Cobra brake booster question

Bdude93

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Oct 16, 2020
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Hello,
New, First post!
I’m in process of a ground up restoration of a 90 LX (to cobra clone) front brakes are in. Now I know that the cobra brake booster is a bit of a pain to install. I believe 86 and earlier requires strut tower “massaging” and virtually all years require booster hole enlarging. My question is... is the process any easier with a completely empty engine bay? Without the engine or any other parts in the way? Cause my engine bay is freshly painted in eastwood ceramic chassis satin black and I’d hate to scratch it up getting this in...
Appreciate any input especially from those who have done it
 

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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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So, not to kick you in the nuts but, I think a cobra did not come with coil overs, tubular k member and lower arms.
Now I'm not criticising your work because it looks spectacular but a clone is the wrong term (in my opinion anyway) a clone is a copy, it's more a tribute, which in my opinion (again) is better than a clone because it gives the builder leeway for better handling and more comfort.
Oh, and more POWER!
Now get back to work.
And post more pics!
 

nickyb

WAIT,you now have a pair?
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I'll be honest with you when I put cobra brake upgrade on my 93lx the booster was a pain but no banging or scatching,just elongated holes and wiggled it in.
 
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Mustang5L5

i'm familiar with penetration
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Yes, it can be done. It’s way easier with an empty bay, but I would painters tape everything in the area as you’ll be wiggling.

93 cobra booster will install the easiest. 94-95 booster will work as well but you’ll have to slot one of the mount holes. I trimmed mine down maybe 1/4”-3/8” on the inside two studs as well.
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
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Word of advise. Cut an old antifreeze bottle open and cut a side of the bottle off to tape to the strut tower. That bottle plastic is almost indestructible and will keep you from scratching stuff. Could use it on areas of the firewall too...not directly behind where the studs will have to slide though. That area won't be seen anyways. When I install those cobra boosters I trim the studs down about 1/4 inch and smooth them around the edge just a little to keep from hanging up on stuff. Put a nut on the stud first. When you back it off it'll chase the threads.

That install is the worse job I've ever done on a mustang. Helps to have the drivers seat removed and a second set of hands with a flashlight to help line the studs up. It's all worth it in the end. You'll feel the difference.
 
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Bdude93

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Cut a half inch off the firewall studs and it slid right in! Was prepared for war and then smooth as silk...
 

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Bdude93

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Nice , and no banging or scratching.
Nope. To be honest I may not have even needed to elongate the firewall holes. Went RIGHT in. Used to above tip of a piece of coolant jug plastic on shock tower to prevent potential scratching. Such a relief
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
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I was afraid to take that much off the studs...I only removed about 3/8ths. Good to know. Glad it all popped right in.
 

ThinBlue502

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I cut the studs on mine as well, slid right in.
Reference picture for V8 booster vs. Cobra booster.
8C506E39-A56F-4534-BA4E-D98D44B9C170.jpeg
 

5.0 Nostalgia

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Great thread! Question: Can this project be done with the engine in the car AND without removing the master cylinder? I already have a 93 Cobra master cylinder and I was hoping to keep the lines connected to it.
 

Mustang5L5

i'm familiar with penetration
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Yes. I've done it that way.

Siphon the brake fluid down a little bit in the MC, and tilt it forward to clear once you unbolt it.

As for getting the booster in place, I found removing my upper intake and just shifting it over to the pass side gave me enough room. I've heard of some people removing a valve cover as well. Mine were stock VC's, but if you have some tall VC's it might be an issue.

And like mentioned, I did trim the studs down a little.

It will go, just need to pick a day where you can be patient with it.
 
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5.0 Nostalgia

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Thanks for the help. I was thinking I would need to take off my upper intake and unplug all the vacuum lines, etc. (luckily I don't have A/C!). Do you mean that you trimmed the studs on the interior side or the studs for the master cylinder (or both)? Also, do you know which hole(s) need to be opened up on the firewall to slide this in? I assume it will be hard to determine that by test fitting!

Thank you again. I hope I am not hijacking the thread.
 

Habu135

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Thanks for the help. I was thinking I would need to take off my upper intake and unplug all the vacuum lines, etc. (luckily I don't have A/C!). Do you mean that you trimmed the studs on the interior side or the studs for the master cylinder (or both)? Also, do you know which hole(s) need to be opened up on the firewall to slide this in? I assume it will be hard to determine that by test fitting!

Thank you again. I hope I am not hijacking the thread.
I just did this mod. Removed my upper intake, windshield wiper motor and pulled the MC forward. Cut down the two passenger side bolts and enlarged the passenger side holes a bit. I also disconnected the clutch cable. Went right in. Screenshot_20210111-163044_Gallery.jpg
 

Bdude93

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Thanks for the help. I was thinking I would need to take off my upper intake and unplug all the vacuum lines, etc. (luckily I don't have A/C!). Do you mean that you trimmed the studs on the interior side or the studs for the master cylinder (or both)? Also, do you know which hole(s) need to be opened up on the firewall to slide this in? I assume it will be hard to determine that by test fitting!

Thank you again. I hope I am not hijacking the thread.
You trim down the 4 studs going into the firewall. I personally just enlarged all 4 holes a bit, but after trimming studs down, I wonder if it was even necessary. But doing both makes install effortless
 

5.0 Nostalgia

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Thanks everyone. I installed the older Baer PBR front calipers (basically the same as the Cobra calipers but the spindles are set up for a 4 lug 12" rotor) and 93 Cobra master cylinder. I thought I could get away with leaving the booster but the pedal effort AND braking is terrible. Was going to install the booster first then finish the project with a 4 lug rear disc conversion.
 

Mstng93SSP

You have a nice rear end there Dave.
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My personal opinion, the cobra booster is more important that the cobra master cylinder. Cobra master with a stock fox booster and the pedal effort is bordering unbearable. However, a stock MC with a cobra booster and it isn't bad. I am NOT saying you shouldn't do both, but if you had to do one first, before the other I would always do the booster first. I had a coupe about 8 years ago that had a 5 lug sn brake setup with a cobra mc and stock booster. Had a panic stop situation on the freeway and it was a very scary moment, both feet on the brake pedal as hard as I could and it just would not stop.