Front Brake Problem - Help / Advice Needed

bigshorty48 · Jul 18th, 2023, 08:11

Hi All
Did a front brake disc and pad change on my 2008 C30 2.4 petrol auto yesterday, and when taking it for a test drive had a noticeable grinding sound coming from the drivers side wheel. It isn't a constant grind, it grinds then goes away and is in time with rotation of the wheel (if that makes sense). I pulled up after a few miles and got a pretty strong burning smell come into the car, which only lasted about 10 seconds. At the same time as noticing the smell, a car opposite me had just started up, so I can't be sure if the smell came from their car or my brakes. I touched the brake disc and it was hot, too hot for me to be able to hold my fingers on the disc for any amount of time.
I'm not a heavy braker, I used genuine Volvo discs and pads, I don't think I have a seized calliper as it was easy to push the piston back in, plenty of brake fluid, I'm a pretty competent DIY mechanic, and done loads of brake services in the past on other cars, so I'm pretty sure I did the job right. I'm gonna pull it all apart again today, clean it up, see if I notice anything out of place, but just wondering if any of you have any ideas what I should look out for? The nature of the grinding sound almost makes me think the disc is warped, but they're new genuine Volvo parts and I find it hard to believe the disc is warped. Brakes were fine prior to changing them, other than judder when I braked with reasonable force, hence the change of discs and pads, oh and there is quite a bit of pedal travel, more than I believe there should be.
Any ideas or comments on what I should be looking at would be greatly appreciated.

Simmy · Jul 18th, 2023, 09:38

did you release any fluid through the bleed nipple when you pushed back the pistons ? if not it possible that you may have too much fluid in the master cylinder. check the level. it is also possible to flip the seal in the brake booster if there is a lot of resistance when pushing back pistons ps never touch brake discs with your fingers they can cause nasty burns. did you clean the hubs before fitting the new discs?

Tonyjenx · Jul 18th, 2023, 10:06

To get a grinding noise there must be a problem with the disc or the pads. First check there isn't and debris between disk and pad. You could also swap pads from one wheel to the other which would tell you if it's a pad problem or a disk problem. Good luck🤞

bigshorty · Jul 19th, 2023, 16:10

Many thanks for your replies.
Decided to tear down and rebuild the drivers side braking system, but with being more thorough than I normally would with cleaning and greasing. Once I got it rebuilt and the wheel went back on, I gave it a spin and it sounded tonnes better, and after taking it for a test run, the grinding noise had gone away. My guess is that I hadn’t cleaned or greased something properly. I will say that I didn’t let any fluid out of the bleed nipple, and the level in the reservoir had gone up, should this be something to be concerned about? I went on a pretty long test run and the brakes seemed fine all that time.

MDS40 · Jul 22nd, 2023, 15:45

Sometimes the flimsy disc guard/splash shield can get bent and cause it to contact the disc.

StatusRed · Jul 23rd, 2023, 13:11

Quote:

Originally Posted by bigshorty

Many thanks for your replies.
Decided to tear down and rebuild the drivers side braking system, but with being more thorough than I normally would with cleaning and greasing. Once I got it rebuilt and the wheel went back on, I gave it a spin and it sounded tonnes better, and after taking it for a test run, the grinding noise had gone away. My guess is that I hadn’t cleaned or greased something properly. I will say that I didn’t let any fluid out of the bleed nipple, and the level in the reservoir had gone up, should this be something to be concerned about? I went on a pretty long test run and the brakes seemed fine all that time.

In theory, when you pushed back the piston the brake fluid in the reservoir should have just returned to the level it was at last time the pads were changed. Unless brake fluid was added in between when the pads were quite worn, or if moisture has been adsorbed and increased the overall volume of fluid?

Anyway if it is a bit high I don't think there's an issue siphoning some off from the master reservoir?

Jul 18th, 2023, 08:11	#1
bigshorty48 Junior Member Last Online: Oct 13th, 2023 14:01 Join Date: May 2022 Location: Shaftesbury	Front Brake Problem - Help / Advice Needed Hi All Did a front brake disc and pad change on my 2008 C30 2.4 petrol auto yesterday, and when taking it for a test drive had a noticeable grinding sound coming from the drivers side wheel. It isn't a constant grind, it grinds then goes away and is in time with rotation of the wheel (if that makes sense). I pulled up after a few miles and got a pretty strong burning smell come into the car, which only lasted about 10 seconds. At the same time as noticing the smell, a car opposite me had just started up, so I can't be sure if the smell came from their car or my brakes. I touched the brake disc and it was hot, too hot for me to be able to hold my fingers on the disc for any amount of time. I'm not a heavy braker, I used genuine Volvo discs and pads, I don't think I have a seized calliper as it was easy to push the piston back in, plenty of brake fluid, I'm a pretty competent DIY mechanic, and done loads of brake services in the past on other cars, so I'm pretty sure I did the job right. I'm gonna pull it all apart again today, clean it up, see if I notice anything out of place, but just wondering if any of you have any ideas what I should look out for? The nature of the grinding sound almost makes me think the disc is warped, but they're new genuine Volvo parts and I find it hard to believe the disc is warped. Brakes were fine prior to changing them, other than judder when I braked with reasonable force, hence the change of discs and pads, oh and there is quite a bit of pedal travel, more than I believe there should be. Any ideas or comments on what I should be looking at would be greatly appreciated.

Jul 18th, 2023, 09:38	#2
Simmy Premier Member Last Online: May 12th, 2024 12:32 Join Date: Mar 2017 Location: Manchester	did you release any fluid through the bleed nipple when you pushed back the pistons ? if not it possible that you may have too much fluid in the master cylinder. check the level. it is also possible to flip the seal in the brake booster if there is a lot of resistance when pushing back pistons ps never touch brake discs with your fingers they can cause nasty burns. did you clean the hubs before fitting the new discs? Last edited by Simmy; Jul 18th, 2023 at 09:41.

Jul 18th, 2023, 10:06	#3
Tonyjenx New Member Last Online: Feb 27th, 2024 07:56 Join Date: Mar 2023 Location: Llanelli	Brake problem. To get a grinding noise there must be a problem with the disc or the pads. First check there isn't and debris between disk and pad. You could also swap pads from one wheel to the other which would tell you if it's a pad problem or a disk problem. Good luck🤞

Jul 22nd, 2023, 15:45	#5
MDS40 Senior Member Last Online: May 8th, 2024 09:52 Join Date: Sep 2017 Location: Berkshire	Sometimes the flimsy disc guard/splash shield can get bent and cause it to contact the disc. __________________ 2006 S40 2.4 SE Auto. Ruby Red. 83K Miles Some previous cars include: Jaguar x type: Mazda 6 : Mazda 626: Ford Sierra 2.0: Toyota Celica ST 1600 : Hillman Avenger: Triumph Spitfire: Oh and a Volvo 340 GL 1984 company car from new.

Jul 19th, 2023, 16:10	#4
bigshorty New Member Last Online: Dec 3rd, 2023 22:10 Join Date: Jul 2023 Location: Gillingham	Many thanks for your replies. Decided to tear down and rebuild the drivers side braking system, but with being more thorough than I normally would with cleaning and greasing. Once I got it rebuilt and the wheel went back on, I gave it a spin and it sounded tonnes better, and after taking it for a test run, the grinding noise had gone away. My guess is that I hadn’t cleaned or greased something properly. I will say that I didn’t let any fluid out of the bleed nipple, and the level in the reservoir had gone up, should this be something to be concerned about? I went on a pretty long test run and the brakes seemed fine all that time.

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