Knocking noise under braking - running out of options to check.

[madjack]

Hi

 

My son owns a 2015 Citigo Montecarlo and recently under braking a noise has started to occur (almost like someone knocking on a door) coming from the rear end.  After taking it to the garage and slowly trying to eliminate options (drivers rear shocker leaking, drivers wheel bearing and just recently rear brake shoes) I am running out of possibilities and so are they.  The garage have suggested that the noise will go once the brakes have bedded in (as they believe this was the cause) and it has only been a couple of days however the noise is louder now than prior to having the shoes fitted and more consistently happening when the brakes are applied.

 

Has anyone experienced similar issues and can suggest any possible next steps to check.  Need some help!

[Chris GB]

Pull the drums off and have a look at the inner surface. Citigo is prone to the rear brakes sticking on if they've got moisture ingress. Could be done shoe material stuck to the drum.

[madjack]

Drums have been off and shoes replaced.  Garage never mentioned that this was an issue (and were looking for it) but did say give it a few days to bed in.  Would you suggest a new set of drums or can they be cleaned up?

[StevesTruck]

Loose exhaust?

 

Wheels not done up right?

[madjack]

No to wheels.  Exhaust is an interesting one and the garage said the front end of the exhaust is moving slightly (rubber mount) but not needing replacement.  Noise is only from rear and only under braking.  I suppose it could be hitting something as the weight shifts but the knocking seems speed determined.

[Chris GB]

Easy way to narrow it down is to gently apply the handbrake and see if that causes the noise. I definitely had these symptoms with both my Citigos of left out in windy rainy weather and I cleared it by running with the handbrake gently on for a short time (10 seconds at a time perhaps) periodically. If it's got really bad, new drums may be needed.

[Ray-Welshman]

Hi I had this problem with a 2013 Smart car, the noise was caused by a brake drum being out of true i.e. run-out, with the car jacked up and the handbrake slightly applied until the brake is just binding, when turning the wheel see if you can hear any knocking or feel the drum intermittently binding as you turn the wheel, the knocking noise is caused by the out of true drum hitting the brake shoes.

Regards, Ray..

[madjack]

Thanks Ray

Might have a conversation about the drums as it seems a few posts have mentioned this as a possible.  I don’t think they are pricey so would you recommend replacing for new ones (seeing as the shoes are new on)?