REVscene - Vancouver Automotive Forum

Spectre_Cdn · 09-01-2012, 06:44 PM

I've been noticing two anomalies while braking, recently.

When I was going down Cypress the other day, the brake pedal would pulsate slightly as I braked. The steering also felt lighter during this time. I hadn't noticed this while driving around the city/highways.

Right before the car comes to a stop at slow speeds, the front brakes make a sound (not a squeal)... similar to a single knock on a piece of wood.

The rotors are OEM Honda and have been turned once by the dealership. I can't recall the last time the rotors have been changed, but they are likely more than 7 years old.

I don't have a micrometer or the tool that measures the consistency of the thickness, so I have no idea of the rotors' condition. Attached are pictures of marks on the rotors, after applying brake cleaner. Also, the car had been parked for three months, up to the last week of August.

Any ideas?

SumAznGuy · 09-01-2012, 07:00 PM

I'm pretty sure your rotors are too thin and those marks are cracks.
Check out the difference in material between the contact area and the tops and middle of the rotor where the rust is.
Check the marks and see if the cracks follow the vents in the middle of the rotor.

fliptuner · 09-02-2012, 12:31 AM

Regardless of whether they're cracks or not (I actually think they're pitted from sitting), it would seem that they're warped anyways and since they've already been resurfaced once, are due for replacement.

You can wipe them down with brake cleaner and scuff/clean the pads to get the rest out of them but I'd recommend you just as soon replace the pads and rotors.

Spectre_Cdn · 09-02-2012, 06:40 PM

The marks seem to be only on the surface, but new rotors and pads are on the way. I looked back at the service records and the rotors haven't been changed since leaving the factory 14 years ago

The pads were changed in '09, which was when the rotors were machined. Do I have to use new pads with new rotors, or should I wait until the current pads are done before replacing them?

SumAznGuy · 09-02-2012, 09:18 PM

Just take some sand paper and a block of wood and resurface the face of the pads and you can resuse them for the time being.

How many km's do you have on the current rotors?

Spectre_Cdn · 09-02-2012, 09:28 PM

The rotors have been used for almost 175000km. They were machined at 138828km.

I'm thinking of attempting to replace the rotors/pads myself, but I'm also hesitant because they are brakes after all. I don't want to mess it up, although there are many DIY's for 6th-gen Civics out there. Is there anything that I can potentially break?

Puck Luck · 09-02-2012, 10:37 PM

To me, those marks look like they were left from the brake pads, not cracks. At that milage, with original rotors, you are probably due for new rotors. If you don't have a mic or caliper to measure the rotor, (19mm i think is the min) try a open end 19 mm wrench and see if you can slip it over the edge of the rotor. If you can, its close enough to the minimum. When i cut rotors, typicaly 1/4 mm - .3mm or so comes off. The rotors start off at 21mm.
If you diy, might need a impact driver to remove the set screws onthe rotors. Or you can use a center punch to get the screw moving. (which looks like someone already has used)

SumAznGuy · 09-03-2012, 09:08 AM

Actually, brakes aren't that hard to work on and the chance of messing them up isn't that high unless you are trying to screw them up.

While at it, take the time and get some help and bleed the old fluid out of the brakes too.

Soundy · 09-03-2012, 09:32 AM

If you're talking about those evenly-spaced radial lines... I'd bet those all correspond to the "fins" that join the two discs together. If those are showing through, your rotors are BADLY worn down and should be replaced ASAP.

My dad had that happen once on his van - kept driving and driving with the brakes grinding until one time, he had to make a panic stop, there was a crunch, and bang, and suddenly... no more grinding: where the outer disc attaches to the hub, had ground right through, and with the hard stop, the whole disc assembly just snapped loose from the hub.

Spectre_Cdn · 09-16-2012, 09:18 PM

I replaced the pads and rotors today. The original rotors still had almost 20mm (19mm is the service limit, as mentioned above), and the pads had 6mm left (1.6mm limit).

Not bad for 14 year old rotors!

...but the rotors were starting to warp. And it seemed like the marks were from the pads, and not from cracking.