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Thread: Braking - pulls to LEFT...

  1. #1

    Braking - pulls to LEFT...

    Car is a fully restored 72 T 'hot rod', never wrecked or rusted car, and all of the suspension and brake components are new (using late Carrera calipers front and rear). Stock 72 master cylinder. Noticeable pull to the left when the brakes are applied - at speed or even at a few or less miles an hour coasting to a stop...steering wheel will quickly turn left. Issue has been present since its day one drive to present with 800 miles. Same symptom too from its initial 'garage floor' alignment to a properly done alignment rack alignment by a very experienced early 911 tech, so I'm confident it is not an alignment issue. Brake pedal has always been high and firm...not a hint of air in the system, so I have not yet re-done a brake bleed. I'm suspecting a front caliper issue...not sure if the LEFT is over-achieving, or the RIGHT is under-achieving? Any good way to tell? Other thoughts most welcome. Thanks.
    Last edited by mac73s; 06-04-2020 at 07:24 AM.

  2. #2
    Serial old car rescuer Arne's Avatar
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    Almost always the side opposite the pull not working a full capacity. Look for one or more stuck pistons, or a blocked fluid line.
    - Arne
    Current - 2018 718 Cayman, Rhodium Silver, PDK

    Sold - 1972 911T coupe, Silver Metallic; 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  3. #3
    Quote Originally Posted by Arne View Post
    Almost always the side opposite the pull not working a full capacity. Look for one or more stuck pistons, or a blocked fluid line.
    Thank you for the prompt and helpful reply. All brake lines are new as well, and all calipers seemed to bleed well (and the same), so I'm not thinking a blocked fluid line (unless you mean internal to the caliper?). If I remove (or at least undo) the RIGHT caliper and pull the brake pads out, I assume a light application of the brake pedal should show outward piston movement, and then be able to be compressed back...make sense, or a better way to check? Thanks again.

  4. #4
    member #1515
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    do not pull the pads out without inserting a spacer, maybe an old set of pads. the pistons might pop out.
    New hoses too?
    David

    '73 S Targa #0830 2.7 MFI rebuilt to RS specs

  5. #5
    Serial old car rescuer Arne's Avatar
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    Quote Originally Posted by mac73s View Post
    Thank you for the prompt and helpful reply. All brake lines are new as well, and all calipers seemed to bleed well (and the same), so I'm not thinking a blocked fluid line (unless you mean internal to the caliper?). If I remove (or at least undo) the RIGHT caliper and pull the brake pads out, I assume a light application of the brake pedal should show outward piston movement, and then be able to be compressed back...make sense, or a better way to check? Thanks again.
    As David notes, pull the caliper off, but leave the pads in place. Insert a shim a bit thinner than the rotor. Late Carrera rotors are 24mm thick, so a piece of ½" to ¾" plywood would be good. With the shim and pads in place, apply the brakes gently to see if both pistons move.
    - Arne
    Current - 2018 718 Cayman, Rhodium Silver, PDK

    Sold - 1972 911T coupe, Silver Metallic; 1984 911 Carrera coupe, Chiffon white; 1973 914 2.0, Saturn Yellow; 1984 944, Silver Metallic

  6. #6
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    Inspect or replace the flex line on the front brake caliper opposite the direction it pulls. I once had one that was faulty from the start. Same exact symptoms, drove me crazy trying to solve. If the hose end is not installed properly the inner liner can be cut, pushed into the fluid path and act like a one way check valve. Some fabricators run a ball bearing of the correct size through the hose after it's made as a check.


    Quote Originally Posted by mac73s View Post
    Thank you for the prompt and helpful reply. All brake lines are new as well, and all calipers seemed to bleed well (and the same), so I'm not thinking a blocked fluid line (unless you mean internal to the caliper?). If I remove (or at least undo) the RIGHT caliper and pull the brake pads out, I assume a light application of the brake pedal should show outward piston movement, and then be able to be compressed back...make sense, or a better way to check? Thanks again.
    1970 911E Coupe

  7. #7
    Quote Originally Posted by R3350 View Post
    Inspect or replace the flex line on the front brake caliper opposite the direction it pulls. I once had one that was faulty from the start. Same exact symptoms, drove me crazy trying to solve. If the hose end is not installed properly the inner liner can be cut, pushed into the fluid path and act like a one way check valve. Some fabricators run a ball bearing of the correct size through the hose after it's made as a check.
    Thank you to all who have continued to offer thoughts and directions. R3350 - can you explain further what you mean about the flex line 'hose end possibly not installed properly'...THANK YOU

  8. #8
    Incorrect corner weights will also do that.
    Early S Registry member #90
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    Fort Worth Tx.

  9. #9
    Thread Killer dummkopf's Avatar
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    Right caliper piston(s) stuck.
    72 911S Targa #0807 95+% German.

    Paul Harrop 12.5% German.

    Early S #2059

  10. #10
    Junior Member
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    Quote Originally Posted by mac73s View Post
    Thank you to all who have continued to offer thoughts and directions. R3350 - can you explain further what you mean about the flex line 'hose end possibly not installed properly'...THANK YOU
    Hose manufacturing defect requiring replacement of the flex hose.
    1970 911E Coupe

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