I have a 2004 Cadillac Escalade EXT with 180k on it. Yesterday I was doing about 30 miles an hour when with no warning, my front wheels locked up for about 30 feet. They released on their own and have been ok for the last 20 miles or so. No codes or lights. Any ideas?
If it was one front wheel locking up...I'd suspect an internally failed brake hose. Especially due to its age and even more so if recent brake work was done. Twisting and kinking a brake hose can cause it to split internally and cause its inner part to act as a check valve...thus holding pressure.
With both front brakes locking up and releasing...hydro-booster failure. Not repairable, has to be replaced as a unit. Can be tedious to bleed air with new installation.
The following explains how to test:
(Start at #5 for self applying brakes)
Slow or incomplete pedal return:
1. Run pump at fast idle.
2. Pull the brake pedal rearward with approximately 10 lbs. force and release. Measure the distance to the floorboard.
3. Make 100-lb. brake application. Release brake pedal and measure distance to floorboard. The brake pedal should return to its normal position (step 2). If measurements are the same, go to step 5.
4. If the brake pedal does not return properly, check the pedal to be sure it is operating freely. Correct any sticking or binding as necessary.
5. If brakes are self applying and pedal is free, check for obstruction in the return line or a kinked connection between hydro-boost and pump reservoir. If obstruction or kink is found, go to step 6, otherwise go to step 7.
6. Remove obstruction or replace line as required. If condition remains, check for a damaged reaction end. If damaged the hydro-boost should be replaced or repaired.
7. If brake pedal is free of any binding conditions and return line is free of obstructions, remove the master cylinder cover.
8. Observe the brake fluid in the reservoir while rapidly depressing the brake pedal one inch.
9. Fluid surface should have some movement or spout in the forward reservoir section. Minor spouting may occur in the rearward reservoir. If no movement or spouting of fluid occurs in forward reservoir, the hydro-boost unit is defective and must be replaced or repaired.
You should readup on the complaints in regard to service brakes on this vehicle:
https://www.carcomplaints.com/Cadillac/Escalade/2004/brakes/service_brakes.shtml
