your cam grinder about a cam that can work with power brakes.
Unless of course if it's a track car then you can deal with it

I agree and disagree. Nothing wrong with running manual brakes on the street. My ex-girlfriend's 69' Camaro had manual brakes from the factory. If everything is matched right, they work fine. She weighed 98lbs in season, and 88lbs off season, and that car was her daily driver. If she could push a manual brake pedal, anyone can.

The lobe seperation on the cam really starts eating into the manifold vacuum. I was pulling 9.5" at idle, and the brakes need at least 16". That was with a 110 degree lobe sep. I think if you went to a 112 degree lobe sep you would be fine. I agree in the way that bringing the valve timing closer together can bring a higher peak power on the dyno with a sacrifice to your driveability and overall power curve. This is where "what you want out of the car" really comes into play. I now run a 112 degree lobe sep custom ground cam. I am not sure it makes as much peak power, but it definitely has a better power curve, and much better driveability. Not sure this new cam would do any better on the track. I never drop below 5000 rpms on the track. On the street you are always fighting the tires for traction anyway.

I have pictures of all the stuff I made for the manual brake conversion. If you are serious about doing it, PM me, and I will email them to you. I did a thread about it years ago as well. Might be able to find it on my CP as well.

Kurt

 

[Fordfreak93]

I’ve never converted one but I’ve driven one. The difference was huge. That said, upgrading the brakes will offset a lot of that

I have manual brakes. I did it for the same reason, had a big cam, and the power brakes were unreliable. I had two dedicated vacuum cannisters, and a dedicated vacuum gauge so I could monitor how much vacuum I had for braking at all times, and the power brakes still didn't work. As for converting to manual brakes, it kind of depends what you want out of the car, how big your brakes are, and how old your knees are. So I tried the manual master cylinder on the stock brakes first, and I can say flat out IT DOES NOT WORK. You need bigger front brakes with a manual brake master cylinder.

I run an Aerospace street kit with stock rear brakes. I was not willing to sacrifice my parking brake to have Aerospace all around. I drive it on the street all the time. The Aerospace brakes are a pretty good size PITA to install. The pedal was no problem. You have to pull the pedal assembly out, and drill a hole in the pedal arm for a knew mounting point for the master cylinder rod. Bad news is, the brake light switch is integrated into the factory armature on a Mustang, and it won't work with the manual brake setup. Aerospace recommended using a pressure activated switch on a T with the brake lines. I figured that was one more thing to leak, so I made a little bracket and put a stoplight switch in there from a Camaro.

As far as driveability, it's honestly not that bad, unless you are switching between your Mustang and a Focus RS like I am. You really have to push with manual brakes; they work fine, but it's not what you are used to. Then you get in the RS, forget it has power brakes, and nearly kill yourself. Not kidding, that thing stops so hard it'll make you puke. Panic stops are fine. It works fine with my ABS. No real complaints.

I probably would have done something else if I had to do it over again. I want a car that is a little more in line with my old fart knees. I have a ripping hard clutch (SPEC 4+) on top of the manual brakes. I think the car is a little hard to drive for a car that really isn't that fast. Your other options are a vacuum pump, or a hydroboost system off a 4.6L Fox chassis. I've heard of people getting an electric vacuum pump off of a 2002 Cobra R, even for non Mustangs. They used to be under $200, not sure what they go for now.

Kurt

I had manual brakes on a 87 with a big block 460. It was terrible to drive on the street. My set up was not done correctly ( like everything else on the car ) used a spacer plate and the stock master cylinder with 4 cylinder brakes. It stopped OK at the track, but every time someone's brake lights would come on my sphincter would pucker up. I can remember plowing through a few intersections and past a few turns.

If you're going to do it....spend money and do it right.

Thanks for the replies, that's exactly what I was looking for. I'm just doing the standard 99+ PBR front/ 94 GT/V6 rear conversion, so no big brakes. I wish that I could test drive a manual brake car just to really know, but I'm pretty sure it will feel stiffer than I want on the street. I think I am going to keep my power brakes and look into a vacuum pump system, that's a good idea. I thought going to manual brakes would just make it simpler, but I don't want to lose too much driveability either. The struggle is real!

 

[General karthief]

I was not say'n anything bad about non power brakes, we argee they have to be set up right, I kinda like my knees, I don't want to be like mike.

 

[revhead347]

Thanks for the replies, that's exactly what I was looking for. I'm just doing the standard 99+ PBR front/ 94 GT/V6 rear conversion, so no big brakes. I wish that I could test drive a manual brake car just to really know, but I'm pretty sure it will feel stiffer than I want on the street. I think I am going to keep my power brakes and look into a vacuum pump system, that's a good idea. I thought going to manual brakes would just make it simpler, but I don't want to lose too much driveability either. The struggle is real!

I don't think it will work with that brake combination. If you are in North Georgia anytime, I'll let you test drive it.

Kurt

 

[Fordfreak93]

I don't think it will work with that brake combination. If you are in North Georgia anytime, I'll let you test drive it.

Kurt

You don't think what will work?

 

[revhead347]

You don't think what will work?

No I don't. I think it will be like trying to stop a steam locomotive on the street. The 1 and 1/8" bore they use on manual master cylinders just isn't matched to the flow demands of those calipers. The PBR setup isn't a whole lot better than the stock stuff. The rotors are bigger, but the floating calipers still need a lot of flow.

Kurt

 

[Fordfreak93]

No I don't. I think it will be like trying to stop a steam locomotive on the street. The 1 and 1/8" bore they use on manual master cylinders just isn't matched to the flow demands of those calipers. The PBR setup isn't a whole lot better than the stock stuff. The rotors are bigger, but the floating calipers still need a lot of flow.

Kurt

Thanks for the heads up. I'm probably going to keep my power brakes like I mentioned before. I definitely won't be happy with the manual pedal on the street!

 

[HotFox]

Yup keep them power brakes, worst case run a stand alone electric vacume pump to power your booster. The OEM's have been doing this on the diesels since the 80's. It should be possible with not much money.

I went from manual as installed by previous owner, back to booster and power. Of course when it was manual it was just Lincoln fronts 4 lug and did not stop well. Now it or PBR/SN95 rear with correct booster and MS. Night and day difference in stopping.

 

[Mustang5L5]

The issue is trying to run manual brakes on a system designed for power brake booster assist.

Plenty of cars run manual brakes without issue, but it all depends on the components use. Forget factory manual setups as they were engineered from scratch as a manual setup. Aftermarket manual setups also are designed from scratch to be manual. I'll say right now that the 99+ gt pbr"s are massive calipers with a large surface area and will require plenty of fluid flow.

Just install a 1993 cobra booster and vacuum canister.

 

[Fordfreak93]

Yup keep them power brakes, worst case run a stand alone electric vacume pump to power your booster. The OEM's have been doing this on the diesels since the 80's. It should be possible with not much money.

I went from manual as installed by previous owner, back to booster and power. Of course when it was manual it was just Lincoln fronts 4 lug and did not stop well. Now it or PBR/SN95 rear with correct booster and MS. Night and day difference in stopping.

The issue is trying to run manual brakes on a system designed for power brake booster assist.

Plenty of cars run manual brakes without issue, but it all depends on the components use. Forget factory manual setups as they were engineered from scratch as a manual setup. Aftermarket manual setups also are designed from scratch to be manual. I'll say right now that the 99+ gt pbr"s are massive calipers with a large surface area and will require plenty of fluid flow.

Just install a 1993 cobra booster and vacuum canister.

Thanks for talking me off the ledge guys! There is no way I'll be happy with manual brakes, so the power brakes will stay. I'll look into vacuum pumps and canisters to help with the assist. I need to stop trying to eliminate everything, some stuff has to stay in the bay! lol

 

[90lxcoupe]

Are manual brakes ok for a car that will be driven on the street? Yes
Can you tell me how the pedal feel is? If you get the ratio and master cylinder right, the feel is great, obviously it a more firm pedal, but nothing that would stop me from doing it again
How are panic stops? For me, no different than with power brakes
Was it a pain swapping in the new pedal? It isnt the most fun you will have. I did mine with the dash out.
Do you regret converting to manual brakes? No
Anything else you can share? Thanks in advance...
I went with the maximum motorsports conversion kit, seems to be the best one on the market. Also, make sure your master cylinder is properly sized and you have a good brake proportioning valve.

 

[CarMichael Angelo]

Meh,....I went through the whole ordeal on the red car....Cobra fronts and rears, Wilwood 7/8" MC, re-configured intersect point on the brake pedal,...Wilwood adj prop valve.....

Stopping the car was still waaay harder than I expected it would be...and trying to lock up the fronts was impossible.

I had them then, I do not have them now, Sam I am.

 

[revhead347]

Yeah, just do the Cobra R electric vacuum pump.

Kurt

 

[cleanLX]

It's pretty rare to see folks running a cam "bigger" than what I am on the street (286/286, 250/254, 673/648 107* installed at 105*), and my factory power brakes work just fine.
So, I'll ask, just how much cam are you looking to run?
Give Buddy Rawls a call, and tell him you want to keep the power brakes. Done.

 

[CarMichael Angelo]

It's pretty rare to see folks running a cam "bigger" than what I am on the street (286/286, 250/254, 673/648 107* installed at 105*), and my factory power brakes work just fine.
So, I'll ask, just how much cam are you looking to run?
Give Buddy Rawls a call, and tell him you want to keep the power brakes. Done.

its Lobe separation/centerline that makes a difference in how much vacuum an engine will make with a particular cam.
If your cam wasn't so N/A friendly, and was ground on something like a 110/112 CL, you'd be complaining about not being able to stop as well.