I was reading on the M3 forum that some people have issues with a soft pedal after bleeding and its most likely air in the ABS. The following thread talks about bleeding the brakes with the engine running. They said it made a huge difference in pedal feel. Can anybody comment on this?

post 33 and 34

http://m3forum.net/m3forum/showthrea...=193412&page=4

 

I use a vacuum pump and the brake pedals feel good after bleeding. I do not turn the engine on.

Perhaps that is for ABS recycling?

 

As long as the res. doesn't go dry you should never have a problem with a brake bleed. Thus the reason for the pressure bleeder, no chance of running the res dry.

I gotta say.......some of those folks really don't know how to use a pressure bleeder. Sheesh!

 

I wouldn't try that, if you had the ABS pump activate it would cause you to get air in the pump.

 

I have this same problem! I flushed my brake system with new fluid and ended up with a mushy pedal. Tried bleeding the system twice afterwards, and didn't get any better.

How would I go about getting air out of the ABS system (if that is indeed what has happened)?

 

ABS air bleed - either (a) you need a scantool that can activate the air bleed cycle (like AutoEnginuity) while using a pressure bleeder, or (b) go out on gravel and lock up the ABS about 10 times to move the bubbles around, then try pressure bleeding again.

 

... and again, ... and again, most likely.

 

Yep. Some folks have reported success with the ABS lockup approach. Personally, I NEVER got mine to bleed properly until I got AutoEnginuity. Now i use it every time I bleed, and all is well.

 

Unless you let the fluid reservoir run dry and induce air into the system there is no reason why you'd have air in the ABS pump.

Fancy pressure and vacuum systems are great: for speed. They also can aerate fluid and in the hands of lesser experienced users force fluid through fast enough that you may overlook the reservoir level dropping so quickly. Use with caution.

An alternative to all this hassle is a simple, but highly effective, gravity bleed: Open bleeder nipple, let drain into bucket, continue to fill reservoir as fluid is displaced, note color change, close bleeder, rinse with WATER, done. One caliper or one end of the car at a time doesn't matter. But you'll need two buckets...

Or you could do like me: have the race car on stands all bleeders open and flowing. (oh you know where this is going) Get lost in too many phone calls, come back the next day and find it all empty. Again. DOH! Start over...and bleeding the hand brake is a pain in the butt too. Got rock pedal again now just took a couple more bottles of fluid than expected.

 

Thats how I have done it the last two times. Its very easy and does not really take that long. However my pedal is just not as good as it was new... It just has a little bit of movement before you begin to feel the resistance of the brakes. Other than that its great. Possibly its just the way my master cylinder is...?

 

Should not be any different. Assuming there was NO pumping of the pedal then no air will be introduced as 'back flow' into the caliper body while the bleeder is open.

As a side to that however you may want to check slide pin lube both front and rear. The longer pedal may have nothing to do with bleeding and everything to do with excessive travel on the guides. Just a thought.

 

Todd, can you elaborate on the slide pin lube. I think I know what you are talking about but not 100% sure. Is it the allen head screw with the rubber spacers that it slides on? What do you use for lube if I am thinking correctly?

Number 5 on the image below?

 

Yessir. Also shown to be an issue on the rears. I recall a big push for some bronze bushings about five years ago. I did a set for a local customer here and they helped. Not sure who has them today but a quick search should turn up info on them and supply.

 

Yeah - the bushings helped me too. But R56 MCS calipers are even better.

 

Thanks for the advice guys. I was positive that I didn't let the reservoir run dry, but I think the abs might have air in it, because the ABS system seems overactive, and the pedal is definitely mushier than when I started.

Looks like I'm stuck having to buy the autoengenuity. Does anyone know where I can get it from?

I don't really see any other way around it.

 

How about their website:

http://www.autoenginuity.com

 

Where are you located? Might be able to find someone in your area who already has it or something equivalent...

 

if you're going to buy it - bimmerzone had the best deal on autoenginuity + the BMW/MINI extensions when I got mine. Still far from cheap.

 

I recommend the Motive Power Bleeder. I used this on mine and it was awesome. I have the kit for both my MINI and our Subaru.

 

Another Important thing to do or not do when bleeding the brakes manually is pump the pedal fast. When you pump the pedal fast you aerate the fluid with little tiny bubbles. Then when the car sits for awhile the bubbles form larger bubbles. So pump slow and steady when bleeding manually.

FYI I see spongy pedals on cars using ATE super blue alot, that's why I only use Motul, unless a customer request something else.

 

Interesting....
I've been using Super Blue for years (not only the MINI) and have never had a spongy pedal.
I use a Motive Power Bleeder and only pressurize to 8-10 PSI.

Jim

 

Hey guys, unfortunately I'm located in Australia, but thanks very much for the kind offer. My friend has a VAG-COM cord for his alfa (OBDII), can I use that, or is it a seperate one for R56 MINIs?

Yeh I did some research on autoenginuity, but I was looking to see if any vendors sold it cheap or as a package or whatever.

 

I know a mechanic that can do the ABS recycle for me.

But surely I don't have to use a pressure bleeder, can I just do the old two-man push and release method to avoid aeration?

Also, does the ABS recycle process actively move the bubbles out of the ABS pump, or does it just open the ABS pump valves? That is, do I have to bleed a lot of fluid out?

 

The ABS air bleed just cycles through opening the ABS valves in a specific order over a period of maybe 15-20 seconds (I've never timed it, but it doesn't take long). It's designed to work with a pressure bleeder - so adequate volume of fluid flows through the system during that period - you setup the pressure bleeder, open a bleeder screw, start the ABS Air Bleed, wait for it to complete, then close the screw. In that period of time, a few ounces of fluid will flow, but not a lot. I use a bit less than a liter when I do a full flush and bleed. Takes no more or less whether I do the Air Bleed or not.

I think you'd have a stroke before you got it to work right doing the two-man open and pump method - unless you timed the pump at exactly the right time, and press very slowly... and I'm not sure you'd move enough volume to clear the ABS in that case.

 

There is no possible way to "aerate" the brake fluid with a home use pressure bleeder. You are only working with 10-15psi. The biggest trick is after you have attached the cap and hose to the reservoir and pumped it up to the desired pressure and then cracking the cap to let out a bit of air. This causes the pump to push brake fliud thru the previously empty hose all the way to the reservior thus removing any unwanted air from the pressure bleeder.