oo10inz

What’s up guys i have a quick question or two about the brakes on my 15 F Sport. So sometimes when the car is warming up and at around a 1k idle i have to really keep on the brakes to keep it from moving, i’ve also noticed times where i went from R to D i stopped in R and the shifted to D and the car started moving and i swear i didn’t let off the breaks at all. the front breaks were replaced by the previous owner at a shop in 10/18. i’m not sure if these are normal instances? i’m wondering if maybe a brake fluid exchange would fix these issues? any thoughts or input is greatly appreciated. thanks guys!

ex00

Have you checked your brake fluid also making sure there is still meat, assuming the pads were actually replaced. Look at the color of the fluid as well.

oo10inz

Ya the pads are good per the dealership’s inspection that was done in November after i bought it. i will check the fluid color today

Cicnus

Same here. 2016 350 AWD F-Sport. I noticed this once it got around 30F and below. But first i noticed that after letting the car warm up for 10 minutes and setting off to drive, with the car at a standstill, foot on the brake in Drive, i could feel the whole car vibrating. Not intensely shaking, but in comparison to how my phone feels in my pocket when its vibrating, but the whole car is doing it. After experiencing that for a little while, i noticed that once the car is fully warmed up, the vibration goes away. After a little while i also noticed the same thing you're experiencing with the brake, which also goes away after the car has completely warmed up. I was at my dealer getting a carwash and ran into my service adviser, so i brought it up to him. He had said that the car is working hard to get it up to the optimal operating temperature, which is why he thinks that the car would be vibrating like that, and that it shouldnt be a problem. At the time i didnt notice the whole brake thing so i hadnt brought it up. He also said that if it got worse or anything to bring it in, otherwise just mention it at my next service interval and they'll double check to make sure nothing is wrong. Over the past two months since then, i havent noticed any difference with the vibration or braking, so im just assuming its normal.

Also when i first started experiencing the vibration, i was able to narrow it down to the HVAC system in the car. If i turned the heat/ac completely off via the off button, the vibration would go away completely. I can only assume it would be the same for the brakes, but i havent actually tried it. Maybe try that to see if you're experiencing the same exact thing as me. My car is under full warranty so im not really worried about it since my service adviser said it sounded normal to him.

Edit: Also, wanted to note that i do not experience this when its warmer out. During the summer time when turning on the A/C right away, i didnt have the vibration or braking thing. Seems to be once the car registers that the temperature is below freezing point.

oo10inz

Thank you for this! ya mine is the same once warmed up it’s fine. i haven’t tried shutting off the Hvac system. Honestly none of what it’s doin necessarily worries me these cars have their reputation for a reason (i’m also on the last legs of my power train warranty) But i am in a similar climate to yours so i should have mentioned that in my first post as i did not notice this until the mornings got much colder

NickCaesar

My 2015 350 AWD does similar things. When cold, and in gear it really accelerates quickly just by me letting my foot off the brake. Like I can hit 8km/h just by letting off the brake. Only does it when cold. Brand new brakes and brake fluid, still does it. Just the way it is I supppse.

NickCaesar

i have the same car and it vibrates noticeably when warming up to. A lot. Never tried shutting down the hvac system to see if that’s it but once the cars warm it doesn’t do it. Haven’t really noticed if it does that in the summer but definitely vibrates like heck in winter.
Also I’m huge into letting the car warm up a couple minutes before driving in the winter, I live in Canada where we routinely have weather that reaches -35 degrees Celsius + a ton of snow and ice to get off the windshield but IMO 10 min idling is to long. Your wasting gas. Warm it up for 3-5 min while you clean off the snow/ice from the car than take off, it heats up quickly by driving just baby it the first few minutes and your good to go. You’ll notice a huge decrease in fuel economy by idling 10 min. Do about half that and that’s assuming it’s really cold and you have snow and ice to clean off the car.

oo10inz

Yup exactly this thank you that’s a good way to put it.

NickCaesar

there was actually a thread on this a year ago somewhere on here, but I’m guessing it’s normal if it happens to so many people. When it happens it still catches me off guard cuz the car takes off like I’m hitting the gas even though I’m not. But it only goes up to about 8km/h without hitting the gas.

oo10inz

and i’m also wondering if this is why sometimes goin from R to D that it goes with out releasing the brake

NickCaesar

Mine doesn’t do that. Are you sure your not subconsciously letting off the brake a bit? If the brakes are pressed firmly that’s almost impossible. A small sensation is normal, but if your car is moving forward while the brakes are firmly pushed somethings wrong. Make sure your not pushing the brakes really lightly. Push the brake pedal down nice and firm and going from R to D should not cause the car to move forward. You’ll feel a slight “bump” well call it but car should not move forward.

oo10inz

ya that may be it. i may not have them pressed as firmly as needed at that moment