Brakes locking up after near accident, any thoughts?

C

[email protected]

2
#1
Messages
72
Likes
0
Location
Milwaukee
#1
I was recently on the highway and needed to jam on my brakes in order to nearly avoid a braindead driver who cut in front of me. I literally came to a full stop.

At htis point my brakes were completely locked. It was as if I was trying to drive with my emergency brake on. After about a minute of slow accelleration they finally released. Has anyone heard of this happenning?? If so, why? Is this a caliper malfunction?

Please advise!!!! Thanks in advance....

(1994 BMW 325 convertible)
 
E

epj3

Senior Member
#2
Messages
7,370
Likes
0
Location
Lancaster, PA
#2
It happened to me once in our pontiac montana when the engine stalled while driving, while moving I put it in neutral, turned it on, put it in drive, touched the brakes a bit and the same thing happened -- only they re-released after I restarted the van.

It sounds like your ABS might be malfunctioning -- as in the pump makes a bunch of pressure but the valves are messed up, so it keeps that pressure in the system. Obviously it cant hold all that pressure for too long, so eventually it lets go.
 
frolf

frolf

2
#3
Messages
4,412
Likes
5
Location
Wayzata, MN
#3
i think epj is on to something. one thing that can happen when brakes get super hot is that the pads can stick to the rotor, but i don't think your rotors/pads got that hot unless they really really sucked. thats why you never leave your ebrake on if you have been at an autocross, track event, or a long stint of hard driving.
 
Wadula

Wadula

1
#6
Messages
5,379
Likes
0
Location
Paderborn, Germany
#6
the stick to the rotor theory is exactly what my first thought was. nfortunatelly the right vocab is missing my repartoir, but in german we refer to that as "verglasen" which basically means that the surface of the rotor gets that hot that the metal moleculars reform to a glass like surface. your brake does not at all work good after that effect. it can happen that the heat you need to have that happen makes the pads stick to the rotor´s surface.
 
M

manuel

2
#7
Messages
2,195
Likes
0
Location
Houston
#7
crazy german!!! [ohcrap]

Wadula said:
the stick to the rotor theory is exactly what my first thought was. nfortunatelly the right vocab is missing my repartoir, but in german we refer to that as "verglasen" which basically means that the surface of the rotor gets that hot that the metal moleculars reform to a glass like surface. your brake does not at all work good after that effect. it can happen that the heat you need to have that happen makes the pads stick to the rotor´s surface.
Click to expand...
 
Wadula

Wadula

1
#8
Messages
5,379
Likes
0
Location
Paderborn, Germany
#8
crazy who? whom are you talking to? me or the guy that sits in my head and tells me to do things i do not like to do...but then...sometimes...i do them...and he wins...and then...sometimes...i win...but who am i? am i me or him? or is he me?

serious, it is a common problem with steel rotors. they can heat up that much that zthe surface is no more able to create enough friction needed to turn the velocity energy into heat, which is exactly what happens when you brake.

once i made it to crack the rotor with one single breaking manouver. rainy out side, high speed on the autobahn and a truck changing on my lane. result was an emergency brake that heated up the brakes so much that the water on the streets surface quenched the steel of the rotor. as a result i had two rotors with cracks like liz taylor has!
 
W

wantanM3

New Member
#11
Messages
24
Likes
0
Location
UK
#11
For what its worth we've had one of our cars brake discs overheat and ended up with a huge crack down it!....Certainly knew about it when it wen't!
 
C

[email protected]

2
#12
Messages
72
Likes
0
Location
Milwaukee
#12
Thank you for all of your input.

It was a very hard brake, from 65mph to dead stop - so the heat to rotor theory makes sense to me.

Since then I have replaced the rotors with some Brembo drilled and slotted rotors and I now have a new quality set of brake pads. Hopefully this will not happen again--I will give them a true test once the rotors are broken in.

thanks again
 
You must log in or register to reply here.


Top