130i to M135i Brake upgrade project

[AndyBish135i]

Very nice Ian

[Poormans]

Anyone got a clue how long the seals would last given normal circumstances? I've got some performance rear calipers of unknown vintage. Would like them to run as free as new calipers. But not looking to waste time & effort if they'll be fine for another couple of years.. thoughts?

Maybe I can pressurize them gently with some air, to try and measure piston retraction?

[THETYRANT]

Anyone got a clue how long the seals would last given normal circumstances? I've got some performance rear calipers of unknown vintage. Would like them to run as free as new calipers. But not looking to waste time & effort if they'll be fine for another couple of years.. thoughts?

Maybe I can pressurize them gently with some air, to try and measure piston retraction?

Seals will last a very long time if corrosion doesn't get in there, so if outer dust seal is good and pistons are free to move they should be fine but if in doubt only way to know is strip them and inspect and then you might as well rebuild with new seals, its not costly just fiddly.

Using air gently should move pistons ok, just make sure you have some wood or something between them to stop flying out, also keep fingers out the way!

Another thing is to make sure the body of caliper where pad slides against is free from corrosion and crud, the M135i calipers ive bought were only 4 years and 30k miles old and I would guess never been touched during service as were very crudded up where end of pads touch body, used to be case that a routine service would involve pads out, clean up and regrease to make sure all is free to move....but those days are long gone it seems!....I cleaned this area up before blasting and painting, hope to get them on car soon as want to get a trackday in soon to help with winter blues!

Ian

[holland130i]

Got some silver stickers and have gone for below for now.... just need to get them on car over xmas and see how they look on.

Wow that looks awesome mate!!!

i am also seriously looking into doing this on my car in the near future...



Mark.

[Poormans]

Seals will last a very long time if corrosion doesn't get in there, so if outer dust seal is good and pistons are free to move they should be fine but if in doubt only way to know is strip them and inspect and then you might as well rebuild with new seals, its not costly just fiddly.

Part of the reason I'm asking is I've a set of AP's for the 2 wheeled machine and they've had a very easy life and they are probably around 10 years old. And they don't run retract properly. Come to think of it, they've been in storage for a long time so maybe the seals aren't the issue but the fluid between piston and caliper body gone sticky..

Using air gently should move pistons ok, just make sure you have some wood or something between them to stop flying out, also keep fingers out the way!

Do I come across like that big of a tool? Ain't got a compressor yet.. Good point though, I'll try and fill up the caliper with fluid as to reduce the spring effect. With a tire or shock pump that should give me control over the pistons.

Another thing is to make sure the body of caliper where pad slides against is free from corrosion and crud, the M135i calipers ive bought were only 4 years and 30k miles old and I would guess never been touched during service as were very crudded up where end of pads touch body, used to be case that a routine service would involve pads out, clean up and regrease to make sure all is free to move....but those days are long gone it seems!....I cleaned this area up before blasting and painting, hope to get them on car soon as want to get a trackday in soon to help with winter blues!

Ian

Yeah I noticed that bit to be unpainted, and the alloy has corroded to a point it started to expand. So I'll gently clean it up, and treat it with a light dab of ceramic grease afterwards. Also noticed "08" on the casting so probably 10 years old, think I better check how much new seals will be.

Also eyeballed a front brake set from an BMW I ate. Much prefer the blackness of them over the blue ones, they claim to be very low miles and can be max 4 years old.. and look like the exact same casting as the m135i's. However they come with discs, which I can only assume are virtually unsellable. The brakebook doesn't have them listed, so no dimensions to see how far they are off other applications..

[THETYRANT]

You can just use a footpump as well should be enough to get pistons moving.

Interesting on the i8 brakes ( i presume that what you mean with I ate ?) as looking on realoem the brake rotor on those are near same basic size as M135i etc at 340mm x 29mm vs 340mm x 30mm on the M135 etc, however the i8 discs are 1kg lighter so presume there are quite a few other differences.

Calipers on early i8 cars look to use same pads as M135i etc but on later cars pads are smaller/lighter so caliper changed it seems.

[Poormans]

Presumed right! They seem to have less offset as well.. not sure just these two things add up to a 1kg weight saving though.

Had a quick look but can't spot any differences by eye just yet. Some of them have a sticker on them "BMW I" and a blue line. Looks like it's on the newer cars but not sure. Maybe it's down to the low and high HP model..

[THETYRANT]

Unless you can get some to borrow or mega cheap to measure up first i would avoid i8 calipers, doesnt take much difference in shape/dimensions to cause a huge headache with fitment, plenty of F2x x35i/x40i calipers out there which go straight on

[THETYRANT]

Test fitted my new calipers today to check a couple of things, first was how the pads sat using them on 130i discs as mine have good bit of life yet and thought I might be able to use them up with Brembos, 130i discs are only 330mm compared to 340mm on M135i there was as expected around 4.5mm pad friction overhang which I could soon modify, however due to deep radial depth of the M135i pads they are under hanging disc nearest hub as well so not good, also discs don't run central due to different offset and thickness so will just buy some M135i discs

Wanted to check my 264wheels for clearance as well because spokes looked less curved around caliper and sure enough they foul calipers!, only just and as I was planning 12mm spacers on front now I have plenty of camber its not a problem, my 208wheels fit as previous but only just!

Will get some discs ordered up then can get fronts on at least as want to get on track soon, stock pads are getting down and don't want to make a set of track pads for stock calipers if im changing them.

Ian

[Poormans]

.. they are under hanging disc nearest hub as well so not good, also discs don't run central due to different offset and thickness so will just buy some M135i discs

Bugger!


Seen some eccentric bushings to replace the stock threaded bushings in the rear calipers, is that the way to get those Fxx calipers onto Exx cars?

[THETYRANT]

.. they are under hanging disc nearest hub as well so not good, also discs don't run central due to different offset and thickness so will just buy some M135i discs

Bugger!


Seen some eccentric bushings to replace the stock threaded bushings in the rear calipers, is that the way to get those Fxx calipers onto Exx cars?

Anymore details on those bushings? Rear calipers bolt right up once you enlarge hole in hub, discs are another matter as earlier in this thread but with e39 m5 discs it's pretty nice setup just little trim to pads required.

[THETYRANT]

Finally got some discs ordered so I can get these M135i calipers on, well front ones at least as need to sort those first and was hoping to get some genuine BMW or other 2piece ones but in the end budget dictated some Ferodo 1 piece discs from www.brakeparts.co.uk @ £50 each would do the job, they came today and look nicely finished so will get them on this weekend hopefully, I weighed one of these for reference at 11.5kg which is as expected more than the 2piece BMW with its Ally hat, which Realoem has at 10.3kg (interested to know if that's accurate) but for less than half the price of even pattern 2piece ones these will do for me and being Ferodo quality will be good im sure

Once these are on and settled in I will get some rears sorted so I can complete the conversion.

[Poormans]

Ally hat, which Realoem has at 10.3kg (interested to know if that's accurate)

Just put them up two different scales and got 10.0 and 9990gr for plain m135i 340mm discs with +-20k miles wear.

[unutterable83]

For what it’s worth, I never got around to trimming my rear pads on m5 discs, and I have done 10k now and still no wear marks on the inner disc, I assume any pad over hang just burns/breaks off


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[THETYRANT]

Finally after having calipers for months i got fronts on the car last night with the new Ferodo discs, pads wise calipers came with part worn bmw pads so skimmed level at work on surface grinder and fitted those for time being.....now need to pull finger out and get rear setup fitted next but pics below of front.

Freshly bolted up...



Wheels on and few miles done to start bedding everything in, all good ...once ive a few miles on discs will get some proper pads fitted