New pads won’t fit over new rotors… - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AllGoNoShow · 11-16-2021, 11:27 PM

This truck is fighting me every step of the way- my 68 had what looks like a regular CPP front disc brake conversion put on it but it was still 6 lug. I am swapping to 5 lug and went to install stock size PowerStop rotors (drilled/slotted) and ceramic pads. I c-clamped the calipers piston in as much as possible (it still sits proud about 1/16 of an inch of the caliper body), and the rotor actually measures 1.28, and when I try to put the pads on I can barely get them over the rotor and they aren’t going to get all the way on without a lot of encouragement from a baby sledge hammer. I’ve done tons of brakes and never ran into any this tight. Is that extra .03 on the rotor thickness really causing this problem, is there anything else I should be looking at?! Absent either running the old pads or turning the rotors I am out of ideas. Or is power stop just junk?!
Posted via Mobile Device

tim_mc · 11-17-2021, 09:43 AM

My guess is that your old rotors are standard duty 1" thick ('81-'87) while the new ones are heavy duty ~1.25" thick ('69-'87).

Caddylackn · 11-17-2021, 01:42 PM

Can you just plane down the pads a 1/16" or so sanding them with some emery cloth on a flat board?

Since you already have the parts, this seems to be the simplest solution.

AllGoNoShow · 11-18-2021, 05:53 PM

I ended up picking some parts store brand pads and they fit fine and are, collectively 1/10 of an inch smaller then the powerstop ceramic brands. PowerStop apparently cannot make pads that fit over their own rotors….not impressed.
Posted via Mobile Device

jaros44sr · 11-18-2021, 07:15 PM

If you decide to machine some surface area off, my son has a shop about 1/2 hour south of you, I'm sure he.would do it

11-16-2021, 11:27 PM	#1
AllGoNoShow Registered User Join Date: Feb 2020 Location: Rochester, NY Posts: 200	New pads won’t fit over new rotors… This truck is fighting me every step of the way- my 68 had what looks like a regular CPP front disc brake conversion put on it but it was still 6 lug. I am swapping to 5 lug and went to install stock size PowerStop rotors (drilled/slotted) and ceramic pads. I c-clamped the calipers piston in as much as possible (it still sits proud about 1/16 of an inch of the caliper body), and the rotor actually measures 1.28, and when I try to put the pads on I can barely get them over the rotor and they aren’t going to get all the way on without a lot of encouragement from a baby sledge hammer. I’ve done tons of brakes and never ran into any this tight. Is that extra .03 on the rotor thickness really causing this problem, is there anything else I should be looking at?! Absent either running the old pads or turning the rotors I am out of ideas. Or is power stop just junk?! Posted via Mobile Device

11-17-2021, 09:43 AM	#2
tim_mc Registered User Join Date: Jan 2019 Location: St Peters, MO Posts: 434	Re: New pads won’t fit over new rotors… My guess is that your old rotors are standard duty 1" thick ('81-'87) while the new ones are heavy duty ~1.25" thick ('69-'87). __________________ 1967 C20, 350 SBC w/Comp roller cam, 700R4 w/3.42 posi, PS, 4-wheel PDB, Old Air AC & GM Tilt column.

11-17-2021, 01:42 PM	#3
Caddylackn Registered User Join Date: Jun 2016 Location: Bremerton, WA Posts: 171	Re: New pads won’t fit over new rotors… Can you just plane down the pads a 1/16" or so sanding them with some emery cloth on a flat board? Since you already have the parts, this seems to be the simplest solution. __________________ 1969 Custom Camper C20; Factree Air, 350/TH400/Dana 70U with C30 wheel cylinders, Disk brakes, H4 conversion, headlight relay mod, 3G 135 amp alternator. 7500 GVW

11-18-2021, 05:53 PM	#4
AllGoNoShow Registered User Join Date: Feb 2020 Location: Rochester, NY Posts: 200	Re: New pads won’t fit over new rotors… I ended up picking some parts store brand pads and they fit fine and are, collectively 1/10 of an inch smaller then the powerstop ceramic brands. PowerStop apparently cannot make pads that fit over their own rotors….not impressed. Posted via Mobile Device

11-18-2021, 07:15 PM	#5
jaros44sr Registered User Join Date: May 2006 Location: Philadelphia, Pa. 19454 Posts: 9,421	Re: New pads won’t fit over new rotors… If you decide to machine some surface area off, my son has a shop about 1/2 hour south of you, I'm sure he.would do it __________________ Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.