6G Celicas Forums

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

I just went through an issue with slider pins. They should be easily movable, so you'll definitely want to take them out, clean them up, and grease them before driving.

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

Test the emergency brake and if it works go for a drive to make sure the brakes are working correctly. Unless youre riding the ass of the car in front of you, your emergency brake and engine can stop you quickly enough. In an emergency, you could turn the key to ACCESSORY (which kills the motor) and downshift to bring the car to a halt, while still having steering(if you turn it to OFF you lock the steering). The rear parking brake will hold the car at 4-7 clicks when properly adjusted. You can push the car by hand or use the running engine to test that it works. If its a manual all this is simpler, for an automatic the parking brake should prevent the car from rolling in drive without brake pedal depressed. There are adjustment nuts on the parking brake lever inside the center console for you to fine tune it.

The disc brakes are self adjusting but through the hydraulic system. When you press the brake pedal, the pads will fully contact the rotors, and when you let off the pedal the pads partially retract. The slides shouldnt be sticky (the grease is so thick they wont exactly be as smooth as butter though) or else you will experience uneven pad and rotor wear as well as noisy, squealing brakes.

Some drag on the brakes is okay, the pads need to bed into the rotors before they operate optimally. To bed the pads into the rotors you should get onto an uncrowded section of highway. From 60 mph, apply the brakes hard(like maybe 75% of their capacity) to bring the car down to around 5mph. Do not allow the car to stop moving or the pads will deposit an uneven layer of material onto the rotor. Accelerate back to 60mph and repeat the procedure 10 times in rapid succession or until you can smell the brakes cooking. You may experience some brake fade before you finish. Once you have done it 10 times or can smell the brakes overheating, continue driving for 10-20 minutes to give the brakes a chance to fully cool, without ever coming to a complete stop. Once the rotors have cooled you have finished bedding in the rotors. The rotor will now have a slight greyish coating on it, this is material from the pads which has transfered onto the rotor. The rotor will also have brown or blueish markings on it, this means the rotors have heated up significantly and tempered as they cooled down.

This post has been edited by Special_Edy: May 14, 2014 - 3:59 PM

Thanks, I do appreciate the responses. I will be back as soon as I finish following up on your helpful advice. As for the sliding pins, I rebuilt the calipers, first taking them down to bare metal before rebuilding and painting them. I was pretty careful to make sure the pins were sliding when the brackets were on the bench. But now that they are mounted on the car, the calipers aren't movable by hand.

Later

Sorry, forgot to say that this is a manual transmission and when I pull the e-brake full up it counts 10 clicks.

Remember, the tool I ordered to set the rear drum clearance should be here on Friday. I will, however, skip that step in order to gain more information, and go back to it later.

A little more information to give you before I put the tires back on and take for a drive:

Front disc brakes: possible to turn the rotors by hand. . . left side is easy but can tell the pads are lightly ‘dragging’; right side is very hard to rotate by hand (easy if I use a breaker bar on a lug nut -- no tires). Checked for interference with backer plate and the closest any rotor comes to the backer plate is 2 to 3 mm. Cannot get a thin flathead screw-driver in between any pad and rotor through the hole in the caliper. Pushing and pulling on the rotor using both hands has no effect on the dust boots around the sliding pins. It’s like a very tight package with new rotors and pads in there together.

Rear drum brakes: with drums on and e-brake pulled tight (still 10 clicks), I cannot possibly rotate the drums by hand, not even a little. When the wheels are on (very next step) I will first check to see if I can push the car by hand, then using the engine, with the e-brake pulled up.

Then I will take her for a short drive and let you know what happens.

Continued. . .

When I put on the rear tires I could not tighten the lug nuts without causing the tires to rotate even though the parking brake was full on. The same was true for both of the front wheels with no brake applied, parking or otherwise (I know the parking brake doesn’t affect the front wheels), but the right front was more resistant to the torque than the left, and it made more scraping noise.

Once the wheels were on and the car was back on terra firma, my wife and I pushed against the parking brake being full on and we were able to easily push the car out of the garage and into the driveway. My wife was very concerned that the car would get away from us and roll down the (slightly inclined) driveway and go into the street since the car seemed to be picking up a little speed. We easily stopped the car, and there was no incident.

Next, we got into the car and started it up and began to drive down the driveway, stopping, driving, stopping, backing up, going forward. . . there were some scraping sounds coming from the right front wheel and elsewhere, but not bad. The stopping power seemed very much improved over the way the brakes operated prior to my doing this work. So, we moved on into the street and turned into the cul de sac.

When we had gotten about 50 feet, a loud, cyclical sound (once every tire revolution) began to be heard, which was especially loud when we turned to the left in the cul de sac and began to drive back to our driveway. It sounded to me like something was badly grabbing the rubber tire; a very unusual sound, like rubber against metal maybe, and seemed to be loudest once each tire revolution.

As we drove back into the driveway the sound had almost stopped, but there were other sounds of brakes rubbing that could still be heard. I asked my wife to drive the same circuit with me running alongside the right front wheel all the way. This time the sound was almost gone, yet there were still other scrapping sounds, so when we got back we put the car back on jack-stands and first removed the front tires. We never got the car above something like 15 mph.

I thought I discovered the problem causing the loud sound from the right front. When I was looking for what might be scrapping together to make that noise I spotted one of the four silver metal brake pad mounting slides that fit into the torque place (caliper mounting bracket) was not seated properly. It was quite out of position, but still partially inside its proper place, pretending it was holding the pad ear. I got a punch and drove it back down into its seat. When I then tried to use a breaker bar and lug nut idea to turn the rotor it was, unexpectedly, really hard to turn and made a lot more scraping noise that even before we took the short ride.

I then examined the left front and tried to move the caliper with my hand. It seemed to permit just a little movement this time, judging from watching the dust boots, unless I was fooling myself.

Oh, the parking brake. . . the brake lever seems to be very high when pulled tight, and it now counts 11 clicks to pull tight. To me it seems as if it needs to be adjusted from the cabin by loosening the lock-nut and so forth, and I will try to do that tomorrow.

After I do that I think I will take the car back out on the road again and see if more driving around might slowly get things sorted out. I don't see anything wrong, unless the slide pins on the calipers are not moving smoothly, something I believe I cannot know for certain unless I remove the caliper. I think the calipers are installed correctly. If driving around a while doesn’t help, I might try taking them out to see how they look.

With luck, the drum brake tool will arrive on Friday and I will be able to make the initial setting of the shoe/drum clearance on the rear wheels. Maybe that is when I should take up the slack in the parking brake?

All suggestions are much appreciated. Thanks to all people who have read this and offered suggestions. This is all new to me and I really need help.

The rubber-on-metal noise and rotation noise are definitely due to the slider pins. Ask me how I know. Your story sounds identical to the last week of my life- trust me. It's a slider pin issue in the front right.

I'm no help with the rear drums though.

Then thanks richee3, I will begin there tomorrow morning. I tried to be as specific as possible just so someone (like you) would see a connection and bring it to my attention. Good work in helping me out. Many thanks again.

Your certain you bled all the air bubbles from the front calipers? I have a GT with rear disc, but I've always adjusted my emergency brake via the adjustment nuts on the lever itself.

Special Edy

Did a lot of 'bleeding' during that process, attempting to make sure I changed out all of the brake fluid while getting rid of the air. I did more work that I am trying to write up, including a photo that I don't know how to upload.




Think I got all the air out of the calipers because I used a lot of brake fluid and did a lot of 'bleeding' in the hopes of cleaning out my brake system, like changing out the brake fluid, though I did not mess with the master cylinder in any way except keeping it topped off. The front calipers were pumping clear fluid (had a clear tube so could see) for a long time.

drums suck. next time i need to change mine i'm swapping them out for discs.

More useful information about my problem:

I took your advice and started by taking out the slide pins on the mounting bracket (torque plate) of the right front caliper.

The bottom slide pin, the one with the rubber bushing, was extremely hard to remove (surprised me how hard I had to work to get that sucker to come out). Once out, I could see that the rubber bushing had swelled. I had used a little packet of grease that I, now, can’t remember where it came from, so suspect it was that grease that caused the rubber to swell.

You can see the swelled bushing on page two of:

http://s1273.photobucket.com/user/GuiermoVilla/library/

If these two images don’t clearly show it, I measured the bushings with a micrometer and determined that the one that swelled was 0.024” larger than the extra one I had left over.

I cleaned off the old grease on both slide pins and applied Sil Glyde, which advertizes that it is good for caliper slides and can “stop slide sticking, and ease rebuilding of rubber parts: o-rings, grommets, boots, and seals boots against moisture.” After putting both pins back in, both were easily manipulable by hand, moving in and out easily.

Then I got inside the car and pumped the brakes a few times, hoping to get the calipers to set up around the rotors, and then tried to use the breaker bar and socket to turn the right rotor, thinking that I might have fixed the problem. No such luck. . . the rotor was very tight and hard to turn, making a bad scraping noise from the short turns I applied.

Then I looked carefully around the rotors and discovered that the back side of the rotor was running extremely tight against the back side of the mounting bracket, and either the bracket or the top rear pad support plate was scraping hard against the outer back edge of the rotor, causing the last quarter inch to the edge to be a little damaged.

I decided to put the front tires back on and drive the car around in my driveway and short street to see if it was acting any better, or if the problem was the same as yesterday. The problem is now different. It is no longer cyclical. It gets loud when I make left hand turns, but I can hear a little of it when turning right as well. During a left hand turn, there is a constant loud scraping noise. When driving straight, it almost goes away.

Since it was starting to rain, I put her back in the garage and decided to make this report before taking another step. I do plan on opening up the left side caliper pins to put Sil Glyde in them as well, because I suspect the other side will have the same bushing swelling going on.

NOTE: I don't know how to place images in these posts. Help me.



What do you feel it is about drum brakes that make them suck?



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

This post has been edited by Langing: May 16, 2014 - 11:05 AM

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?

Discs are newer technology and they are a lot better than drums.
Working on drums is a pain where as discs are very simple.

Thanks, I believe what you say is correct. My brake rebuilding project forced me to learn how both types work (my 94 has rear drum and front disc). Though they are somewhat Rube-Goldberg in comparison, the drum brakes didn't seem all that hard to understand or put together, however, initially getting the drums off took us about two hours, trying to figure out how to stick two screwdrivers in a little hole in the dust plate into the darkness and turn a thingy to unstick the shoes, according to a diagram I didn't understand. And, assembling them must be somewhat non-intuitive because I made at least two assembly errors which required taking parts back off again. Still haven't got the parking brake right. Had one side with its shoes reversed from the other rather than a mirror image.

The only thing I found difficult with the discs, other then getting the exact concept down, was figuring the proper way to lubricate the slider pins. Used a grease at first that caused the rubber bushing on the lower pin to swell, locking the pin in place. I would have never found that problem except one guy read my comments and told me my problem sounded exactly like his. Without his comment I don't know how long it would have been before I found that stuck pin, and I know it would have worn one of the pads far faster than the other.

So, my experience pretty much verifies what you said. As far as disc brakes being a lot better. . . well, the entire auto industry is almost finished changing over to all four wheels having disc brakes. Drum brakes have been around since the beginning, and it has taken quite a while for the newer and better technology to take over. The reason for the slow changeover, I feel, must be related to the issue of dealing with the parking brake.

To post pictures from your Photobucket, simply copy/paste the [img] tags, the fourth one in the list of links they give you.

Glad to hear that you're making progress and that you got the slider pins figured out!

THANK YOU richee3! I think that's going to speed up the process, so let me test it out.

Ok,what I want to show now is how I knew that something was really messed up in my right front disc brake (other than hearing all the racket the wheel was making when I tried to drive on it)

Since the loud sound seemed clearly to be coming from the right front, that's where I started looking. Twice during my checkout regime, when I popped off the tire after driving, I discovered a pad support plate in the lower inside position that looked loose in its slot in the torque plate (caliper mounting bracket).



The first time I just hammered it back in place, thinking, good, I've fixed another problem. The second time it happened, I dug deeper. That's when I saw the ugly scarring on the backside of the brand new rotor.



At first I was thinking that the top part of the torque plate was interfering with the rotor, but then I took the inside brake pad off and that flipped out the pad support bracket at the bottom position. All of a sudden I could clearly see a mound of rotor dust that had accumulated in the recess where the pad suport plate was supposed to be. More than that, I could see that the rotor and the mounting bracket were coming together at a small acute angle, a sure sign that they were not parallel to one another, and I have a very strong feeling that parallelism is a requirement in this situation.

IMO something is wrong with the mounting surface(s) of the caliper mounting bracket, possibly something I had messed up when I was aggressively cleaning them prior to painting. I wasn't intending on painting, but when I had them almost bare metal clean, I watched a Youtube vidwo and heard a guy saying that you never want to leave clean metal exposed to the elements; it causes immediate rust to form all over it. When I couldn't get clear high temp spray paint, I settled for black. Now I rather like the effect. Funny how I stumble into things.



Evidently, it must have been when I was backing up that the rotor pushed the pad support plate out of position each time.

So, there it was, clearly the caliper mounting bracket was causing the interference, as it was bolted on. So, I wanted to come back here to show the experts what I had discovered and ask them what's the easiest (or correct) way to fix this problem.

While waiting, I moved along to the left front wheel to check it out, and of course expected to fix another sticky slide pin with another swelled bushing. I was not disappointed. Sure enough, that lower slide pin with the rubber bushing was locked as tight as the right side had been. So, I fixed that and regreased the upper slide pin as well. Then I examined both sides of the rotor, the mounting bracket, the pad support brackets, everything about that disc brake assembly that I could think to check. I even caused the rotor to revolve so I could check for any bad sounds. It looked and sounded about as perfect as I could have hoped. Yes, there was a very slight grinding sound, as the pads were lightly touching the rotor. So, I torqued down the caliper bolts and the lug nuts and declared that wheel finished!

Still feel a bit far from being complete, but my to do list is now fairly short:

• wait for the drum clearance tool to arrive (should be today)
• set the drum clearance to 0.024"
• take up the slack in the parking break
• set all the brake pedal parameters to book values
• test the booster
• finish fitting the right front caliper mounting plate so it no longer interferes with the rotor
• take the car out to 'embed?' the brakes (get friction material onto the drums and rotors)
• declare victory and write it up

Let me make a prediction. I am guessing, and it is ONLY a guess (bases on experience), but I almost know for certain that I am going to need more help, so I am going to keep this thread going until I am completely done. This is, to me, a relative novice, a major project. Thanks to everyone who is helping.

Here's a question based on my current understanding of how the drum brakes are supposed to work:

For the final adjustment of the drum brakes, the Celica shop manual says to initially set drum brake clearance (distance between shoes and drum) to 24 thousandths of an inch (0.024"), and then mount the wheel and you are good to go. I interpret that as saying the shoes and drums should not be in physical contact when they are properly adjusted.

Yet, all DIY advice I have seen says otherwise, that the final step in adjusting drum brakes leaves the shoes and drum in contact, but only slightly, i.e, there should be a slight drag you can detect when you rotate your tire by hand. Some YouTube videos even show somewhat more than 'slight' contact (e.g., see the Expert Village video, where the guy explains that you should be able to spin your tire about one complete revolution when turning it as hard as possible)

https://www.youtube.com/watch?v=iN6z0oIZLBk).

If I was to follow the shop manual, literally, I would set the adjuster such that there is the (measured) proper 'clearance' of 0.024". Though the shop manual said nothing about this, if, when I spin the wheel by hand, I find there happens to be a little drag, I believe I should back the adjuster off just enough that the wheel begins to spin freely. Might that not be more in tune with what the shop manual was trying to accomplish? It said absolutely nothing about spinning the wheel as a check on the adjustment for proper 'clearance'.

Leaving the drum brakes with "just a little drag" means that for the first several miles, at least, you will be rubbing off friction material until the 'clearance' becomes great enough that the shoes and drum actually do not have any physical contact.

Now, it is true that people advise 'bedding in' brakes after putting on new pads and shoes, so that friction material becomes deposited onto the drums and rotors. The process they recommend, getting the car up to speed and braking sharply, but not all the way down to zero speed, then repeating for something like 10 times, uses the foot brake, not the parking brake. Getting the brake system heated up by forceful repetitive braking is an intentional consequence of the procedure.

I believe the final adjustment of the drum brakes, by setting the 'clearance' to 0.024", is not done to help with the 'bedding in' process, it is done to give the automatic adjusting feature of the drum brakes an initial starting point, from which the parking brake (in my Celica) or moving the car in reverse (in some other cars) gets its calibration so that it can begin to perform its function from a known starting point, as its function is to continually keep the proper 'clearance' at approximately 0.024" on both rear brakes, while there is an ever increasing gap between the shoes and drum as the shoes wear. As the gap increases, each time the parking brake is released, it moves the adjuster wheel one tooth worth of 'clearance' tightening.

Please carefully read the section DRUM TYPE BRAKE ADJUSTMENT in the document SECTION 3: DRUM BRAKES located on the Kevin Sullivan AUTOSHOP 101 website:

http://www.autoshop101.com/

What is the flaw in my logical reasoning? I say that my reasoning must be incorrect because all advice (at least what i have seen) is contrary.

This post has been edited by Langing: May 18, 2014 - 6:29 PM