Right rear is making a horrible thumping noise (with video)
 

After replacing my rear brakes my right rear side has been making a horrific noise. It fades in and out across several days as to its severity. For a while there it stopped almost completely. Yesterday and today it sounds like it does in the movie.

A couple notes...

1. I had trouble turning the piston (like the FSM says to do) to get enough clearance to put the pad in.

2. It only does it under light or no throttle situations and light braking. Getting on the gas or hard braking makes the noise stop.

http://www.youtube.com/watch?v=zzkltHOX10c It first starts about 20 seconds in. But it's pretty obvious what sound I'm talking about though. The last ~15 seconds is also a good section to watch because it demonstrates what it does when I'm going really slow.

So... any clue what it could be

86 Sport

I would check the caliper sliders. I've seen worn ones that cause the caliper to "bounce" on the slider, but when you jam the brake pedal it locks the caliper at its maximum level of play - which doesn't cause a "bounce"

But also, I would check the driveshaft/u-joints and CV's. Same theory as above would apply. Much less likely since I'm confident the noise is from the tire area and there doesn't appear to be any vibration at speed.

Is there any pulsation in the pedal when the noise occurs?

Thanks for the reply classic. I'll check the caliper slider (after I figure out what it is). I was thinking it sounded like something was bouncing but I couldn't think of what it could be.

There's no pulsation when this occurs and no vibration at speed. I have had front u joint problems but those feel and sound different. I'm 97% sure this sound is coming from the tire area.

If it is the caliper slider I hope it hasn't done [too much] damage.

I didn't think it was possible to screw up putting on rear brakes, but I apparently pulled it off. :wallbash:

Ok, after looking at the FSM/Parts Fiche I haven't found a conclusive answer on what a caliper slider is. Google results make it seem like it's the bolt that lets the caliper slide upwards, which seems to make sense. Any confirmation on that?

Edit: Ok, I found this http://www.dreamsofdrifting.com/ae86/sliders/index.htm . I think I know what it's talking about now. The above question still stands.

The slider is the bolt that holds the caliper to the bracket and the pin you slide the caliper onto when reassembling everything.

Did you lubricate them? Tightened the bolt correctly?Torqued the lug nuts properly?

No, I think, yes. Guess I'll do/check on the first two.

does it do it in reverse? or just forward?
to me it sounds like a worn out bushing. on Decel it bounces around.

WOuld check the cv. Put it up in the air with it in netural and spin the wheels by hand and see if you can hear it. You can even drive it on the jack stand (slowly) to see if you can pinpoint the cause of the noise. Since your car is a sport (with no lsd) you can block one wheel (when you are in netural) and spin one wheel at the time to see which wheel is the cause of the sound.

I'm not sure. I'll try it in a bit in reverse and see if it does it.

I'll take a look at the CV and see if the boot looks good. I'll also probably try to pinpoint the noise like you were saying.

I took off both wheels and looked for things obviously wrong. I found one bolt that didn't seem to be tightened enough (I couldn't turn it by hand but could with a wrench). After putting everything back on the noise was gone when I took it for a quick drive. Hopefully it wil stay gone...

Classicauto told me how to test to see if my caliper slider was messed up and the drivers side one seemed to be. It moved a bit when I wiggled it. All the bolts were as tight as I could get them. While moving my car my girlfriend said the sound was coming from the drivers side so maybe that was the one actually making the noise and somehow the interior acoustics made it seem like it was the other side while I was driving.

3 new questions :D

1. Is there supposed to be a bolt or screw here? I'm thinking no because neither side has one and I know I didn't take them out.
https://www.rx7club.com/attachment.p...1&d=1180396211

2. Do you think this tearing of the rubber around the piston is worth worrying about?
https://www.rx7club.com/attachment.p...1&d=1180396502

3. If I do end up replacing a caliper, what else would be good to replace while I'm doing that? I.E. rotor, hub, etc.


It seemed to do it in reverse but not as bad.

sounded like a really bad wheel bearing. does the noise get louder when you turn left or right?

any pulsation in the brake pedal?

The answer to #1... There is not supposed to be a bolt there...
The answer to #2... Yes, But it would not cause your problem...
The answer to #3... Rebuild the caliper... Have the rotor turned...



You said that the thumping generally happens during slow driving and when there is little or no acceleration?
It sounds to me like a bad bearing... They will seem fine until you slow down or when you are going to slow to build centrifical force... Since it is a pretty simple thing to do; I would tear the entire thing down from the wheel down to the spindle and make sure everything looks good...

wow my sisters lexus does this pretty bad and i am assuming it is a wheel bearing.

have you confirmed the problem yet?

+1 on the wheel bearing. good point made on the centrifugal force acting on it.

if you want to rebuild the caliper thers a great writeup here, and its WAY cheaper than buying a new one.

https://www.rx7club.com/2nd-gen-archive-72/writeup-cheapa%24%24-brake-repair-boot-spring-485757/

Not that I've noticed. If it comes back (God forbid) I'll do some more testing on this and make sure.

Nothing noticable.

Nope. I made it go away though by taking off the tire, making sure everything was tight, and putting it back on. :dunno:

Thanks for the answers.

It always, and only, happens during in-gear decel, neutral decel, light braking, and VERY light throttle (~5%). It seems to get louder when I'm going very slow. It may be because the road noise isn't overriding the sound... but I still think it's louder during low speed. As you can see at the end of my video, it seems to be extremely loud while barely creeping along.

--> Wouldn't going faster cause more centrifical force?

--> Are wheel bearing hard to replace?

Good ole Archives. :) I'll consider doing this for general purposes, but it's also a daily driver. It seems fairly easy and far less is replaced than I would think.

--> However, that wouldn't help me if I was having a problem with the slider, would it?

1) There's no way thats a bad wheel bearing. But either way, the rears on the FC are a bit of pain to do. It requires a press.

2) The tear in the rubber boot...not too bad. May eventually lead to a sticky caliper once enough brake dust makes its way into the piston bore.

3) That odd bolt hole with the threads? Its there for removal of the rotor. If its seized on you crank a bolt in it and the pressure will pry the rotor away from the hub. Its supposed to be there.

Glad its gone but thats a very stange problem. :scratch:

Once again, thanks for the replies classic. :)

Were you referring to the first picture I put up? If so, do you think there's any harm in not having it? I don't have one on either side and I know I never touched them.

Yeah, I thought so too. It's come and gone before so I'm really hoping it stays gone this time. I know it started right after I replaced my rear brakes. I was pretty damn pissed. If there was one thing I thought I could do without messing anything up I thought it would be replacing the rear brakes. We're not talking rocket science. Take off the wheel and remove 1 bolt... :wallbash:

Some aftermarket rotors are made with the hole, and some without. Probably had one replaced in the car's past without a hole. Certianly no harm in not having it. Besides - if they do get seizes on, God made these great little creations called "hammers" :lol:

Oh goodie, I get to use a big ass hammer. :D Well I hope not because that would mean something broke. Oh well...

On a serious note, as long as it's not a bad thing I'm ok with it.

The only time you need that hole is when replacing the rotor...if you look you'll see that the hub is not drilled/tapped below that hole.
There isn't supposed to be a screw in there during normal operation.

BTW, when you DO replace the rotor (and judging by your pics you will be using that "pry hole") give the hub face a good wire brushing to remove rust/scale (pay special attention to the center lip) and then lightly coat with anti-seize- this will make subsequent removal much easier. You may never see the benefit but the next owner will.

Wait, what's wrong with my rotor? I'm assuming you're saying something is by how you worded the fact that I will be using that pry hole.

I don't know that anything is wrong with your rotor (warped/thin beyond spec)...I was just saying that, judging by the corrosion evident around the center lip and the studs, when the time DOES come to replace it, that rotor is not just going to slide off- you'll need to insert a bolt into the threaded hole and lever it to remove the rotor.

Which is exactly what that hole is for.
Yes?

Ah, I thought you were saying that it looked like it was needing replacing soon by looking at the picture.