1991 Crown Vic parking brake

Discussion in 'General Automotive Tech' started by FalconFuturaWagon, Jul 30, 2020 at 8:11 PM.

  1. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    I've got a 1991 Crown Vic. The parking will only engage about half the time. When it engages, you can feel the ratchet when you depress the pedal. When the brake will not engage, their is not ratchet feel and the pedal will not stay down.

    Anybody have any leads of what to look for as I try to solve the problem.
     
  2. KevinVarnes

    KevinVarnes Well-Known Member

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    These used an automatic parking brake release that would release the parking brake once you shifted from park to reverse or drive. Try engaging it while in park and then shift into drive and see if it works properly. Could be something with that system causing the issue. The actuator itself is a little white half moon shaped piece that is mounted on the steering column close to the firewall. They are prone to leaking (vacuum), but when they do they tend to not release the brake at all.
     
  3. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    Kevin

    Thanks for the info. The parking brake will release correctly when I can get it to engage. It releases automatically when you shift from park into a forward gear. You have to release the brake manually when you shift into reverse. That follows the description in the owner's manual.

    I'm trying to track down why the EB won't engage every time. I know I have to hold the brake pedal down before engaging the EB...found that in the manual.
     
  4. KevinVarnes

    KevinVarnes Well-Known Member

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    I guess I was wondering if the automatic release wasn't somehow malfunctioning and trying to release the parking brake even when it is not supposed to. That could keep the brake from engaging. You could try disconnecting the vacuum to the actuator and plugging the vacuum hose and seeing if that does anything for you.
     
  5. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    Interesting thought. I looked for the actuator a little while ago but didn't see it. I'll try again tomorrow and try your suggestion.
     
  6. KevinVarnes

    KevinVarnes Well-Known Member

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    Shows what I know. It has been a while since I've been in to these cars. I just looked at my '91. I couldn't see the crescent moon shaped actuator on mine. Must be up on top of the column close to the shifter. I did see a silver vacuum actuator mounted to the side of the parking brake mechanism. There should be a vacuum line coming out of the firewall side of the actuator and a rod coming out of the other side that actually releases the parking brake. You should be able to visually check that to see if that rod is always fully releasing and disengaging from the parking brake and allowing the parking brake to catch without taking anything apart.
     
  7. OldFox

    OldFox Curmudgeon

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    Discounting nothing, consider the following scenario:

    Brake shoes wear and get adjusted. EBrake goes clear to the floor and gets adjusted. Brake shoes finally get changed. EBrake is now too tight and won't go down far enough to engage the pawl. Solution---loosen the EBrake adjustment.​
     
  8. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    The emergency brake works IF...you depress the EB pedal really quickly! If you push it down with a normal motion, it will not engage. It worked 8-10 times in a row just now. With all the plastic cladding under the dash, it is almost impossible to see what is going on without dismantling stuff. I can sure see a difference between the 91 Crown Vic and the 65 Falcon...much more room under the dash to work on things in the Crown Vic but, once you wiggle yourself into position in the Falcon you can see that you are working on!

    OldFox...the car only has 42,000 miles on it. I don't believe there has been any brakes shoes/pads replaced.

    Thanks for sharing you thoughts and ideas.
     
  9. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    Not the 'same' vehicle, but the same basic design. My '96 F-150 has a bent manual release, and if it doesn't return forward, the pawl will not engage the sector gear, so I have to manually push it back before it works. So, first, are you testing the p-brake pedal when the engine is running or not? Does the pedal not engage in either instance, or just when the car is on or off? It's almost like the vacuum control on the column is misadjusted or broken, and if the engine's running, it could be pulling the release lever. I also have the Ranchero in my avatar still, and it does have vacuum release, but the vacuum switch is messed up and so when I start the car, if the p-brake is set, it instantly releases. I have to remember to shut off the engine before setting it, and have my foot on the brake pedal before I start the engine.
     
    Last edited: Aug 1, 2020 at 1:43 PM
  10. KevinVarnes

    KevinVarnes Well-Known Member

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    I would still take a look at the actuator on the side of the parking brake mechanism. You can see what is going on mechanically without taking anything apart (at least you can on my car).
     
  11. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    Took the car out this morning and the brake would not set with the engine running. Got it home...nothing with the engine running or off. I took the padded panel (bolster?) under the steering wheel off and could not see anything that helped me. I'm going to have to get a shop manual and a 1991 Ford Illustrated Parts Manual soon to help track things down. Put everything back together.

    Just went out to check your questions and the brake is now setting with the engine running or off.

    I'm not sure the car is really a 1991...seems more like a 2020!
     
  12. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    Keven

    While I had the panel off under the steering wheel, I saw a white box about 1" square and 2 inches long. There is a tiny plastic tube connected to a small box on the side of the white box. I've got a bad picture of it. Is that the actuator? Sorry for my ignorance about the CV. It's going to take me a while to get up to speed on this "modern" car...much different than my 65 Falcon.
     

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  13. KevinVarnes

    KevinVarnes Well-Known Member

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    I'm talking about on the parking brake mechanism itself. In the attached picture my finger is pointing to the rod on the actuator that actually releases the parking brake. I would make sure that thing is fully extended (it will retract to release the brake) and/or see if it is doing anything. On the other end of the silver actuator canister is the vacuum hose connection.
     

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  14. FalconFuturaWagon

    FalconFuturaWagon FordFan

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    Thanks for the picture. I pulled the kick panel off (gotta to get used to the cars with the clip/snap on parts) and cannot find anything like the canister you showed Kevin. If your picture is from your 85 LTD, Ford must have made some changes by 91. The brake is now in the works every time mode...it worked 12 times with the kick panel back on and the engine off and 2 with the engine running.

    At this point, the parking brake is in my morning prayer request!
     
  15. KevinVarnes

    KevinVarnes Well-Known Member

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    That picture is from my '91 Crown Vic (not listed in my sig). Aside from it being a sedan and having a 351 it should be identical to your wagon. I didn't have to remove anything to get that picture. It is visible under the dash right by the parking brake mechanism. My '85 LTD is a fox body and is a completely different car. I don't think it has the automatic parking brake release.
     

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