94 STS - Complete loss of brakes
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Cadillac Seville / Cadillac Eldorado Forum Discussion, 94 STS - Complete loss of brakes in Past Cadillac Vehicle Discussion; Late the other night I was coming home from the airport and my brakes COMPLETELY and INSTANTLY failed. Just before ...
  1. #1
    CaddyInParadise is offline Cadillac Owners Member
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    94 STS - Complete loss of brakes

    Late the other night I was coming home from the airport and my brakes COMPLETELY and INSTANTLY failed. Just before that I got off the highway and down the ramp, the car stopped normally and straight. Pedal height was good and felt fine, no dash lights or DIC messages. At the next red light less than a mile later, I hit the pedal and it sank right to the floor. I nearly stood up on it trying to stop and ended up in the middle of the intersection. Thankfully it was nearly midnight and I was the only car on the road and was only going about 35. I only had a block to go, so I very slowly made it home using the emergency brake and using my left hand to hold the manual release lever so I could modulate it.

    The next morning I checked out the car expecting to find something crazy like a master cylinder separated from the booster or a completely empty reservoir. What I did find was more common - a rusted section of brake line just in front of the left rear wheel.

    I fixed the line, bled the system all around and it is working fine once again. The fluid level in the reservoir was low, but not even low enough to set off the low fluid warning.

    I have had other Cadillacs suddenly blow rubber brake hoses, rear wheel cylinders explode, calipers fail, etc and every time one of these failures occurred, I still had partial brakes due to the system being split diagonally over the wheels. In this condition the car should be good for a couple stops until the brake fluid is completely pumped out and it sucks up some air, right?

    So my question with all this rambling mess is why did this seemingly common failure take out my brakes on all four wheels so suddenly with no warning? Why didn't the front left and rear right brakes attempt to grab at all, even just the once? Any insight would be appreciated as this scared the living daylights out of me.

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  3. #2
    amunderdog is offline Cadillac Owners Connoisseur
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    Re: 94 STS - Complete loss of brakes

    Hope someone has a clue.
    Our parts mobile did that. 1994 Seville I took some brake parts off right rear.
    Figured it's a parts car no use trying to put it all back together, So I just stuck the caliper back on no pads.
    went to move it to it's resting place and like yourself; right to the floor and nearly drove off into the pond.

  4. #3
    arctic_man's Avatar
    arctic_man is offline Cadillac Owners Fanatic
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    Re: 94 STS - Complete loss of brakes

    I believe the reason is there is no brake pressure anymore. Your pressurized system is now unpressurized due to the leak. Without pressure the fluid doesn't compress, and doesn't push in the brakes.

    I had the same problem with my Seville last summer. Rear line blew and caused all my brakes to stop working. Had a mechanic replace the line and bleed the system and I was good to go.

  5. #4
    oldstuff is offline Cadillac Owners Fanatic
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    Re: 94 STS - Complete loss of brakes

    The master cyl on all cars since the 60's when they changed over to the dual system have a balanced application of brakes. Dual system refers to the system having two seperate but balanced systems, each applying brakes to two wheels, When one of the dual chambers loses fluid the other drops the petal to about an inch from the floor and applys the brake on the other two wheels as a safety. If your brakes didn't have any stopping power when one side lost fluid you only had one side working and it quit. Better look into replacing your master cyl. as half of it isn't working.
    Dave

  6. #5
    johnny kannapo's Avatar
    johnny kannapo is offline Cadillac Owners Connoisseur
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    Re: 94 STS - Complete loss of brakes

    The master is a duel spool valve and won't completely fail at the rear. Front drive cars nowadays have a duel main fluid circuit and operate diagonally (1 front & 1 opposing rear on these cars normally. If the traction mode in play it changes the rules and I know OBD 2 cars with RSS or CVRSS operate all 4 wheels separate according to sensed wheel traction, steering input, & sensed yaw, acceleration, speed, switching from the normal duel/diagonal fluid circuits to 4 wheels working independant off the BDVM. I don't know what years the systems got this complex. OBD 2 was implemented in 96.

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    oldstuff is offline Cadillac Owners Fanatic
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    Re: 94 STS - Complete loss of brakes

    The dual system was mandated by law for safety purposes so I doubt they would completely abandon the concept. No matter how complex they have become there would have to be residual braking when a line breaks, whether it is diagnal or front/rear and the portion of the master cyl not affected would apply that. The balancing action of the spool valve is what gives a lower predal but it takes hold before the floor unless the remaining brake action has also failed.
    Dave


    Quote Originally Posted by johnny kannapo View Post
    The master is a duel spool valve and won't completely fail at the rear. Front drive cars nowadays have a duel main fluid circuit and operate diagonally (1 front & 1 opposing rear on these cars normally. If the traction mode in play it changes the rules and I know OBD 2 cars with RSS or CVRSS operate all 4 wheels separate according to sensed wheel traction, steering input, & sensed yaw, acceleration, speed, switching from the normal duel/diagonal fluid circuits to 4 wheels working independant off the BDVM. I don't know what years the systems got this complex. OBD 2 was implemented in 96.

  8. #7
    oldstuff is offline Cadillac Owners Fanatic
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    Re: 94 STS - Complete loss of brakes

    " I only had a block to go, so I very slowly made it home using the emergency brake and using my left hand to hold the manual release lever so I could modulate it."
    That is Bull. The 90s Cadillacs didn't have a pull lever you could reach unless you had 4ft arms and eyeballs on the end of your fingers.
    You could drive home using the E brake by simply puting your foot on it because as soon as you put it in gear the brake would release and stay that way until you put it in park and then pushed it to set it.
    Dave

  9. #8
    CaddyInParadise is offline Cadillac Owners Member
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    Thread Starter
    Quote Originally Posted by oldstuff View Post
    " I only had a block to go, so I very slowly made it home using the emergency brake and using my left hand to hold the manual release lever so I could modulate it."
    That is Bull. The 90s Cadillacs didn't have a pull lever you could reach unless you had 4ft arms and eyeballs on the end of your fingers.
    You could drive home using the E brake by simply puting your foot on it because as soon as you put it in gear the brake would release and stay that way until you put it in park and then pushed it to set it.
    Dave
    You say that like the vacuum release actually works in these cars when they age. Out of my 5 Cadillacs, only one worked. The rest required finding the little release lever as on this Seville. Good thing us tall people come with proportionately long arms.

  10. #9
    oldstuff is offline Cadillac Owners Fanatic
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    Re: 94 STS - Complete loss of brakes

    If It doesn't work your heater probably doesn't work either.
    I can reach as far as anyone and can't find that lever without a lot of groping and still see out the windshield. I still say it's bull.
    Dave

  11. #10
    2kflhr's Avatar
    2kflhr is offline Cadillac Owners Enthusiast
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    Re: 94 STS - Complete loss of brakes

    Not sure about a '94 but on my '97 it's impossible, there is just a little tang you pull on to release the e-brake. You'd have to rope on it to manually release it whle driving.

  12. #11
    CaddyInParadise is offline Cadillac Owners Member
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    Thread Starter
    Quote Originally Posted by oldstuff View Post
    The master cyl on all cars since the 60's when they changed over to the dual system have a balanced application of brakes. Dual system refers to the system having two seperate but balanced systems, each applying brakes to two wheels, When one of the dual chambers loses fluid the other drops the petal to about an inch from the floor and applys the brake on the other two wheels as a safety. If your brakes didn't have any stopping power when one side lost fluid you only had one side working and it quit. Better look into replacing your master cyl. as half of it isn't working.
    Dave
    After bleeding the remaining wheels after the line replacement it possible that the other side didnt have as much stopping power as it could have. The fluid looked awful and there could have been moisture or air in them, soaking up that last bit of pressure needed for stopping. After replacing the line, I sucked all the remaining fluid out of the reservoir with a turkey baster and filled it with new. Bled the brakes until I saw fresh fluid in the clear hose, topping off the reservoir as I went. Let's hope I don't end up in a ditch anytime soon.

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