2001 Corolla, ~ 180K.

Did rear brake drums 2 mo ago.
New springs, shoes, and drums.

Get a thunk thunk thunk from each wheel (presumably from the wheel) when depressing the brake pedal past a tiny bit.
Noise gets louder as I brake harder. Exists all the way to a stop, though softens with constant brake position as the vehicle comes to a stop,
Starting off with the emergency brake on-- noise immediately present, increases with speed and increases as e brake further engaged.

Backing up briskly in reverse and hitting brakes to slow down vehicle does NOT produce the noise. Immediately driving forward --> noise is faint but there when braking, eventually returns to same intensity.
I am aware that reversing and braking adjusts the brakes.

What is being adjusted when braking in reverse (literally, mechanically)?

What is not functioning correctly that is causing the thunking?

Are the shoes extending unevenly (non concentrically) , then getting stuck "off angle?"
The e brake is adjusted so there is essentially no increase in braking. It should be tighter but the drag is too strong. The e brake applies evenly and the hardware in the back moved quite freely when disassembled.
The drums were installed so that they barely fit over the shoes, with a tiny tiny bit of rub --not unlike after installing new pads on disc brakes.

Was I supposed to put grease on the backing plate so the shoes move freely?

Anyone?

First drum brake job in 30 years,


THe only other piece of info is that the thunking was gone for about 2 weeks

 

Make sure the wheels are bolted on tightly. Do the brakes hump like warped drums?

 

I torqued the wheels to Toyota spec, which was something surprisingly low like 78 ft lbs.

This will sound silly but I've not driven a rear drum car since 1992. All my Sattys have been 4 wheel disc.
It is rhythmic like a warped drum. I have not removed it to check the runout as the vehicle is rarely near me.
The part I do not understand is that if it was a simple warped drum, how does the adjustment in reverse change the braking force (less thunking) for the same pedal movement?

Thank you.

 

Now, I'm not a mechanic, but have serviced my own cars for over 45 years. It sounds to me like you have the self adjusters put in backwards. If not that, then check the return springs and make sure you have them in the right place. Lastly, check where the notch is at the bottom of the shoe and make sure it's pushed up against the pivot pin at the bottom of the backing plate. Hell, just watch this video. Be sure to double check the positioning of the self adjuster. The have to sit in the notch cut out on the shoe just right. This video is a very good one as to seeing where everything SHOULD be. Good luck with it.

 

Thank you, Rube.
i will check it out.

 

No problem, derf. It's been my experience with drums that most of the time it's either a spring, mis positioned shoe or the drum out of round. Did you have the drums checked and turned?

 

They were brand new drums and brand new shoes. Brand new springs.

Watched several YouTube videos to ensure springs are att^in the correct location. Same with the direction of the adjusters.

How do those work anyway? They just seem to act as a hard stop for the shoes when the brake pedal is released, and the springs are pulling everything back in.

Like I mentioned, it was think free for two weeks, then went back to thunking. The drums did not come warped.

Did I not put the shoes close enough to the drum when I put the drums on? I didn't want too much drag for fear of....warping a drum.

However, is it possible that the shoes are too far away, I'm overextending the springs, and things are pulling back in out of alignment.

Im trying not to overthink this but if something can warp a drum in two weeks, there is likely something fundamentally wrong... either me or the setup

 

The self adjusters SHOULD work for you, derf. In the past, I usually drove the car in reverse and hit the brake pedal hard several times in order for the adjusters to set them to the proper position. I don't know if the newer cars adjust like that or not. Back in the old days, I used an adjusting tool or two screwdrivers through the backing plate to adjust them too. You have to make sure you're turning the star wheel in the right direction to tighten the shoes against the drum. Adjust until the drum is hard to turn and then back them off until you hear a slight rubbing and light resistance. It's a pain in the neck, trust me, to do it this way if the back up and slam on the brake several times doesn't work. And SOMETIMES, the little pin with the twist retainer piece can break and cause a shoe to shift. I forgot about that one.

 

In my experience with that type of drum brake is that the parking brake lever adjusts the brake shoes not backing up. If you can raise the brake pedal with the parking brake then the shoes are too loose and need to be adjusted.
And if you have any shake when on the brakes that you can duplicate with the parking brake you have warped drums or drum. Jack it up and lightly apply the parking brake until you locate the warped drum by hand rotation. Don’t get your knuckles between the tire and the ground.

 

I'm sorry. I meant parking brake adjustment in a previous incarnation of myself. We discussed that in round one, months ago.

The parking brake can exactly duplicate the thunking. It's coming from both sides. Don't need to jack it up but will to confirm.

With regards to the parking brake and shoe adjustment:

I'll have to have owner check to see about the brake pedal/parking brake thing. Not something I would ever have thought of. Damn (in a good way)
I obviously have to do the shoes first.
.I adjusted them so that the drum just barely barely fit over them. They seemed a little tight at the time. But that was then and the shoes have worn some since then.

The little metal tab that sticks into the gear notches on both adjusters was firmly in place when I adjusted them, as I had to hold it out of the way to be able to spin the adjustment wheel.
The parking brake is adjusted so that it locks he rear wheels almost at the top of its travel, but doesn't add any drag on the first click. After I did the brake shoes and drums, I went to check the parking brake and the lever flew up as it was totally loose. tooik me a zillion rotations of the adjusting bolt to get any tension in it.
I'm not disputing the drums are warped -- just trying to figure out why in only 2 weeks......
Unless they were slightly warped to begin with and the heat of use just made it worse.

This prob won't get updated until I next see the car at my house. So please don't think I'm ungrateful for the assistance.
I'll post an update when I have one.
And I will check the runout on new drums before I leave the store this time.

Should I even bother getting these cut? I've always been told that without removing a really substantial amount of material, something warped sufficiently badly will prob warp again in the same location. Any truth to that?