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Rear Drum Brakes and Parking Brake


adallak

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As I described in another post, I have replaced the both wheel cylinders rand flushed the brake system on my RWD. It appeared the parking brake did not hold the car on an incline. Finally, had a chance to see what was going on and make adjustments per manual. Depressed the brake lever per the FSM three inches and adjusted the adjustment nut at the equalizer. The manual recommends to tighten the nut until the right wheel rearward with two hands but cannot be turned forward. Interestingly, I could turn the wheel forward but not rearward! So I went ahead and adjusted the nut so I could not turn the wheel at all. Stopped the car on the incline (some 20 degrees), shifted to neutral, depressed the parking brake pedal all the way down, released the regular brake pedal ad the car slowly moved down. There was some braking, but just not enough to hold the car still. What should I do next? It is not a nice feeling knowing you do not have parking brakes. Still better to be aware though. LOL

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Are all of the emergency brake cables moving freely through their various attachment points and cable covers if present? It sounds like you may only have one rear wheel activating upon application of the parking brake. A stuck cable(s) is the most likely reason.

Never underestimate the amount of a persons greed.

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Are all of the emergency brake cables moving freely through their various attachment points and cable covers if present? It sounds like you may only have one rear wheel activating upon application of the parking brake. A stuck cable(s) is the most likely reason.

From what I saw the underbody is in a very good condition (a Florida car) and the cables were in good condition too. No restrictions, no rust. Nevertheless, will work on brakes today - the drum brakes are too tricky compared to disc ones. Will also play with adjusters. It was my impression every single click of the adjuster makes a difference.

Correct me if I am wrong, but as far as I remember, the parking brake levers inside the brakes were arranged so that the left one would prevent rather rearward movement then forward while the right one was arranged to prevent rather forward movement of the car when the parking brake is applied.

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Correct me if I am wrong, but as far as I remember, the parking brake levers inside the brakes were arranged so that the left one would prevent rather rearward movement then forward while the right one was arranged to prevent rather forward movement of the car when the parking brake is applied.

That doesn't sound exactly right, but it may just be that I'm not uderstanding your description correctly. Let's try this: Both emergency brake cables normally enter through the backing plate at the same point...typically at the bottom of the drum, and towards the front of the car. Its purpose is to pull on the activating lever, which is supposed to mechanically force the shoes apart, and stop the brake drum from rotating. The cables inside of their metal coverings, should move freely by hand, not requiring excessive force to pull out and easily return with spring pressure (inside the drum).

Most of the other cables sort of "float in midair" between their attaching points (no cable covers). The most suspect part of this system, assuming that all parts are assembled correctly, is the metal covered cable which extends from the drum to the next support (transition) point. Try detaching both ends from the brake parts and pulling on each end of that enclosed cable, if it doesn't move you've found your problem.

Never underestimate the amount of a persons greed.

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Correct me if I am wrong, but as far as I remember, the parking brake levers inside the brakes were arranged so that the left one would prevent rather rearward movement then forward while the right one was arranged to prevent rather forward movement of the car when the parking brake is applied.

That doesn't sound exactly right, but it may just be that I'm not uderstanding your description correctly. Let's try this: Both emergency brake cables normally enter through the backing plate at the same point...typically at the bottom of the drum, and towards the front of the car. Its purpose is to pull on the activating lever, which is supposed to mechanically force the shoes apart, and stop the brake drum from rotating. The cables inside of their metal coverings, should move freely by hand, not requiring excessive force to pull out and easily return with spring pressure (inside the drum).

Most of the other cables sort of "float in midair" between their attaching points (no cable covers). The most suspect part of this system, assuming that all parts are assembled correctly, is the metal covered cable which extends from the drum to the next support (transition) point. Try detaching both ends from the brake parts and pulling on each end of that enclosed cable, if it doesn't move you've found your problem.

Thank you for the reply. The bad thing about drum brakes is that you cannot really see what happens inside... I am sure I did everything properly (though not from the beginning).

Yesterday adjusted the equalizer nut per manual. Took the car for a short test dive. None of the wheels overheated and I could stop the car on an incline with parking brake. Washed the car and drove to the nearby mall for a couple of beer. It is a 15 mile drive. As soon as i parked in the parking lot I knew there was something wrong. The RR wheel was literally smoking... Let it cool down. In about two hours wanted to take the wheel off to asses the damage. But the lug nuts except one would not come off. All I could do in the parking lot was loosening the equalizer nut and hope that the adjuster inside the drums were adjusted properly. Drove to home with no problem. Soaked the lug nuts with penetrating oil. In the morning managed to loosen four nuts. Cannot remove the last one without rounding it. Soaked it again and will try tomorrow. Probably the parking lever inside the right drum did not release properly. Just a guess. Again, I tested the wheels several time for drag before taking to a test drive...

On the side note, I have noticed that the left axle would rotate easier compared to the right one (the drums removed). Is it normal for a RWD car?

A classic case of "if it ain't broke, do not fix it". A routin brake system flush turned into something I did not expect.

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I still think you have a frozen emergency brake cable, and once it is applied, it won't release. While your down there spraying that penetrating oil around, give those brake cables (the part inside the coverings) a good dose. Only drawback being that it may free up the cable before you can acertain that it is(was) indeed stuck.

On the side note, I have noticed that the left axle would rotate easier compared to the right one (the drums removed). Is it normal for a RWD car?

That's a tough one, and honestly no. Funny thing about rear differential gears though, when you turn the left rear wheel forward, the right wheel wants to turn backwards. If that's not happening, your right rear wheel has a problem. Try it with the brake drums removed to see how it SHOULD feel. Drum brakes, properly adjusted and maintained, will not add additional drag to either wheel.

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Sorry! I do see where you did remove the drums to check wheel drag. You might be dealing with a bearing problem now, I'm sorry to say. I can think of no other cause for this, except make sure that the car is in neutral so that you don't add drag from the driveshaft turning. Also watch that driveshaft while you are doing this to make sure it is acting the same regardless of which way you are turning the wheels. It may stay completely stationary if the trans is in park, but all of the forward rotations of the left wheel should translate to exactly the same number of rearward rotations of the right wheel in that case. This is due completely to the ring and pinion (planetary gearset)inside the rear differential.

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JohnyG,

Thank you for the input - it's very informative for this Fleetwood is so different from the Seville. Whatever I deal with - it is different! I never had a chance to lift the both rear wheels up. The reason is that the car is really big and heavy. Securing the car by blocking only the front wheels with no transmission involved is quite scary. Yesterday I could not even shift out of Park when one of the rear wheels was in the air. lol

Okay, for now, the biggets issue is the darn lug nut I cannot loosen up. I used to smile when people would have problem with a lug nut - how in the world they did that?! Now, I am in their shoes... propane torch, tapping, soaking with penetrating oil. nothing helped. Sure, I can try a three feet piece of pipe - but I am afraid I will either ruin the wrench or brake the stud. Arghhh! lol

On the side note, I have been thinking what kind of damage smoking shoes and a heated drum could cause. Probably the rubber seals of the new wheel cylinder are gone. The DOT3 probably boiled. All the springs inside the brake could soften because of heat and weaken... The tire could develop a slow leak... Now, the worst part is that if something happens to the wheel or brakes, I cannot even remove the wheel to replace it with the spare!

HOW CAN I GET THAT LUG NUT OFF?!

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You had the lug nuts off before, how is the one so tight now that it won't come off? Use a 6-point socket and a breaker bar and a cheater bar if necessary)to remove the nut. If you break the stud, they sell them every day at the GM parts counter.

I wouldn't worry about the seals in the new wheel cylinder, boiling fluid, etc. If the wheel cylinder is not leaking, it is fine. It sounds like the initial setting of the lower shoe spreader/adjuster was too tight on the one side.

Forget about one wheel turning easier than the other... you didn't have a bearing/differental issue before you started on the brakes and you didn't touch anything in the diff. so it is very unlikely you caused any issue there.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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You had the lug nuts off before, how is the one so tight now that it won't come off? Use a 6-point socket and a breaker bar and a cheater bar if necessary)to remove the nut. If you break the stud, they sell them every day at the GM parts counter.

I wouldn't worry about the seals in the new wheel cylinder, boiling fluid, etc. If the wheel cylinder is not leaking, it is fine. It sounds like the initial setting of the lower shoe spreader/adjuster was too tight on the one side.

Forget about one wheel turning easier than the other... you didn't have a bearing/differental issue before you started on the brakes and you didn't touch anything in the diff. so it is very unlikely you caused any issue there.

KHE,

Thank you for the reply. On the Fleetwood I always use a torque wrench to tighten the lug nuts to the spec (something I have never done on the Seville). That said,, all the nuts were supposed to be equal. After the thermal effect, I could not remove any nut while the wheel was still hot. But after it cooled down and all the nuts were soaked with penetrating oil for a few hours, I have managed to remove four of them.

I have retracted the shoes on the RR wheel by readjusted the adjuster by more than a turn, and will probably not touch the equalizer nut for a while. Can live without parking brake for now. Will try to apply more tongue to loosen that nut and see what happens.

UPDATE. The stupid thing is off. A 3/4"x36" pipe did it. I was afraid the wrench will break at the pivot as the pipe bent quite a bit. lol

The saddest thing in life is wasted talent

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I played with rear brakes today again. Adjusted everything per the FSM. Unfortunately, adjustment of the shoes is quite subjective. The manual suggests measuring the inside diameter of a drum and the outside diameter of the shoes before installation of the drum, but I do not have such a caliper. There should be 1.25 mm difference in the diameters. Any measurement technique I could suggest has accuracy comparable to 1.25mm per the manual, so I cannot rely on my own measurements.

It's been my understanding that if one applies the service brakes while moving in reverse, the lever inside the brake rotates the star adjuster irreversibly to extract the shoes. Despite I have disassembled, cleaned, and lubed the adjuster, I am not sure self-adjustment is actually happening. The LR wheel makes noise which pretty much sounds like loose shoes... Argh!!!

I can hold the cat on an moderate incline with the parking brake, but I do not have any confidence in these brakes anymore. I asked the neighbor who works on his truck all the time about his drum brakes and his reply was "I never ever touch the parking brake"... That's not cool with me.

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The self adjusters are know not to work as they should with time.

I'm not talking about Cadillacs in general, this is my experience from dealing with drum brakes on several Volvos and Jeeps. My guess is that the darn levers bend when brakes are stuck from beeing parked for a long time (with parking brake activated).

I have never ever seen a drum brake work nearly as good as the parking/e-brake in a disc brake Cadillac. This is because the lever on the disc brake system works "directly" on the pad with a large leverage.

Drum brakes have more travel and also a lower leverage. Keep in mind that this construction certainly is over 60 years old...They weren't as picky with the brakes back then, just glad if the car finally stopped sort of.

If the self adjustment don't work as supposed there is no need to panic since the drum brakes shoes lasts longer, i.e. don't need to be adjusted on a regular basis.

A manual adjustment once or twice a year usually does the trick.

Despite the self-adjustment they work pretty good when assembled right ;)

Can you imagine what I felt like when I was going to do the brakes on my wifes last Jeep? I had all those little springs, levers and shoes apart just to realize that they had sent me the wrong kit...

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The self adjusters are know not to work as they should with time.

I'm not talking about Cadillacs in general, this is my experience from dealing with drum brakes on several Volvos and Jeeps. My guess is that the darn levers bend when brakes are stuck from beeing parked for a long time (with parking brake activated).

I have never ever seen a drum brake work nearly as good as the parking/e-brake in a disc brake Cadillac. This is because the lever on the disc brake system works "directly" on the pad with a large leverage.

Drum brakes have more travel and also a lower leverage. Keep in mind that this construction certainly is over 60 years old...They weren't as picky with the brakes back then, just glad if the car finally stopped sort of.

If the self adjustment don't work as supposed there is no need to panic since the drum brakes shoes lasts longer, i.e. don't need to be adjusted on a regular basis.

A manual adjustment once or twice a year usually does the trick.

Despite the self-adjustment they work pretty good when assembled right ;)

Can you imagine what I felt like when I was going to do the brakes on my wifes last Jeep? I had all those little springs, levers and shoes apart just to realize that they had sent me the wrong kit...

Jan, thank you for the reply. I do realize that the drum brakes are not a rocket science. Some thought was put in it, but they are not perfect to say the least, and it is amazing how manufacturers use them again and again... Now, I understand why some people replace the stock drum brakes with disc ones.

I am not that dumb or lazy, but raising and lowering the car a million times, taking off and putting back the drums, wheels, all the springs, bells and whistles, taking the car to a test drive, discovering clunks I did not have before, eventually annoyed me to the point, that I decided to put everything back, readjust the parking brake and the shoes so that neither ever drags, and live with that. Probably, I will replace all the hardware and the shoes some time in the spring.

There were certain things I did not like about my 91 Seville. Now I have stuff I hate in my Fleetwood! LOL

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I'm going to change pads and shoes on my wifes Jeep Wrangler soon. Can't say that I'm looking forward to that. :D

Just to get the drums off can be a pain in the xxx. That reminds me that I have to buy a grinding machine in order to remove the edges in the drums.

That makes it easier to remove them the next time.

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I'm going to change pads and shoes on my wifes Jeep Wrangler soon. Can't say that I'm looking forward to that. :D

Just to get the drums off can be a pain in the xxx. That reminds me that I have to buy a grinding machine in order to remove the edges in the drums.

That makes it easier to remove them the next time.

Jan, you sure know that you can retract the shoes through the opening in the back plate. If you retract them far enough, the drum should get off easily. I used a tiny screwdriver to push the adjuster lever ad rotate the star with a piece of metal I bought at a hardware store.

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I'm going to change pads and shoes on my wifes Jeep Wrangler soon. Can't say that I'm looking forward to that. :D

Just to get the drums off can be a pain in the xxx. That reminds me that I have to buy a grinding machine in order to remove the edges in the drums.

That makes it easier to remove them the next time.

Jan, you sure know that you can retract the shoes through the opening in the back plate. If you retract them far enough, the drum should get off easily. I used a tiny screwdriver to push the adjuster lever ad rotate the star with a piece of metal I bought at a hardware store.

It works fine to retract the shoes most of the time but sometimes they stick to the edge if you are unlucky. Then the spring force isn't enought to drag them past the edge and you have to hit the drum with a large rubber mallet or equivalent to make the shoes move past the edge.

This is usually only a problem when the drums haven't been serviced for a while.

Funny enough it seems like this problem is more of a Volvo problem :D

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I'm going to change pads and shoes on my wifes Jeep Wrangler soon. Can't say that I'm looking forward to that. :D

Just to get the drums off can be a pain in the xxx. That reminds me that I have to buy a grinding machine in order to remove the edges in the drums.

That makes it easier to remove them the next time.

Jan, you sure know that you can retract the shoes through the opening in the back plate. If you retract them far enough, the drum should get off easily. I used a tiny screwdriver to push the adjuster lever ad rotate the star with a piece of metal I bought at a hardware store.

It works fine to retract the shoes most of the time but sometimes they stick to the edge if you are unlucky. Then the spring force isn't enought to drag them past the edge and you have to hit the drum with a large rubber mallet or equivalent to make the shoes move past the edge.

This is usually only a problem when the drums haven't been serviced for a while.

Funny enough it seems like this problem is more of a Volvo problem :D

Now I know that even a Volvo may have issues! :D

The saddest thing in life is wasted talent

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How are you doing with your rear brakes?

Well, all I can tell, this work on my rear brakes and particularly taking off and putting back many many times the pretty heavy and large wheels from uncomfortable positions, probably resulted in calling 911 two times during the day. Looked and felt like a popped out hernia in a location I never had before... The ER people could not diagnose it immediately and basically told me to see my doctor, which I cannot afford at the moment. So... I wrapped myself up with a wide belt and am afraid of even properly breathing. lol

I have chosen "wait and watch" strategy. Cannot even think about working on my car since that was quite painful and scary experience. Need to replace the harmonic balancer as well.

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Whoa! Sorry to hear that. I've been down that road myself so I know what you mean. It will take a very long time to heal on its own, something like a year, if you don't re-injure it along the way. Most people (myself included) start to feel better in a month or two and go out working and lifting again.

After doing that about 25 times in 15 years I finally wised up! (I'm a slow learner I guess) :fighting0025:

Finally got the operation on my back and have been great ever since. Best money I ever spent, and wish I would have done it sooner.

I wish I could be there to help you out with those brakes. I'm sure I could figure it out. By the way, you can replace the studs in the brake drums fairly easily (if you can still find them for sale) so if you (well, maybe your helper) twists one off, don't worry about it. Also remember that you need to hold the ratchet back with one screwdriver before the shoes will back off using another screwdriver, then the drums should slip off.

Never underestimate the amount of a persons greed.

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Whoa! Sorry to hear that. I've been down that road myself so I know what you mean. It will take a very long time to heal on its own, something like a year, if you don't re-injure it along the way. Most people (myself included) start to feel better in a month or two and go out working and lifting again.

After doing that about 25 times in 15 years I finally wised up! (I'm a slow learner I guess) :fighting0025:

Finally got the operation on my back and have been great ever since. Best money I ever spent, and wish I would have done it sooner.

I wish I could be there to help you out with those brakes. I'm sure I could figure it out. By the way, you can replace the studs in the brake drums fairly easily (if you can still find them for sale) so if you (well, maybe your helper) twists one off, don't worry about it. Also remember that you need to hold the ratchet back with one screwdriver before the shoes will back off using another screwdriver, then the drums should slip off.

Thanks Johny, I am sure I figured out the brakes and they will be all right. I did manage to remove the stuck lug nut with a 3' 3/4 steel pipe. I am sure I just overstretched myself disregarding my age. Searching the internet to figure out what happened t my abdominal. Does not really look like a hernia because of weired location. More like a damaged muscle. Funny that two ER doctors could not figure out what was wrong.

I'll update as I feel more confident to work on the car again! :) Right now I spend most of the day laying on my back and keeping my right hand over the injured spot. lol

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