[vexingv]

when changing pads, do most people reuse the caliper guide pins and the expansion springs? wear sensors too (provided they havent tripped yet)
guide pin front/rear part#: 34116850934 / 34216857152
expansion spring front/rear part #: 34116862801/ 34216857151
buying these parts essentially about another $100 since multiple sets have to be bough for front/rear sets

my 2016 M235x is approaching 40K miles. this will be my first time doing brakes on any vehicle. after watching some videos, the process seems pretty straightforward. i measured the brake pads when i recently rotated my tires and they are ~6mm so plan on doing the brakes myself soon. during a dealer brake job do they typically replace all those parts too? the service guide says to replace the spring and pins if vehicle is over 48 months.

my planned purchase parts list:
-akebono eur ceramic pads
-motul 600
-bleeder kit
-stoptech stainless steel lines
-anti-squeak brake compound/lube
-brake cleaner fluid/spray
-various tools: wrench 11mm (for bleeding), caliper/pad spreading tool

anything else i may be missing to complete a brake job?

[aerobod]

You will also need a punch to drive out the guide pins and a means of measuring the brake disc thickness to confirm it is above the minimum spec: https://www.newtis.info/tisv2/a/en/f...rakes/J7O1UV0e

Also bear in mind that with Motul RBF600 you need to bleed once per year to avoid excessive moisture in the brake fluid, as it is aggressively hygroscopic compared with lesser DOT 4 fluids.

[vexingv]

Originally Posted by aerobod

You will also need a punch to drive out the guide pins and a means of measuring the brake disc thickness to confirm it is above the minimum spec: https://www.newtis.info/tisv2/a/en/f...rakes/J7O1UV0e

Also bear in mind that with Motul RBF600 you need to bleed once per year to avoid excessive moisture in the brake fluid, as it is aggressively hygroscopic compared with lesser DOT 4 fluids.

so would you suggest i change the pins and springs above?

i measured my rotors--the front ones at least, the rear i cannot access due to the shield--and they were still within spec.

i don't plan to track my car, do i really need to do a brake flush annually?

[dradernh]

Originally Posted by vexingv

the service guide says to replace the spring and pins if vehicle is over 48 months.

If you've got a 2016 then it sounds like you're due or will be soon.

Originally Posted by aerobod

You will also need a...means of measuring the brake disc thickness to confirm it is above the minimum spec: https://www.newtis.info/tisv2/a/en/f...rakes/J7O1UV0e

Also bear in mind that with Motul RBF600 you need to bleed once per year to avoid excessive moisture in the brake fluid, as it is aggressively hygroscopic compared with lesser DOT 4 fluids.

The part number for the BMW instrument used to measure the brake disc thickness is 83300495451. Germain BMW sells the tool for a very good price (for a BMW piece, anyway): https://parts.germainbmw.com/oem-par...10-83300495451.

Castrol SRF has a high boiling point and is non-hygroscopic. That product is generally a better choice for a street car that doesn't see regular/annual brake fluid flushes.

Originally Posted by vexingv

i measured my rotors--the front ones at least, the rear i cannot access due to the shield--and they were still within spec.

i don't plan to track my car, do i really need to do a brake flush annually?

I think you need to remove the rear caliper to measure the rotor thickness back there. I haven't looked at tis in a while and so I'm not sure, but I think the caliper bracket bolts (34206850536) are supposed to be replaced when you re-install the calipers. They're no. 15 in this brake service diagram: https://www.realoem.com/bmw/enUS/sho...15#34206850536.

IIRC, at a maximum of 3% water content your brake fluid is supposed to be changed. You can buy a brake fluid tester and check the moisture content yourself.

[aerobod]

Originally Posted by vexingv

so would you suggest i change the pins and springs above?

i measured my rotors--the front ones at least, the rear i cannot access due to the shield--and they were still within spec.

i don't plan to track my car, do i really need to do a brake flush annually?

Personally I would change the pins and springs on my own car, that being said, they are likely OK.

The RBF600 is not the right fluid for general road use if it is not flushed enough, it is a case of the rate that it absorbs moisture that is the problem, it reaches the moisture absorption limit faster than most DOT 4 fluids, at that point brake system corrosion starts. The BMW fluid is good for 2 to 3 years in contrast. Some further info: https://drspower.com/products/motul-rbf-600.

As far as I know there is only one very high temperature brake fluid that is not too hygroscopic so can be changed at 2 years or more intervals, that is Castrol React SRF, but I'm not sure if it is low enough viscosity to be used in current BMW brake systems, that call for low viscosity DOT 4 fluids. For that matter RBF600 is not a low viscosity fluid, but probably will work OK overall.

[msendit]

Originally Posted by vexingv

so would you suggest i change the pins and springs above?

I'd just use common sense -- if they look rusty (maybe the pin likely to get stuck or something), go ahead and change them. If not, I wouldn't bother.

[vexingv]

Originally Posted by aerobod

Personally I would change the pins and springs on my own car, that being said, they are likely OK.

The RBF600 is not the right fluid for general road use if it is not flushed enough, it is a case of the rate that it absorbs moisture that is the problem, it reaches the moisture absorption limit faster than most DOT 4 fluids, at that point brake system corrosion starts. The BMW fluid is good for 2 to 3 years in contrast. Some further info: https://drspower.com/products/motul-rbf-600.

As far as I know there is only one very high temperature brake fluid that is not too hygroscopic so can be changed at 2 years or more intervals, that is Castrol React SRF, but I'm not sure if it is low enough viscosity to be used in current BMW brake systems, that call for low viscosity DOT 4 fluids. For that matter RBF600 is not a low viscosity fluid, but probably will work OK overall.

thanks for the info. i did not realize i would have to change my fluids more frequently with the motil fluid. as i'm just street driving, i'll cancel the motul fluid that was already ordered and am looking at Pentosin DOT4 LV or BMW OE. as for the pins and springs above, i found that Centric makes this hardware kit too. total of $20 for the set, which is much cheaper than BMW OE, not sure if there's any reason to get OE on such a part.

[Maynard]

Good you aren't going with track fluid for this. Factory fluid is very close in terms of boiling point, and also designed to work properly with your ABS - you'll never exceed it's capacities on the street. You also need to cycle the ABS to get all the old fluid out, so it may be cheaper to pay a good indie shop that has the ISTA machine - you can buy code readers that can do this, but if you aren't planning to flush brakes often, the flush kit plus gizmo will cost a lot more than a good service. The pins and springs aren't really stressed parts, but I see them for $12/set thru Zeckhausen, and for that it would probably be worthwhile to replace them (at least get one extra set so that when you drop a pin and lose it you aren't screwed). A heavy flat metal bar works better than a hammer for driving the pins back in due to space issues - if you are superOCD, protect the pin area with some painter tape first (i.e. 1"x1/4"x12-18" steel was what I saw being used very well). If you can find them, the drift pins with a cup-tip are the hot ticket, but not essential. IIRC, you also need to depress the brake a little while doing the line-replacement, or else you drain out the master cylinder, and bleeding that is a real PITA (I had a shop do it as part of my season-opener flush/padswap so not exactly sure).

[overcoil]

I use a fine steel wool to polish the pins.

Also I changed out the pad wear sensor when a dealer parts guy said they definitely should be changed even if not tripped - but I don’t know. When accessing the fender side of the sensor, use good lighting even a magnifier to see how the plug is undone - the tab gets pressed in as I recall, you shouldn’t need to pry off the outer plug but press in the tab on the inner socket - but verify.

[vexingv]

Originally Posted by Maynard

Good you aren't going with track fluid for this. Factory fluid is very close in terms of boiling point, and also designed to work properly with your ABS - you'll never exceed it's capacities on the street. You also need to cycle the ABS to get all the old fluid out, so it may be cheaper to pay a good indie shop that has the ISTA machine - you can buy code readers that can do this, but if you aren't planning to flush brakes often, the flush kit plus gizmo will cost a lot more than a good service. The pins and springs aren't really stressed parts, but I see them for $12/set thru Zeckhausen, and for that it would probably be worthwhile to replace them (at least get one extra set so that when you drop a pin and lose it you aren't screwed). A heavy flat metal bar works better than a hammer for driving the pins back in due to space issues - if you are superOCD, protect the pin area with some painter tape first (i.e. 1"x1/4"x12-18" steel was what I saw being used very well). If you can find them, the drift pins with a cup-tip are the hot ticket, but not essential. IIRC, you also need to depress the brake a little while doing the line-replacement, or else you drain out the master cylinder, and bleeding that is a real PITA (I had a shop do it as part of my season-opener flush/padswap so not exactly sure).

ISTA to bleed the ABS? is it really necessary vs just using a power bleeder? won't a regular flush push fluid out as well? otherwise that just made brake bleeding a much more cumbersome procedure. i actually do have an ENET cable already and have some older versions of that software around somewhere, but never really used it.

[FaRKle!]

Originally Posted by vexingv

ISTA to bleed the ABS? is it really necessary vs just using a power bleeder? won't a regular flush push fluid out as well? otherwise that just made brake bleeding a much more cumbersome procedure. i actually do have an ENET cable already and have some older versions of that software around somewhere, but never really used it.

You need ISTA or a scanner capable of activating the DSC module/ABS valves to completely change the fluid in the system. Power bleeding alone will leave the old fluid in the closed off sections of that valve assembly. That said, you don't really need to do that unless you get air in there so changing your fluid with just a power bleeder is fine. I change my brake fluid (Castrol SRF) once a year since I do track the car regularly, and don't bother to do DSC module/ABS valves unless I'm really bored... ABS still works plenty fine.

[Maynard]

Originally Posted by vexingv

ISTA to bleed the ABS? is it really necessary vs just using a power bleeder? won't a regular flush push fluid out as well? otherwise that just made brake bleeding a much more cumbersome procedure. i actually do have an ENET cable already and have some older versions of that software around somewhere, but never really used it.

To fully change fluid you do need to flush the ABS this way. And I can tell you from personal experience that if you just do it the usual way, it will leave a fair amount of old junky fluid in there that will migrate out as you use them (DK if only with ABS activation, but I suspect it circulates either way). I think it is important for full flushing, probably less so for the mid-season refreshers. I switch from stock fluid for winter to track fluid, so I get this done w/ISTA at start and end of season. sounds like you are replacing old fluid with new, so would also be a good idea in your case (not 'necessary' - but you can find dozens of mechanics that will tell you it isn't really necessary to flush any brake system, most commuter cars go to the junkyard with the factory fluid still in there and doing 'fine' all the way).

[ggggbmw]

Originally Posted by dradernh

I think you need to remove the rear caliper to measure the rotor thickness back there. I haven't looked at tis in a while and so I'm not sure, but I think the caliper bracket bolts (34206850536) are supposed to be replaced when you re-install the calipers. They're no. 15 in this brake service diagram: https://www.realoem.com/bmw/enUS/sho...15#34206850536.

I just pull the shield away from the rotor when I measure the rears discs. Just enough to clear the caliper. It's fairly springy and snaps right back into place.

If you're not tracking, definitely stick with the OEM or Pentosin LV fluids. I use the Pentosin LV for winter use. NONE of the high-temp brake fluids are anywhere near the 'low viscosity' values of the OEM LV fluid. Massive differences. (SRF and RBF 600 are similar viscosity.) And I have no doubt the LV fluids perform better from an ABS cycling perspective.

Does it matter? Well... I want top performance out of my ABS and stability control when it's cold and icy. Living in Minnesota, I get a lot of that. So, I take the effort to put LV fluid back in the fall when I put the winter tires on. If you live in the south, it's probably not worth it.

[vexingv]

Update: Parts have been arriving slowly throughout the week, but i finally got the last shipment yesterday. But there was an issue with one of the ECS Exact Fit line; the metal connector isn't the correct length/distance from the caliper.

I had already prepped my car on jack stands and removed the old pads while i waited for parts to arrive. i guess now i'll only be able to change the pads. beyond loosening the master cylinder cap to allow me to push the pistons back, will i be ok delaying a brake bleed/flush until after i install new brake lines?

in regards to stainless steel lines, any recommendations? The ones that i see for sale are from StopTech, Goodridge, Turner Motorsports, and ECS. The Turner and ECS ones look pretty similar (and i was told that StopTech actually is the company that make the ECS lines).