BMW M5 Forum and M6 Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
1,056 Posts
Discussion Starter #1
I've noticed that my ABS on this M5 kicks in too early and can even be dangerous. I've owned two M5s in the past with PSS tires so I know how they're supposed to feel when stopping and how quickly they're supposed to stop. A week ago I was speeding into an off ramp and ABS kicked in when braking last minute causing me to go into the corner too fast and understeer way too much for my comfort. I know when I'm able to brake and how much room I have in a healthy E39 M5 and my current braking performance is scary bad (especially in the wet).

I've heard of ABS upgrades on E36s and E46s and I'm wondering if anyone knows of an upgrade for the E39?

If there aren't any upgrades I'll just have my current module rebuilt and hopefully that'll solve the issue unless there are any other possible causes for early ABS actuation you guys know about?

I've also been considering the E65 master cylinder upgrade (M5board link) for better pedal feel which I'll probably do at a later time when I ensure my ABS (and rest of the car ?) is functioning perfectly.
 

·
Registered
Joined
·
19 Posts
I've noticed that my ABS on this M5 kicks in too early and can even be dangerous. I've owned two M5s in the past with PSS tires so I know how they're supposed to feel when stopping and how quickly they're supposed to stop. A week ago I was speeding into an off ramp and ABS kicked in when braking last minute causing me to go into the corner too fast and understeer way too much for my comfort. I know when I'm able to brake and how much room I have in a healthy E39 M5 and my current braking performance is scary bad (especially in the wet).

I've heard of ABS upgrades on E36s and E46s and I'm wondering if anyone knows of an upgrade for the E39?

If there aren't any upgrades I'll just have my current module rebuilt and hopefully that'll solve the issue unless there are any other possible causes for early ABS actuation you guys know about?

I've also been considering the E65 master cylinder upgrade (M5board link) for better pedal feel which I'll probably do at a later time when I ensure my ABS (and rest of the car ) is functioning perfectly.
The best upgrade you can do for the break system is to get Brembo calibers 6 pistons front and 4 pistons rear
I have them for 2 years now and very good performance on the road


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #3
The best upgrade you can do for the break system is to get Brembo calibers 6 pistons front and 4 pistons rear
I have them for 2 years now and very good performance on the road


Sent from my iPhone using Tapatalk
Don't really need big brakes honestly, ABS will kick in early with them as well. If I can lock up the wheels from 120 on stock brakes no need for a BBK! Unless I was tracking the car and it was an upgrade to avoid brake fade. Not worth the money for me. Good pads would be an upgrade I'd do though, just gotta fix my ABS first.
 

·
Registered
Joined
·
99 Posts
A few things I wanted to check with you. For me, sharp impacts on the road (like the joint between two road parts on a bridge) while braking caused the ABS to incorrectly activate, and I would not be able to apply proper brake force afterwards for about 1 to 2 seconds. Very dangerous, and I got into an accident one time because of it.

I upgraded to brembo bbk’s front and rear to try to solve the issue, and it was still happening.

Long story short, it turned out to be worn stock front shocks on the car that was causing this to happen.

Replacing the shocks with new BMW shocks completely fixed this issue.

Doing some research, it seems like a semi-common flaw on the e39 platform with the shocks and abs system,

Are your front shocks in good shape? When were they last replaced?
 

·
Registered
Joined
·
109 Posts
If something’s wrong with the ABS you will get a warning light. The ABS didn’t cause the initial friction loss, it was triggered by it.

The cars you are comparing yours to are as you state “healthy”. Have you fixed your shimmy? Did you get your way out of spec alignment solved? Find out why your tires are wearing unevenly? If the suspension can’t maintain a proper contact patch or something is loose/wobbling around you can’t ask the car to give you maximum grip. If that’s all been sorted check your tires?

All three of your posts come down to the same answer- get the suspension and steering and alignment addressed by someone who knows what they are doing.

FWIW if you still have an undiagnosed suspension issue, maybe doing hard corners at high speed is not a smart idea? Maybe?
 

·
Registered
Joined
·
109 Posts
Doing some research, it seems like a semi-common flaw on the e39 platform with the shocks and abs system,
Not sure “flaw” is the right word for a worn out shock absorber not being able to dampen spring movement over bumps and keep the tire firmly on the road. I think “worn out part that needs to be replaced” fits a little better. ;)
 

·
Registered
Joined
·
99 Posts
Not sure “flaw” is the right word for a worn out shock absorber not being able to dampen spring movement over bumps and keep the tire firmly on the road. I think “worn out part that needs to be replaced” fits a little better. ;)
Thank you. I do see your point. The reason why I felt it was a "flaw" in the e39 platform was because this is the only car that I've owned that exhibited premature abs activation from sharp bumps because of the worn shocks; This is before showing any of the other common symptoms of worn shocks on the car.
 

·
Registered
Joined
·
109 Posts
Thanks Kotani that’s a great insight to share. My car just hit 70k I will definitely keep that in mind. I would usually look for other signs of tired shocks, I’m sure others would too, knowing that will definitely help some people out!

Maybe that is the posters problem, but from the looks of his other posts it seems there is definitely something off with his suspension and steering, but perhaps the shocks are an issue as well. I just hope he can get it sorted.
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #9
If something’s wrong with the ABS you will get a warning light. The ABS didn’t cause the initial friction loss, it was triggered by it.

The cars you are comparing yours to are as you state “healthy”. Have you fixed your shimmy? Did you get your way out of spec alignment solved? Find out why your tires are wearing unevenly? If the suspension can’t maintain a proper contact patch or something is loose/wobbling around you can’t ask the car to give you maximum grip. If that’s all been sorted check your tires?

All three of your posts come down to the same answer- get the suspension and steering and alignment addressed by someone who knows what they are doing.

FWIW if you still have an undiagnosed suspension issue, maybe doing hard corners at high speed is not a smart idea? Maybe?
The ABS issue is something I noticed from the time I bought the car. I haven't been driving it hard since the wobble began and I noticed the alignment issue, just asking because I was gonna have the ABS module rebuilt anyway to ensure it's perfect and wanted to know if there are any products out there that just limit the ABS activation point in general for better high performance driving.

Of course it would work better when everything else on the car is perfect, I was just curious if there are aftermarket options for further improved braking. From threads I've seen on here, people generally notice an improvement in braking with an ABS module rebuild, for example better pedal feel and modulation. Can't hurt to ensure my car is as solid as possible in that regard.

I just purchased the car last year, I've been perfecting it lately, trying to figure out every possible issue and fix it so the car performs how it would've out of the factory, or better with OEM+ mods.
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #10
Are your front shocks in good shape? When were they last replaced?
They've been replaced recently and don't have enough use yet to justify them as a possible worn part in my opinion. However you have a good point, it is possible that shocks would cause this, as well as various other aspects with the car like my camber alignment issue I've been trying to figure out in my other thread which @mattparsons brings up.

While fixing every issue I'm also looking for good mods to improve my car's performance hence making this thread, the on ramp incident might've been less prominent if my alignment was perfect but when I realized there were modded ABS modules for other models that further delay ABS actuation I figured it would make a good performance improvement if they were available for the M5.
 

·
Registered
Joined
·
109 Posts
ABS module won’t effect the pedal feel. If the master cylinder is going that can give you a soft pedal. Also semi metallic pads (such as the stock jurids) typically have a softer feel, although with a high initial bite, good cold friction and they tolerate heat well.

A ceramic pad will give you a firmer pedal and much less dust, but have lower bite and less cold temp friction, but a lot of people love them for the pedal feel and low dust. Personal choice obviously.

My point (and Kotanis’s) though is that the brakes can be effected by a suspension issue (which it looks like you have) so before you go throwing parts at the car which will cost you money, address what you know is wrong first, then move on to improvements (which after fixing the problems may improve on their own).
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #12
ABS module won’t effect the pedal feel. If the master cylinder is going that can give you a soft pedal. Also semi metallic pads (such as the stock jurids) typically have a softer feel, although with a high initial bite, good cold friction and they tolerate heat well.

A ceramic pad will give you a firmer pedal and much less dust, but have lower bite and less cold temp friction, but a lot of people love them for the pedal feel and low dust. Personal choice obviously.

My point (and Kotanis’s) though is that the brakes can be effected by a suspension issue (which it looks like you have) so before you go throwing parts at the car which will cost you money, address what you know is wrong first, then move on to improvements (which after fixing the problems may improve on their own).
I've seen a bunch of threads over the years that say rebuilding/replacing their ABS unit helped with their pedal feel, here's one - Soft brake pedal - Mystery solved So for less than $200 it's certainly worth doing in my opinion.

And yes you're 100% correct, I'm not throwing parts at the car at the moment, my current priority is my alignment issue, I just like to plan ahead for what I'm doing in the future. Braking is high on my priority list so after my alignment is solved, in about 10k miles when my brakes are worn, I'll be doing a few braking upgrades like ABS module rebuild, bleed, factory brake ducts w/ brake duct fender liners, and maybe the master cylinder upgrade as well as a normal brake/ebrake job.

Fixing my suspension issues will definitely improve braking performance, however I'm looking to extract the most performance possible out of this car, I'm very careful with mods so I like to plan everything ahead of time so I know I'm only using the best possible parts.

Thanks for your feedback on my threads, I appreciate your help.
 

·
Registered
Joined
·
12,835 Posts
mattparsons gives good advice.

Before doing mods, get the car sorted properly back to baseline. You obviously have issues and the ABS module is not our main one. Making upgrades is just going to make finding the underlying issues more difficult.

It is your money, but I suspect there is nothing wrong with the ABS module unless you still have brake issues after all the suspension issues have been sorted. Even then, low pedal is rarely an ABS module issue (and if the ABS module is bad, you should get a bunch of ABS error lights on the dash).

Good luck with getting this properly sorted.

Regards,
Jerry
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #14
mattparsons gives good advice.

Before doing mods, get the car sorted properly back to baseline. You obviously have issues and the ABS module is not our main one. Making upgrades is just going to make finding the underlying issues more difficult.

It is your money, but I suspect there is nothing wrong with the ABS module unless you still have brake issues after all the suspension issues have been sorted. Even then, low pedal is rarely an ABS module issue (and if the ABS module is bad, you should get a bunch of ABS error lights on the dash).

Good luck with getting this properly sorted.

Regards,
Jerry
I appreciate your feedback and you're 100% correct but like I said in my previous post, I'm absolutely not touching anything related to the ABS or braking until everything else is sorted out. I'm very careful about every mod or work I do to my car so I would like to begin planning my complete braking system upgrade sooner than later even though I won't be touching it until at least October.

I put a lot of thought into everything I do to this car so rest assured this thread is only in reference to something I'll be doing no sooner than 6 months from now :) If you think that's crazy you should see the list of 15+ other items that I've been thinking about and planning on doing at some point in the future ;)

I understand it's unlikely my ABS module has an issue, I'm more than happy to spend $150 on the peace of mind knowing everything's functioning perfectly.

Regardless, what I really want is an ABS upgrade! Rather than having a rebuilt OEM ABS module, I want to know if there are any upgrades available that I can make that'll give me improved performance over stock when I divert my focus to braking after everything else is totally sorted out.

Anyone know of any upgrades available? Is there any coding that can be done or would this be a hardware upgrade?
 

·
Registered
Joined
·
109 Posts
Ah cool- sorry to jump to a conclusion (my bad). I have seen it many times (and I’m guilty of it myself) where a mystery issue makes one start replacing things, just didn’t want you to lose any money (that could go into other upgrades!).

Sounds like a good plan overall. Definitely look into pads as well when you are refreshing things, they have a big influence on pedal feel if you are keeping stock brake components. After a refresh like you listed the cars gonna feel brand new (or better)!

And please know my replies to you are honestly in the spirit of helping (I am not meaning to sound snarky) I know in posts it’s hard to know how someone is coming across.
 

·
Registered
Joined
·
446 Posts
I appreciate your feedback and you're 100% correct but like I said in my previous post, I'm absolutely not touching anything related to the ABS or braking until everything else is sorted out. I'm very careful about every mod or work I do to my car so I would like to begin planning my complete braking system upgrade sooner than later even though I won't be touching it until at least October.

I put a lot of thought into everything I do to this car so rest assured this thread is only in reference to something I'll be doing no sooner than 6 months from now :) If you think that's crazy you should see the list of 15+ other items that I've been thinking about and planning on doing at some point in the future ;)

I understand it's unlikely my ABS module has an issue, I'm more than happy to spend $150 on the peace of mind knowing everything's functioning perfectly.

Regardless, what I really want is an ABS upgrade! Rather than having a rebuilt OEM ABS module, I want to know if there are any upgrades available that I can make that'll give me improved performance over stock when I divert my focus to braking after everything else is totally sorted out.

Anyone know of any upgrades available? Is there any coding that can be done or would this be a hardware upgrade?
OP- You no doubt are aware that ABS stands for "anti lock braking", and does just that, it doesnt cause brakes to lock up, it prevents it.
When activated, you should feel a juddering in the pedal as they momentarily lock and release.
This can feel alarming especially in the M5 with large width low profile tyres.

If the ABS were not working you would just experience lock up as in a car without ABS.
That is, no pulsing, no lock and unlock, just screeech of tyres and ploughing straight ahead.
As gsfent said, if the ABS was faulty, you should have warning lights for the ABS and the DSC.
Have you run any software program over it?
Peake reader only shows engine codes, you will need Inpa DIS etc to read the fault codes.

And you could perform a simple test, get into a situation where the DSC intervenes to restore traction, if you are comfortable doing that, and if it does, the ABS must be working correctly, I would think.

The other common front suspension traction problem is caused by the front thrust arms being worn out.
The symptoms are similar to what you have experienced, braking on broken surfaces causing weird feeling loss of traction and juddering in the front wheels.
Either get to a suspension shop for a check up, or you can do a simple test, drive forward from rest in first gear say 6 feet and stop quickly, without locking up. Have some one standing just to the side and watching the front wheel carefully.
If the thrust arms have lots of play, the front wheel will move backwards noticeably as the car comes to a stop under the brake load. This is a good simple test at no cost.
Ask me how I know.
If your shocks are good as you say, the thrust arms are a likely suspect.

You didnt mention if you have aftermarket and/ or oversize wheels/spacers etc?
These could affect things too.

Hope you sort ti out.
Cheers
 

·
Registered
Joined
·
1,056 Posts
Discussion Starter #17
Ah cool- sorry to jump to a conclusion (my bad). I have seen it many times (and I’m guilty of it myself) where a mystery issue makes one start replacing things, just didn’t want you to lose any money (that could go into other upgrades!).

Sounds like a good plan overall. Definitely look into pads as well when you are refreshing things, they have a big influence on pedal feel if you are keeping stock brake components. After a refresh like you listed the cars gonna feel brand new (or better)!

And please know my replies to you are honestly in the spirit of helping (I am not meaning to sound snarky) I know in posts it’s hard to know how someone is coming across.
No worries! I definitely understand and I've seen it a bunch of times as well. I appreciate you trying to make sure I'm not doing the same, I should've made it more clear in my OP that I'm just planning for the future with this thread. Thanks!
 

·
Registered
Joined
·
1,520 Posts
My ABS was failing and caused ABS kick in early during normal braking (no emergency braking moments). I had ABS module replaced and the braking was restored.
 

·
Registered
Joined
·
12,835 Posts
OP

I am no stranger to mods! Just look at my signature! LOL

Let's focus on the ABS module. It has been sometime, but if I recall correctly, to remove the ABS computer, you have to remove some bolts/screws and an electrical connector. If so, just unplug the electrical connector and you should effectively eliminate the ABS module from braking. Then you can see if it is the problem. The ABS module can be bad (as noted above although no indication by that poster if the ABS/DSC lights on the dashboard were lit) but that has been super rare based on reporting here over the years.

One other thought about thrust arm bushings. If replaced, I believe they have to be tightened with the suspension loaded. I don't recall if yours were replaced. If they were, you need to check with whoever did yours if they did it as required by BMW (loaded or unloaded, whatever the proper method is). If they were not and you are replacing, I recommend the X5 bushings. More robust but no harsher ride. They need to be installed 180 degrees opposite based on the keyway location. See old thread "Crevier sucks" or similar.

Regards,
Jerry
 
1 - 19 of 19 Posts
Top