soft brake pedal

[NFGTragedy]

I was just curious what you guys think... When my car is off the pedal is rock hard but when the car is running its very soft. It stops the car near 1 inch to 1/2 from the floor. I have the stock fox booster/MC but I have a 5 lug swap with the sn95 calipers. I have heard that the sn95 calipers are horrible at holding air so I'm hoping its that but I also caught word that it might be my MC. The car had the brake lines unhooked for the 5 lug swap and I replaced the soft lines with braided lines. Thats why I think its just air... but also my booster/MC came from a parts car I had that sat around for a little over a year before it went in my car. Could the MC have gone bad then?

Should I try a bleed first or does this sound like a MC from the start?

 

[85ragtop]

I would give bleeding a try. Sounds like air in the lines.

 

[stangjunkie]

+1 sounds alot like air in the lines... had this problem on my old mans kit car which was lincoln disk brakes up front and turbo coupe rears (obviously to make it 5lug and 4 wheel disk)

 

[Mustang5L5]

If it gets hard as a rock with the engine off its not really air in the lines. If the pedal were still spongy then, then i would agree that it was air though.

However, if you arer running SN95 brakes with SN95 disks out back, then your problem is an incorrect MC. You really should be running a 4-wheel disk MC, like the '93 Cobra, or 94-95 GT/V6 or 94-95 Cobra...and Sn95/93 cobra booster. You should really have an adjustable prop valve at this point as well

If you have just the SN95 fronts and rear drums, then i would lean more to a booster/MC problem.

But easiest thing to do first is bleed and rebleed. Sn95 REAR calipers are the ones notorious for trapping air. The fronts usually bleed fine. For the rear you should remove the caliper, turn it with the bleeder up, put a block of wood in it and bleed like that.

 

[Roland69]

for the 5-10 minutes it takes 2 guys to bleed them do that to start. Remember to start at the wheel furthest from the MC

RR
LR
RF
LF

 

[Roland69]

and as soon as you crack a bleeder screw or unhook a line you must bleed the brakes.....