DavidAlphin Posted September 18, 2014 Share Posted September 18, 2014 Last year I posted a topic talking about a rebuild I'm doing of my 1996 LGT. I've finally gotten money sorted out to at least start the project. First thing that is getting fixed, is the brakes. New pads, swapping good rotors off of another legacy, doing the master cylinder, and replacing the booster. As the 96 LGT has discs on all 4 corners and I plan on replacing the calipers to bigger ones…should I go with a single or dual diaphragm booster? I've read up on them and it seems to be that dual's are better for 4 disc setups... Link to comment Share on other sites More sharing options...
johnegg Posted September 18, 2014 Share Posted September 18, 2014 doing the master cylinder, and replacing the booster. you sure are energetic. in the 9 years i have been reparing, reading online about repairing, and posting about repairing, i can only remember 2 - 3 times a when a master cylinder was bad, and never remember a booster cylinder being bad. but you suit your self. as for calipers, my 97 GT and 98 outback have the same front calipers. the only ones that may be bigger would be WRX. but i don't see the need. rebuild or replace the ones you have, this will improve your stopping. or just clean and re-lube the slide pins. Link to comment Share on other sites More sharing options...
spooln30 Posted September 19, 2014 Share Posted September 19, 2014 Yeah in 16 years fixing cars for a living I've never replaced a brake booster on a Subaru. Don't think I ever did a master either. When a booster goes bad you should be able to hear it leak when the brakes are being applied and you'll have a super hard pedal. Masters as long as the fluid is changed when it's dirty they usually last a long time on Japanese vehicles. Link to comment Share on other sites More sharing options...
DavidAlphin Posted September 19, 2014 Author Share Posted September 19, 2014 Well, here's the situation… The pads aren't bad, the rotors are still in good shape, plenty of fluid in the system, no air in the lines… Casually stopping for a red light, traffic, or a stop sign…the pedal is almost on the floor for it to really start grabbing… Any thoughts on what might be causing that... Link to comment Share on other sites More sharing options...
johnegg Posted September 20, 2014 Share Posted September 20, 2014 air in the system, bleed the brakes, fronts first then the rears. did you replace a caliper or brake line recently? Link to comment Share on other sites More sharing options...
Osei Posted September 21, 2014 Share Posted September 21, 2014 Also possible frozen caliper. Look at your rotors. If they are not completely shiny in the pad area, that(those are)is the culprit(s). O. Link to comment Share on other sites More sharing options...
DavidAlphin Posted September 23, 2014 Author Share Posted September 23, 2014 air in the system, bleed the brakes, fronts first then the rears. did you replace a caliper or brake line recently? Negative. Nothing has been changed... I'll bleed the brakes in a weekend or two to see if that helps out as well as change the rotors and pads and see if that helps...I'll update accordingly. Link to comment Share on other sites More sharing options...
johnegg Posted September 23, 2014 Share Posted September 23, 2014 air compresses, liquids especially hydraulic fluid and brake fluid does not. so if you have a soft pedal it is air in the system. a few tests, pump the brakes, does the pedal firm up.? pump the brakes before you start the car, hol d, it and then start the car. what happens?? soft pedal, loose pedal, long travel pedal, mean trouble. are you loosing fluid.? pump the crap out of them and look for leaks. Link to comment Share on other sites More sharing options...
twisty Posted September 24, 2014 Share Posted September 24, 2014 old, worn out fluid compresses more than good fluid as well. so does water in the lines. not as much as air, but it does feel squishy. if the fluid is really dark, change that shit out and flush the system. Link to comment Share on other sites More sharing options...
DavidAlphin Posted September 24, 2014 Author Share Posted September 24, 2014 air compresses, liquids especially hydraulic fluid and brake fluid does not. so if you have a soft pedal it is air in the system. a few tests, pump the brakes, does the pedal firm up.? pump the brakes before you start the car, hol d, it and then start the car. what happens?? soft pedal, loose pedal, long travel pedal, mean trouble. are you loosing fluid.? pump the crap out of them and look for leaks. I've done the basic brake tests. Pump the brakes 10 or so times with the car off, first thing in the morning. Pedal becomes extremely heavy. Pressed and held the pedal as far as it would go, cranked car...pedal sunk to the floor. With car running, I'll pump the pedal and it'll gradually become heavier as load is put on the vacuum and system...let system stabilize...goes back. There's really no peal feel from the top of the pedal, down to about 60-75% depressed...then it'll gain weight to about the 90% point...then suddenly grab hard when on the floor. I can feel the brakes engaging as I press the pedal, but I feel no real weight in the pedal until it's almost on the floor. To give you an idea, I can drive the pedal to the floor with almost no effort where as in my Accord, I'll actually have to put some effort in it until it hits for the floor. I'm beginning to believe it's air in the system, not the booster/master cylinder. old, worn out fluid compresses more than good fluid as well. so does water in the lines. not as much as air, but it does feel squishy. if the fluid is really dark, change that shit out and flush the system. I will snag a photo of the brake fluid when I leave work today. Link to comment Share on other sites More sharing options...
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