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Front disc brake install problem

unimogger

Full Member
Joined
Aug 7, 2019
Messages
214
Loc.
Philthadelphia
I’m finishing up a front disc installation. Rotors are new, calipers are reman thunderbird, knuckles and mounting is f150 supercab.
Brake pads are generic organic from flaps
The combined thickness of the pads and rotor is .075 more than what will fit in the calipers. The piston is fully seated in the caliper. Would you, try exchanging parts, or mill a little off the pads? 1mm off each pad would do it.
It’s the last thing to check off before we mount the body, so I’m frustrated.
 

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Hazegray

Sr. Member
Joined
Aug 10, 2004
Messages
795
If it was me, I would take the brake pads back and compare with a quality set. Manufacturing tolerances are not what they used to be...:(
 

Timstrk

Full Member
Joined
Apr 8, 2014
Messages
193
If you mill it this time you'll mill it every time. Fix the problem now and not have it again.
 

Apogee

Contributor
Bronco Guru
Joined
Nov 26, 2005
Messages
6,033
If you mill it this time you'll mill it every time. Fix the problem now and not have it again.

That's only true if the problem is not the pads, and it's likely that the issue is the pads.

If the F150 Supercab front brakes used the same brakes as the F150/Bronco applications, that should be a FMSI D50/D92 brake pad backing plates with thickness of .535" and .674" respectively if my information is correct. Those differences come pretty close to equaling the amount that your system doesn't fit: 1.269" - (.535" + .674") = .06"

The factory truck rotors are nominally 1.20" thick, so those look good.

Tobin
 
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U

unimogger

Full Member
Joined
Aug 7, 2019
Messages
214
Loc.
Philthadelphia
That's only true if the problem is not the pads, and it's likely that the issue is the pads.

If the F150 Supercab front brakes used the same brakes as the F150/Bronco applications, that should be a FMSI D50/D92 brake pad backing plates with thickness of .535" and .674" respectively if my information is correct. Those differences come pretty close to equaling the amount that your system doesn't fit: 1.269" - (.535" + .674") = .06"

The factory truck rotors are nominally 1.20" thick, so those look good.

Tobin

Thank you for this info.
A few additional findings:
I popped off the anti squeal backing plates and measured them, after thinking that perhaps they were adding the "extra". But they are .025" thick, so even without them the pads will not fit. While checking my measurements, I realized that the pad thickness varies slightly, up to about .02 which certainly doesn't help. So, IF they were in spec, and IF I removed the anti squeal shims, they might fit. With this info I called the FLAPS and explained my debacle, and asked that they measure a set of the better pads. Not sure if they are semi met or ceramic, but the Bosch brand pads are similar, and will be too thick. So, I'll just mill a bit off of these
 
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