Two Problems w/ 1990 Camry. Help Please...

[m4ducky]

Just the other night, driving on the freeway. I had to break immediately hard to avoid an accident. all seemed well after that. but once i pullled into a parking lot at the mall. i noticed a noise when i brake. shreaking kind of a noise. brakes are new. well didn't care to take much notice to it. and drove back home alright. BUT the next morning while going to church about a mile away, i would press on the gas and nothing, couldn't accelerate or move. Thought i had it on neutral but nope. turned on the engine and waited, turned it back on and the acceleration would work for a little while then when i press on the gas it would just make the acceleration noise and i can't move, happens everytime i stop or a block. some1 pls help.

[don24mac]

You say the brakes are new, but how new? And, are both front and rear new? Sounds like the front pads or rear shoes are sticking and sticking hard if you can't even go or accelerate. If the pads and shoes are new, then I'd suspect a problem with the master cylinder or vacuum assist diaphram. If the pads/shoes are older I'd suspect a problem with one of the calipers or rear shoe pistons.

The first thing to try is, after stopping the engine with no pressure on the brake pedal, then with the engine still off, push on the brake pedal. Does it initially feel firm? It should. Press it again. It should still feel firm, but less so then the first time. Again, and it will even be less firm, and you'll notice the pedal getting closer to the floor each time, too. This is how a properly functioning vacuum assist diaphram should feel as the stored vacuume is used up.

If the above seems normal, you can jack the car up, see if each wheel rotates fairly easily (you may feel the pad slightly). If all but one is able to be rotated, check the stiff wheel's calipers or pistons. If all wheels are quite hard to rotate, or you can't rotate them at all, there's a problem with the master cylinder or the vacuum brake assist mechanism.

Also check for free play in the parking brake. But, this is unlikely the problem if it happened so soon after hard braking.

[m4ducky]

Originally Posted by don24mac

The first thing to try is, after stopping the engine with no pressure on the brake pedal, then with the engine still off, push on the brake pedal. Does it initially feel firm? It should. Press it again. It should still feel firm, but less so then the first time. Again, and it will even be less firm, and you'll notice the pedal getting closer to the floor each time, too. This is how a properly functioning vacuum assist diaphram should feel as the stored vacuume is used up.

ok i did what you said. it feels firmer and firmer and further away from the floor each time i press on it.

[don24mac]

OK, I've checked the OEM Toyota Repair Manual for the 90 Camry.

One thing I forgot about and could very likely be the problem is a cracked or distorted brake pad or brake lining. I've seen this happen after hard braking before. It causes brake dragging, and is usually caused by very hard braking (as you described in your first post) or prolonged braking where the pad heats up rapidly. It can cause what you describe.

So, I'd first check for that.

Other posibilities mentioned in the manual are:

Parking Brake out of adjustment
Booster pushrod out of adjustment
Transition or return spring faulty
Wheel cylinder or caliper piston sticking
Adjuster broken
Master cylinder faulty

Also, since I mentioned the booster (vacuum assist) heres the method for properly checking it. However, I would now suspect a cracked or distorted pad(s) as the most likely cause of your problem.

To test the brake booster (vacuum assist) for Air Tightness:

Start the engine, and stop it after one or two minutes. Depress the brake pedal slowly. If the pedal goes down furthest the first time, but gradually rises after the second time or third time, the booster is air tight.

Depress the brake pedal while the engine is running and stop it with the pedal depressed. If there is no change in pedal reserve travel after holding the pedal for thirty seconds, the booster is air tight.

For an operational check, depress the brake pedal several times with the engine stopped, and check that there is no change in the pedal reserve distance.

Depress the brake pedal and start the engine. If the pedal goes down slightly, the operation is normal.