Rear Brake Disc/Rotor Replacement

[pierremcalpine]

I had two pleasant surprises when I replaced my rear discs over the weekend.

The first was that there is actually room to take the rear discs out without having to take off the caliper carrier. I hadn't even though to try previously but I came across a youtube video for an Audi where the same thing was possible. Nice. I'm not sure if this is the case for all models. What I can say is that my Volvo disc part # is 30769059. I wonder if the same is possible for the front...

The second was that no special tool is required to push back the piston once the EPB has been rewound. You can use a c-clamp or some channel-locs.

[Semnoz]

Yes, was pleased to find this is the case on my V70 too when I replaced the rotors and pads yesterday evening.

It's certainly a squeeze to feed the rotor in, but no sharp edges, so quite harmless for the rotor surface.

This was with 302mm dia solid rotors. I'm not sure if vented rotors would have squeezed through.

I can also confirm I was able to slowly push the piston back using a wind-back tool (my pads were very worn, so I had to push the piston through it's entire travel). Unfortunately I wasn't able to first loosen the bleed screw as bizarrely the 10mm end of my bleed-screw/hose-nut spanner was too tight, and the 11mm end was too loose ??!!

I did remove the master-cylinder fluid reservoir cap, but the fluid level hardly rose when I pushed the pistons in, so not sure removing the cap made any difference. I wasn't too happy about pushing the pistons in without loosening the bleed-screw, but they did push in very easily and smoothly, so that put me at ease a bit.

Controlling the EPB with VIDA DICE was very easy, although the 5th option to 'Test the Installation' didn't provide any status message, it simply wound the brakes off and on again, so didn't actually tell me it was a successful test. Maybe it only says something if the test fails ? Anyway, the brakes worked perfectly afterwards.

My only 'unknown' in all this is whether I was supposed to have fitted vented rotors. These tend to be thicker, and I recall that even with the piston pushed in all the way, the caliper only just fitted over the new pads, so a thicker rotor would have made it even more of a struggle. Is there another version of the V70 rear caliper that's wider to accommodate vented rotors ?

[big square car]

I did my rear discs and pads a few weeks ago and also found the discs came out without removing the bracket. I need to do the front ones soon but I'm not sure if that will be the case with them. I too was baffled to find that I had no spanner that would fit the bleed screw! I just pushed the piston back slowly using a G clamp with no ill effects although I would have preferred to open them. I had also read that the discs could seize onto the hub so a few days before doing the job I squirted some WD40 where the hub comes through the disc, wiping any surplus away and taking great care not to allow any onto the friction surface. The disc lifted off no problem. I used an Autel EST301 to retract the EPB motor

[tt82]

I've done it twice now with a G-Clamp, didn't know you could do it without removing the caliper though.

[big square car]

Yes you take the caliper off but not the bracket.

[Semnoz]

I did have to remove the caliper and bracket when doing the front discs.....

I ended up having to re-use the old caliper and bracket bolts as I didn't get any with the rotors/pads (Brembo). Interestingly the rear rotors/pads (again Brembo) did come with caliper bolts.

[big square car]

Thanks Semnoz for that information. I'm now forewarned!

[bobsy852]

i need to replace the rear discs and pads on my 2008 V70 before it's MOT.
Glad to read here that I won't need a special wind-back tool.

However, I don't have access to a VIDA system, I read somewhere that I can wire the EPB up to a spare car battery to wind the EPB off? is that correct?
I presume I run wires from the battery to the nearest connection of the EPB system and then just reverse the wires if it tries to wind the EPB on further?

[1monkey600]

That's how I did mine. Get two preferably different coloured wires about a metre long with a female spade connector on one end of each wire.

Make sure the Handbrake is on before you start.

Before touching the brake calipers, pads, etc : open the cable connector plug at the back of the caliper and fit the spade connector ends of the wires inside the connector. Touch the other ends of the wires to the spare battery and , as you say, if nothing (or very little) happens then swap the battery terminals.
You should hear it winding out for a few seconds then as soon as it stops release the wires from the battery. You can then remove the spade connectors from the back of the caliper, reconnect the connector plug and carry on as per the old days to remove the pads, disc, etc.

Repeat the process on the other wheel. Once it is all buttoned back up you can use the EPB button to reset the pistons.

I believe a small 9v battery (like the ones in smoke alarms) will also work so you don't have to have a spare car battery lying around

[bobsy852]

Thanks Monkey! Perfect description! I'll get some wire and connectors before I start!

Luckily i have a spare battery at the moment as my BM is off the road for winter so I can use that! Thanks!