Rear Brake Disc/Parking Adjustment Options

[trdproven]

Are there any adjustments that need to be made if you put on a new caliper I noticed these celicas use a duo servo mechanical drum parking brake design, where the cable goes into from behind the rotor vice externally. is the only rear parking brake adjustment in the center glove only? I keep reading you adjust something in the rotor first and then move on to the adjustment in the center glove. is that an adjustment in the rotor where that rubber plug is? I noticed when I looked into the rubber plug, its not very clear what to adjust there, the toyota service manual is not very detailed. it says to adjust something so that pads basically lock the rotor, the description sounds like drum brakes but it was listed under disc brakes and drum brake shoes had its only paragraph. Just wondering if anyone knew. I'm used to the hondas rear brake set up.

This what the manual says:
Disc Brakes
Raise and support rear of vehicle. Remove rear wheel. Release
parking brake. Remove adjustment hole plug from rear rotor. Turn
adjuster until parking brake shoes lock rotor. Back off adjuster 8
notches.

This post has been edited by trdproven: Jul 7, 2012 - 2:56 AM

[trdproven]

#1. I noticed if I grab my wheel with handbrakes on, my car can move about an inch back and forth before the hand brakes lock the wheel, is that normal? It’s the same thing when I tighten the wheels with a breaker bar it moves about an inch then locks allowing me to tighten my lugnuts. Isn't it supposed to be tight from the beginning meaning already the wheel does not spin? In other cars, they are already locked so can't say for sure whats normal.

that's normal. the parking brake shoes have some rotation that allow the wheel to turn a little.

Sounds good.

#2. Also when I have the car lifted, with handbrakes not on (released), I can spin the tire each about a good spin 10 times, is that normal drag for brakes? Should it be less spins? I noticed it being less on other cars when I try to get ideas but comparing.

that also sounds normal to me. after replacing the brake shoes, the wheel was able to spin about 6-8 times depending how hard i turn them. there shouldn't be any drag by the shoes when the handle is released

**I actually replaced the caliper and the pads, not sure if meaning shoes is the same thing.
.

#3. I also noticed that the drag sound from the pads sounds a bit inconsistent on the right side from the left side, the left side sounds more like consistent drag which should be the normal one. The right side seems like a skipping dragging sound, not a constant whooshing sound.

could be warped rotors.

**thats what i was thinking, but shouldn't I get a weird braking result, like vibrating braking or uneven pad wear? The old pads looked fine. and if I recall it didn't have that sound before just now.

#4. Is there some type of adjustment inside the rotor? I noticed there is a rubber plug that when you remove, there is a hole to see inside the rotor. But I do not see anything to adjust. Toyota manual says the emergency brake is duo-servo, not sure what that means, but the cable runs to just behind the rotor, the manual says to adjust something but I don't see anything in there. For the handbrake when I pull up according to the manual says it should be between 4-7 click when you pull up, that’s about what I get, so I guess that adjustment is still ok. So I am still not sure if I still need to adjust anything inside the rotor.

duo-servo means there are two pistons pushing against the brake shoes. that's how drum brakes are usually set up (example). but in the celica's e-brake setup (example) there are no pistons but it's still set up that both shoes push against the rotor. there isn't anything else to adjust besides the star-wheel at the bottom and the nut for the cable at the handle.

**Gotcha but does the term brake shoes mean the GT's have pads and then shoes on the inside too? Your description sounds like an ST where the drum shoes are in the inside and push up against the rotor from the inside.

The rotor has a hole in it large enough to stick a flathead screwdriver through. This is different from the two bolt holes which you can use to push the rotor off of the hub. The hole in the rotor should be lined up with the largest hole in the face of the hub to allow access to the adjuster wheel.

Once the rotor is in place, turn the rotor so that the access hole is at the bottom. This will allow you to catch the adjuster wheel.

**I saw the rubber plug, looked in there, there was a hole, but did not see anything on the inside that I could adjust in fact, the access hole, seems to follow the rotor hole. Do I need to release the rotor off first to get to the access hole, or i just have to rotate it to the south? No matter what I did, the outer hole and inner hole access seemed to follow each other so Im curious cus I drive it around and the two holes are still lined up no matter the position. I might be thinking that its good so all I have to do now is rotate it to the south to access it.

Temporarily install two or three lug nuts to ensure the rotor is properly positioned on the hub.

**This is what I read, but what does putting lug nuts on do? i was just thinking the lugnuts move with the rotor no matter what.

Turn the adjuster and expand the shoes until the rotor disc locks. With a flathead screwdriver in the wheel, move your hand down to expand the shoes, and move your hand up to pull the shoes back.

**what is being meant by shoes here again? Are we both on pads or shoes? Does the disc brakes have the same adjuster?

Return the adjuster eight notches.

Now you can adjust the position of the parking brake lever. Four to seven clicks of the lever should produce full engagement, requiring 796 N (44.1 lbf) of force. If otherwise, you must adjust the relationship between the lever and the cable.

To do so, remove the centre console. Loosen the top lock nut, then adjust the lower nut until travel is correct. Torque the lock nut with 5.4 N–m (48 in.–lbf) of force.

The last step is a repeated road-speed adjustment -- the parking brake is self-adjusting.

Drive the vehicle at about 50 km/h (30 mph), then with the parking brake release button pushed in, pull on the lever with 88 N (19.8 lbf) of force. Hold the lever and drive the vehicle for about 400 meters (0.25 mile), then release. Repeat two or three more times -- once or twice is probably sufficient if neither the rotor nor shoes are new.

Shoes is being used frequently maybe I do not understand the design or something? Not sure if we are all on the same page, but then again, terminology is confusing me here. but just to know, you have to press in the lever, pull up the handbrake, drive for .25 miles and still have the button pressed in the whole time?

thanks for the help guys! looking forward to clarification first. I'm going to redo the crush washers again, i hate brand new ones sometimes, they seem tough to seal sometimes.

This post has been edited by trdproven: Jul 8, 2012 - 5:27 AM