Rear Brake Caliper stuck this morning (AGAIN!)

Discussion in 'Boss 302 and S197 Technical Forum' started by Duane Black, Apr 29, 2019.

  1. Duane Black

    Duane Black TMO Advanced

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    Greetings citizens of TMO;

    I've had a saga with rear brakes that just won't quit. The left rear caliper appears to have gotten stuck this morning at work... pulled into my parking spot and was overwhelmed a bit by the alluring odor!

    So this started several months back. I swapped brakes to go to Roebling Road in January, and the brakes stuck to the point that it was dragging the car down BADLY. Like, you couldn't accelerate BAD. Then suddenly, they freed up after a mile. IT was also both brakes that particular occasion.

    Fast forward a couple of months. The LR sticks on the way home from work, and it hasn't been bothered in a few weeks. With two incidents in close succession, I replace calipers.

    Then I go through the bit where I had calipers not stop leaking. I replaced both rear calipers with new Motorcraft parts ordered through Tasca Ford just a few weeks back.

    I swapped my brakes over to street after my Charlotte adventures Sunday. I also had a crack in a left rear rotor (not uncommon honestly - need to upgrade to those bigger ones you guys tell me about) and I move on with life.

    I get to work this morning... the left rear brake was hot after getting to work, but the car never seemed to drag. It was hot enough that the cue was a smell when I got out of the car that overwhelmed again. I had the brake cylinder open when I pushed the piston back in. I did notice these new motorcraft cylinders seemed to be stiffer to turn back in than the parts store rebuild but I thought that could be better quality seals. They weren't overwhelmingly difficult, they were just more difficult than my parts store ones.

    I'm thinking this is connected to changing pads somehow or another. But... it's a game that is just getting old.

    I did not bleed the brakes - figured I'd wait until I change race brakes back in. The system was never opened beyond a master cylinder cap.
     
    Last edited: Apr 29, 2019
  2. TMSBOSS

    TMSBOSS TMO Addict

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    I have seen this from a slight misalignment of the piston with the pins on the back of the pads.
    Another item to check is the caliper brackets. Are they straight?
     
  3. Duane Black

    Duane Black TMO Advanced

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    What's a good way to check the caliper bracket to make sure it's straight? It's new with the calipers, I know that doesnt' always mean it's straight. It also didn't do this game until I changed pads - I'm thinking there is a connection.
     
  4. captdistraction

    captdistraction I am the breaker of things

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    The pins should be at the 12 and 6 o’clock positions.

    Do you have aftermarket brake lines?


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  5. Duane Black

    Duane Black TMO Advanced

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    I'll take it off and look at it. I've got those little "noise cancellers" that sit on the rails - don't like how they work on this particular caliper, might just take them back out.
     
  6. Duane Black

    Duane Black TMO Advanced

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    Oh, the hoses are the J&M Stainless Steel variety....
     
  7. captdistraction

    captdistraction I am the breaker of things

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    I think they share the design with Russell, with new pads the banjo bolt may be too long and it binds the piston.


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  8. Duane Black

    Duane Black TMO Advanced

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    They’ve been on for years - why would the issue just now develop after a pad change?
     
  9. captdistraction

    captdistraction I am the breaker of things

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    I ran into something similar and it only showed up with new pads. Ran for years ok otherwise.


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  10. Duane Black

    Duane Black TMO Advanced

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    Very intriguing... can you show me a part number to the correct banjo bolt? Or give me an idea of what I am looking for?
     
  11. Spencer Terry

    Spencer Terry TMO Intermediate

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    I agree, I would throw the stock lines back on it and see if that helps. I have had quite a few issues with rear brake lines and have gone back to stock at this point.
     
  12. JAJ

    JAJ TMO Addict

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    The 2013/14 GT500 brake hoses and the Boss 302 brake hoses were made from a low-expansion rubber hose that is very close to the performance of a stainless line. I had stainless lines (with shorter banjo bolts) on my 2011 Brembo GT, but I had no inclination to change the hoses on my 2014 GT500. Ditto my GT350, which has amazing brake presence and feel. Those "high performance" rubber lines are excellent and because they're OEM, it all works properly.
     
  13. Duane Black

    Duane Black TMO Advanced

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    Intriguing, very intriguing....
     
  14. Coz

    Coz TMO Race

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    I have the J&M lines front and back on my 2014 with no issues. Upgraded to the 13-14 GT500 13.8" rear rotors with the existing calipers.
     
  15. Duane Black

    Duane Black TMO Advanced

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    I’ve never seen an issue with fluid flow bleeding that i recall. Could try it. Would the stock hose having sat in a garage for 2-3 years change anyones opinion? New hose? Throw the stocker on?
     
  16. Coz

    Coz TMO Race

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    I do not believe the J&M and Russell lines are the same. The J&M lines have the square fittings at the ends while the Russells have the round fittings.

    If I recall when I got the J&M lines about 3 years ago they did not come with the crush washers or banjo bolts and I bought new OEM washers and bolts.

    You do have crush washers on either side of the brake line banjo bolt fitting, correct?
     
  17. Duane Black

    Duane Black TMO Advanced

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    I put new cooper washers and reused factory banjo bolts.

    Btw they’ve been in since early last year/mid 2017? Just start having problems in 2019....
     
  18. Drlee50

    Drlee50 TMO Race

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    The most likely problem is the caliper itself. Over time, the piston and it's adjacent wall develop rust and corrosion etc. Dirt gets in there etc. The piston then gets shoved back in, to max travel open, you install pads and pump brakes, pushing piston back out . the piston then gets all that rust and debris wedged in there and limits its free travel. Now it's hanging up and you are experiencing the symptoms. Replace the caliper. They are cheap

    Sent from my LG-H932 using Tapatalk
     
  19. Duane Black

    Duane Black TMO Advanced

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    Would agree, but...

    This is a brand new Motorcraft caliper replacing the brand new parts store caliper that blew seals
     
  20. Drlee50

    Drlee50 TMO Race

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