S40 (New) Brakes : Help needed please! Rear caliper won't fit over new disc + p

[StatusRed]

Hi everyone!

So today was my baptism into DIY car mechanics and it's been a very stressful and challenging day.

I've been following guides online for changing the pads and discs and I've managed to get the new discs and pads on one side (although I'm not entirely confident about the way I've done it - felt like I've used too much force) but the other side I just cannot get the caliper back over the disc and pads...

I had ordered a caliper rewind tool but it got lost in the post, then went out and ordered a square drive rewind tool (which doesn't fit) so instead I tried the poor mans method of using pliers and screwing the caliper back in. It did turn and I kept turning and turning until I thought it looked as far as I could get it to go back but I imagine this is the problem..

I've posted some pictures up if anyone could let me know if the piston should go back further or whatever I'd be grateful. Any advice on next steps also please?

My car is currently up on axle stands overnight and I need to finish the brakes ASAP so if anyone knows where I can get a suitable tool (if I need one?) click and collect - or to rent - that would be great!

Thanks,
Eddy

Unfinished side:


"Finished" side:


Piston on "finished" side:

[StatusRed]

Added photos! ^

[Rusty1]

Hard to tell from the pics but I wouldn't be surprised if the piston should go back in further than that, that's all it can be if the first set fitted ok. Have you removed the brake master cylinder cap to allow fluid to go back in? You may have taken up all the available space doing the first set and now there's no room for the second. If you haven't taken off the cap wind the offending piston back out a little to relieve the pressure before you do so.

[StatusRed]

Originally Posted by Rusty1

Hard to tell from the pics but I wouldn't be surprised if the piston should go back in further than that, that's all it can be if the first set fitted ok. Have you removed the brake master cylinder cap to allow fluid to go back in? You may have taken up all the available space doing the first set and now there's no room for the second. If you haven't taken off the cap wind the offending piston back out a little to relieve the pressure before you do so.

Hi Rusty, the master reservoir cap was unscrewed then placed loosely on top the whole time so I don't think that's the problem.

Do you know where I could get a proper rewind tool which can be click and collected that fits? I can't find the complete set for click & collect with all the adaptors and I'm cautious about getting another tool with 1 or 2 adaptors because the square drive I bought wouldn't fit!

[Rusty1]

I don't I'm afraid, I haven't had to do it yet but the time is not far off.

[StatusRed]

I've just ordered another 22pcs set off Amazon and paid for fast delivery.. Hopefully it gets here on Thursday before I head off to Manchester for the weekend.

[cheshired5]

Leave the reservoir cap on and instead, open the caliper bleed nipple when winding in the piston. Stick a tube on the nipple to catch what comes out.
You don't want crap fluid being forced back up the system.

Best advice with brakes, steering, suspension etc..... Never start the job without the proper tools and always have a plan B or C.

[StatusRed]

Originally Posted by cheshired5

Leave the reservoir cap on and instead, open the caliper bleed nipple when winding in the piston. Stick a tube on the nipple to catch what comes out.
You don't want crap fluid being forced back up the system.

Best advice with brakes, steering, suspension etc..... Never start the job without the proper tools and always have a plan B or C.

So you definitely think that the piston isn't pushed as far in as it can go?

Is it worth trying this tomorrow or do you think it would be best to wait for the rewind tool to arrive?

Cheers.

[Dirty Rooster]

Originally Posted by StatusRed

... other side I just cannot get the caliper back over the disc and pads...

I had ordered a caliper rewind tool but it got lost in the post, then went out and ordered a square drive rewind tool (which doesn't fit) so instead I tried the poor mans method of using pliers and screwing the caliper back in. It did turn and I kept turning and turning until I thought it looked as far as I could

I'm not familiar with this particular car's brakes but there's a lot of screwing/turning going on here.
I usually use a G-clamp for pistons, or crowbar. No turning.
Reservoir cap off.
I cannot see where pliers would come in handy ...

[cheshired5]

Originally Posted by StatusRed

So you definitely think that the piston isn't pushed as far in as it can go?

Is it worth trying this tomorrow or do you think it would be best to wait for the rewind tool to arrive?

To me, it looks like there's a touch more travel available in that piston but if there isn't, the only other cause is the aftermarket pads and discs being too thick but I'd say that's unlikely.

Make sure the handbrake is off when working on rear brakes.

As I mentioned earlier, if you haven't got the right tool (winding in this case) I'd wait.