1994 Brake Problems. Help or Advice Please. Non ABS. Very Dangerously Low Brake Pedal
 

My sister borrowed my car. She called and said I need to change the brakes. (I thought to myself, "No, it hasn't been long since I changed them"). Anyways, I buy new brakes, and head to her house. I tested the brakes when I got there, and the pedal went way down toward the floor. I take a tire off to start changing the brakes, but the brakes are still good... at least 70% of the pad left. I changed them anyways. All four front brake pads are 100% brand new now. (sorry for caps, but bold isn't working for me)

HOW CAN I TELL THE DIFFERENCE BETWEEN ABS MASTER CYLINDER/BOOSTER, and NON ABS MASTER CYLINDER/BOOSTER???

I still have the same problem. The pedal goes down, way to close to the floor. The car will stop when I drive it, but there is something wrong in the brake system. I hope someone can help me identify the problem!

This is what I've done so far, and symptoms exhibited: Car is 1994 Toyota Camry 4 Cylinder Front disc brakes are 100% new. Changed today Rear brakes are drums, and haven't done anything to them except bleed them after changing master cylinder and booster. Changed master cylinder and Booster (Not sure if it's ABS version or not, HELP HERE PLEASE!) I'm sure the Camry is NON ABS.

How do I know if the cylinder and booster I bought is for NON ABS???? I bleed brake booster, and all brake lines. Several, Several, Several times. Pumping and bleeding, pumping and bleeding, repeat, repeat, repeat. The pedal still goes really low to the floor, but is able to (Slowly / Dangerously) stop the car. The front right brake doesn't seem to be working properly. When the brakes are pumped, and I open the bleed valve, brake fluid will come out, but the pedal doesn't move at all.... Is the piston stuck?

It's really late, and I'm having trouble thinking about what all we done earlier today. If you think you can help me, please post with all the information you need, and any questions you need answered in order to have a better idea of helping me. I really need to get this car back up to running condition as it is a daily driver at the moment! Thank you. Thank you! I'll be online.. maybe later to check responses, but definitely tomorrow morning

Most online parts outlets such as Rockauto and PartsGeek have photos of the both parts. See link below for one.

https://www.rockauto.com/catalog/raframecatalog.php?ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=ce9p1rs36etcaualtdpbr2iva5

Click on the photo to enlarge it.

There are listings for Non-ABS, ABS (also called 4-Wheel ABS) and for rear disk brakes. Standard rear brakes on the 4-cylinder were drum. Compare photos with what you have on the car.

The original Toyota ABS master cylinder differs VERY slightly from the non-ABS. This difference is the location of a stopper bolt located underneath the cylinder body (the long tube/body that the reservoir and brake lines mounts to). This bolt when installed it looks like the head of a bolt.

The bolt for the ABS cylinder is located at the FAR end (radiator side NOT firewall side) of this cylinder. The non-ABS bolt is located further inboard (toward firewall) and underneath where one of the reservoir fluid intake bosses molded into the cylinder. There are two bosses. The correct boss location is the closest to the radiator on the cylinder.

I don't know what your knowledge of bleeding is thus will cover all procedures for the car. The procedures are the same for ABS and non-ABS.

Bleed the master cylinder. If it is on the car, disconnect all brake lines. If possible use hoses to route the fluid from the cylinder line ports back into the cylinder reservoir. If not, place a container under the master brake cylinder to catch the fluid that will flow out when bleeding the cylinder.

Fill reservoir.

Hold fingers over all brake line attachment fluid ports. Have someone SLOWLY depress the brake pedal to the floor while you let the fluid flow out by releasing your fingers. Use fingers to seal ports for outside air intake and have the helper to release brake pedal. Repeat this process until your are sure all the air is out of the cylinder (3-4 times).

In the process make sure the brake fluid level does not drop to below minimum setting on reservoir.

Connect all brake lines to cylinder.

Toyota does not state what brake cylinder to bleed first but suggest the longest line first.

Connect a hose to the selected brake bleeder valve to be bleed. A clear hose is better as it allows viewing of air bubbles in the line.

Have helper depress brake pedal several times then hold pedal to floor. Open bleeder valve and allow excess fluid to flow out.

When fluid stops flowing out tighten bleeder valve. Then repeat the brake pumping, holding pedal to floor and opening bleeder valve process. Repeat this whole process until no air comes out.

During the bleeding process make sure master brake reservoir does not become too low.

Once done, move to the next longest brake line until all lines are bleed.

Wash any brake fluid off paint as it can damage it.

As to the disk brake issues that might be causing problems.

With the tire off, have someone apply the brakes why you watch the piston in the brake caliper for movement. The caliper has one large piston. It is possible the piston may be frozen, stuck, have limited movement, etc. Then when the brake pedal is pushed the piston does not move or only moves slightly.

If you were to try to bleed this a brake having this problem, it would bleed normally but the brake still not work OK.

If you suspect the piston is frozen, remove the caliper and attempt to press on the piston to determine if it is free to move. You can use a pry bar to pry and push the piston or a large clamp to squeeze it. You can grip the piston outer exposed area with pliers to attempt to move the piston in and out. Don't pull the piston out too far or it will come out, there is no stop. Don't press on the brake pedal with the caliper dismounted or the piston will pop out of the caliper under pressure. The idea is to check for free movement. If all is OK, it make still take some force to move the piston, but it will move.

If the piston is frozen, has very limited movement, is extremely difficult to move it may the caliper may need to be repaired or replaced.

If your not sure what the piston should be doing, compare the movement action with the other side which appears to work normally.

Thanks for such an informative reply.

The master cylinder I put on the car was set up for ABS. Now I have another master cylinder (NOT ABS, which is what I need) and brake booster, and I'm waiting for the weather to clear up so I can install it.

I will check the caliper piston tomorrow too. The piston being stuck is what I was worried about. I was hoping I just didn't prime the master cylinder correctly, and the excess air was causing it not to bleed properly.

If the piston is stuck, is there a way I can fix it, do I need to have it repaired professionally, or replace the part all together.


Online parts catalogs... I'm such a dummy. I didn't even think to look at the difference between the two cylinders. Anways, I asked around, and figured it out, and now I have a second opinion, so I'm certain I have the correct one.

I'll update this thread when I get to work on it. Probably tomorrow. I hope it's all good news when I'm done, but if you don't mind, check back in this thread in case there is a problem, and I need some advice.


Thanks again

In the olden days repairing a caliper was SOP, today replacing it is SOP. There are rebuilt or new calipers available.

Parts such the piston, seals, etc are also available if wanting to rebuild.

Have check for any leak in the system? Seems to be your brake system has no pressure at all. Master may be the culprit or check for any worn out brake line before you proceed on overhauling the pistons.