Front brake disc and pad replacement

Repository of 'how to do' articles relating to the Z3 and M roadster/coupe
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Ian_C
Joined: Sun 10 Dec, 2006 20:10
Posts: 2415

  Z3 roadster 2.8
Location: Lytham St Annes

Front brake disc and pad replacement

Post by Ian_C »

I'm assuming that you've got your zed jacked up and the front wheel removed.

You will need:

1 x medium flat bladed screwdriver (to get the anti-rattle spring off)
1 x 7mm allen key caliper removal tool (to get the caliper off)
1 x 16mm spanner (to get the caliper carrier off)
1 x 6mm allen key (to get the brake disc off)
1 x long nose pliers (to remove the brakepad wear sensor)

1. Remove the anti-rattle spring using the flat-bladed screwdriver:



2. If you're doing the passenger side, pull the disc wear sensor out with the long nose pliers:



3. Unscrew the caliper retaining bolts from the inboard side of the caliper (you'll have to pull the plastic weatherproofing caps off first) using the 7mm allen key caliper removal tool:



4. Wiggle the caliper free, remove the pads and make sure the caliper is supported otherwise you risk pulling the flexi tubing out of it!

5. Remove the caliper carrier bolts using the 16mm spanner (you might need some WD40 as these can be very tight!) and remove the carrier:



6. Remove the brake disc retaining screw using the 6mm allen key.

7. Fit the new disc and refit the caliper carrier.

8. Unscrew the brake fluid reservoir cap under the bonnet and watch for brake fluid overflow while you do the next bit (I put a rag around the filler neck to soak anything up)

9. Compress the caliper piston back into the caliper housing using a block of wood and a G-clamp:



10. Clean the caliper mounting surfaces and fit your new pads ensuring that you apply some Copper Grease where metal meets metal.

11. Refit the caliper and anti-rattle spring.

12. Apply the brakes a couple of times to and then check the brake fluid level and remove brake fluid as appropriate to get the correct level (you can either get it out of the reservoir directly using a pipette or bleed it from the caliper).

13. Job done:



14. Do the other side!
Guest

  

Bed in your brakes

Post by Guest »

For those installing new pads and/or rotors it is good idea to bed in the brakes using this process. Especially if you go for any kind of fast road or race pads.

I did exactly this when I changed and it really does work.

Simon
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SpunkyM
Joined: Mon 08 Mar, 2004 18:26
Posts: 1142

  M roadster S54
Location: Harrogate

Post by SpunkyM »

Yeh give it a go - you will be surprised how simple replacing pads is (in which case you can ignore points 5, 6 & 7 in the guide).
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Paul.Stuhlfelder
Joined: Wed 01 Dec, 2004 14:31
Posts: 1020

  M roadster S50
Location: Caernarfon
Contact:

Post by Paul.Stuhlfelder »

Is the wear light supposed to go out by itself, or does it need to be reset @ BMW garage?
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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Post by c_w »

Paul.Stuhlfelder wrote:Is the wear light supposed to go out by itself, or does it need to be reset @ BMW garage?
The wear sensor is attached to the pad but stands proud by a few mm; when the brakes wear down they start wearing this sensor too and it breaks the circuit inside it cauing the lamp to come on; when this happens you have to buy a new sensor (about £12) (or join the wires together! :dunce: ).

The light goes out by itself after a new sensor is attached. Incidentally, the ABS light does this too so you don't need a dealer reset. It's only airbags that require a dealer rest AFAIK as it's a more complex system.
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pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Post by pingu »

A point to note.

If you are only changing the pads, and not the discs, just undo the lower caliper bolt, and pivot the caliper upwards. Hold it in position with tie wraps (or whatever). You can then replace the pads.

Remember to cater for the possibility of brake fluid coming out of the reservoir. If the caliper can't be pivoted because of the groove on the rim of the disc, you need to push the pads apart. You can do this by using a pair of heavy duty pliers (Mole) to squeeze the pad against the caliper, or a suitable lever to spread the pads apart (I've used a crowbar widthways before). Do not lever against the disc.
Pingu
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Deano1712
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Joined: Sat 05 Aug, 2006 12:56
Posts: 1396

  M roadster S50
Location: Leeds

Post by Deano1712 »

To add something to this guide...

If during this job you find the rusty calipers and brackets too rusty next to your shiny discs they can be refurbished with some hard work.

You will need to remove all (or most) traces of rust. Shot blasting is the best way, or hours with a dremel (as i did with the rear calipers shown in the pic). If you can get the parts shot blasted its the best way, it gives a great key for paint.
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If you have any traces of rust at all left then a treatment with a proprietary rust remover prior to paint is in order.
Paint 2 coats using a primer such as red oxide as shown.
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I used two top coats of brush on smoothrite. Nice job!
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I think there are companies that can do all of this work for you inc powder coating etc. Its a cost vs time balance. Clearly I went down the Yorkshiremans route!
Z3M with a few mods...and a little bit more power
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