Sport Scraping rear brake.

Hi, I was wondering if anyone would know how to solve an issue I’m having with my 2005 L320 4.2, I overhauled all brakes, including the shoes and rear right calliper was replaced for new. I’m now getting a scraping noise, hubby said it sounds like the parking break. I had changed all brakes about 7 months ago, I’m just flummoxed as to why my brakes are acting up again. Before I changed them, my back wheel was sticking and alloys overheating. Now it’s making scraping and scratchy noise. Don’t hear it so much at motorway speed but quiet obvious when driving in towns. Any help or insight as to what is causing it and/or knowing how to fix it would be very much appreciated. TIA.

It could well be the backing plate - or the shoes have delaminated and it's the metal-on-metal noise from the park brake shoes.
The park brake shoes have a very narrow window of acceptable adjustment, any corrosion on the backing plate where the shoes make contact with it needs to be dealt with and a nickel grease applied. The initial adjustment process is also rarely followed correctly, which can lead to dragging shoes.

Graculus said:

It could well be the backing plate - or the shoes have delaminated and it's the metal-on-metal noise from the park brake shoes.
The park brake shoes have a very narrow window of acceptable adjustment, any corrosion on the backing plate where the shoes make contact with it needs to be dealt with and a nickel grease applied. The initial adjustment process is also rarely followed correctly, which can lead to dragging shoes.

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Hi, I like the advice about shoe adjustment as mine are scraping slightly just now but I also have a binding calliper piston to deal with. However, I did have a problem with the shoe holding pin that came loose and sounded like a stone trapped in the drum. Worth pulling it all apart to check everything, if the backing plate needs changing the whole hub has to come off. If you don’t have the tools get it into a trusted Indy.
Tricky

The backing plates can be / are changed without removing the hub quite easily if you're handy with MIG/TIG welding.
The adjustment process is this:- (slightly different from the one published on Topix but the way it is done in most dealerships.)
Assemble shoes on backplate, with both adjusters backed off fully and a small amount of Nickel brake grease on the rubbing points, ensure both shoes can move with a small amount of pressure at 3 O'clock or 9 O'clock, if not, then re-check the rubbing points for corrosion causing excessive friction.
Once OK & brake disc fitted, use a screwdriver to adjust the shoes outwards, rotate the disc every six clicks of the adjuster in the direction of forwards movement of the car, once you start to feel shoe drag, keep rotating whilst giving the edge of the drum part of the disk a few good cracks with a copper hammer, you'll feel the friction reduce as the shoes self-centre. Keep tightening at 3-4 clicks at a time until you can only just rotate the disc and there is no more freeing-off when you hit the edge of the drum with a copper hammer.
At this point, back off the adjuster by exactly 12 clicks, rotate the adjustment point to the 4mm hex socket for the wedge adjuster, slack off the screw and give it a wiggle to release the adjuster (if re-using old shoes, check for free movement and reset to fully off position before fitting), nip up the screw, fit the dust plug, refit the service brakes (this can be done with the service brakes fitted but be aware of some extra drag from the brake pads) apply & release the park brake three times & recheck for free movement.
That's it!.
There is a 'bedding in procedure' which is supposed to be carried out if new discs are fitted on old shoes, don't bother, just use a coarse file to remove any burrs or high spots on the shoes before fitting new discs - the friction material is quite soft as it has to grip only at low speed or when stationary so will clean up easily. It's also a good idea to give a blast of compressed air into the adjustment hole periodically to clear out any brake dust etc. if there's significantly more from one side or the other, investigate why.