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apples12

Single metallic clunk when applying the brakes

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Hi all

I have a new noise on my 520d... It's a single metallic clunk which occurs when the brakes are applied. 

 

If the car is rolling forward and I tap the brakes I get a clunk...if I didn't apply brakes hard enough or car has enough momentum and it keeps going forwards and I tap the brakes again...clunk. 

 

Any ideas what it could be?

I've checked the passenger side front caliper and all is torqued down correctly. 

 

One thing I do know is that the shim between the pad spring plate thingy is missing on that side, likely after the garage did the wheel bearings and discs etc. 

 

Any advice appreciated

 

 

 

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I'll replace the spring clips with new ones from BMW over the weekend along with giving the calipers a good clean and see where we go.

 

Is it normal to replace the caliper carrier bolts if they're ever removed or can they be reused?

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23 minutes ago, apples12 said:

I'll replace the spring clips with new ones from BMW over the weekend along with giving the calipers a good clean and see where we go.

 

Is it normal to replace the caliper carrier bolts if they're ever removed or can they be reused?

 

They can be reused.

 

Make sure you lubricate the area the pad comes into contact with the caliper but only in those small areas where the pad tab and caliper meet. Also, don't clean the caliper mechanically i.e. with a wire brush in those same areas as the caliper is coated/machined and you don't want to damage it. Use brake cleaner spray and a good rub with a cloth.

 

ATE Plastilube is what I use and is the same stuff used by BMW workshops. 

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56 minutes ago, Matthew Ashton said:

 

They can be reused.

 

Make sure you lubricate the area the pad comes into contact with the caliper but only in those small areas where the pad tab and caliper meet. Also, don't clean the caliper mechanically i.e. with a wire brush in those same areas as the caliper is coated/machined and you don't want to damage it. Use brake cleaner spray and a good rub with a cloth.

 

ATE Plastilube is what I use and is the same stuff used by BMW workshops. 

 

Noted - the caliper bolts are only £4 each, I usually use the Textar brake paste stuff on just the slidey bits of the pads where it contacts the caliper but I'm not sure if the garage that did the work with the wheel bearings put anything on there, if they did, it was not obvious and most likely copper grease. 

 

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As others have said I would strip and clean everything, including the alloy to disc mating faces and the disc to hub mating faces.  The spring retainer clip should be renewed when over 4 years old.  Also worth checking the security of the brake splash shield as these fixings are known to corrode out and make a noise.

 

 

 

1 hour ago, Matthew Ashton said:

 

They can be reused.

 

 

I've always re-used the caliper cradle bolts (E39, E60 and F10) myself, however BMW (newTIS) do say they should be renewed.

 

As I'm about to take my brakes off again to replace my bearings, I've got a set of replacement cradle bolts and (spring clips) from Cotswolds to go back on as they have been re-used twice now, without issue I may add.  The new bolts have a Torx head instead of a standard hex head. 

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52 minutes ago, 535i Andrew said:

As others have said I would strip and clean everything, including the alloy to disc mating faces and the disc to hub mating faces.  The spring retainer clip should be renewed when over 4 years old.  Also worth checking the security of the brake splash shield as these fixings are known to corrode out and make a noise.

 

 

 

 

I've always re-used the caliper cradle bolts (E39, E60 and F10) myself, however BMW (newTIS) do say they should be renewed.

 

As I'm about to take my brakes off again to replace my bearings, I've got a set of replacement cradle bolts and (spring clips) from Cotswolds to go back on as they have been re-used twice now, without issue I may add.  The new bolts have a Torx head instead of a standard hex head. 

I should add the new splash shields were replaced on the fronts when the wheel bearings were done as one side had corroded and broke off, caused a lovely scratch in the alloy and I subsequently tore it off before it went in. 

 

Really do hope it's something this simple

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