Brake pedal feel after bleeding

I

InterlagosMC

Member
I’ve just finished a few large jobs on my M which included all new pads, new rear discs and all callipers rebuilt. I have since bled the system through with a pressure bleeder and then used ISTA to bleed the abs pump through but my issue is I still feel that the pedal has a bit of dead travel before the brakes bite. When I watch reviews people always say the brake pedal bites instantly which is what I want but I’m beginning to think it’s not possible on these cars with the stock brake setup. If anyone can confirm either way or has any advice please let me know.
Thanks
 
I never had good pedal feel with the stock system. I always wondered if my car had something wrong but after bleeding it several times, it never improved. Then I put some Brembo’s on and now feel is ver nice.
 
My old e92 felt really good by comparison for instant pedal bite, even the van I drive for work has a much better initial feel. I just assumed I had done something wrong considering any review I watch state that all pedal controls are instant which I would believe includes the brake pedal but good to know it’s not just mine.
 
I can confirm pedal feel isn't great even after few bleeds on stock pads. The brake system isn't the best to start with squishy one-piston caliper.

I'll replace the pads in couple of days to endless mx72+. I have hopes this will improve things as pads contribute a lot to brake feel.

If not, then next "stop" will be brembo front calipers as others suggest. Although I feel it's a bit of an overkill for road driving alone... we'll see :)
 
insider said:
I can confirm pedal feel isn't great even after few bleeds on stock pads. The brake system isn't the best to start with squishy one-piston caliper.

I'll replace the pads in couple of days to endless mx72+. I have hopes this will improve things as pads contribute a lot to brake feel.

If not, then next "stop" will be brembo front calipers as others suggest. Although I feel it's a bit of an overkill for road driving alone... we'll see :)
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I’m sure my old 3.0si had better pedal feel than the M does, I’m wondering if it’s an air leak on the master cylinder or the brake booster
 
Argenta said:
Sure u bled the correct order?
(RR-RL-RF-LF for LHD)
(LR-RR-LF-RF for RHD)
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I did the initial bleed for RHD as you look at the car from the front bumper as (LR-RR-RF-LF) I did in that order as the brake pipe runs down the right of the car and then goes under the petrol tank over to the left rear making it the furthest away from the master cylinder. The ISTA bleed told me to do it a different way however.
 
That doesn't sound quite right - mine has always felt every bit as good as my 3.0Sis did.
 
My brake pedal was as you described on factory brakes, replaced everything , same pedal feel.
I drove a 997 4s and it made me seriously hate the M pedal feel, hell even an e46 330ci had a better brake pedal.

I put stoptech sport pads, it did improve pedal feel but still no where close to what a sports car should be.

I believe the only solution is a 4 or 6 piston front caliper at least.
 
///MC said:
My brake pedal was as you described on factory brakes, replaced everything , same pedal feel.
I drove a 997 4s and it made me seriously hate the M pedal feel, hell even an e46 330ci had a better brake pedal.

I put stoptech sport pads, it did improve pedal feel but still no where close to what a sports car should be.

I believe the only solution is a 4 or 6 piston front caliper at least.
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Wont necessarily help... I put Stoptechs 6pot front, 4pot rears on mine pretty early on in my ownership. Brake pedal firmness remained the same as stock but more linear brake feel. I drove an M3 CSL with an AP kit, not sure which one, and the brake pedal was much more firm than mine, i mean no comparison at all.

All else being equal/healthy i think the pedal firmness with aftermarket brake kits has to do with the new piston diameters compared to the OEM ones :idunno:
 
///MC said:
I put stoptech sport pads, it did improve pedal feel but still no where close to what a sports car should be.
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Second this! Compared to other sport cars, I can only describe stock brake feel as not confidence inspiring.

ga41 said:
Wont necessarily help... I put Stoptechs 6pot front, 4pot rears on mine pretty early on in my ownership. Brake pedal firmness remained the same as stock but more linear brake feel. I drove an M3 CSL with an AP kit, not sure which one, and the brake pedal was much more firm than mine, i mean no comparison at all.
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This is also my experience - I have 4pots on z3mc and it is better, but still not quite on par. On the other hand, even some single-piston calipers cars can have very good feel with good pads. Hence my current improvement is to mount better non-organic pads.
 
For what it is worth, I have 6-pot e82 performance calipers with 4-pot 996 rears, pedal feel is very nice, firmer and linear, however, they have less bite. based on some basic math I have done, probably the option would be Megane rs front calipers with rear e82 performance calipers. but is a bit of a faff to make e82 rears work on the e86M's.

with the setup I have, there is about 12% less clamping force, I can still engage ABS, or can run more aggressive paths. Overall a good improvement for weekend drives, as neither, stock, nor the e82 setup is really a track worthy setup.
 
Has anyone tried changing the brake master cylinder to better suit the Caliper sizes, I know that brake force would reduce with a larger MC but it would give better pedal feel?
 
I know I have ATE pads (assuming they're the OEM), and my brake pedal has pretty much instant bite with minimal travel; when they're hot they grab even harder with very little travel. I drove my old 3.0si and the Z4M back to back and when I jumped on the M, I kept accidently applying more brake pressure when heel and toeing as the brakes are that much sharper than they were in the 3.0si.
 
Suspect there is some air still in the system, it may need further bleeding. I had this once when I fitted braided lines on a car where I couldn’t get all the air out of the abs module, triggering an abs activation and bleeding again sorted it but took a lot of fluid passing through to get all the air out.

Stock Z4M brakes and my pedal is firm and strong initial bite.
 
InterlagosMC said:
Has anyone tried changing the brake master cylinder to better suit the Caliper sizes, I know that brake force would reduce with a larger MC but it would give better pedal feel?
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It would have a similar effect to what maupineda describes when dropping total piston area - less clamping force and the feeling of it being a bit more linear/longer (without the other benefits of upgraded calipers - better heat dissipation, more consistent pad vs disc geometry etc).

I think we're talking about a couple of different things here though - perhaps you can clarify, OP?

"Firmness" is the feeling of a direct connection between your foot and a hard pad making contact with a hard, unyielding disc. "Bite" is the point at which you feel actual retardation kicking in. A lot of non-sports cars have very early and aggressive bite but with crap, spongy pedal feel. If you drive something like the 997 mentioned above, you'll find that Porsche usually like to set up their brakes relatively "long" and progressive by most standards, but the feel is really nice and in some cases it can feel almost as if you're pressing directly on the brake discs with your foot.

With the Z4M, most people think it's unnecessarily over-servo'd, i.e. the brakes bite a bit too early and non-linearly (especially when you consider the fact that they are actually very good at stopping the car and most Z4M drivers can drive a bit). It's the same theme of erring on the side of caution that you find in loads of other areas of the way the car is set up - the rear toe-in and camber, the emergency braking function, intrusive TC, the "I AM BRAKING VERY HARD NOW" brake light display etc.

FWIW, mine bite very early and the feel is ok but not the best. It was improved a bit by upgrading the front calipers, but not night and day. I'm still on stock pads and have rear factory lines, so those are a couple of obvious things to try and upgrade in the future.
 
It's worth giving the calipers a few clonks with a rubber mallet when bleeding, BTW. I'm not sure how much of a difference this will make with the stock calipers, but I find loads of little bubbles stuck in the brembos that the INPA ABS routine can't do anything about (and maybe is the source of a lot of them!).
 
MrPT said:
InterlagosMC said:
Has anyone tried changing the brake master cylinder to better suit the Caliper sizes, I know that brake force would reduce with a larger MC but it would give better pedal feel?
Click to expand...

It would have a similar effect to what maupineda describes when dropping total piston area - less clamping force and the feeling of it being a bit more linear/longer (without the other benefits of upgraded calipers - better heat dissipation, more consistent pad vs disc geometry etc).

I think we're talking about a couple of different things here though - perhaps you can clarify, OP?

"Firmness" is the feeling of a direct connection between your foot and a hard pad making contact with a hard, unyielding disc. "Bite" is the point at which you feel actual retardation kicking in. A lot of non-sports cars have very early and aggressive bite but with crap, spongy pedal feel. If you drive something like the 997 mentioned above, you'll find that Porsche usually like to set up their brakes relatively "long" and progressive by most standards, but the feel is really nice and in some cases it can feel almost as if you're pressing directly on the brake discs with your foot.

With the Z4M, most people think it's unnecessarily over-servo'd, i.e. the brakes bite a bit too early and non-linearly (especially when you consider the fact that they are actually very good at stopping the car and most Z4M drivers can drive a bit). It's the same theme of erring on the side of caution that you find in loads of other areas of the way the car is set up - the rear toe-in and camber, the emergency braking function, intrusive TC, the "I AM BRAKING VERY HARD NOW" brake light display etc.

FWIW, mine bite very early and the feel is ok but not the best. It was improved a bit by upgrading the front calipers, but not night and day. I'm still on stock pads and have rear factory lines, so those are a couple of obvious things to try and upgrade in the future.
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Thanks for the input, so I have rebuilt the callipers all around, fitted brass bushes and am running braided lines with ebc bluestuff pads currently, did have pfc z rated but they weren’t the best for pedal feel. When bleeding I did as prescribed by bleeding the Calipers all around and tapped calipers as they were bleeding. Pedal has more dead travel than I would like but when it bites it feels really good. I just want it that when I press the pedal down I don’t want so much travel before any braking feel
 
MrPT said:
InterlagosMC said:
Has anyone tried changing the brake master cylinder to better suit the Caliper sizes, I know that brake force would reduce with a larger MC but it would give better pedal feel?
Click to expand...

It would have a similar effect to what maupineda describes when dropping total piston area - less clamping force and the feeling of it being a bit more linear/longer (without the other benefits of upgraded calipers - better heat dissipation, more consistent pad vs disc geometry etc).

I think we're talking about a couple of different things here though - perhaps you can clarify, OP?

"Firmness" is the feeling of a direct connection between your foot and a hard pad making contact with a hard, unyielding disc. "Bite" is the point at which you feel actual retardation kicking in. A lot of non-sports cars have very early and aggressive bite but with crap, spongy pedal feel. If you drive something like the 997 mentioned above, you'll find that Porsche usually like to set up their brakes relatively "long" and progressive by most standards, but the feel is really nice and in some cases it can feel almost as if you're pressing directly on the brake discs with your foot.

With the Z4M, most people think it's unnecessarily over-servo'd, i.e. the brakes bite a bit too early and non-linearly (especially when you consider the fact that they are actually very good at stopping the car and most Z4M drivers can drive a bit). It's the same theme of erring on the side of caution that you find in loads of other areas of the way the car is set up - the rear toe-in and camber, the emergency braking function, intrusive TC, the "I AM BRAKING VERY HARD NOW" brake light display etc.

FWIW, mine bite very early and the feel is ok but not the best. It was improved a bit by upgrading the front calipers, but not night and day. I'm still on stock pads and have rear factory lines, so those are a couple of obvious things to try and upgrade in the future.
Click to expand...

Very much agree with everything you have written.

I never had a problem with initial bite, if anything it was too pronounced. Since then I've disabled few brake boost flags in ecu/module, maybe that helped a little, but hard to say.

Firmness aka softish pedal - still present. Non-linear and inconsistent braking force according to pedal pressure (e.g. braking at 100kph vs 150kph) - still there. And this is how I would describe brakes that don't inspire confidence, even if they brake well until overheated.
 
ap BBK all round here - awesome pedal. Still one of the braking systems ive had the pleasure to use, track use needs a suitable pad however but the change is so quick and easy its not an issue. over 5k now days sadly.
 
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