Low pedal.

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spinman_1949

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Ok I am going to start with this issue.

Just drove the 1969 GTS from Orange to San Diego. Got here in one piece. A good portion of the trip was heavy traffic so on and off the brakes. As to brakes. Stocl Disc/drum no pwr.

Later in the trip I had a long run of high speed needing no brakes. So when I went to the brakes the pedal went halfway to floor. Talk about Holy Sh..... So I pump the pedal and the brakes come back up. But as the trip continues the problem happens more and more with shorter periods of no braking in between. When I got home I pulled the reservoir cover and the good news is there is plenty of fluid. Kind of dark actually. Not a good sign. So let me guess.

Likely master cylinder I am thinking. Could use some expert opinon though.
 
Sounds like the master cylinder...if not maybe a rusted line
 
340wedge said:
Sounds like the master cylinder...if not maybe a rusted line
Click to expand...

I remember people mentioning rusted line, but the symptom in that case was the brakes not releasing as I recall. I suspect it is the master. I think the easy way to check is to just push on the pedal and see if the pedal goes down over time.

Thx for responding.
 
If the brakes were new it might have just seated them and now they need to be readjusted.
Could be that simple.
 
Take a good hard look at the calipers & slides(if equipped). Check for binding especially when hot. Make sure the pistons are not retracting into the bore when the pedal is released. Check the hoses too while your there. Master cylinder will usuall cause the pedal to sink while you are at a stop with your foot on the brakes.
 
Lonewolf3165 said:
Take a good hard look at the calipers & slides(if equipped). Check for binding especially when hot. Make sure the pistons are not retracting into the bore when the pedal is released. Check the hoses too while your there. Master cylinder will usuall cause the pedal to sink while you are at a stop with your foot on the brakes.
Click to expand...

I think I am noticing some pedal movement at a stop, It is hard to tell of course. I do not think the master is totally shot. Just bleed past the seals. I will check the other issues as well. What would cause the pistons to retract? The problem did get worse the longer I drove the car, but I would think that a long run not using the brakes would cool them. I also thought warped rotors could force the pistons back, but I feel no pulse in the pedal.
 
Brakes are not new. Plus it happened over and over with more frequency.
 
Master Cylinder for sure. Held pedal down and in about a minute it was all the way to the floor. No leaks that I can find. Pump it a few times and it is hard and at the top.

Told by some members to go to the newer aluminum unit with the plate adapter. Found on Ebay, but also found this. Anyone seen these? The descrption indicates they will be needed if I use the later MC.

http://www.ebay.com/itm/32093839221...em=&sspagename=ADME:X:AAQ:MOTORS:1123&vxp=mtr
 
Master cylinder is the most likely problem.
My Duster started doing the same thing a couple of days ago.
It has new rear wheel cylinders, brakes and drums.
It also has new turned rotors, brakes and calipers.
The only thing left is the master cylinder.
 
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