North American Turbocoupe Organization



brake booster or not???
turbogirl Offline
Junior Member
#1
okay i have a question to ask.first havin trouble with brakes,no brake lines are leaking already checked.tooh it to a trusted mechanic and they said that the master cyinder wasleaking into the brake booster.i have 4 wheel disk brakes with abs.what do yal think i should replace master cylinder or booster or both???the car was using a thing of brake fluid a day.



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friends dont let friends drive imports
87 turbocoupe
friends dont let friends drive imports
87 turbocoupe
the tbird version of christine!!
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Jeff K Offline
Administrator
#2
You mean it empties the plastic tank in a day? Holy crap! You have a BIG problem!

A MC can leak internally, but where it leaks into is going to fill up pretty quick at the rate you are using fluid. Are you SURE it isnt leaking from somewhere else? Did you park it on some clean pavement, and apply the brakes pretty hard and hold them down for a minute, and then look under the car? Sometimes very small leaks in rusted lines will only shoot out fluid under high pressure, and not just drip drip all the time.

How does the pedal feel? Does it sink when you hold the brakes on?

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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turbogirl Offline
Junior Member
#3
yes we have checked everything there is no marks or leaks left when my car is sat on clean pavement.and yes when u sit at a stoplight u slowly lose the pedal the car starts rolling bac without me even realizing it.i about rolled into another car one night.and it sinks to the floor.the pedal is mushy and soft.its like theres nothing behind it its just uh i dont know thats the only way to decribe it.mushy yep mushy

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friends dont let friends drive imports
87 turbocoupe
friends dont let friends drive imports
87 turbocoupe
the tbird version of christine!!
Reply

TurboE Offline
Posting Freak
#4
Park your car somewhere at home or whatever and with the key not started but in the ON position pump your brakes and hold it to the floor and keep doing this eventually the brake pump will come on (you should here a buzzing motor noise). Keep doing this eventually from what you describe i has to be leaking somewhere check all lines small fittings and maybe bleaders on the calipers or the calipers them selves pull the wheels off. If its bad enough to roll on you at a stop light you should be able to find this problem. I have a complete assembly of the brake booster/reservor/master cylinder, with a fairly unused brake switch (the one that bolts on and is green) that cost $120. I dont know what this is worth i remember ford telling me a new pump is like $800 or something. Let me know what you or anyone else think its worth. Good luck.
-88 TC Black
5spd, Precision SC50 T3/T4, QH/SD Tune, Gillis, AFPR, 255FP, WB O2, K&N, Ported E6, 3" DP, ATR 2.5" Duals, 3:73 Rear, Konis, Eibachs, 18" Voxx Wheels, X Drilled Rotors.
-06 G35 Coupe Diamond Graphite
-97 Pathfinder
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Dick Murphy Offline
Member
#5
If the pedal is going down at stoplights and you don't see external leaks, the problem is most likely an internal leak in the master cylinder. I haven't replaced one on an '87-88, but on the earlier TC's, it's a $20 or less part if you get a rebuilt component. Bleed the brakes properly after installation. Again, my '88 has had no brake problems, I'm reflecting the experience from my '86 Cougar. However, after 40 years of car maintenance, if it goes down at a stoplight, check the master cylinder.



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88 TC
86 XR7
91 Mustang LX with 85 XR7 motor
77 Lotus Esprit
87 Mercedes 190
66 Mustang
I wonder why my wife thinks I have too many cars??
88 TC
91 Mustang LX with 85 XR7 motor
77 Lotus Esprit
87 Mercedes 190
91 Mercedes SL 300
66 Mustang
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