Need expert advice on finishing 94 Celica brake job Options

[Langing]

JULY 22 UPDATE: "BRAKE JOB" FINISHED. (See comment of today's date.)

JUNE 2 UPDATE: REAR BRAKES FINE NOW; FRONT RIGHT STEERING KNUCKLE DEFINITELY BENT (AT THE EARS); SEEKING ANOTHER KNUCKLE.

MAY 28 UPDATE: NOW WHAT? THE REAR WHEELS ARE LOCKED BUT THE PB IS DOWN! WHAT THE HECK IS GOING ON?

MAY 27 UPDATE: SATISFIED THAT THE REAR DRUM BRAKES ARE NOW FUNCTIONING PROPERLY; PROBLEM DEFINED DOES NOT AFFECT THE BRAKE AT ITS PROPER ADJUSTMENT OPERATING POINT; MOVING ON TO NEXT TASK

MAY 23 UPDATE: REAR DRUM BRAKE PROBLEM DEFINITION IS NARROWING SUCH THAT AN EXPERT MIGHT BE ABLE TO HELP ME (SEE LAST POSTS)


This is my first experience doing such an extensive job on my Celica, and I have the Green Books (FSM). Everything looks beautiful (to me), have photos.

I have finished replacing/rebuilding all parts of the brake system -- meaning at all four wheels (including new hardware, hoses, wheel bearings, etc) and am ready to put her back on the road, but . . . with all new shoes, pads, drums and rotors, how can I know they are working properly? I’ve already discovered a couple of assembly mistakes I had to correct, which tells me there may be something else I am missing?

First known issue: because I don’t have a vernier caliper longer than 6”, an AMPRO T71558 Brake Drum Resetting Gauge will arrive on Friday so I can set the ‘clearance’ between the shoes and drums at the rear. Beyond that I have some confusion on how the parking brake works to maintain the proper clearance, given the initial setting of the rear brakes. I want to be totally clear about what I am doing so I am not making a stupid but costly mistake.

For example: the manual says to verify that the parking brake levers (on the rear shoes) turns the adjusters (they do) and then to minimize the length of the adjusters (I did), then install the drums and pull the parking brake lever (in the cabin) all the way up until a clicking sound can no longer be heard (did that as well). The very next procedure is to check shoe clearance, but the last step left the parking brake on? And I was thinking that engaging the parking brake and then releasing it was the cause of the adjuster turning, and that it turns only by just one gear tooth distance. All that said, the manual has me just setting the initial clearance, popping on the drums and tires I'm good to go. Is that really all I need to do to make sure the rear breaks are functioning properly?

Second issue: with new rotors and pads on the front disc brakes, there isn’t a lot of free space in the caliper bracket and there is a scraping sound when I turn the rotors by hand, so there is obvious interference. I don’t know whether the slide pins are not working well, since the calipers aren’t sliding in and out when hand manipulated, or are they just supposed to rub together until enough friction material wears off that they can begin to have enough space to work once the car is on the road? How do I check them BEFORE I put her on the road, so I can be certain they are working properly?

My inexperience has me ready to go, but dead in the water.

This post has been edited by Langing: Jul 22, 2014 - 11:06 AM

[Langing]

Second Issue: the thin metal dust cover plate may be slightly bent and rubbing the rotor, just bend it a bit with your hand.

I bend it nearly everytime I work down there...

Are you referring to the stamped metal backing plate (or dust plate) that, on the front disc brake, is fixed to the steering knuckle, and on the rear drum brake is where the parts get mounted, and gets bolted to the carrier when you bolt on the hub assembly? It's a little bigger than the rotor and looks somewhat like a fan?

I have very carefully gone around all those to make sure there is no interference, and I don't think this is my problem, if we are talking about the same thingy.



Found a major cause of the right front brake noises:

Photos that go along with this text can be found at Photobucket at:

http://s1273.photobucket.com/user/GuiermoV...Brake%20Problem


I dug deeper into the right front brake, and discovered that the lower inside pad support plate was knocked out of kilter in the same way as I reported earlier. Since this has happened twice now, rather than just driving it back into its seat, I more closely investigated why it happened, which led me to finally recognize that there is not enough room between the rotor and the torque plate to permit proper installation of the lower inside pad support plate without causing interference and, thus, damage to the rotor (see rotor scarring photo).

My theory is that the pad support plate gets knocked out of position when I drive in reverse. When I removed the caliper and inside pad, and the lower inside pad support plate, I could see an accumulation of rotor dust that had been scraped by the interfering pad support plate/torque plate a the lower inside position (see photo). Previously I had thought the problem was at the top, but this convinced me otherwise.

Since the torque plate is tightly bolted to the steering knuckle it is fixed in relation to the rotor. Since rotor runout is virtually nil, as I turned the rotor and watched it moving pass the restricted point, I never saw any variation in distance between the rotor and torque plate at the lower inside space where the pad support plate (which had been removed) is supposed to fit. Of course, there is the tell-tale pile of scraped off rotor dust visible in that space on the lower part of the torque plate. With the caliper, inside pad, and lower inside pad support plate removed, turning the rotor was easy and did not generate any sounds. Thus, I believe I have found the cause of my problem in the front right brake.

To fix this, I am open to suggestions. Looking carefully at the photos, I think it can be seen that the torque plate, as currently mounted, is not perfectly parallel to the rotor. Perhaps this could be corrected by slightly grinding one side of the torque plate mounting surface (where it mounts to the knuckle)? Grinding would reduce the thickness of the torque plate, which would tend to move the restriction more away from the rotor, which seems important to do? Maybe the torque plate could be made to fit exactly parallel to the rotor at the same time? As you can see, I am guessing at a solution to my problem. I have not yet acted on my impulse. Rather, I will examine the slide pins on the left side brake and probably replace the lower pin bushing, and use the better grease on both of those slide pins.

Of course it might be that the rotor is somehow unlike the OEM rotors, in a way that it makes a tight fit, but shouldn’t it be parallel to the torque plate? Seems to me like the new rotor isn’t the problem. Also, the lack of runout indicates that the rotor is mounted flat parallel onto the flange of the hub, and therefore is perpendicular to the axle.

Anyone with some good ideas?