Soft brake pedal fixed - Nicole, may be of help to you
10-15-2009, 01:54 PM
#48
Cottage Industry Sponsor
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Hi Jon:
There were some concerns about how the previous work might have affected the bias valve:
Was the system drained enough to allow corrosion in the old valve?
Did bleeding in the rear first cause the valve to "stick"? Remember initially only the rear brakes were working...
So, it seemed like a good idea to replace that valve before doing any further work. The part isn't really all that expensive (about $90).
We can't say, if the valve or the vacuum bleeding is responsible for the improvement we are seeing now. He replaced that valve before doing any bleeding whatsoever, but reported that during the first bleed there were quite a few bubbles coming out of the master cylinder. Remember: We had bled the master many times.
Let's wait and see what happens in the next few days, where the car will be driven about 1000 miles.
There were some concerns about how the previous work might have affected the bias valve:
Was the system drained enough to allow corrosion in the old valve?
Did bleeding in the rear first cause the valve to "stick"? Remember initially only the rear brakes were working...
So, it seemed like a good idea to replace that valve before doing any further work. The part isn't really all that expensive (about $90).
We can't say, if the valve or the vacuum bleeding is responsible for the improvement we are seeing now. He replaced that valve before doing any bleeding whatsoever, but reported that during the first bleed there were quite a few bubbles coming out of the master cylinder. Remember: We had bled the master many times.
Let's wait and see what happens in the next few days, where the car will be driven about 1000 miles.
10-15-2009, 02:48 PM
#49
Under the Lift
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Nicole:
That's great. I do recall when the rear brakes only were working, and working hard (bluing the rotors from heat). We did get a lot of air out of the system and then the fronts started working too, but I recall we got a most of air out of the rear calipers, which I thought was odd.
Marvin seems real good (I got to meet him with Nicole) and I will add his shop, RennShop, to our local resource list.
That's great. I do recall when the rear brakes only were working, and working hard (bluing the rotors from heat). We did get a lot of air out of the system and then the fronts started working too, but I recall we got a most of air out of the rear calipers, which I thought was odd.
Marvin seems real good (I got to meet him with Nicole) and I will add his shop, RennShop, to our local resource list.
10-15-2009, 02:48 PM
#50
Under the Lift
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Nicole:
That's great. I do recall when the rear brakes only were working, and workiong hard (bluing the rotors from heat). We did get a lot of air out of the system and then the fronts started working too, but I recall we got a most of air out of the rear calipers, which I thought was odd.
Marvin seems real good (I got to meet him with Nicole) and I will add his shop, RennShop, to our local resource list.
That's great. I do recall when the rear brakes only were working, and workiong hard (bluing the rotors from heat). We did get a lot of air out of the system and then the fronts started working too, but I recall we got a most of air out of the rear calipers, which I thought was odd.
Marvin seems real good (I got to meet him with Nicole) and I will add his shop, RennShop, to our local resource list.
10-15-2009, 02:52 PM
#51
Rennlist Member
Great news, Nicole! Now you don't have to drive waSAABi to SFest or hitch a ride!
Another data point: having just installed the exact same calipers that Nicole has on my 78 with its much simpler brake plumbing, calipers completely disassembled(but not split) for powdercoating and rebuilt with all-new seals, I had no issues getting the system bled and the pedal rock-hard. I mention this as it confirms what most of us thought, that starting with dry calipers should not present any particular challenge in and of itself.
Another data point: having just installed the exact same calipers that Nicole has on my 78 with its much simpler brake plumbing, calipers completely disassembled(but not split) for powdercoating and rebuilt with all-new seals, I had no issues getting the system bled and the pedal rock-hard. I mention this as it confirms what most of us thought, that starting with dry calipers should not present any particular challenge in and of itself.
10-15-2009, 03:12 PM
#52
Cottage Industry Sponsor
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Yes, Marvin from the RennShop in Santa Clara is awesome! Very methodical in his approach to repairs, and ZERO BS.
His shop is neat and clean, and he seems to enjoy the challenges of working on our 928s - which is rare among Porsche mechanics these days.
His shop is neat and clean, and he seems to enjoy the challenges of working on our 928s - which is rare among Porsche mechanics these days.
10-15-2009, 03:19 PM
#53
Fleet of Foot
Rennlist Member
Rennlist Member
Very happy for you Nicole, the nightmare is finally over. Enjoy driving your car again. Amy & I look forward to seeing you and your car at SF09.
