A great day followed by a BAD night - rear brake issue

Discussion in 'Boss 302 and S197 Technical Forum' started by Duane Black, Mar 25, 2019.

  1. Duane Black

    Duane Black TMO Advanced

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    So I just posted in the lap times - setting a 2:15.83 for a new personal best at VIR and having a great time instructing a student in a Corvette made for a spectacular set of days at VIR - great weather, great times.

    That night things went to shit. On the way home, the pedal felt SOFT. I thought I must have boiled fluid, but checking my master cylinder revealed it EMPTY!!!! (or almost). In my garage a puddle quickly formed around the left rear wheel. My original calipers got "sticky" several weeks back and were both replaced. The new one was now leaking BADLY!! I took it O'Reilly and got a new one under warranty, which was another issue concerning it came with no e brake spring and I had to go back and get the one off my old one, which led to an interesting exchange between me and a manager.

    I'm thinking this may have been related to the fact that my rear brake pads were VERY low, maybe an 1/8th inch left when I took them off- yikes!! paper thin.... my fronts weren't much better. So I have a couple of sets of rear pads and I got some new front pads ordered from Porterfield just this am as I type.

    Has anyone else had this issue with replacement rear calipers? Is there a brand I should target? Should I get the O'Reilly shit off the car ASAP before it gets me killed? I'm thinking if these parts store calipers were bad, there would be crash in Lemons and Champ every other lap related to it.

    I got my daily driver pads in for the week and am just super paranoid now, it took me about 3 hours to get everything squared away last night.


    Days like the ones I had made me love this and want to kepe pressing on at this. Nights like this, however, make me just want to rest on my laurels and move on to other things.

    I suppose I could use advise on brakes and words of encouragement to carry on.
     
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  2. Bill Pemberton

    Bill Pemberton TMO Addict

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    Duane, hang in there , as I have had similar things happen and the main cause is often simply that I was getting faster. You set your best time this weekend, were hitting much higher speeds and on a fast track. Really not a big surprise and I think your concern is more of a simple " heads up," of needing to check your pads more often. Similar issue , years back , made me realize I needed more aggressive pads , as well as needing to check more often. I actually kept the same brand of pads , but moved up onto a more aggressive one. I assumed since everyone else was using the same pad as I was, with no problems,yet I was running quicker than them and should have realized more speed ,more wear. Good luck, nice times at VIR, and enjoyed the video!
     
  3. Duane Black

    Duane Black TMO Advanced

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    That pad wear caught me a bit off guard - I'm driving faster, braking deeper, on stickier tires, and they aren't lasting as long as they used to - damn things must not be made as well as they used to be! LOL.

    The brake caliper bleeding out of the piston on me nad making a puddle under a wheel is the most concerning thing. I can buy pads or take fewer sessions and sleep at night. This caliper shit has me shaken though.
     
  4. gww52

    gww52 TMO Advanced

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    What are you using for a race pad?
     
  5. Duane Black

    Duane Black TMO Advanced

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    ST43 Raybestos. This was their 5th event - Roebling was a 3 day event with my instructor clinic (10 sessions?), then VIR in October (7 sessions), Roebling Road in January (6 sessions? maybe 7?), then Road Atlanta earlier this month (7 sessions) and then VIR this past week (7 sessions.) I'd say they've had a good run....
     
  6. Bill Pemberton

    Bill Pemberton TMO Addict

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    Keep in mind there could be quite a few causes, and one could even relate to excessive heat build up if your pads were close to metal on metal, but I would just put on your new ones and check more often the next time you are at the track?
     
  7. Duane Black

    Duane Black TMO Advanced

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    They were really close on that side....
     
  8. Coz

    Coz TMO Race

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    Have you upgraded to the rear 13.8" 13-14 GT500 rotors? That may help with heat dissipation and prolong pad and seal life.

    In the meantime, taking off the rear dust cover can help with cooling.

    Also what AdvanceTrac setting are you tracking it with?
     
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  9. Duane Black

    Duane Black TMO Advanced

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    AdvanceTrac off (hold the button 10 seconds) and hte dust shields have been gone for a year. Stock rotor
     
  10. blacksheep-1

    blacksheep-1 TMO Addict

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    I think Bill Pemberton is on to something, that guy in Kuwait should be tagged in this thread.
     
  11. TMSBOSS

    TMSBOSS TMO Addict

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    Duane

    I had the same issue with rebuilt rear calipers on my Boss. I swapped out the originals because they showed signs of being hot....a lot. So, i bought a set from Advance, one lasted a single day before leaking, the other is on its third year. There are not that many rebuilders for calipers. The stores/chains don't rebuild, they buy in lots. So moving from one store to another may not get you to a different rebuilder.

    Advance track will decide that its needed and turn back on. Got to love computers. I smoked a set of rear pads in one day before i swapped out the ABS module.
     
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  12. Duane Black

    Duane Black TMO Advanced

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    Mine did that but being an automatic, I drive with two feet. I haven't had the issue on 200tw tires primarily and my "skinny" 285 wides. I figured out if you ever got both feet off the petals and let the car "free wheel", it would turn on traction control. If you stayed in control of hte car, even just a TINY FRACTION of braking and gas, it wouldn't engage... probably a chore in a 3 pedal car though. On RE71R, I would engage advancetrac in hog pen at VIR and occasionally at NCCAR for autocrossing. It seemed going to RS4 negated that issue.
     
  13. scmscout

    scmscout TMO Advanced

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    Duane, I have replaced 4 of the parts store brand rebuilt rear calipers, it seems once pads wear enough they leak, I carry a spare set with me, trying to get a set of OEM but they seem hard to find.
     
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  14. 2012-Boss

    2012-Boss TMO Addict

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    I would put on a set of new Motorcraft / Ford OEM built calipers. I have seen them run down into the backing plates without leaking. I have also routinely seen the rears run down like you are talking about without leaking.
     
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  15. Duane Black

    Duane Black TMO Advanced

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    I had never seen a caliper just leak without pedal pressure before this. It just dripped endlessly
     
  16. xr7

    xr7 Overdosed on TMO

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    I would pop the caliper apart and inspect the seals, perhaps an inferior seal has melted. Calipers aren't that difficult to rebuild and you can use a quality part rather than trust the junk sold at most of the auto parts stores.
     
  17. Duane Black

    Duane Black TMO Advanced

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    I’ve never rebuilt a caliper. I need a tutorial on this....
     
  18. TMSBOSS

    TMSBOSS TMO Addict

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    A caliper without E-Brakes is straight forward. Remove piston, remove old seal, clean caliper bores, clean piston, hone if pitted or scored. Place new seal in the grove, lube with brake fluid or an assemble lube, push piston into bore. Ensure piston is fully seated on the bore and that it slide freely. If it binds, remove and inspect seal, piston and bore.

    A few more steps with a E-Brake.



    DANGER Will Robinson. Be Very cautious if you remove the piston with air pressure. If you have a regulator on your air supply, crank it way down. Under 5 PSI. If possible put a small piece of wood in the caliper to catch the pistol if blowing out. Better yet, remove mechanically.
     
  19. Duane Black

    Duane Black TMO Advanced

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    So I’ve had issues with the front dual pistons before. Like one piston moves in more than the other and bevels my pads abd ends thrn prematurely. Any advise for that?
     
  20. blacksheep-1

    blacksheep-1 TMO Addict

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