Something else too. I think I know what is the problem, but I'd like clarification.

79 Fox

Active Member
May 21, 2019
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My brakes feel almost completely useless. The pedal has absolutely no resistance until it is almost bottomed out. Then, it gets insanely stiff, but the brakes don't grab well at all. The car has later fox brakes, and an '85 town car master cylinder, as well as a fresh proportioning valve. Everything is new. I believe that the issue is the town car master cylinder. Is that in fact the case? Or is there some sort of adjustment that I need to do? The brakes are fine for normal around town driving, but if I needed to stop suddenly, I would most certainly run into whatever shoots out in front of me. I also wouldn't trust them over 50 miles per hour period.
 
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Mustang5L5

This is a big reason why I pulled it out
Mod Dude
Feb 18, 2001
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You are correct that the MC is not correct.

Later fox 60mm calipers and drums...just need to run a stock 86 GT MC.

The 1” bore TC Mc would give you a stiff Mc as the bore is too large.
 

79 Fox

Active Member
May 21, 2019
122
14
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A van down by the river
You are correct that the MC is not correct.

Later fox 60mm calipers and drums...just need to run a stock 86 GT MC.

The 1” bore TC Mc would give you a stiff Mc as the bore is too large.
Thank you very much.
What is required to mount and use an 86 GT MC? I'd imagine that the setup is different than an '85 Town Car MC. I thought that I had read that they use a different style flare for the brake line, and that something is metric.

Edit: Would I really use an 86 GT MC? The brakes are from an 87-93 mustang if I'm not mistaken.
 
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Mustang5L5

This is a big reason why I pulled it out
Mod Dude
Feb 18, 2001
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I assume you have a 79 fox?

The change from SAE to metric was in 1987. So a 1986 MC (or even 1979) should still bolt up.

Here's the logic. The brakes from a 87-93 are 60mm. The 1986 brakes also used a 60mm caliper with the smaller rotor. Caliper piston size remained the same, which is all the MC cares about.

The town car MC required adapters to use. So how was yours installed? Have a photo?
 

79 Fox

Active Member
May 21, 2019
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A van down by the river
I assume you have a 79 fox?

The change from SAE to metric was in 1987. So a 1986 MC (or even 1979) should still bolt up.

Here's the logic. The brakes from a 87-93 are 60mm. The 1986 brakes also used a 60mm caliper with the smaller rotor. Caliper piston size remained the same, which is all the MC cares about.

The town car MC required adapters to use. So how was yours installed? Have a photo?
I do indeed have a 79.
I was never told about adapters for the town car MC. Mine bolted up without a problem.

Thank you very much for your help. I will be buying an 86 GT MC later.
 

Mustang5L5

This is a big reason why I pulled it out
Mod Dude
Feb 18, 2001
31,701
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Massachusetts
You may need adapters. There may be another MC that is a more direct bolt on. What brakes did your ‘79 originally come with? I believe some models had 9”?

Trying to see if there is an easier option
 

Rdub6

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