Rear brake shields scraping on rotors

[xzirri]

As one issue is resolved, another one appears. I did my rear rotors and pads yesterday. As I took the car for a spin around the block, there was a constant scraping sound from both wheels. Took off the brake rotors to have a look and it appears the brake shields are touching the rotors. To be more specific, the edge of the backing plate for the parking brake scrapes on the inside of the parking brake drum part of the rotors. Seeing as I am unable to bend the plate back, I think I need to get ahold of new ones for both sides.

I looked into getting some aftermarket ones, as they are a lot cheaper, but they come without the parking brake anchor. I have to use the anchors from the old brake shields, which is OK.

However, the only video I could find regarding the brake shields mentions that they had to weld the anchors onto the plate, and I don't have the tools or knowledge on how to do so. Have anyone else replaced these shields before? Any tips or tricks on how to fasten the anchors without welding?

[Stivino]

It will probably be caused by corrosion of the drum/disc on the edge that "mates" with the backplate.

[xzirri]

The back plate is very rusty and I could see shiny metal along the edge of the plate from where it was scraping. I can't bend it away from the rotor/disk because that would cause the back plate to break since it's so rusty. I need a new backplate, which means that I need to move the anchor for the parking brake springs from the old plate to the new plate. The video I mentioned is this one:

https://youtu.be/BRQMSHwkl14

[Stivino]

There's no point fitting new backplates of the it's the discs that are fouling them.

[xzirri]

What do you mean? The rotors are new.

[Stivino]

Sorry I didn't read it properly.

If they are making contact, first you need to find out why. There must be something amiss.  It should have been spotted when you were fitting them.

 

[xzirri]

The grinding happens on the new rotors but not the old ones. The old ones are quite worn (they were already quite used when I bought the car 3 years ago) so I suspect that the plate already had been rubbing on the rotors for a while.

Seeing as the back plates are rusty to the point where they disintegrate when you apply medium force to them, I'm thinking they might as well be changed now, since my MOT is due September.

[yossarian247]

I have had this issue in the past and I would attempt to bend the back plates carefully away from the discs. However I have also encountered them being so corroded that they disintegrated, so I simply binned them and used the car without. Of course you do so entirely at your own risk, but it is not an MOT failure and did not affect the braking performance in any noticeable way on my cars. 

[xzirri]

Did you bin your rear shields? How did you mount your parking brake? No parking brake is an automatic fail in Norway.

Looking at the repair manual, there is a nut that is screwed on to the anchor at 140 Nm, wonder how I'm supposed to be able to do that without the anchor spinning around... I'll see what happens, worst case I'll try and find someone who knows how to weld

[yossarian247]

Sorry, I missed the fact that you have a drum parking brake. The type of brakes I was referring to were those where the parking brake operates by holding the pads against the disc, so the back plate is merely a dust shield. 

[xzirri]

Talked with the mechanics at Toyota yesterday. They told me that I most likely would have to install new bearings if I replaced the back plate, as they "in 9 out of 10 times disintegrate upon removal". Also, he informed me that those anchors were welded on to the plates.

I decided I could try bending, cutting and/or ripping the back plate with some pliers. After 3 hours of work, I finally got it to work. I forgot to adjust the parking brakes properly, so I'll have to do so before the MOT.

Only sound I can hear now is pads rubbing slightly on the rotors, but that normal during the first few miles, right?