Cobra booster installed [email protected]#$

Steel1

Mustang Master
Aug 18, 2017
1,372
654
143
51
Connecticut
Had some time today so fired up the heater in the garage and started my Cobra brake booster install.
Back story, last winter I upgraded to 4 lug rear disc and master cylinder but decided to try it with the stock booster, pedal was too hard for my liking
so unfortunately I knew what I needed to do.

I know changing a heater core on these cars is commonly know as the number one pain in the [email protected]# , imo installing a Cobra booster on a car with engine, harnesses
etc. intact has to be a top 3 pain in the [email protected]#!! Probably didn't help that the engine in my car is a 351w based stroker with taller deck height.

I will admit I am not great a documenting things because I kind of get into a zone when I'm working on cars and forget to take pics along the way.
But if anyone is curious here's a brief description with some pics of my process and a few pics attached.
Things I needed to remove :
Lower steering wheel cover
Knee bolster
Knee bolster reinforcement
Removed master cylinder and mounting bracket rotated forward / down. Surprisingly you can move it quite a bit saved me from bleeding brakes again thanks @Mustang5L5
Dipstick and had to bens tube out of the way ( probably 393w issue )
Unplugged large harness connection by drivers strut tower to give me slack to pull it up out of the way
Various vac hoses
Firewall clutch adjuster, had to screw it all the toward firewall
Drivers valve cover
Clutch cable bracket

Old booster was pretty easy to remove , pushed drivers seat all the way back and it's a pretty straight shot to upper nuts for booster using a combo of extensions and deep 3/4"
socket, lower nuts are easy to get to as well as removing clip etc. on pedal stud. Removing knee bolster is key to getting to the upper mounting nuts.

Fitting the Cobra booster was a lesson in patience to say the least !
I had the booster in and out probably 8-10 times with multiple flogging sessions between my 3lb sledge and strut tower. I know people have said they've gotten this booster in without massaging strut tower but there was no way around it for me.
I would get booster a little closer every time then mark strut tower , pull out booster , flog tower , reinstall and so on.
Took me about 5hrs. by myself for removal and install , still need to reinstall drivers valve cover but I want to touch it up first since it got a few nicks during the process.
Anyways here's some pics , I did measure pushrod length using MM instructions prior to install.
0124211132.jpg

0124211132a.jpg

0124211229.jpg

0124211227.jpg

0124211624.jpg

0124211633.jpg
 
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ThinBlue502

Advanced Member
May 7, 2019
175
311
73
39
Ohio
I was totally ready for the type of drawn out, life decision questioning battle you just described when I did mine. I cut down the studs on the booster just a little bit, went right in. No BFH, no hating my life. At least there. Getting those nuts on the studs under the dash, God have mercy. I felt like a T-Rex with my arms bent like that under there.

Did you cut your studs at all?
 
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Mstng93SSP

You have a nice rear end there Dave.
15 Year Member
Nov 29, 1999
2,185
2,495
184
Mililani, Hawaii
Either cut the studs down or elongate the holes closest to the engine and it will slip right in. I have done the booster swap in under an hour start to finish. No banging strut towers, very little swearing.
 
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Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
2,241
1,636
133
Long Island, NY
Had some time today so fired up the heater in the garage and started my Cobra brake booster install.
Back story, last winter I upgraded to 4 lug rear disc and master cylinder but decided to try it with the stock booster, pedal was too hard for my liking
so unfortunately I knew what I needed to do.

I know changing a heater core on these cars is commonly know as the number one pain in the [email protected]# , imo installing a Cobra booster on a car with engine, harnesses
etc. intact has to be a top 3 pain in the [email protected]#!! Probably didn't help that the engine in my car is a 351w based stroker with taller deck height.

I will admit I am not great a documenting things because I kind of get into a zone when I'm working on cars and forget to take pics along the way.
But if anyone is curious here's a brief description with some pics of my process and a few pics attached.
Things I needed to remove :
Lower steering wheel cover
Knee bolster
Knee bolster reinforcement
Removed master cylinder and mounting bracket rotated forward / down. Surprisingly you can move it quite a bit saved me from bleeding brakes again thanks @Mustang5L5
Dipstick and had to bens tube out of the way ( probably 393w issue )
Unplugged large harness connection by drivers strut tower to give me slack to pull it up out of the way
Various vac hoses
Firewall clutch adjuster, had to screw it all the toward firewall
Drivers valve cover
Clutch cable bracket

Old booster was pretty easy to remove , pushed drivers seat all the way back and it's a pretty straight shot to upper nuts for booster using a combo of extensions and deep 3/4"
socket, lower nuts are easy to get to as well as removing clip etc. on pedal stud. Removing knee bolster is key to getting to the upper mounting nuts.

Fitting the Cobra booster was a lesson in patience to say the least !
I had the booster in and out probably 8-10 times with multiple flogging sessions between my 3lb sledge and strut tower. I know people have said they've gotten this booster in without massaging strut tower but there was no way around it for me.
I would get booster a little closer every time then mark strut tower , pull out booster , flog tower , reinstall and so on.
Took me about 5hrs. by myself for removal and install , still need to reinstall drivers valve cover but I want to touch it up first since it got a few nicks during the process.
Anyways here's some pics , I did measure pushrod length using MM instructions prior to install.
0124211132.jpg

0124211132a.jpg

0124211229.jpg

0124211227.jpg

0124211624.jpg

0124211633.jpg
You used the Cardone 5473155?
 

Steel1

Mustang Master
Aug 18, 2017
1,372
654
143
51
Connecticut
I was totally ready for the type of drawn out, life decision questioning battle you just described when I did mine. I cut down the studs on the booster just a little bit, went right in. No BFH, no hating my life. At least there. Getting those nuts on the studs under the dash, God have mercy. I felt like a T-Rex with my arms bent like that under there.

Did you cut your studs at all?
Didn't cut studs but I did elongate the upper let hole slightly until my dremel broke.
 

Steel1

Mustang Master
Aug 18, 2017
1,372
654
143
51
Connecticut
Either cut the studs down or elongate the holes closest to the engine and it will slip right in. I have done the booster swap in under an hour start to finish. No banging strut towers, very little swearing.
Yeah I didn't cut studs but did elongate upper left hole a bit, I'm still thinking having the taller deck height of a 393w may have played
into it.
 
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Reddevil91

10 Year Member
Mar 3, 2010
1,477
652
163
This was the first big task I did alone, swapping to the cobra booster and 5 lug. Had no idea wtf I was doin, asking help on here every 30 minutes, looking on you tube etc. I’ve seen some guys say they finished their swap in like a day or so. It took me a week or more lol, but I did it and it was a learning experience, I was also swapping out all the suspension at the same time, plus redoing the rear end. I remember my wife came in bc I was yelling, she said are you ok I thought you said it was gonna be fun? I yelled f*#% yeah it’s a blast, then heard the garage door shut and there was nice whiskey drink waiting for me lol!!
 

Willybill32

Active Member
Jul 16, 2019
246
102
53
Lexington, KY
Just curious...I did the 4-lug rear disc conversion on my '86, along with '87-'93 front spindles and calipers, all with the stock '86 master cylinder. The pedal was quite hard and I didn't like it. Members of this forum (Mustang5L5?) suggested a larger bore diameter master cylinder, and I put an '85 Lincoln MC on it with the stock booster and I got really good pedal feel.
 

Steel1

Mustang Master
Aug 18, 2017
1,372
654
143
51
Connecticut
Just curious...I did the 4-lug rear disc conversion on my '86, along with '87-'93 front spindles and calipers, all with the stock '86 master cylinder. The pedal was quite hard and I didn't like it. Members of this forum (Mustang5L5?) suggested a larger bore diameter master cylinder, and I put an '85 Lincoln MC on it with the stock booster and I got really good pedal feel.
I tried leaving the stock booster and just upgrading the m/c but pedal was too hard for me so had to bite the bullet and upgrade the booster.
Seems like it's hit or miss , some people get away with the stock booster maybe just a matter of preference.
 
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