I am going to try exercising the ABS myself as a final chance to fix my crap brakes. Does anyone have moe info. on doing this? I know I need a 12V pulse to each solenoid in the actuator but I am not sure exactly what wires I am applying this 12V to. I looked at Helms and still wasn't clear. My plan is to run a wire from the car's battery to the wire for each ABS solenoid and have a push button switch in the middle to zap the solenoids with 12V. Any help is greatly appreciated.

Thanks :-)

 

did you ever get a chance to try different pads before you do this?

 

I figured this was cheaper. I thought why pay for new pads when I can do this for free and just see what happens. New pads may be next on the list.

 

I'd be careful about actually running a straight 12V to a solenoid for fear of shorting somethig out (now that would really be a bummer).

Here's a suggestion which is not really as crazy as it sounds.
How about putting the car securely up an jackstands, and with the car running and foot lightly on the brake pedal, have someone try and rotate each of the individual wheels by hand (out of gear). I'd think that this would simulate the conditions under which ABS is supposed to activate. JMHO Ed

Any gravel roads nearby?

 

Onyx sorry it took so long to answer, and just noticed your IM since I have a pop-up blocker and filter on and don't recieve notification like that.

The 12v abs solonoid activation method was described to my Mark Basch himself as to exactly the method he was using on YOUR car.

I have not done it nor have I seen it done, only had it described to me by Mark himself when I had the problem and was having Larry Bastanza help me on this coast with similar issues.

WE did what I described before and what Ed (Zyg) suggested. I drove the car all over a bunch or dirt roads and with loose surface and just pounded on the brakes till abs activated every time, took my brother laong for the fun ride and made him literally sick to his stomach after about 100 or so stops.

Then at Larry's house we bled the car 3 times using the 2 person method with a bleeder bottle with a one way check valve affixed to the caliper bleeder nipple and Larry opening the valve only half way and maintaining pressure, never fully opened and always using a 2x4 peice of wood on the floorboard so the brake pedal didn't go too far.

After about an hour of good solid flushing and bleeding we took it for a spin and the brakes were back to as close to the original feel as I remember.

NOW, since my brake problems, I have driven multiple cars, some with brand new brake systems, some with abs and some without, and None of them were rock solid with the exception of funny enough my Non ABS 95 Altima, which actually has drum rears.

My R brakes are awesome, the car stops on a dime and even beforehand and heel-toe is back to normal positions. BUT the pedal has the slightest sink and I mean Slight before the brakes engage. But once they are activated the car comes to a gut wrenching halt. Pads are front: Cobalt GT/VR's, rear: Cobalt GT/Sports, Lines Goodridge SS, Fluid Motul RBF 600, Rotors, Front: cracked autozones that need replacement, rear: Cobalt/Centric. Car has maybe 500 miles on it since the bleed and several autocrosses and No issues whatsoever.

I do however have a nice perfectly brand new MC sitting in my garage that turned out to Not be the issue after replacement and advice by more than 3 reputible people online.

Bleed, Bleed and bleed again until you get the pedal back. This worked for me Finally/eventually.

And I find it hard to believe that Mark Basch hasn't solved your issues, especially since I had spoken to him for advice after you had been to him 1 or 2 times prior and then he and Larry kept in contact to exchange info to figure out my issues.

Best of luck once again and I do totally understand where you are and coming from.

Anton

 

My problem is finding some good dirt roads to do this on.

Mark did say he exercised the system quite a bit. Mark's opinion was that the brakes seemed fine to him, however I feel the problem is not solved because the pedal throw varies so much during driving. In the morning it feels really good but after driving for awhile it does soften up.

I will maybe try Ed's suggestion. Ed, my understanding of ABS brake function was that it compares the speed of each wheel witht he speed of the vehicle and if the speed of the wheel is less than the speed of the vehicle, ABS activates. Thus, wouldn't turning the wheel with the car motionless not satisfy the condition for ABS to activate?

 

I don't have dirt roads in the city....so I just used a garden hose and thoroughly soaked the street in front of my house... my neighbors may think I am crazy and weird, but my brakes work !!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zygspeed &raquo;</TD></TR><TR><TD CLASS="quote">Here's a suggestion which is not really as crazy as it sounds.
How about putting the car securely up an jackstands, and with the car running and foot lightly on the brake pedal, have someone try and rotate each of the individual wheels by hand (out of gear). I'd think that this would simulate the conditions under which ABS is supposed to activate. JMHO</TD></TR></TABLE>

I will check the helms when I get home, but this does not sound like it will trigger the system.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">I will check the helms when I get home, but this does not sound like it will trigger the system.</TD></TR></TABLE>

No chit

 

I honestly think the best method to accomplish activating the ABS is to directly force each solenoid to operate.

If you look at the Helms the ABS Control Unit has two lines to each solenoid (each pair of wires and solenoid corresponding to a given wheel). One wire is the positive, other is the negative. If I remember correctly the Helms indicates that 12V to the solenoid turns it off, and 0.3V or less turns it on. I am guessing this refers to the potential difference between the positive and negative wires? This is what I am not sure on. I may try to call Mark Basch and ask there.

UPDATE:

I found this link on the NSXPrime website; it deals with the NSX, which has a different ABS setup (or so it seems):

http://www.danoland.com/nsxgar...s.htm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">I will check the helms when I get home, but this does not sound like it will trigger the system.</TD></TR></TABLE>

LOL!
Does the Helms also admonish you about lift throttle oversteer?

Frankly, I'm not absolutely sure it would work.
Might have to get all wheels spinning (rotating) at the same time.

However, the reason I did make that suggestion is because in the early days of ABS I've heard that a few mechanics working on Mercedes braking systems have had injuries wherein someone moved a wheel with the ignition on whilst working on a brake caliper and this then made the caliper move causing the poor bloke damage to his fingre(s).

Just trying to help. Ed

P.S. nice writeup on that NSX.


Modified by zygspeed at 4:52 PM 6/17/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zygspeed &raquo;</TD></TR><TR><TD CLASS="quote">LOL!
Does the Helms also admonish you about lift throttle oversteer?
</TD></TR></TABLE>

Huh? What does a service manual have to do with driving technique?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">Huh? What does a service manual have to do with driving technique?</TD></TR></TABLE>

Alright, back on topic. Good suggestion nonetheless Ed. I would try it but my friend has my jack and jack stands.

 

In case anyone was interested, I did the method I had described above using the tutorial I posted earlier in this thread. The tutorial was for an older NSX ABS system (which differs from ours somewhat) but with help over the phone from Mark Basch I was able to get it to work.

All you have to do is pull the relay for the ABS and take a switch (simple SPST will do great) and plug one end in to one of the copper sockets where the relay used to be, and the other end in to the remaining copper socket. You then disconnect the connect for the ABS modulator unit. You connect one wire to ground on the battery and connect it to the common ground of the ABS modulator unit (where the connector used to be plugged in; see Helms ABS section for exact pin location and description). You then run a wire with another SPST switch from the positive battery terminal to one of the other eight smaller pins ; each of which corresponds to one solenoid of each solenoid pair for each wheel (the ABS modulator contains four pairs of solenoids; two for each wheel; one is "in" and one is "out").

As described by Mark the prodecure is to then run the ABS pump for about 15 seconds using the SPST switch you wired up earlier; you should shut it off once you hear the pump straining which means the modulator has pressurized (note that I could not hear any strain, maybe due to a faulty ABS where my solenoids aren't closing properly??). You then open and close the solenoid you wired to the battery earlier using the second SPST switch. According to Mark you should ehar fluid rushing through the solenoid (I did not, again maybe due to a faulty ABS, need to confer with Mark first).

Just wanted to get this up here in case anyone ever needed to know the procedure again; if there is any interest I can post a formal "How To" with pictures. All in all easy procedure; and I recommend over just trying to trigger the ABS using a dirt road, etc.

Did this fix my brakes? They feel somewhat better, but still have their mushy moments; I am wondering if I have a fault ABS, but need to touch base with Mark Basch and see what he thinks. If I can get some time off of work I may go to his shop and have him show me the procedure personally.

 

Very Good information

And yes I think this would be a great writeup to include pics for any people in the future with these issues, IE Yoshi? Etc, etc... Because the more we talk about it, seems the more people have similar issues.

According to Mark this method is the more effective or 100% method for cycling the ABS solonoids, so I'm guessing that if it didn't do the trick then yes, you may have an ABS/solonoid/valve issue and hopefully you'll have it fixed soon.

I really feel for you and understand where you are, and appreciate the time you take to post your results and whatnot because before we started talking about this, noone understood or knew what the heck was going on and all we got was
"keep bleeding" or "change the MC" which was clearly not the case or solution for either of us and possibly others.

Best of luck, keep us posted and let us know what Mark says.