Brake Rottors strange wear pattern

[ptjones]

I think unless you do alot of City driving like a Cab, It seems to me they should last 300k-400k  miles. IMO At 139k mi. not much wear. :)

 

Paul

[bberg7794]

I have this strange wear pattern on my. Rotors does anyone has the same problem

Please see the pictures and tell me if this is normal. Dealer said this is normal Is it? They say not to be worry about it because my car breaks with the engine. Most of the time

image.jpgimage.jpgimage.jpgimage.jpg

 

 

First 2 are rear rotors left and right

Second 2 are front rotors left and right

 

 

I have the same thing going on with my car. However I got 75K miles on the original pads and rotors. Front pads seem to have about 60% life left and rears have 40%. I will try some spirited braking and hope this goes away. I know I am bringing up a thread that is over an year old and wanted to see what other members are seeing!

 

 

My brakes look the same as the ones shown in Post #1, braking performance is still excellent and I use Mechanical brake once in a while with tranny in Neurtral. You've got a good dealer because my local dealer gave me a lot of BS about it and wanted me to change the pads and rotors for a lot of money

 

 

My dealership quoted me over 1000$CAD to change all four rotors and pads because pads were worn and rotors rusty on my 2013 C-Max with 35K km on the odometer!

 

I asked a mechanic friend to check it out. On the front, the inside face of the rotors were OK but the outside face showed a pattern similar to the photos in the post above. New pads and cleaning should do the trick.

 

In the back it appears that both sides are quite rusty as it seems they have hardly been used probably because of regen braking. In addition, one and possibly both caliper pistons are seized.

 

I do not drive much and I admit that I have not engaged in "friction" braking to any extent. Does anyone know whether Ford recommends procedures to alleviate the minimal use of such braking with hybrids? And also whether dealerships are told to be on the lookout for this problem when they do regular maintenance?

 

Thanks

 

 

Just took the car in for a list of concerns.   Getting close to the end of standard warranty ~33k miles.   One issue i stated was minor brake noise on the right rear in the morning while driving (no brakes applied).   This was really minor but thought I would put it down on the list to have it looked at.   They ended up resurfacing the rotors in the rear.  Said I had lots of pad left. 

 

I have 52,000 miles on my car now, but my rotors looked like the ones in the photo by the OP right after I drove the car off the lot and have only gotten worse.  My pad wear is minimal.  The brakes have occasionally been noisy while driving at low speed and now they can be grabby if I am braking a bit aggressively.  I too am concerned about the health of the calipers.  Since winter (salt application) is winding down up here, when I go to get my studded tires replaced with my summer tires, I am going to ask my mechanic to assess the overall health of the braking system.  This really is about my only complaint about the vehicle.

 

 

[obob]

I have 52,000 miles on my car now, but my rotors looked like the ones in the photo by the OP right after I drove the car off the lot and have only gotten worse.  My pad wear is minimal.  The brakes have occasionally been noisy while driving at low speed and now they can be grabby if I am braking a bit aggressively.  I too am concerned about the health of the calipers.  Since winter (salt application) is winding down up here, when I go to get my studded tires replaced with my summer tires, I am going to ask my mechanic to assess the overall health of the braking system.  This really is about my only complaint about the vehicle.

 

 

 

This might save you some money and help the grabbiness.

 

http://fordcmaxhybridforum.com/topic/4083-brake-rottors-strange-wear-pattern/?do=findComment&comment=64806

 

If you think the problem is with the rear brakes the emergency brake can be applied.  This might shake up some glazing.

 

There is a lot of incentive for a mechanic to recommend a brake job that has to do with the high profit of a brake job.

Edited April 5, 2017 by obob

[SnowStorm]

Yes, you really have to watch mechanic's "recommendations".  A local garage failed me at inspection for rusty brakes, or some such foolishness.  I went to my tire dealer and his inspector was furious that someone had failed them - saying they were just fine.  I payed for another inspection and haven't been back to the other place since.

[fbov]

... A local garage failed me at inspection for rusty brakes, or some such foolishness....

So did mine.

 

Except my mechanic was right, rotor surface was flaking off. Not the first time I'd seen the failure mode, so no foolishness, just what I'd expect from a good mechanic. 

 

Frank

[ptjones]

So did mine.

 

Except my mechanic was right, rotor surface was flaking off. Not the first time I'd seen the failure mode, so no foolishness, just what I'd expect from a good mechanic. 

 

Frank

Is that caused from what they put on the ice on the roads during the winter? :sad:

 

Paul

[fbov]

You mean salt? Quite likely. It's a major export crop. You passed the mine if you took I-390 to Corning. 

Frank

[SnowStorm]

The "rusty brake police" are going after The Enterprise again.  I had my tires rotated and was told that I would need rear brakes and rotors soon due to rust.  The rears look very much like the OP's rear ones and also, the way they have looked for about 150k miles (at 167k+ now).  My tire shop has been passing them for years (after they were failed by someone else - post #29 above).  So I'm left wondering if there's some easy way to clean off that mottled look on the outer part of the disc before the next inspection.

• Has anyone had their discs resurfaced?
• Also, what is the minimum thickness for the pads?

I guess with hybrid friction brakes its "use them or loose them"!  So much for "saving the planet".

[homestead]

Have you tried braking hard a few times to use the brake pads to clean the rotors?

[cr08]

Or simply brake in neutral. No need to hard brake at all to overcome regen.

[obob]

deleted  ( I just repeated post 28 )

 

I have had bad brakes and rotors in another car and the brakes actually don't stop as well - they stop like drum brakes in a car going over 95 mph but not as bad (need to press harder).  I suspect your car still stops really well.

Edited November 6, 2018 by obob

[klem]

Having new tires put on today (Tire Rack / Yokohama Avid Ascend GT - USD$143/EA) and the install shop pointed out the rust on the rotors that look just like these pictures and quoted me > $750 for the 4 rotors and pads.  The pads still have a ton of life at 54K miles.  I also have had no braking issues and get high braking scores.

 

I'm glad I checked this site and see this wear, or rotor rust as the tech called it, is common and normal.

 

Reading down the thread a little, I see a lot of talk about regen braking.  This is my first hybrid.  Could someone please explain how I should be braking?  Do the pads actually hit the rotors when braking and the brake display on the dash shows the braking animation (I don't know what to call it)?  What is the difference between friction braking vs. regen braking?  Is there a best practice I should follow for coming to a stop?

 

 

[cr08]

Regen braking is where the brake pads are not doing any of the braking, pads not touching the rotors. It is up to the traction motor that normally propels the car to now act as a generator, creating a braking force itself, and putting that energy back into the battery.

 

Friction braking is as it sounds. That is when the brake pads are being used.

 

The brake coach focuses on just the regen braking. So the higher the score, the more braking is done via regen vs friction brakes.

 

As far as best practice I couldn't say definitively. Efficiency wise it is best to try and max that braking score at all times. If rust does become an actual issue, if it was me I'd take every now and then and just do a normal but consistent braking pass in neutral. Doing it in neutral completely disables regen so it will all be on the friction brakes like a non-hybrid so it should scrape off the surface rust pretty effectively.

 

From my experience with my Energi, there is a noticable effect on brake feel when it has or is raining and I've taken to occasionally doing the above neutral brake in those conditions otherwise when the car gets down to under 5mph and the friction brakes kick in they grab pretty harshly.

[SnowStorm]

Looks like my rear rotors must be replaced to pass inspection - both my dealer and tire shop are saying this.  The dealer explained that the law changed recently (Virginia) to say that you must have "full contact".  Apparently, that mottled look isn't "full contact".  Dealer wants $385 and tire shop $280 (IIRC) to replace rear rotors and pads.

• Are those prices about what one would expect?
• Any real caution on DIY?  Parts look to be <$100.  Do I need that special tool to compress the calipers?
• How about sanding down the rotors with a random orbital sander and then doing some hard stops in neutral?  Maybe that will get them back close enough to "full contact" to pass????
• Any stainless rotors out there?

Need inspection this month.

[plus 3 golfer]

I've not changed brakes on my C-Max.  But, looking at the Service Manual, I see nothing that should cause issues and the procedure looks like all the other rear brake jobs I've done.  I've never used a piston retractor tool.  I simply disregard the warning in the Manual: 

4. NOTICE: Do not pry in the caliper sight hole to retract the pistons as this can damage the pistons and boots. 

And sometimes have to use a c-clamp to push the piston all the way in especially when replacing rotors and pads.  Parts stores use to lend tools like a piston retractor when purchasing from them.  Don't know whether they still do.

 

I don't see how sanding could ever work on the rotors as it would be hard to get a sander "flat" on the surface of the disc all the way around.  I'd just spend the $100 rather than likely wasting a lot of time with poor results.

 

SS? Have no idea but sounds expensive.

 

Another reason I love AZ: No state required periodic inspection of cars and no emissions inspections since I do not work / live in an air quality control area.

[djc]

If the rear caliper piston is like most other Fords with rear discs, the caliper piston requires rotation to go back in, hence all the special tools available to do that.  I just received one of the cheaper type from Amazon today:

 

https://www.amazon.com/gp/product/B0002SQUFY/

 

As for cost, I just had C-max front rotors and pads replaced and to my surprise the dealer quote was lowest of the half dozen places I called - but only because Ford is running a coupon for $180 to replace pads and turn rotors.  Replacing the rotors is higher but just by the cost of the rotors ($65 each).  So total was $310 plus tax.

The job took 4 hours (they had quoted 1.5 hr.)  They had to call in a more experienced tech because the caliper bracket bolts were frozen.  He used a torch.

(The rear caliper bracket bolts have a much lower torque spec so should be less difficult to remove.  I hope.)

 

https://owner.ford.com/maintenance/service-coupons-and-offers.html

[SnowStorm]

So I went ahead and had the dealer replace the rear brakes so they could go ahead with the inspection.  This "rusty" rotor "full contact" stuff has me irked.  I could "need" new rotors every year from now on if I can't keep that mottled pattern at bay.  I'm getting suspicious of a self serving scam.  I could see requiring new brakes if the pads were really only hitting part of the rotor, leaving the rest truly rusty.  But with this mottled pattern it looks like the pads contact the full face or the rotor but the rotors are rusting faster than they are getting worn down so little depression form.  For all we know, that pattern may be acting like sand paper and creating more friction - hence, better brakes!  Its getting more disgusting than my failed transmission - and could cost just as much in 9 years!

 

I wanted the old parts from my car but didn't get them - apparently they forgot.  My hope was to find a way to lightly "resurface" them.

 

We need stainless rotors but it looks like only motorcycles and boat trailers are that lucky.

Does anyone know anything about coated rotors?  They are supposed to hold up better against rust.

And what about break-in (or is it brake-in!) procedures to minimize the problem?

[Bill-N]

Since there's no regen when the transmission is in neutral, you may want to try braking in neutral occasionally just to give the brakes a bit of work to do.

[djc]

 

Does anyone know anything about coated rotors?  They are supposed to hold up better against rust.

And what about break-in (or is it brake-in!) procedures to minimize the problem?

 

My take (in order of decreasing confidence):

 

a) rust breeds rust (the rust pits don't get scrubbed by the pads so once formed they continue to corrode)

 

b) you don't need the full rotor surface (some rotors are sold with grooves or holes drilled through)

 

c) coating the rotor only prevents rust on the areas the pads don't contact - it's cosmetic

 

d) break-in is more for pads than rotors and is mainly to get them rapidly up to spec performance than to affect long-term life.

 

e) open / spoked alloy wheels such as the C-max OEM exacerbate the problem of rotor rust, esp. in rust belt.

[ptjones]

I think the main problem is the chemicals they use on the roads in snow country. With 223k miles my rotors look fine. I do avoid using the brakes as much as possible. :)

 

Paul

[SnowStorm]

Since there's no regen when the transmission is in neutral, you may want to try braking in neutral occasionally just to give the brakes a bit of work to do.

So we have thought - and I've done it a number of times.  However, I soon noticed that you can shift to N, brake to a stop and still get a braking score - even 80 or 90 percent!  The whirligig thingy is gone but you can get a high score as if regen happened normally.  Has anyone else noticed this behavior?  With more experimentation it seems that if you shift to N before taking you foot off the accelerator, you don't get a score.  I need to try it some more to be sure.  Question is, if you get a score after shifting to N, did it really use regen or did it just show the score as if regen had happened.  I guess I'll have to try the two scenarios, jump out, touch the rotors to see if they heated up and hope I don't get burned!

[plus 3 golfer]

I know that if coasting in N (foot off accelerator and brake), there is no regenerative braking and no score.  This makes sense because the regenerative braking with no brake pedal applied should simulate engine braking when in D and no engine braking when in N.  It also makes sense that if one pushes the brake pedal while coasting in N, one should still get regenerative braking.  

 

Just look at ForScan and monitor brake pressure and current flow of the HVB. There may even be a PID for regenerative braking.   If regenerative braking occurs, current will flow into the HVB.  If brake pressure increases above a threshold amount, friction braking occurs.  Next time out I'll test and record what happens.  

 

We know that there is a Brake over Acceleration software which I hope would work in all gears in case of issue with gear status.  This may be why perhaps "With more experimentation it seems that if you shift to N before taking you foot off the accelerator, you don't get a score" -  perhaps the algorithm kicks in and uses friction brakes. 

 

Brake Over Accelerator

The brake over accelerator feature may not be active during low speed operating conditions. This enables unique drive maneuvers such as trailer tow, boat launch and retrieval or operation in hilly environments where the operator may require the application of both the accelerator pedal and the brake pedal during low speed maneuvering. The brake over accelerator feature will be active at speeds greater than 16 km/h (10 mph).

 

In the event the accelerator pedal becomes entrapped, such as by an object lodging the pedal, the brake over accelerator feature will reduce engine power when the brake pedal is applied.

 

The hybrid vehicles achieve a result similar to the brake over accelerator feature by reducing power if the brakes are applied while the accelerator pedal is pressed.

Operators that rest a foot on the brake pedal when also applying the accelerator pedal may activate the brake over accelerator feature. The brake activation is detected by the PCM from the electrical brake switch. In addition to brake over accelerator comments, the customer may bring the vehicle in for repair to address concerns such as a hesitation/stumble or a lack/loss of power. In the event of a hesitation/stumble or a lack/loss of power concern, carry out normal vehicle diagnostics for the appropriate symptom code. If the brake over accelerator feature is suspect, the BRKOVR_ACTION, BRKOVRD_POSS and DIST_BRKOVRD PIDs will display a brake over accelerator event occurred.

 

In the event the brake over accelerator feature is suspected as the cause of the customer concern, explain to the customer the details of the override system as described above. Additionally, make sure the customer is aware that resting a foot on the brake pedal while driving may cause the activation of this feature. This also results in activation of the brake lights on the vehicle while driving. For additional information refer to the Owners Literature. 

[ptjones]

You can watch the SOC for the HVB with the ScanGaugeII while in Neutral to see if it goes up when you apply the brakes. I do know that when the ICE is running in Neutral the SOC goes up.  I thought there was no regen in Neutral when stepping on the brakes. 

 

Just tried it out and as I remembered stepping on the brakes in Neutral doesn't charge up the HVB.

 

Paul

[plus 3 golfer]

Ok, I recorded about 20 PIDs while shifting to N and D, ICE on / off applying brakes to see when regen occurs. I plotted the data but it would take too long to clean up tp make it easy to understand, Bottom line: I saw no indication that regenerative braking occurs when in N. So, shifting to N and using friction brake may promote a normal rotor wear pattern so as not to fail a state inspection. I would think though that the frequency that one would have to do such might be several times a day or perhaps one should stop trying to get 100 % brake score. :)

 

1) Regenerative braking does not happen when in N whether ICE is on or off.

2) Pushing / delaying release of accelerator pedal when shifting from D to N does not start or affect regenerative braking.

3) When in N and ICE on, generator charges HVB whether moving or stationary. You can keep ICE on at around 1400 rpm by pushing accelerator pedal in.

4) Pushing brake pedal in N turns ABS from a status off to on. Hydraulic brake pressure increases and friction braking occurs.

5) Pushing brake pedal in when in D does not turn ABS status to on until maximum regenerative braking can not meet demand of driver.

6) Traction motor will immediately stop regenerative braking (simulating ICE braking when coasting) if shifting from D to N.