[V8] My brakes, what am I doing wrong??

[Dave Saad]

How much fluid are you getting from each caliper?
The general procedure is to bleed the master cylinder, then find the  
wheel that is farthest from the master cylinder (RR?) and do it first,  
then the next farthest,...and so on.
Make sure you take out enough fluid to fill the entire line from wheel  
to master cylinder, and start over again if you accidently let the  
reservoir go empty - thereby allowing another air bubble in the  
system.  You should be getting clean fluid from the wheel cylinders.
Using a pressure bleeder and a helper to SLOWLY pump the pedal is  
probably the best way. Do not let the pedal come UP too fast, or you  
risk sucking air past the seals.

Bleeding the antilock system may take another procedure - so if you  
got air in there, you probably should find any special procedure for  
that.  It is likely to take special equipment to activate the pump and  
valves.

For the light, the circuit is a light bulb and a few switches wired in  
parallel.  You will need the schematic (unless someone knows where the  
switches all are - I do not).  Generally, the switches make a ground  
connection - so unplugging all of them should turn off the light.  
Consult the schematic to be sure, but I am reasonably sure this is how  
this car works.  WHen you unplug the offending switch, the light will  
go out.  When that happens, you have found your problem.  Now figure  
out why the switch is activated.  It is either broken, or it is  
telling you something is wrong with whatever part of the system it  
monitors.
I am only guessing here, but check:
-> master cylinder oil level switch
-> hydraulic oil level switch
-> differential pressure switch (I think this is down near the drivers  
side of the steering gear)
-> parking brake switch


Dave


On Mar 31, 2010, at 2:30 PM, Ingo Rautenberg wrote:

> Seamus,
>
> My guess (and it's only a guess) is that your rear proportioning  
> valve (in
> front of driver's side rear tire) is sticking, thereby not allowing  
> the
> fluid to be properly bled. I suggest some lubricant on the  
> mechanism.  Also,
> 12 psi should be ok in my experience.
>
> Good luck.
>
> Ingo
>
> On Wed, Mar 31, 2010 at 4:10 PM, Seamus O'Carey
> <cheshirecatsbox at gmail.com>wrote:
>
>> I finally finished replacing the brake servo and rear calipers on the
>> silver
>> car, so yesterday I was able to bleed the brakes (swapping in SS  
>> lines as I
>> went), but I must be doing something wrong.  My boss has a pressure  
>> bleeder
>> for his Porsche, so I borrowed it to assist with the bleeding, but  
>> I could
>> hardly get anything to come out of the calipers.  I followed the  
>> sequence
>> described in the manual, keeping the gauge around 10psi, but very  
>> little
>> fluid would come out of the calipers.  When I got back to the right  
>> rear
>> brake no fluid came out at all.  I had to have my roommate help me  
>> do it
>> the
>> old fashioned way (pump the pedal a bunch then hold it while I open  
>> the
>> valve and close it again), but I was under the impression that the  
>> pressure
>> bleeder made that not necessary.  I drove the car around the block  
>> and it
>> stops much better than it ever did before, but the pedal is still  
>> VERY
>> squishy and the BRAKE light is still on.
>>
>> I'm getting pretty frustrated.  The car's been sitting for well  
>> over 6
>> months and even when the brakes are done I still need to do the  
>> shocks and
>> cv boots, before it will really be safe to drive.
>>
>> Seamus
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