# MPG down since replacing front brakes



## Patman (May 7, 2011)

It seems since I replaced my front brake pads, my MPG has been down even more than just for the winter weather. I am looking at my rotors and those appear that they need to be turned also. Actually should have been turned when I replaced the pads, but did not have time. Any ideas what may cause suffering MPG since the pad replacement?


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## brian v (Dec 25, 2011)

Buy some new wheels , atleast IT will look good ! 

What has beèn your average Temperature outside Patman ?


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## Rockhead (Jul 10, 2014)

Are the brake pads dragging?


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## spacedout (Dec 7, 2010)

If you did not turn your rotors, the new pad will wear very quickly. Those old groves in the rotor could be catching the pad and causing more resistance.


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## Patman (May 7, 2011)

I will probably turn on Saturday morning as all the snow is done and it may be in the 40's. 



> What has beèn your average Temperature outside Patman ?


Temps have been down in the 10s - 30s and we have been getting hammered with snow. I have noticed the car does pull a little so I know I do need to turn the rotor. The MPG is not down that much, it is just one of the things I noticed since I replaced the pads. I was just in a hurry when I changed the pads that is why I left them go, I know they didn't look that good! usually I replace them and don't worry about it(surprised I didn't this time but mine was the only car and didn't think ahead) I'll report back after I get everything squared away.


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## jblackburn (Apr 14, 2012)

MPG sucks below 20F.


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## 170-3tree (Nov 4, 2014)

Make sure the calipers move freely!!! And the slides!! Especially if you have a pull.


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## Patman (May 7, 2011)

FWIW, I took the car to a shop and had them turn the rotors and swap the brake fluid also. I know how to do both. However there are several issues, time, cold and WTF I make enough money to let someone else do it esp when time is the issue.


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## brian v (Dec 25, 2011)

Hey it is going to warm up next week . Maybe your MPG will go up ..

Cold Ambient air temp can make your MPG take a nose dive as j has so eloquently stated .. there are many factors at play when dealing with colder temps and the combustion processes with consideration to good MPG .

Give BlueAngels newest thread DIY oil pan heater thermostat removal a perusal at your leasure ! he has some real ideas that are beneficial !


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## jblackburn (Apr 14, 2012)

> Cold Ambient air temp can make your MPG take a nose dive as j has so eloquently stated


:th_salute:


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## Patman (May 7, 2011)

Well I just got the car back after the turning of the rotors and the replacing of brake fluid and I feel like I am driving a new car again! After driving a car for so long you get used to its mannerisms(braking clutch etc.). I was actually getting fed up with how the car drove so....After having the rotors turned and the brake fluid changed it drives like I hardly remember anymore. Stopping is smooth and straight and the car rolls so smooth. Best $200 for automotive labor I have ever spent. I am so glad I pulled out the "crow bar on my wallet to let someone else do it while I was at work. No more thoughts about when will I do it and end up avoiding the issue until it becomes a "moot point" even though it is supposed to get up in the 60s next week. Long enough time to avoid the issue and end up thinking it doesnt drive that bad. now it is done and I can enjoy how it drives again!!! Hopefully MPG will go back up again also?


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## brian v (Dec 25, 2011)

That's Nice Patman .
I need some warm air to , So crisp and clear and less snow.


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## obermd (Mar 3, 2012)

Patman, I wonder how long your brakes have been dragging.


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## Patman (May 7, 2011)

obermd said:


> Patman, I wonder how long your brakes have been dragging.


Me too, maybe since I bought it. Probably explains my crappy/less than par MPG out of an Eco(look at my fuelly sig.). Remember I have never really boasted about having great MPG out of this car.I have always explained it away by city driving, then replacing the pads was the thing that uncovered the problem by dragging.. Hopefully this inadvertently uncovered and solved this problem also. As I said, you just get used to how something drives and end up accepting that is just how it is but wonder how and why others are better. I was trying to fix a problem not caused by my methods of correction(working on the engine). Ergo I tuned/detuned etc. Premium gas helped some but never really got over 35 MPG on the highway even and feeling like the car is under powered. Explains lot of things about this car to me now! Hopefully I will see the MPG go up and be more "Eco Like". If that was truly the cause. I will see soon maybe even get a hypercruzer badge someday.

Initially I was not going to have my brake fluid changed. Just turn the rotors, but I called and asked how much to replace the fluid and they said it was on sale for 89 so I told them go ahead and do it. When I replaced the pads, I was wondering how my rotors were worn/grooved like they were. In my 30 years of working on cars I have never seen wear like they were worn unless they were metal to metal and they weren't. Probably have @15K to go.


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## obermd (Mar 3, 2012)

Here's to improved drivabilty and MPG. :th_dblthumb2:


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## Danny5 (Dec 22, 2011)

brian v said:


> That's Nice Patman .
> I need some warm air to , So crisp and clear and less snow.


You can have some of ours. Going to be upper 80s next week. Bleh.


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## mdubord1024 (Sep 3, 2014)

People still turn their rotors? Didn't think the labor cost vs buying new was even worth it anymore


Sent from AutoGuide.com Free App


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## Patman (May 7, 2011)

mdubord1024 said:


> People still turn their rotors? Didn't think the labor cost vs buying new was even worth it anymore
> 
> 
> Sent from AutoGuide.com Free App


Normally I don't. It was a matter of time, and labor availability and cold. It was easier to have someone else turn the rotors and this also uncovered the problem with always "driving with my brakes on". If I would have been available to do the work and not being so cold after a snow storm, it would have been a wash new rotors vs. replacing. I am very happy I did what I did because it uncovered a brake dragging problem. FYI MPG is up now. looking at 50+ on my way to work.


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## obermd (Mar 3, 2012)

Patman said:


> Normally I don't. It was a matter of time, and labor availability and cold. It was easier to have someone else turn the rotors and this also uncovered the problem with always "driving with my brakes on". If I would have been available to do the work and not being so cold after a snow storm, it would have been a wash new rotors vs. replacing. I am very happy I did what I did because it uncovered a brake dragging problem. FYI MPG is up now. looking at 50+ on my way to work.


So, how's your car doing now?


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## Merc6 (Jun 8, 2013)

You should also bleed the clutch, think that will be on my list in the summer time as well as brake fluid and possible pad/rotor replacement.


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## obermd (Mar 3, 2012)

Patman, have you replaced the clutch/brake fluid yet? I did mine around 150 fill ups. Braking is better and the clutch motion is smoother. The 2015 owner's manual recommends every 45K miles or three years.


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## Patman (May 7, 2011)

obermd said:


> Patman, have you replaced the clutch/brake fluid yet? I did mine around 150 fill ups. Braking is better and the clutch motion is smoother. The 2015 owner's manual recommends every 45K miles or three years.


Yes I did that last Friday when I had the rotors turned. I believe that is what stopped the brake dragging. ? Yes I agree: braking is better and the clutch motion is smoother. Funny I have never replaced my brake fluid before as a maintenance item. Of course I used to replace master cylinders more often "way back when". I will probably replace the fluid again as a maintenance item in the future. All I know is I told a co worker that kinda gave me a look like you really think that did anything? LOL Kinda like that dad disapproves of what I did. He is older than me but not as much of an auto fanatic as I am and his brother used to be a mechanic and does all his automotive working where I do my own!


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## 1877 iris ave (Sep 23, 2011)

Question, why would changing the brake fluid or the pads change the dragging problem, I would think the calipers would be the culprit. Well obviously it did, maybe air in the lines or h2o?


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## obermd (Mar 3, 2012)

1877 iris ave said:


> Question, why would changing the brake fluid or the pads change the dragging problem, I would think the calipers would be the culprit. Well obviously it did, maybe air in the lines or h2o?


Changing the brake fluid didn't cause this. Patman's problem was insufficient clearance between some part of the rotor and the wheel, causing the brakes to always drag just a little bit. This resulted in poor coasting which the ECO MT depends on for fuel economy.


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