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Discussion Starter · #1 ·
I had to crash replace my v2 Bronson frame and SC got me a V3 to replace it. However the new version has internal routing for the rear brake cable.

When swapping the parts over, I the old barb and olive off each brake hose to route the rear through the frame and to do heat shrink cable management on the front. Both hoses got a fresh barb and olive and when installed I bled both the brake, including a flush until I got all clean fluid.

On both brakes I get good lever feel, and I can feel it engage shortly into the throw. I took the bike out on a shakedown ride today and on the first downhill section I could immediately tell they weren't right. Prior I was used to that glorious four pot Shimano bite and stopping power, but these felt like guides under extreme fade on both wheels. I literally couldn't stop like I expected to and almost went off the trail the first time I tried.

I'd say at best the brakes felt like they were operating at 30-40% of normal and it made for a very tense and slow ride out the downhill. At slower speeds they would stop me well enough, but if I got up over 15ish mph it was really bad.

I'm kind of at a loss where to start troubleshooting this, the only thing done to these brakes are moving them to the new frame, the rotors and pads are the same as before and I bled the brakes with the wheels off, pads out and a brake block installed.

I was originally debating just replacing front and rear pads, but those finned pads are 40-50bucks a pop. I'll do it if I can't figure this out, but I'd rather not spend a hundred bucks on new pads while my wallet is still trying to recover from paying for a replacement frame.

I'm hoping someone with more experience wrenching on a bike can point me in a direction to start. Does this sound like a bleed issue, a contamination issues (no idea how), or ?
 

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If the levers are firm it's not a bleed issue. If caliper piston movements seems normal and the pads are properly aligned with the rotors, I'd clean the rotors thoroughly, put new pads in, and bed them. I'd use non-finned pads. If somehow it isn't the pads, you'll have a spare set.

In the past I tried sanding pads, cleaning them, heating them until smoking, etc.. having done those things, I just get new pads now.
 

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How long were the brakes sitting between when you stopped riding and put them on the new frame? If it was a little bit, could have picked up some airborne contaminates, so could try baking the pads on a little toaster oven at 350* and see if you see any smoke coming off them - usually leave them for about 10-15 minutes, then let them cool. Give them a light sand before installing and clean the rotors with alcohol and alight sand as well. For extra security, could do 2 oven cycles straight up to make sure they've burned off any and all contaminates - sometimes they're just too bad and need replacing, but lots of times, this is all that's needed to bring them back.
 

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This happened to me before, I contaminated pads and have no idea how. I’m always very careful with brake fluid/mineral oil and brake pads and always have isopropyl alcohol by the bike stand.
My guess is somehow a tiny bit of fluid got on the rotors or pads. I’d try baking the pads and cleaning and scuffing the rotors with a scotch brite pad first.
Also, if that doesn’t work I’d recommend not replacing pads unless you do pads and rotors together. I’ve found that contaminated pads often embed that crap in the rotor and if you don’t replace both, it’ll just transfer from one to the other. Get your parts on jensonusa.com. Finned 4 pot pads are $26 or $35 for H01A/H03C respectively.
 

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Discussion Starter · #5 ·
I pulled the pads and both front and rear sets were very dark in color. I couldn't tell if they were glazed or contaminated. I gave the pads a soak in IA, cleaned the rotors with IA and then 2x baking everything at 400F first time for 1hr then cooled down, second time for 30min. Lastly I gave them aall light sanding with 200 grit, and hit the pads with the propane torch and rinsed them off in IA.

I mostly put that much work into it as I could do it in stages while I was doing other household chores, and the pads look almost new in terms of thickness. I'll bed them in tomorrow and see how they are. I'm hoping this sorts it out as I'd rather not do a full pad/rotor replacement.
 
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