Soft brake pedal (BBK install)

[MildSeven]

Ok, update of my situation... still unresolved and there's a car show I want to attend Sunday .

 

I currently have my old (previously working) 2002 master cylinder in with 2 ports plugged.

 

Bleeding + Bleeding = Bleeding

I did some gravity bleeding + some gravity bleeding while pumping a little + some bleeding with a helper. + some more bleeding with a helper last night.

 

The 2 rear drums, blead nicely. Nice clear fluid at the end.

 

The passenger front INNER had like bursts of very tiny, tiny bubbles that would go on forever.

 

Video:

 

When we started bleeding the driver front, the pedal went suddenly soft, it was almost like pumping with no resistance (you can even hear the sound of no resistance on the video).

 

We would have to build up pressure to get more of a feel (~6 pumps). It was never ending tiny, tiny bubbles, even though the length from MC to caliper is very short.

 

Video:

 

 

On 9/8/2019 at 9:25 AM, mlytle said:

The three common reasons for soft brake pedal on a 2002 are....

 

1/ front calipers installed upside down.   The bleed valves go UP.  Think about where air goes.....

 

2/ air in system.  Pedal pumping doesn't cut it.  Gotta have a pressure bleeder on the reservoir while pumping pedal slowly.  Especially if major brakes system parts were replaced.

 

3/ rear shoes not adjusted properly.

 

 #1, Wilwood are interchangeable

 

#2 I ordered a motive pressure bleeder last night after my frustrations.

 

#3 nothing changed from before the swap.

 

On 9/7/2019 at 10:02 PM, arminyack said:

Ok< I got mine sorted out. I removed both front calipers, and turned em upside down. I slide them on the rotors so the pads wont push out too far, and then bled them. Big air bubbles, followed by a flurry of small ones, then no bubbles at all. Bingo, a working brake pedal.

 

GO figure.

 

As in you had them on upside down or you flipped them back to right side up after?

 

Photo of my tiny, tiny perrier bubbles :

 

 

 

[M3M3]

5 hours ago, MildSeven said:

#1, Wilwood are interchangeable

 

#2 I ordered a motive pressure bleeder last night after my frustrations.

 

#3 nothing changed from before the swap.

1 - never open the bottom ones.  only bleed the top ones and don't open them too far or air will come in through the thread space.

2 - FINALLY!  that should have been step ONE.

3 - that doesn't mean they were adjusted correctly before.....:-)

 

triple check all or your line connections to make sure they are snug.  you still have air that needs to get out.  make sure you are using the right ports on the MC.   I would go back to the E21 MC rather than kludging an 02 MC that was not designed to work with some ports plugged.

[MildSeven]

29 minutes ago, mlytle said:

1 - never open the bottom ones.  only bleed the top ones and don't open them too far or air will come in through the thread space.

2 - FINALLY!  that should have been step ONE.

3 - that doesn't mean they were adjusted correctly before.....:-)

 

triple check all or your line connections to make sure they are snug.  you still have air that needs to get out.  make sure you are using the right ports on the MC.   I would go back to the E21 MC rather than kludging an 02 MC that was not designed to work with some ports plugged.

 

Thanks Myrtle...

#3 before they felt good , though

 

I think I will swap back to the e21 MC. What are your thoughts on the lack of pre-pressure valve?

[M3M3]

1 hour ago, MildSeven said:

 

Thanks Myrtle...

#3 before they felt good , though

 

I think I will swap back to the e21 MC. What are your thoughts on the lack of pre-pressure valve?

sorry about my item #2....i meant to put a big smiley after that one!

 

no worries on the lack of pressure valve, but it does make regular brake shoe adjustment more important.

[arminyack]

I removed my calipers, turned em upside down, bled, then turned them right side up and re-installed. 

 

Those little bubble you are continuing to see is the air thats making its way past the threads in the bleed nipples. Vacuum bleeders are a PITA, The Motive Power bleeder is the way to go. Before I had this, I smeared a glop of thread sealant on the bleed nipple threads to keep the air from sucking through. It worked, but only for a few bleeds. 

 

[Stevenc22]

Lots of little bubbles probably means air is coming in through the threads, not from the caliper. Put some threadlocker around the threads to try stop air seaping in during bleeding.

[MildSeven]

Weekend Update (got my motive pressure bleeder)

-  I put the e21 (from the bbk kit) back on, I bench bled it first.

-  Using pressure bleeder I checked for leaks by setting it at 15psi. I let it sit for about 40mins. No pressure drop.

-  Bled the brakes, air came out. did it again and again. Everything went well, 0 air.

-  I also flipped the calipers and bled them upside down (from the top). Maybe 1 small bubble.

-  I adjusted the rear shoes.

 

The pedal feels closer to how it felt before the wildwood calipers, which is good. Note: I had e12 calipers before.

 

Issue.    

While driving it on Sunday, it was going pretty fine… except when going down a hill, I started to apply brakes gradually.

I was able to put the pedal to the floor and I kept rolling down. I pumped the brakes and then was able to stop.

 

Could this be the result of a bad master? Are there any tests I could do to validate this?

 

I’m not sure what to look at anymore I just want to drive in peace before it has to be stored for the winter.

 

Thanks again everyone for all the input!

Anthony

 

[M3M3]

yeah!...progress!

 

bleed them again.  sometimes after driving the car, what air may still be trapped somewhere moves on the the caliper.  after major brake maintenance my normal routine is bleed, drive, bleed.

 

dont give up!  ?

 

 

[Stevenc22]

Yeah i fought my brakes, after a master change, for over a year before i sort of had all the air and problems worked out.

[MildSeven]

44 minutes ago, mlytle said:

yeah!...progress!

 

bleed them again.  sometimes after driving the car, what air may still be trapped somewhere moves on the the caliper.  after major brake maintenance my normal routine is bleed, drive, bleed.

 

dont give up!  ?

 

 

 

37 minutes ago, Stevenc22 said:

Yeah i fought my brakes, after a master change, for over a year before i sort of had all the air and problems worked out.

 

Thanks guys.

 

So, I shouldn't assume there might be an issue with MC?

 

I'll do another bleed on the weekend. Anyone know what pressure I should be bleeding at? I was doing 17psi.

 

Also do where can I find a pre pressure valve for my rear line? Does anything generic exist since the part is NLA.

 

Thanks,

Anthony

 

[zinz]

1 hour ago, MildSeven said:

I was doing 17psi

 

Shouldn't need that much.  Even 5-8 psi will get it done.  

 

Ed

[M3M3]

1 hour ago, MildSeven said:

 

I'll do another bleed on the weekend. Anyone know what pressure I should be bleeding at? I was doing 17psi.

don't use that much.  could blow the lines out of the master cyl grommets....huge mess!

 

i only use about 10 psi on 2002 systems.  you are just using the pressure bleeder to keep a positive pressure in the system.  with the pressure in the system, attach bleed bottle to one caliper and open the valve slightly.  then go slowly pump the brake pedal 5-10 times for each valve.  do not need to keep opening and closing the valve.  close after the pumping and move on to the next valve.  it makes no difference what caliper you do first or what order you do them in.   keep checking the reservoir to make sure is does not get below the "min" line.

[MildSeven]

thanks guys!

 

I haven't re-bled it since Sunday's drive and didn't have any issues where there were weak brakes.

 

The pedal doesn't feel as firm as I would like (as it did before with e12 calipers) and i would like some more resistance higher up.

 

On 9/16/2019 at 12:52 PM, mlytle said:

don't use that much.  could blow the lines out of the master cyl grommets....huge mess!

 

i only use about 10 psi on 2002 systems.  you are just using the pressure bleeder to keep a positive pressure in the system.  with the pressure in the system, attach bleed bottle to one caliper and open the valve slightly.  then go slowly pump the brake pedal 5-10 times for each valve.  do not need to keep opening and closing the valve.  close after the pumping and move on to the next valve.  it makes no difference what caliper you do first or what order you do them in.   keep checking the reservoir to make sure is does not get below the "min" line.

 

I didn't pump the brakes while bleeding. I didn't think it was necessary, maybe I will do that.

 

I wanted to get more pedal feel higher up, should i look at a wilwood pre-pressure valve (since BMW is NLA)?

I was trying to find out what the oem valve pressure was, i believe is 6psi. Can anyone confirm this figure?

 

Thanks,

Anthony

[M3M3]

bleed the brakes with the process i outlined.

 

fully bed in the new brake pads.  drive for a few hundred miles.

 

don't mess with check valves. not needed.