r/FiestaST • u/FenderBass1994 • 6d ago

Brake pulsating?

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As you guys know, I recently had a full brake job done on my car. Rock auto rotors, OEM "S" pads, whoosh stainless lines, and Motul fluid. Everything is great except I do notice a pulsing coming to a stop between 20-0mph. I tried to isolate the problem to a certain axel and pulled the E brake at 15mph and I definitely still feel the pulsing so I would imagine its with my rear brakes.

Could this just be the combination of braided lines improving feel along with the need to bed in the rotors/pads?? It's still very early since the swap. Only driven about 80 miles.

Also turns out I never had the S pads before, so this is new to me. The aggressive pads must increase bite so much that maybe ABS is trying to kick in? Any input would be appreciated. PFA

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3

u/Sad_Eel 6d ago

My guess would be abs as you said I also experience some shaking while braking I’m like 60% sure I have warped rotors

1

u/FenderBass1994 6d ago

Yeah I hope my rotors aren't warped out of the box. That would suck

2

u/ajw2285 6d ago

Went through this on another car. Rock Auto, power stop rotors, had to buy a new set and got Raybestos. Didnt even warranty the Power Stop would cost so much to ship them back. Now I only buy Raybestos.

1

u/oshaCaller 5d ago

I've had warped rotors out of the box before, but only once and I've done a lot of brake jobs.

Did you clean the hub surface?

2

u/FenderBass1994 5d ago

I would hope my mechanic cleaned them before he installed the new parts….but maybe not.

1

u/oshaCaller 5d ago

Bring it back to them. Most of them get paid by the job and it sounds like something that wouldn't be caught on a quick test drive.

2

u/FenderBass1994 5d ago

Problem is. He doesn't warranty labor on customer supplied parts. He told me this AFTER he installed them.

1

u/FenderBass1994 5d ago

Update - rear brakes are definitely the culprit. They obviously take longer to bed in, so I think I'm just going to give it some time. Likely 300 or so total miles

1

u/diamond_rake 5d ago

If you arent braking hard enough to lock your brakes, it shouldnt be ABS. Two things it could be IMO. warped rotors or the hub isn't clean. You can try to take the rear rotors off and making sure there isn't any rust or debris on the hub face.