What's the low hum under car after spirited driving?
What's the low hum under car after spirited driving?
Pulled into the garage earlier today shortly after some 'spirited' driving... Obvious smell of brake dust, but a new sound. A low hum from underneath - seemed to be coming from between the rear wheels. As I listened to it, it went out and sounded almost like a pilot light/flame going out - not a pop, but that same kind of 'flame out' noise (can't put the precise words on it)...
Anyone?
Anyone?
Veteran Member
Joined: May 2013
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From: Metrowest Boston
Not sure if your car has the active exhaust vacuum pump, which would be back there. At some point, they deleted the pump and use engine vacuum instead.
If you applied the electric parking brake, it has a high-temperature reclamp, if your brakes were quite hot.
High Temperature Re-Clamp
After heavy use of the brakes, the disc temperatures
can be extremely high. At high brake disc temperatures,
if the vehicle is stationary and the Electric Park
Brake is applied, the EPB module automatically reapplies
the Electric Park Brake as the brake discs cool
down. A temperature model in the EPB module software
calculates the brake disc temperature from brake
application force, the time the brake force is applied
and vehicle speed.
High temperature re-clamp occurs at brake disc temperatures
of 572°F (300°C) and above. Depending on
the temperature, up to three re-clamps can occur, at
varying time intervals, in the 10 minutes following the
initial application of the Electric Park Brake. To limit the
number of re-clamps, the ignition status as well as the
current inclination of the vehicle is considered. If the
ignition is on, a re-clamp will only be performed if the
vehicle inclination is greater than 10%.
If you applied the electric parking brake, it has a high-temperature reclamp, if your brakes were quite hot.
High Temperature Re-Clamp
After heavy use of the brakes, the disc temperatures
can be extremely high. At high brake disc temperatures,
if the vehicle is stationary and the Electric Park
Brake is applied, the EPB module automatically reapplies
the Electric Park Brake as the brake discs cool
down. A temperature model in the EPB module software
calculates the brake disc temperature from brake
application force, the time the brake force is applied
and vehicle speed.
High temperature re-clamp occurs at brake disc temperatures
of 572°F (300°C) and above. Depending on
the temperature, up to three re-clamps can occur, at
varying time intervals, in the 10 minutes following the
initial application of the Electric Park Brake. To limit the
number of re-clamps, the ignition status as well as the
current inclination of the vehicle is considered. If the
ignition is on, a re-clamp will only be performed if the
vehicle inclination is greater than 10%.
Last edited by DJS; Nov 17, 2016 at 01:46 PM.
Wow! That's one smart parking brake. Yes, I think that is what this hum was - however car was on the flat also. Will try without parking brake next time...
Senior Member
Joined: Dec 2009
Posts: 811
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From: SW England
Thinks...even then I think the brake will apply itself, definitely will if the car rolls on its own.
Last edited by malbec; Nov 17, 2016 at 02:12 PM.
Veteran Member
Joined: May 2013
Posts: 6,999
Likes: 2,665
From: Metrowest Boston
We determined in another thread that the 2017s definitely do this, 2014-2015 don't, and I don't recall whether the 2016s do.
The park brake is applied automatically when you select Park. Perhaps you have to select N then release the brake to achieve this....just learning about the F until mine is built.
Thinks...even then I think the brake will apply itself, definitely will if the car rolls on its own.
Thinks...even then I think the brake will apply itself, definitely will if the car rolls on its own.
Parking brake is then highly recommended. Unfortunately the car will not think for you yet... (MY 2018?)
Senior Member
Joined: Dec 2009
Posts: 811
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From: SW England
See https://www.jaguarforums.com/forum/f...estion-172415/
http://www.ownerinfo.jaguar.com/docu.../proc/G1885600
It will apply the brake if the car rolls by itself!
Roll Away Detection
The Electric Park Brake is automatically applied if the
vehicle is stationary, with the Electric Park Brake off, and
then begins to move without operation of the accelerator,
indicating there is no driver intention to pull away.
http://www.ownerinfo.jaguar.com/docu.../proc/G1885600
It will apply the brake if the car rolls by itself!
Roll Away Detection
The Electric Park Brake is automatically applied if the
vehicle is stationary, with the Electric Park Brake off, and
then begins to move without operation of the accelerator,
indicating there is no driver intention to pull away.
Last edited by malbec; Nov 17, 2016 at 04:03 PM.
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Senior Member
Joined: Sep 2015
Posts: 326
Likes: 57
From: SW London, UK
My 2016 doesn't auto-apply EPB when put in Park.
Senior Member
Joined: Feb 2016
Posts: 234
Likes: 79
From: Vancouver BC/ Bucerias MX
In the silly (possibly ) question department....
After "spirited" driving, track or otherwise, it is strongly advised to not engage a "usual" parking brake..as the pads can adhere to the disk....thus with a stick shift, the car is shut off with the tranny in gear....with no hand brake applied.
So, the question...into the pits after a track session....if the car is shut off and the red P shows on the shifter....are there pads stuck on the rear disks...or I'd it a tranny "brake"/ lock ?
Thanks,
Alan
After "spirited" driving, track or otherwise, it is strongly advised to not engage a "usual" parking brake..as the pads can adhere to the disk....thus with a stick shift, the car is shut off with the tranny in gear....with no hand brake applied.
So, the question...into the pits after a track session....if the car is shut off and the red P shows on the shifter....are there pads stuck on the rear disks...or I'd it a tranny "brake"/ lock ?
Thanks,
Alan
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Joined: Mar 2016
Posts: 6,986
Likes: 2,157
From: Canada, eh
I regularly track my car, and on my car parking brake is automatically applying when I shut the car off. During normal driving this is very convenient, on a track - not so much. On my 2016 MT car if I turn off the engine the car will apply parking brake for me and I don't know how to override this. I don't trust the temperature sensor, too easy to warp disks, so I am left with "leave in neutral and let it idle" method. This means I am forced to hang around 2-3 minutes and always take cool-down lap.
Last edited by SinF; Nov 18, 2016 at 12:35 PM.
