Horrible Knocking Noise When Braking.

[johnrobertgordon 0]

I have a horrible knocking noise coming from the front left whilst braking. It only happens when you brake. When you apply the brakes you get a repetative thud,thud,thud noise which continues till you stop. I am tearing my hair out trying to figure it out.........i thaught it was a warped disk so i changed them. I changed the wishbones, drop links were only done 200 miles ago, it had new track rod ends at the same time as the disks. I get scared braking late now...........in case something falls off or gives up.

[jonD6B 0]

Obvious question but have you checked that everything is torqued up right? Does it pull under braking?

[Anthony 1,000]

Is the frequency of the knocking related to road speed or seemingly random? Do you get feedback through the brake pedal and/or steering when it's knocking?

[johnrobertgordon 0]

Obvious question but have you checked that everything is torqued up right? Does it pull under braking?

 

 

not torqued but tight as fuk..........and no it brakes like a dream........thats whats got me confused.

 

Mabe this will help.......right try and keep up, may get confusing............

 

Its a 1.9 gti engine

1.6 gearbox

1.6 auto driveshafts

1.6 auto hubs

1.9 disks

1.6 bendix calipers.

ebc green stuff pads

goodwrich hoses

 

bit miss match i know but i'm tight fisted........had the bits there so used them. all parts are in good knick and all were bolted up proper tight. Nothing is visably fouling and the pads dont seem loose........

 

 

 

 

Is the frequency of the knocking related to road speed or seemingly random? Do you get feedback through the brake pedal and/or steering when it's knocking?

 

 

frequency and spped are related, but you cant feel it in the pedal or steering.........it all feels great.

[nick 3]

This soo weird! I have the exact same thing but from the drivers side rear (I can make it do it with just the handbrake)

Mine is like a metallic clunk that slows down as the cars does.

 

Nick

[johnrobertgordon 0]

This soo weird! I have the exact same thing but from the drivers side rear (I can make it do it with just the handbrake)

Mine is like a metallic clunk that slows down as the cars does.

 

Nick

 

yup...........exactaly the same noise. Sounds as if the caliper is loose..........but its not

[nick 3]

The only thing I can think of on mine is that it failed the mot a few weeks back on a weak rear caliper. The pads were literally rusted into caliper, so I wipped 'em out and cleaned them up. I filed the mating surfaces clean (not the back of the pad, but where it slides at each end)

I'm wondering if I have taken too much off of one of the pads which is letting it slop about in the caliper.

There is no noise going over bumps and if I brake hard I can stop it.

You haven't filed your pads too have you?

 

Nick

[johnrobertgordon 0]

The only thing I can think of on mine is that it failed the mot a few weeks back on a weak rear caliper. The pads were literally rusted into caliper, so I wipped 'em out and cleaned them up. I filed the mating surfaces clean (not the back of the pad, but where it slides at each end)

I'm wondering if I have taken too much off of one of the pads which is letting it slop about in the caliper.

There is no noise going over bumps and if I brake hard I can stop it.

You haven't filed your pads too have you?

 

Nick

 

 

not the pads no BUT i did hae a go at the sliders (the bit the pad ends slide on)

[Yimkin_FJ 0]

This soo weird! I have the exact same thing but from the drivers side rear (I can make it do it with just the handbrake)

Mine is like a metallic clunk that slows down as the cars does.

 

Nick

 

If it is drum braked at the back, then it just might be an ovalised rear drum, but that would be more like a judder than a metallic noise....

 

For the OP, are you sure it is from the front - sounds daft, but in a car odd noises often sound like they are coming from one place whereas they might actually be from a different place entirely!

[hengti 2]

could it be well worn caliper sliders?

 

: does it 'clunk' if you reverse immediately after having braked to a standstill from going forward? (if that makes sense)

[johnrobertgordon 0]

could it be well worn caliper sliders?

 

: does it 'clunk' if you reverse immediately after having braked to a standstill from going forward? (if that makes sense)

 

 

yes, but i thaught they all did that?

[jonah 1]

I'm gonna go with worn caliper sliders as well. Had something very similar on my car when i had 1.6 calipers.

 

What seems to happen is that the caliper runs at an angle to the disc, the pads wear to a taper, and when the caliper is being pulled round to this angle the slider pins grip to the bores. It then only takes a tiny amount of runout of the hub or disc to make the caliper wobble enough for the sliders to creak as they move against this friction.

 

Sounds a bit far fetched I know but that's the only explanation I could come up with when my car was doing it. (wouldn't have described the noise as thud, thud, thud exactly but not far off it, more like a regular cracking noise?) Anyway, that noise and all the other front brake noises completely disappeared when I swapped them for 1.9 calipers.

 

Could also be a loose wheel bearing btw...

[nick 3]

Wheel bearing is a suspect on mine as it is whining a bit, it looks like the 309 beam will have to go on sooner rather than later.

 

Nick

 

P.S. mine is more of a cracking than a dull thud.

Edited May 3, 2006 by nick

[jonah 1]

1.9 rear calipers are the same design as 1.6 fronts so they could suffer the same problems?? Less likely to wear as badly though since they're under much less load. Worth checking to see whether the pads are tapered anyway, and whether you can feel any play in the sliders (or whether they're seized).

[nick 3]

I put a brand new slider kit in when I did the brakes for the MOT, just the pads and the wheel bearing to go now, after that I'm stumped.

 

Nick

 

p.s. sorry for the thread hijack mate.

[johnrobertgordon 0]

no problem, hopfully its the same fix for both cars.

[jonah 1]

It's not the slider pins that wear though, it's the bores in the caliper body (since the pins are steel and the caliper is ali which is softer). So IMO new slider pins won't help.

[johnrobertgordon 0]

It's not the slider pins that wear though, it's the bores in the caliper body (since the pins are steel and the caliper is ali which is softer). So IMO new slider pins won't help.

 

new calipers then?

 

Or a louder exhaust!

Edited May 3, 2006 by johnrobertgordon

[nick 3]

Cured it!

 

I put my new pads in today and it's now completely silent, so I must have been a bit harsh with the file when I cleaned the old pads up.

 

Nick