Brake Pedal Lockup
Thread Starter
Junior Member
Joined: Feb 2023
Posts: 35
Likes: 2
2013 GL450
Brake Pedal Lockup
2013 GL450 - I'm having an issue with my brake pedal occasionally locking up (getting very firm) when at low / slow speeds. Applying more pressure will not stop the vehicle and I have had some near misses.
I flushed my brake fluid after I got the vehicle at 60k miles, using a vacuum pump at the calipers. After I did this, I had some significant brake issues where I intermittently had no brakes. It started out a little spongey and then turned into no brakes. I bled them again with the same method and all was fine. Seems likely I somehow had a bubble in the MC, maybe introduced at the caliper.
After that I have had 3 instances at low/no speed where my pedal has stiffened up and I cannot apply more pressure to stop the vehicle.
I have assumed this is related to my bleeding/flushing of the brakes, but have not had the car long enough to know that.
What part of the brake system is responsible for holding pressure on the pedal? How could bleeding/flushing the lines have introduced this issue?
Thank you in advance
I flushed my brake fluid after I got the vehicle at 60k miles, using a vacuum pump at the calipers. After I did this, I had some significant brake issues where I intermittently had no brakes. It started out a little spongey and then turned into no brakes. I bled them again with the same method and all was fine. Seems likely I somehow had a bubble in the MC, maybe introduced at the caliper.
After that I have had 3 instances at low/no speed where my pedal has stiffened up and I cannot apply more pressure to stop the vehicle.
- One time at a red light while I was inching forward behind another car. Pedal got hard and I had to stomp it s hard I could to stop. Almost had an accident
- Another time in reverse on an incline; the pedal got hard and the car rolled forward. Stomped it very hard and barely stopped
- Same day as above, pulling into a parking spot. Could not stop the car and hit the concrete bumper to stop.
I have assumed this is related to my bleeding/flushing of the brakes, but have not had the car long enough to know that.
What part of the brake system is responsible for holding pressure on the pedal? How could bleeding/flushing the lines have introduced this issue?
Thank you in advance
Thread Starter
Junior Member
Joined: Feb 2023
Posts: 35
Likes: 2
2013 GL450
Does anyone have any ideas on the issue above? I've had this issue 4 times now and am going to stop driving it until I get it sorted out.
I intend to take it to the dealer for an assessment and/or pressure bleed. However, I cannot understand how an air bubble or any similar issue with my previous bleed could cause this problem. Thanks for any advice.
I intend to take it to the dealer for an assessment and/or pressure bleed. However, I cannot understand how an air bubble or any similar issue with my previous bleed could cause this problem. Thanks for any advice.
