F21 Brake pad replacement and jacking questions

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new666uk
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F21 Brake pad replacement and jacking questions

Post by new666uk »

Hi team,

I've seen a couple of how to guides on brake pad replacement and it seems deceptively simple:

Raise car
Remove wheel
Tap the two pins out. I don't have a specific punch but would an old Allen key work if tapped in?
Remove spring/cover
Slide old pads out
Replace sensor
Installation is reverse the above
Celebrate with a manly gesture or chest thump.

Couple of questions:
Do I really need any more tools than a punch and hammer?
Should I grease the back of the new pads to easy into the slot? Any specific grease recommended?
Is there any adjustment needed to account for the thickness difference from old to new pads?
This is a daft one but if I jack up using the jack point, where can I securely place a stand to make sure the car stays in the air?

The idrive reset seems simple enough and I'm just looking at the rest of the job and thinking it looks pretty simple, almost too simple like I've overlooked something.

Sorry for being a noob!

Paul
F21 M135i 3dr auto. Estoril blue, black leather.

Previously:
e46 330Ci M-Sport. Coupe, Imola red with black leather
e36 325iA SE with Alpina trim. Coupe, Black (met) with black leather
e36 325iA SE. Coupe, Lagoon green (met) with cream leather.

Jakey Boy
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Re: F21 Brake pad replacement and jacking questions

Post by Jakey Boy »

Maybe a torque wrench to tighten the bolts back up to spec. (I’m using one anyway)

Other than that, i think you are spot on.

I’m going to use some ceramic grease/lube where the pistons contact the pad.

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golfer
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Re: F21 Brake pad replacement and jacking questions

Post by golfer »

To be honest I’m a little concerned that you are messing with the brakes on a 320bhp car with little or no experience. There is slightly more involved than sliding out the old pads and sliding in the new ones. To do a proper job you need to be cleaning and thoroughly inspecting everything before reassembly with proper lubricants. Only experience will tell you whether the discs will need replacing as well. You are probably only looking at an extra £25-£30 for a mechanic to do the job for you and with that will come a guarantee and piece of mind.
I appreciate that you may want to learn this sort of thing but I would recommend doing it with the guidance of someone who has experience the first time you try.
I dont want to be a party pooper but, as I mentioned earlier, this is the braking system of a 320bhp car we are talking about here.
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2006 E87 130i M sport - Le Mans Blue - gone but never forgotten.

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MikeJM
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Re: F21 Brake pad replacement and jacking questions

Post by MikeJM »

It is straight forward but you need a Hex key to remove the two caliper pins from their housings just not tap out!

I would strongly advice purchasing a BMW caliper piston push back tool which cost between £10 from Europarts or Screwfix.

Also, you must open the brake fluid reservoir cap and continuesly check for fluid expansion when pushing back the pistons.
Brake fluid will strip paint and underseal.

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Re: F21 Brake pad replacement and jacking questions

Post by golfer »

MikeJM wrote:
Sat Feb 15, 2020 3:32 pm
It is straight forward but you need a Hex key to remove the two caliper pins from their housings just not tap out!

I would strongly advice purchasing a BMW caliper piston push back tool which cost between £10 from Europarts or Screwfix.

Also, you must open the brake fluid reservoir cap and continuesly check for fluid expansion when pushing back the pistons.
Brake fluid will strip paint and underseal.
It looks to me that the car is an M135i which will have the fixed Brembo calipers (not sliding ones) and therefore will have the pins with the tiny collets on the end that tap in and out.
2019 F20 M140i Shadow Edition - Melbourne Red.
2006 E87 130i M sport - Le Mans Blue - gone but never forgotten.

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NISFAN
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F21 Brake pad replacement and jacking questions

Post by NISFAN »

For Brembo brakes...

Use a proper pin punch. If tight, an Allen key won’t be easy to use.

I give the whole caliper a spray down with brake cleaner.

Be careful, the paint flakes off easily if you hit the calipers.

You’ll need to press the pistons back into the calipers to allow the thicker new pads in. Take one pad out, push the pistons back enough to get the new pad in, then do the other.

Make sure the fluid resevoir doesn’t overflow as you push the pistons back.


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Chapscrap
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Re: F21 Brake pad replacement and jacking questions

Post by Chapscrap »

Use a Vernier to measure disc thickness, if they’re nearly on minimum it’s not worth replacing the pads alone. + clean pistons (with brake cleaner) and check for corrosion before pushing them back into the caliper. Lubicate back and edges of the new pads before fitting to help avoid brake squeal. If fitting new discs clean the friction surface with brake cleaner to remove the anti rust coating. The list goes on....
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new666uk
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Re: F21 Brake pad replacement and jacking questions

Post by new666uk »

Thanks all.

@golfer yes, this was a thought that it seemed a straightforward DIY job, a way to get my hands dirty, building some knowledge and confidence. I suspect it's only an hour's work for a real mechanic so hardly a bank breaking exercise.

Yes, it's an M135 which I believe is pinned in.

Whilst I'm on the silly question theme can I check if it's one sensor per axle or per wheel?
F21 M135i 3dr auto. Estoril blue, black leather.

Previously:
e46 330Ci M-Sport. Coupe, Imola red with black leather
e36 325iA SE with Alpina trim. Coupe, Black (met) with black leather
e36 325iA SE. Coupe, Lagoon green (met) with cream leather.

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Re: F21 Brake pad replacement and jacking questions

Post by NISFAN »

One front one rear sensor


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new666uk
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Re: F21 Brake pad replacement and jacking questions

Post by new666uk »

NISFAN wrote:
Sat Feb 15, 2020 6:37 pm
One front one rear sensor


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Thanks, that's what I thought.
F21 M135i 3dr auto. Estoril blue, black leather.

Previously:
e46 330Ci M-Sport. Coupe, Imola red with black leather
e36 325iA SE with Alpina trim. Coupe, Black (met) with black leather
e36 325iA SE. Coupe, Lagoon green (met) with cream leather.

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Re: F21 Brake pad replacement and jacking questions

Post by Shagga_P »

You put the stands at a solid point on the front subframe. Like where the lower arms bolt to the subframe.

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