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#1. Re: [E36M3] RE: Soft Brakes - from alex.fadeev@verizon.com
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Date: Wed, 16 Apr 2003 11:47:18 -0500 From: alex.fadeev@verizon.com Subject: Re: [E36M3] RE: Soft Brakes Chester Wong <chester_p_wong@yahoo.com> wrote: > > I think you're not fully understanding what I'm trying to say. Now, > I don't have the Motive brake bleeder and I have the Steve D brake > bleeder. So do I. > When you pump the Steve D brake bleeder, the pump forces the air > through the brake solution.... what? > much like if you blow through a straw through a glass of soap water. It's nothing like that. Steve D's, Movit's and just about every other pressure bleeder contraption I've seen introduces air pressure above the fluid level. That pressure forces the fluid into the brake fluid container and through the lines. More importantly, adding brake fluid to the container and _then_ pressuring it will have an identical effect on fluid's alleged propensity to foam under pressure. > This air causes small bubbles to form and stay suspended in the > solution for a while. I once pressurized the container and opened > up the valve to see what the brake fluid looked like that would > normally go into the brake reservoir. What did I see? Small bubbles > streaming out. Chester, I think you are confused. First of all any bubbles formed under air pressure (under 20 psi, right?) would form both in the bleeder tank, the brake fluid reservoir and for that matter in the lines. Your theory, if true, would doom all forms of air pressure induced brake bleeding. Secondly, any bubbles suspended in the brake fluid (way more are formed when you pour brake fluid into the pressure bleeder container!) will; a). float on top; b). dissipate. There is always air at the top of the brake fluid reservoir. There is a reason why it's stay on top and does not get pushed through the brake lines. Lastly, if you interrupt pressure bleeding and open the brake reservoir, you will see that there are no bubbles in it. Try this and pressure bleed without any fear. > If the motive bleeder pumps air into the tank above the brake fluid, > then that's fine. ??? If you were to stay true to your own theory, wouldn't that be "much like if you blow through a straw through a glass of soap water."... ;-) Chester --- "Dorffer, Rich" <RDORFFER@CleIndians.com> wrote: > IMO - Pumping and pressurizing the container full of fluid in a traditional > brake bleeder (e.g., Motive brake bleeder) does no more to introduce air into > the fluid than your method of using the empty brake bleeder as a pressure > source. Both have up to 20 psi of air pressure pushing the fluid. I entirely agree with Rich. I've been pressure bleeding with Steve D's contraption for years and never had any brake pedal softness on any of my bimmers. I did once help a friend to diagnose his brake pedal softness that was traced to his habit of re-using previously opened brake fluid cans and not blowing old brake fluid out of his bleeder lines. alex f
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#2. Re: Soft Brakes - from Neil Maller
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Date: Wed, 16 Apr 2003 11:54:52 -0500 From: Neil Maller <neil.maller@gte.net> Subject: Re: Soft Brakes on 4/16/03 11:36 AM, "Patrick Buthmann" <patrick@teutonic.ca> wrote: > On a side note, I had virtually the same problem Neil has been having; I just > solved mine by installing the Stoptech's instead :) I've been looking for a slightly more modest solution... Neil (Taking a lunch break from brake bleeding and putting on the track pads) 96 M3
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#3. RE: rockville/annapolis, md shops - from Garrett
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Date: Wed, 16 Apr 2003 09:59:15 -0700 (PDT) From: Garrett <garrettmcw@yahoo.com> Subject: RE: rockville/annapolis, md shops I really like Quality Car Service, on N. Stonestreet Ave, about a block from the Rockville Metro station. 301-340-8269. Neil is a good guy and always does my track tech inspections no-charge despite my attempts to pay him. I do pretty much all the maintenance on the car myself, but if something ever comes up that I don't want to tackle (like the clutch), they'll be doing it. You could do that O2 sensor yourself in about ten minutes... -Garrett
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#4. Re: [E36M3] RE: Soft Brakes - from Chester Wong
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Date: Wed, 16 Apr 2003 09:59:41 -0700 (PDT) From: Chester Wong <chester_p_wong@yahoo.com> Subject: Re: [E36M3] RE: Soft Brakes --- alex.fadeev@verizon.com wrote: > > much like if you blow through a straw through a glass of soap water. > > It's nothing like that. > Steve D's, Movit's and just about every other pressure bleeder contraption > I've seen introduces air pressure above the fluid level. That pressure > forces the fluid into the brake fluid container and through the lines. > More importantly, adding brake fluid to the container and _then_ > pressuring it will have an identical effect on fluid's alleged propensity > to foam under pressure. You can call me confused, you can insult me, whatever...I really don't care. All I know is that when I filled the container with 1 liter of brake fluid and put the pump mechanism and and proceeded to pump, I hear what sounds like air bubbling through brake fluid. Of course, if the container was translucent or transparent, one car verify this. But what does it matter? It really makes no difference to me one way or another as I don't use it anymore. Do what you guys want.... Chester =====
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#5. Re: [E36M3] Susp setup help please - from James Clay
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Date: Wed, 16 Apr 2003 13:10:32 -0400 From: "James Clay" <james@bimmerworld.com> Subject: Re: [E36M3] Susp setup help please Don't worry about it. Unless your DE is in a parking lot, there is no need to set the car up for the parking lot. The tight turns there will not simulate a track event. Suspension settings vary between similar tracks even, a parking lot is too far off from the real think unless you are working toward auto-x. James James Clay http://www.bimmerworld.com Engineered BMW Performance 540.639.9648
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#6. Re: Soft brake pedal - from Chip Mitchell
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Date: Wed, 16 Apr 2003 13:20:29 -0500 From: "Chip Mitchell" <chipm@uga.edu> Subject: Re: Soft brake pedal Okay, second try - hope this one goes through... Tom, I tried your pedal tests with the following results: Pressed pedal twice at park, second pump was much firmer and had much shorter travel. Got back in the car a few hours later, pedal travel is still short/firm. Pulled out of parking space and coasted to a stop, then pressed the pedal and.....soft again! So, your theory makes sense so far. On the street, my experience is like everyone else in that I can pump the pedal quickly and have a much firmer feel on the second pump. I have been experiencing a pulsating pedal under med/hard braking, and I will be replacing rotors whenever my new pads show up. So, I assume new rotors should cure this if it is a runout problem. Is there a good way to test bearing play other than moving the wheel back and forth? ChipM > >-------------------- 8 -------------------- >Date: Tue, 15 Apr 2003 16:21:52 -0400 >From: "Tom Melton" <tom_melton@emoryhealthcare.org> >Subject: [E36M3] re: soft pedal > >When I have seen this on other cars, the problem has always been one of two >things, either tapered pads or rotor runout. > >With tapered pads, typical of a lot of braking systems that see track duty, the >first pedal stroke pushes the pads to the rotors, the second stroke then feels >normal. > >With rotor runout, the runout knocks the pistons back into the caliper (if fixed >caliper), or knocks the pistons into the caliper and the fixed pad away from >the rotor (if floating caliper). IE, the wobble pushes the pads away. Again, >the first pedal stroke pushes the pads to the rotors, the second stroke then >again feels normal. > >One cause of apparent rotor runout can be bad bearings. Sloppy bearings allow >the rotor to wobble in the caliper, simulating rotor runout. > >Another item that can simulate rotor runout is two piece (floating) rotors. If >the rotor does not spin perfectly flat, then again the pads get knocked away, >and you get a long pedal. > >For those of you with this problem, do the following. Park the car, push the >pedal down, release, and push down again. How does the pedal feel on the >second stroke? Normal? > >Leave the car for 4 hours, press the pedal ONCE, how does the pedal stroke feel? > Normal? > >Roll the car at least so the tires rotate a few turns and stop the motion >WITHOUT using the brakes. IE, push it on a level surface, and stop it by hand. > Press the pedal ONCE, how does the pedal stroke feel? Abnormal? > >Reply back after the above tests are done. I am interested to hear/read the >results. > >Tom Melton >95 M3 >82 Vette >86 Vette >etc > >>>> <kim.burgess@att.net> 04/15/03 03:26PM >>> >Date: Tue, 15 Apr 2003 19:21:06 +0000 >From: kim.burgess@att.net >Subject: re: soft pedal > >I too experience the second stroke firm pedal syndrome. All I can figure out is > >that I boiled the fluid at my last event, and need to pressure-bled >again...and that I have a bit of wear on the pads/rotors in spite of the fact >that the system is self adjusting. Can the pads (stock) soften as result of >over-heating and yield soft pedal? How much heat at the caliper does it take to > >heat the fluid to a point of softening (damaging) the rubber brake fluid >lines? > >Kim Burgess >Mike wrote: "If I pump the pedal quickly once, the pedal will >be much firmer and not go as far to the floor on the second press. If >anyone can figure this out I'm pretty sure you'll have lots of new >friends!" >
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#7. rockville/annapolis, md shops - from Luis Rueda
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Date: Wed, 16 Apr 2003 13:33:33 -0400 From: "Luis Rueda" <Luis_Rueda@Interliant.com> Subject: rockville/annapolis, md shops Russell, BMW Excluservice (301-231-5400) in Rockville has an excellent reputation. Luis -------------------- 8 -------------------- Date: Wed, 16 Apr 2003 08:27:41 -0700 (PDT) From: russell <driver8m3@yahoo.com> Subject: rockville/annapolis, md shops does anybody know of any decent shops/mechanics near annapolis (home) or rockville (work), md? need an O2 sensor replaced...dealer said it would be around $300. thanks, russell dakar 99
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#8. RE: Rotor runout and soft pedal - from Tom Melton
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Date: Wed, 16 Apr 2003 16:56:49 -0400 From: "Tom Melton" <tom_melton@emoryhealthcare.org> Subject: RE: Rotor runout and soft pedal Chip, It sounds like your pads/pistons are indeed being pushed away from the rotors, thus causing your longer pedal. You ask is there a way to test the bearings, if you mean other than grabbing the wheel at 12 and 6 o'clock and checking for play, not that I know of. Well, you can also remove the wheel, make sure the rotor is securely fastened to the hub, attach a dial indicator to measure movement of the rotor face, and push/pull on the rotor to see what actual movement there is at the rotor. Other than those, not that I know of. -Tom >>> "Chip Mitchell" <chipm@uga.edu> 04/16/03 11:17AM >>> Tom, I tried your pedal tests with the following results: Pressed pedal twice at park, second pump was much firmer and had much shorter travel. Got back in the car a few hours later, pedal travel is still short/firm. Pulled out of parking space and coasted to a stop, then pressed the pedal and.....soft again! So, your theory makes sense so far. On the street, my experience is like everyone else in that I can pump the pedal quickly and have a much firmer feel on the second pump. I have been experiencing a pulsating pedal under med/hard braking, and I will be replacing rotors whenever my new pads show up. So, I assume new rotors should cure this if it is a runout problem. Is there a good way to test bearing play other than moving the wheel back and forth? ChipM Date: Tue, 15 Apr 2003 16:21:52 -0400 From: "Tom Melton" <tom_melton@emoryhealthcare.org> Subject: [E36M3] re: soft pedal When I have seen this on other cars, the problem has always been one of two things, either tapered pads or rotor runout. With tapered pads, typical of a lot of braking systems that see track duty, the first pedal stroke pushes the pads to the rotors, the second stroke then feels normal. With rotor runout, the runout knocks the pistons back into the caliper (if fixed caliper), or knocks the pistons into the caliper and the fixed pad away from the rotor (if floating caliper). IE, the wobble pushes the pads away. Again, the first pedal stroke pushes the pads to the rotors, the second stroke then again feels normal. One cause of apparent rotor runout can be bad bearings. Sloppy bearings allow the rotor to wobble in the caliper, simulating rotor runout. Another item that can simulate rotor runout is two piece (floating) rotors. If the rotor does not spin perfectly flat, then again the pads get knocked away, and you get a long pedal. For those of you with this problem, do the following. Park the car, push the pedal down, release, and push down again. How does the pedal feel on the second stroke? Normal? Leave the car for 4 hours, press the pedal ONCE, how does the pedal stroke feel? Normal? Roll the car at least so the tires rotate a few turns and stop the motion WITHOUT using the brakes. IE, push it on a level surface, and stop it by hand. Press the pedal ONCE, how does the pedal stroke feel? Abnormal? Reply back after the above tests are done. I am interested to hear/read the results. Tom Melton 95 M3 82 Vette 86 Vette etc
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#9. Re: [E36M3] RE: Soft Brakes - from Jim Powell
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Date: Wed, 16 Apr 2003 17:42:28 -0700 From: "Jim Powell" <jsp98m3@apexcone.com> Subject: Re: [E36M3] RE: Soft Brakes This isn't probably 100% true. The air pump is above the fluid level unless you are pouring in more than a liter and a half on mine and much more than that on the Steve D' unit. Can't say about Motive. Since they copied everyone elses there seemed to be little point in looking at it when I had my own. Anyway. The air is pressurized above the fluid and pushes the fluid into the bottom drawing tube leading to the supply hose. Jim > Subject: RE: Soft Brakes > > I think you're not fully understanding what I'm trying to say. Now, I don't > have the Motive brake bleeder and I have the Steve D brake bleeder. When you > pump the Steve D brake bleeder, the pump forces the air through the brake > solution....much like if you blow through a straw through a glass of soap > water. This air causes small bubbles to form and stay suspended in the > solution for a while. I once pressurized the container and opened up the valve > to see what the brake fluid looked like that would normally go into the brake > reservoir. What did I see? Small bubbles streaming out. If the motive > bleeder pumps air into the tank above the brake fluid, then that's fine. > > Chester
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#10. Re: [E36M3] Susp setup help please - from Jay W. Hudson
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Date: Wed, 16 Apr 2003 18:38:44 -0700 From: "Jay W. Hudson" <jwhud@cdsnet.net> Subject: Re: [E36M3] Susp setup help please Thanks to everyone who replied to my questions. I got some interesting and useful info. Off to the track on Friday. DE on Saturday. Big smiles all the way home. Jay