strange sound when braking

I have a 98 Honda Civic with over 180k miles on it. For the most part, it runs very smooth. However, I've noticed/felt a knocking or clunking sound when I am braking. It will happen only once when I brake until I let off the pedal and brake again. If I lightly touch the brakes to slow down, it does not show up, but if I need to stop at a more normal pace for a red light, I can pretty much guarantee that I'll hear/feel it.

The car is a manual transmission, and typically if I have the clutch depressed when I'm braking (almost always), I can feel the vibration in my left foot. Because of this, I tend to think it is on the driver's side, though my wife says she can feel the vibration on the passenger side.

This is not something new. It has happened in the past and went away, but it is definitely getting more noticable. Yesterday, for a brief moment, I noticed it driving over a bumpy road with each bump, though that symptom has not returned.

Any thoughts?

 

i have 2 guesses for you:
1. rotors may need to be turned (does it shake in steering wheel while braking?)
2. ball joints going bad. usually, ball joints manifest themselves at an up and down abrupt movement of the wheel, like driving on pothole, as for a moment control arm lags behind the hub, resulting in clunk.

'ts something in suspension, if the steering wheel does not shimmy during braking. hub bearings maybe?

 

It might be roters. I was told by a mechanic that you don't typically need to turn the rotors on a Civic as they wear evenly... So I've never done it. I can get a little shimmy in the wheel at high speeds, but typically that's a sign on need to rotate the tires. However, I don't think it shimmys during breaking... I'll pay attention to that next time I drive.

I'm more curios on the clunk/knock when I brake...

For that matter, are either of these problems serious (or for that matter expensive)?

 

Could be ball joints, but I'd be paying more attention to the tie rods........inner AND outer ends.......If I'm reading this right, that you get a knock put no noticeable pedal pulsation....look at the caliper mounting bolts/hardware.....see if any of the rubber slides have gone AWOL

 

You are correct about when I notice it. I'd add sharp turns to it as well. If the car is stopped, and I apply pressure to the brake, I get nothing. I must be moving to notice it. Not sure what that means either.

 

i yet have to see - or hear - a tie rod that makes kluncking noise.
jackstand the front of your vehicle so that both tires are up in the air. wiggle your tire vigorously back and forth horizontally, with hands on either side of the tire diameter. if you have noticeable play - that's probabaly your tierod end or tierod itself. to check on tierod, you need to disconnect it and roll it on a piece of glass. if it rolls smoothly - it's fine.
you may end up with some clicking noise if the tierod ends are severely worn out. but not a cluncking noise.
unless it's a new design, there are no rubber guides for caliper. the only 2 rubber parts on brakes caliper bracket are accordeon type dust boots on steel caliper guides. so far, and i have worked on some very much drilled brakes, i have not seen a single one that will go lose to the point of cluncking. it's brakes, they are made very solid per default.
let's apply some logic: you moving at speed XX and apply brakes. rotor is being slowed down by brake caliper via brake pads. at the same time, car still wants to move forward due to inertia. rotor is attached to hub, hub is attached to control arm via ball joint and to upper body via mcpherson strut. to make a clunking noise - if it's a clunking noise, and that is subjective to judge - something in those 2 points of attachment must momenterally seperate and than come back together, making dull metal on metal impact, which is clunk. or in the parts that are in that configuration: ball joint, spring in the mcpherson strut, control arm bushings. i ran out of parts that can do this.
how serious it is? i have no idea, but will hate for this to end up with cracked ball joint and tire jammed into the tire well after pothole impact. i do not believe it has anything to do with brakes, so i feel good there.
if you hit the brakes and your steering wheel wants to go sidewise in shimmy manner - it's your rotors. no big deal, will just slowly kill your tierod ends and develop carpal tunnel or something in your wrists. i have bad opinion on honda OEM rotors - i had to turn them about every 15K miles, they warped so fast on my my 02 CRV. i finally got fedup with this and installed aftermarket slotted ones, and that was it for the next 70K miles, untill i sold the car.

 

my mind is like faulty coin laundramat dryer - drop a coin in and it'll spin forever.
i believe i had that "middle of the night" insight on this.
1. if you have a higher mileage car and rotors were not routinely turned, they are warped. they are. more or less, but they are.
2. this will result in jerky brakes action, as brakes catch more on high areas and less on lower areas of brake rotor. it does not have to be much or bad, maybe just at the level of tolerance or blaiming it on rough pavement.
3. with higher mileage, your engine mounts "get tired".
4. eingine is the heaviest (biggest momentum/inertia) piece attached to the undercarriage/body.
5. when you start breaking, engine wants to move forward, thus moving on the mounts. let me repharase it: powertrain wants to.
6. it'll stretch mounts and then pull back, following the brakes action.
7. clunk.

put your hands on the valve cover (cold engine, of course), get a good grip, and move that engine back and forth as vigorously as you can. if you hear your clunk - you found it. usually, it'll be the lower mount; side mounts make noise when you turn, as that's when engine moves sidewise during turns.