Rotor replacement - grinding noise from rear

[antony81]

Hi all. I replaced all four rotors and pads recently and all went well except for a grinding noise coming from the rear right. Braking doesn't change it but there is a slight change in noise going around corners. I suspect its the parking brake shoes inside. Both rotors and pads on the rear are identical. I removed the rotor and everything seems fine and I even rotated the adjustment cylinder to draw the shoes inwards away from the rotor but it made minimal difference. Anyone had this issue? It's not the brake shield as I can see all the way around and it never gets close to the rotor. Nothing else near it either.

I'd like to be able to rotate the rotor with the wheel off but I can't seem to disable the parking brake. I've put it in neutral and audibly heard the brake release as usual, but when I try and rotate the rotor it moves an inch or so then locks. Is there anything else I should be doing to fully release it? I've only got one wheel up.

 

[Volfy]

With 1 wheel up, you're rotating the entire center drive shaft and part of the transmission, so it'll be more difficult to turn compared to both rear wheels up in the air. Also, you're working the rear differential, which is okay if it's an open diff. If you have LSD, not sure if that'll engage with just manually turning 1 rear wheel. I've never tried it. I've always jacked up both sides when doing brake work.

In any case, it does sounds like your drum brakes are bound up somehow. You can always make sure the parking brakes are working correctly, by taking off the rotor/drum and eyeball the shoes as the parking brake is engaged and disengaged.

 

[antony81]

With 1 wheel up, you're rotating the entire center drive shaft and part of the transmission, so it'll be more difficult to turn compared to both rear wheels up in the air. Also, you're working the rear differential, which is okay if it's an open diff. If you have LSD (Limited Slip Differential), not sure if that'll engage with just manually turning 1 rear wheel. I've never tried it. I've always jacked up both sides when doing brake work.

In any case, it does sounds like your drum brakes are bound up somehow. You can always make sure the parking brakes are working correctly, by taking off the rotor/drum and eyeball the shoes as the parking brake is engaged and disengaged.

Yeah that was going to be my next step - having both wheels up and good call activating the brake with the rotor off. Thanks

 

[basysmith]

Yeah that was going to be my next step - having both wheels up and good call activating the brake with the rotor off. Thanks

I just did all four rotors and pads and am having the exact same grind sound from the rear right. I too suspect the drum brakes but can't be stuffed taking everything to bits again.

Did you end up fixing yours?

 

[antony81]

Nope couldn't find the cause. I adjusted the drum pads numerous times winding them in away from the rotor. I suspect the actual rotor may have been manufactured with an internal diameter slightly too small (wasn't Kia/Brembo but Mtec which is a cheaper brand roughly equal to EBC so the drum pads were wearing heavily on it and no amount of adjustment would fix it. Eventually they bedded in - just a time thing sadly but was really annoying. Can't say whether this was definitely the issue though but there was a noticeable grove in the inside of the rotor after a couple of days so guessing it was. If it's just one side you could try swapping the rotors over left to right and see if it the sound follows. I didn't have time to do that.

I just did all four rotors and pads and am having the exact same grind sound from the rear right. I too suspect the drum brakes but can't be stuffed taking everything to bits again.

Did you end up fixing yours?

ee

 

[basysmith]

I had another look tonight and discovered if if I bent the shield it would alter the scraping grinding noises.

I still have the same issue though. It's not the drum pads. It's not the caliper or pads. I can't see any obvious gouging in the rotor from rubbing grinding etc. and when I turn right especially around round abouts the grinding scraping becomes much worse. When going straight though it almost goes away.

I'm going to try and remove the shield and see what happens. It's the only thing that changes anything when I flex it towards the rotor from the top (which pulls it away from the bottom).

 

[Volfy]

Removing the rear dust shield is no easy feat. I replaced mine after I did the Brembo retrofit. Since I was also replacing the open diff with an LSD, it was worth it. The whole drum brake assembly has to come off to get at the dust shield. Drum brakes are a b**** to work on... this one was no different.

It would be a crap ton of work just for nuisance noise diagnostics.