Brakes are locking up and no releasing until it cools down

Hi,

First, confirm the brake pedal is fully releasing. If there is a drag on the brakes, they will heat up. As a result, the brake fluid can expand and causing the brakes to do this.

If you are certain that isn't an issue, then I need you to try something. When the brakes lock up, open the bleeder on the brake caliper to see if the brake releases. If it does, then we have an issue before the caliper. If it doesn't release, you have something causing the caliper to hang up and overheat.

Also, if you haven't, have the can-bus system scanned to see if there are any codes related to the brake system. CAN stands for controller area network. Basically, the modules and computers are tied together via a few wires. By scanning the can, it will identify any codes regardless of components.

Here is a video showing it being done:

https://youtu.be/InIlnsjOVFA

Let me know what you find or if you have other questions.

Take care,

Joe

Okay. If this wasn't an issue prior to the new hydro-boost being installed, I have a feeling the pushrod between the master cylinder and hydro-boost has no play causing the brakes to be slightly applied when you release the brake pedal. Heat would cause the brake fluid to expand until the brakes lock up. Do you remember having any trouble with that?

Don't laugh but I need you to try something. When the brakes heat up and lock, loosen the brake master cylinder to see if they release.

Let me know.

Joe

Hi,

Was everything bled properly? Did you bench bleed the new master cylinder? Here is a video that shows how bench bleeding is done:

https://youtu.be/WDxvEQrMkBg

When you installed the new master cylinder, did you pay attention to the pushrod?

If you have no pedal at all, something isn't connected properly. Even if there is air in the system, you should be able to pump up the brake a bit. It may go to the floor again, but you should feel some resistance.

When you bled the front brakes (after new hoses) was there a lot of air that came out?

If you look at the attachments below, they are the directions and pics specific to your vehicle for master cylinder replacement. Take a look through them to make sure nothing was missed.

Let me know.

Joe