I have a 1994 camry xle with 80K on it. For some reason after driving for 15 -20 minutes it gets really sluggish and then it locks up i believe all four wheels. I replace the caliper,hose and pads no good. PLEASE HELP it is such a great car.

 

Make sure it is not the transmission that has a problem.

If all four wheels lock up the issue may be in the master brake cylinder or power brake booster, together they controll all four brakes.

Next time it locks up try relieving some brake fluid pressure by opening the master cylinder bleed valve.

 

If it locks up and i open the master bleed valve what will that do. I am not to familiar with braking systems.

 

The brakes are hydraulic operated. Each brake has a hydraulic cylinder that is pressured by the master cylinder. When pedal is pushed down a hydraulic piston moves inside the master cylinder creating pressure in the brake lines. The line transmits this force to the brake cylinders; there another piston moves forward to push the pads or shoe against the drum or disk. When the brake pedal is released, the pressure in the brake lines and brakes cylinders should go back to zero. If not the pads or shoes will drag or lockup.

As the only item connected to all 4 wheel brakes is the master cylinder and proportioning valve on or the other most not be releasing the fluid pressure in the brake lines. The proportioning valve just allocates more fluid pressure to the front brakes then rear as the front does most of the stopping.

If the all the brakes are locked up, you can release the brake pressure by opening a bleed valve on each wheel cylinder, or the undo the brake lines going to the master cylinder. The fluid pressure should then drop to zero. This will just release the brakes; it does not solve the problem. Be careful, as brake fluid will remove paint.

Check to see it is not just one brake. If the car has ABS this can also be cause for problems.

Check all the flexible hoses on the brake system as one may be expanding. A dragging brake can heat up the brake fluid causing it to expand and force the piston/brake shoe or pad further into the disk or drum.

 

what u need to do is go out side of the car as soon as it happens...... if the brakes are frozen the wheel should get really hot....not only that but u could probably smell the brakes....its a weired smell...... but i have the exact same car and i found at one point a similar thing was happening to me like the car would start shakeing and it started to drag and whatnot and i work at a toyota shop as a mechanic get under the car and try to shake the e brake cables around cuz they tend to freeze up on those cars...... they are a big black cable looken thing comeing out from behind the back wheel running tword the front of the car..... u should be able to grab onto them right in front of the wheel...... but the other thing is if ur not sure its brakes sometime when the catalyst converter becomes clogged when it gets hot it will swell up inside and restrict the car and the car can stall out......i dunno just a long shot but give it a try...... best bet is to bring it to ur mechanic..... just have them check it out