Stoned Brakes (brake removal and front end jacking)

Portgordon

Portgordon

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MG ZS EV
We set off in the MG this weekend and a very short distance down the road started hearing an awful noise coming from the car. It started low volume and at first we thought it was the radio! (it sounded like static), then we opened then windows and realised it was indeed coming from the car and getting louder, turning into a definite grinding sound (and a horrible one at that!).

With the car jacked up and on axel stands:
img_3065.jpg


It turned out that somehow, a stone had managed to get in between the back of the brake disc and the dust shield! No idea how.
img_3070.jpg


I know there are quite a few posts about rust, so I was prepared for it, but I am still surprised by the amount of rust which is already forming on many components!

I had to remove the calliper and pull the disc back in order to get to the stone out:
img_3077.jpg


img_3076.jpg



I've just posted a blog entry detailing the adventure, with more pics and details:

www.markreid.co.uk
 
Last edited:
Portgordon said:
We set off in the MG this weekend and a very short distance down the road started hearing an awful noise coming from the car. It started low volume and at first we thought it was the radio! (it sounded like static), then we opened then windows and realised it was indeed coming from the car and getting louder, turning into a definite grinding sound (and a horrible one at that!).

With the car jacked up and on axel stands:
img_3065.jpg


It turned out that somehow, a stoned had managed to get in between the back of the brake disc and the dust shield! No idea how.
img_3070.jpg


I know there are quite a few posts about rust, so I was prepared for it, but I am still surprised by the amount of rust which is already forming on many components!

I had to remove the calliper and pull the disc back in order to get to the stone out:
img_3077.jpg


img_3076.jpg



I've just posted a blog entry detailing the adventure, with more pics and details:

www.markreid.co.uk
Click to expand...
Great post. Thanks for sharing. What sort of mileage have you covered?
 
Rust on underbody components, castings, shocks, etc. is totally normal, on all cars, they're only finished with minimal black paint and are heavily built. Its the sheet metal work you need to keep an eye on.
 
I've seen this problem many times on other cars.
Always sounds worse than it is and I usually manage to clear it by reversing with full lock on.
 
Wow, that is a huge stone by comparison to the normal road grit that usually causes this problem.
 
Yup, had this on my Leaf a few times, sounds horrible , sometimes clears itself but I had to get a brake check to remove one time. Not had it on the MG yet after 16 months...
 
Joe said:
I've seen this problem many times on other cars.
Always sounds worse than it is and I usually manage to clear it by reversing with full lock on.
Click to expand...
That has worked for me as well, although I’ve only had the fright a couple of times in 40+ years driving ..….
 
I suspect the neighbours in the houses near where I pulled over to investigate must have been watching horrified as I tried that very thing repeatedly :LOL: forwards, backwards, turning full lock and wiggling side to side, scraping loudly the whole time🤪
 
Portgordon said:
We set off in the MG this weekend and a very short distance down the road started hearing an awful noise coming from the car. It started low volume and at first we thought it was the radio! (it sounded like static), then we opened then windows and realised it was indeed coming from the car and getting louder, turning into a definite grinding sound (and a horrible one at that!).

With the car jacked up and on axel stands:
img_3065.jpg


It turned out that somehow, a stone had managed to get in between the back of the brake disc and the dust shield! No idea how.
img_3070.jpg


I know there are quite a few posts about rust, so I was prepared for it, but I am still surprised by the amount of rust which is already forming on many components!

I had to remove the calliper and pull the disc back in order to get to the stone out:
img_3077.jpg


img_3076.jpg



I've just posted a blog entry detailing the adventure, with more pics and details:

www.markreid.co.uk
Click to expand...
Thanks for posting !.
I have just checked out your detailed break down on the link you left.
Brilliant bit of work to rectify the situation, you have to wonder how the hell that stone managed to get wedged behind the brake disc though ?.
You mention the 7mm Alen key you needed to remove the brake calliper retaining bolts.
It is not a common size in a lot of standard sets you purchase, that is why the motor industry started using this 7mm size a long time ago now.
It is purely done to put people off from servicing their own brakes.
They can be sourced a lot easier now, but rarely in a DIY set of keys.
If you have a 7mm socket and drive ratchet, you could consider cutting the end from the standard Alen key and use that in a socket, to enable the use of a ratchet ?.
Ask me how I know ;) .
Great job OBTW !.
 
I would have tried bending the shield away from the disc before dismantling anything.
That should move the stone, possibly down to the bottom of the shield and if it didn't drop out (too big) then it may come out easier when you started driving.
 
Kithmo said:
I would have tried bending the shield away from the disc before dismantling anything.
That should move the stone, possibly down to the bottom of the shield and if it didn't drop out (too big) then it may come out easier when you started driving.
Click to expand...
I definitely did also :)(y)

If the stone had been smaller, or wedged more towards the edge then it might have worked, but for the size and where it had lodged itself it was easier just to pop the pads and disc off.

The dust shields are actually pretty robust too, I was expecting them to be a bit more flimsy so was pleasantly surprised. Also didn't want to bend or damage the mounting points, or risk scratching the disk by trying to hard to extract the stone.
 
Portgordon said:
but for the size and where it had lodged itself it was easier just to pop the pads and disc off.
Click to expand...
I agree, once the two 7mm calliper retaining bolts are removed, it’s just a case of removing the single torx screw that retains the disc to the hub assembly and it’s off.
I am pretty sure you could refit the calliper without pushing the pads back.
Just makes life a little easier I guess.
You have to remember to pump the foot brake pedal after reassembly, if you pull back the pistons in the calliper though !.
Quick fix, no visit to the dealership required.
Nice one 👍.
 
I remember when brake fluid would strip off paint if it went near it (it’s different now I think). If you pushed back brake pads in their calipers you had to be very careful that brake fluid didn’t squirt out the top of the master cylinder and go on the cars paintwork.
 
Portgordon said:
I definitely did also :)(y)

If the stone had been smaller, or wedged more towards the edge then it might have worked, but for the size and where it had lodged itself it was easier just to pop the pads and disc off.

The dust shields are actually pretty robust too, I was expecting them to be a bit more flimsy so was pleasantly surprised. Also didn't want to bend or damage the mounting points, or risk scratching the disk by trying to hard to extract the stone.
Click to expand...
Do you have to disconnect the battery on the MG ?
I know on the Prius it used to prime (pressurise) the brakes if you opened the driver's door even before you switched it on if the battery was connected. Hence with the caliper off the disc, the pads would close up.
I don't recall if the brakes prime on the MG before actually turning it on.
 
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