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

[Special_Edy]

Never press the brake pedal when the caliper or drum is off. You wont destroy anything, but you will push the piston out of the slave cylinder/caliper. This would necessitate bleeding the cylinder/caliper until the piston is returned far enough to reassemble the brakes, or if the piston was pushed all the way out the brake fluid would escape and the system would need to be purged of air.
I havent seen a pair of drums disassembled on a 6gc before, I have rear disc. Perhaps you could put the rear end on jackstands and have your wife depress the brake pedal(keep the wheels on). I would be curious to see if the same tire that spins freely when the PB is engaged also spins freely while the hydraulic brake is applied since both systems utilize the same brake shoes. This would determine if the issue was with the drum/shoes or with the linkage of the PB. Just make sure she is lightly applying the brakes, perhaps have her slightly increase pressure until you can no longer rotate the wheel by hand and determine if this threshold is balanced between the two rear wheels

This post has been edited by Special_Edy: May 19, 2014 - 9:09 PM

[Langing]

Never press the brake pedal when the caliper or drum is off. You wont destroy anything, but you will push the piston out of the slave cylinder/caliper. This would necessitate bleeding the cylinder/caliper until the piston is returned far enough to reassemble the brakes, or if the piston was pushed all the way out the brake fluid would escape and the system would need to be purged of air.

Roger that. When I first had the brakes reassembled, I decided to bleed the system, starting with the front discs (forgetting that I had not put the rear drums back on) , and asked my wife to step on the brake pedal a few times and hold the pedal down. We had gone through the cycle a couple of times and I was kneeling at the front right wheel, watching the brake fluid flowing out of the bleeder valve, when she asked me what that strange noise was. I asked “what strange noise.” She said it sounded like a burst water balloon, like water spraying. Immediately I rushed to the driver’s side rear, and found the wheel cylinder had blown brake fluid all over the place. Almost all of it went up into and around the wheel well, so I caught it before it destroyed my nice epoxy painted garage floor! So, by experience I definitely understand what you are saying.

I havent seen a pair of drums disassembled on a 6gc before, I have rear disc. Perhaps you could put the rear end on jackstands and have your wife depress the brake pedal(keep the wheels on). I would be curious to see if the same tire that spins freely when the PB is engaged also spins freely while the hydraulic brake is applied since both systems utilize the same brake shoes. This would determine if the issue was with the drum/shoes or with the linkage of the PB. Just make sure she is lightly applying the brakes, perhaps have her slightly increase pressure until you can no longer rotate the wheel by hand and determine if this threshold is balanced between the two rear wheels

That is great advice! Just the kind of help I was looking for. I thought it such a good idea that I enticed my wife to follow me to the garage to try out the experiment before going to sleep (it was after 11 pm, and she leaves for work at 7 am). I remounted the right rear tire, so both rear tires were on and then I asked her to begin pushing on the brake pedal while I tried to spin the tires by hand. We weren’t able to get the brake to hold the rear wheels, which seemed strange to me, until I realized that I still had the caliper and pads of the bad right front wheel off, the other remaining problem. Since the brake was moving the piston (luckily, she was not stomping on the pedal), I figured that was why it wasn’t stopping the rear tire from moving. Since it was so late, I called it a halt so she could get some sleep. But your suggestion was a good, definitive way to isolate the problem down to the brake parts or the PB cable, and I do thank you for the suggestion.

Now. . . my next move this morning is to take the ‘star wheel’ adjuster off the right rear so I can examine it to see if it might be left wheel’s adjuster. Maybe the two adjusters are mixed up.

Check me if I am wrong, but the way I figure it, the adjusters are operated by an actuating arm that moves downward (behind the adjuster screw, when viewed facing the wheel), turning the ‘star wheel’ such that you will see the gear teeth moving upwards whenever it is ‘adjusting’ the brakes (tightening the clearance; expanding the adjuster screw). That is true of both the left and right side drum brakes, the teeth will move upward when the adjuster is operated. Since the adjuster screws are oriented from back to front exactly the same on both sides, one of them must have its threads reversed from the other. They are NOT the same.

I was not aware of this difference when I was assembling the rear drum brakes, so it would have been very easy for me to have gotten them installed incorrectly, and this might explain the erratic behavior I have described. I will check this out today and let you know what I find.

If that isn’t the problem, I will still have time to put the right front wheel back together so my wife and I can run your experiment tonight.

And thank you so much for taking the time to digest my problem and make suggestions. I feel that I am getting very close to achieving success.