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Brake Problem with my GTC

Discussion in 'Vintage (thru 365 GTC4)' started by steve meltzer, Sep 5, 2019.

  1. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    First, as usual, forgive me for X-posting with TY. My GTC runs great, stops great, steers straight, etc. For several months now from time to time, with the only consistency being that the car is fully warmed up (never from cold start), and I think only hot ambient temps (not too sure about that, as it's almost always hot here in Houston) the car exhibits this: once stopped, like to park the car, manipulate into a parking space or stop sign, upon trying to get the car to move forward (or back) it feels like the wheels are locked up. Engine revs perfectly, goes into gear, but it feels like the car is chained to the concrete. Yesterday (temp=100°), luckily, it happened on my way home from a stop at O'Reilly's. With great and anxious effort, I got the car to move on home (about 3-4 angst-filled, compete stops) until it was absolutely immobile in my driveway. Car couldn't move a mm on it's own, nor trying to roll it by hand. Neither forwards, nor back. 2 hours later, with the car cooled off, a 5 year old could have rolled it by hand. Parked easily in the garage, as normal.

    I was in a hurry and didn't jack the car up to see if I could tell if a caliper was stuck, but I wish i had. Nor did I shoot an IR gun at the calipers, tho I did this about 6 weeks ago, but can't recall the circumstances. At that time, they were spot on equal on the fronts and 2°, but equal, but of course less, on the rears. Pedal feels absolutely normal. Brakes bled about a year ago, booster rebuilt about 5 years ago. When you slow down, but but don't stop, it stops straight, and doesn't lock up, nor pull to one side.

    I believe this is in the MC, but it sure seems atypical. Could be in the booster I suppose. How do i figure this out and differentiate the two, or do I just put in a new MC and go from there? It will be hard to replicate these symptoms when I have a jack, IR gun, time and safe place to do some diagnostics. I'm pretty certain it's in the brake controls, but am open to all suggestions. thanx steve
     
  2. Bob Zambelli

    Bob Zambelli F1 Rookie
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    Nov 3, 2003
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    Robert G. Zambelli
    Are you using silicone brake fluid?
     
  3. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    No, I'm using traditional DOT 4. Might be less likely with DOT5/silicone ??, but I don't think this is related to the type of fluid. thanx steve
     
  4. TTR

    TTR Formula 3
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    Mar 29, 2007
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    Timo
    How long have brake (flex/rubber) hoses been in service ?
    Or better yet, how long ago was the entire brake hydraulic system completely/thoroughly rebuilt/restored/serviced ?
    If the answer to either or both is 10+ years, well...
     
  5. turbo-joe

    turbo-joe F1 Veteran
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    Apr 6, 2008
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    romano schwabel
    you may use an infrared thermometer to meassure the brake temperature on all wheels
    if at the same axle left and right the same or nearly the same temperature too hot then it would be a problem of the mastercylinder. same when all 4 brakes have the same high temperature. may be the actuator for the piston in the mastercyllinder has no play to the pison? sorry, don´t know the name in english, in germany it is called "schnueffelspiel".
    if only 1 brake is too hot then it is a problem of this caliper.
     
  6. TerryG!

    TerryG! Karting

    Feb 12, 2017
    65
    Central UK
    Steve - way back on my 250GTE I had a similar sounding fault. We traced it to the brake compensator valve assembly. It was full of crud and preventing the front wheel calipers from releasing, except after a long delay.
    Probably a red herring but perhaps worth a check.
     
  7. colombo2cam

    colombo2cam Karting

    Jan 31, 2019
    180
    Full Name:
    Ted Reimel
    I had a very similar issue and it turned out to be the master cylinder. (275)
     
  8. Ferrari_250tdf

    Ferrari_250tdf Formula Junior

    Mar 3, 2005
    283
    There might be something floating around in the brake fluid that occasionally blocks the release of the pressure in the lines. Flush the whole system and check for small particles. A fast cure is to open the bleeding valve of the caliper on the blocked wheel and release the pressure. Relatively easy on a wire wheel since you reach the valve through the spokes.

    Safe braking!
     
  9. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    WOW! thanx for all of the responses. As noted, the servo/booster was rebuilt about 4 years ago or so. All calipers and lines flushed a year ago, and only about 100 miles. The master cylinder rebuilt 6 years ago (by me with adult supervision...so, it is suspect). Hoses are at least 15 years old.
    I drove the car around the neighborhood for at least 20 minutes yesterday. Many, many, many stops, ambient temp was 100°. Couldn't replicate the problem whatsoever. I don't want to stray too far from home and get stranded.

    I did shoot an IR gun at all calipers and the readings were very, very consistent, but that data is not useful, because you want it when the wheels are locked up, and again, that's very hard to replicate. Most likely will try again to reproduce the symptoms, get a jack under the car and try to spin the wheels, shoot an IR reading, and maybe crack open a line at the MC to see if it helps...if it does, probably MC, if not, booster. Right? thanx steve
     
  10. Ferrari_250tdf

    Ferrari_250tdf Formula Junior

    Mar 3, 2005
    283
    You might not be able to reproduce this because you don't know where the little particle is floating around. What happens is that if it is for example near one brake caliper it might occasionally block the pressure release. You brake relatively soft and release but the pressure in the fluid doesn't release and therefore the caliper locks and therefore the heat in this caliper rises therefore the pressure in the fluid rises too which puts more pressure on the pads until the wheel locks completely.
    You then have two options:
    1. wait until the caliper is cold again and the particel starts floating free again
    2. release the pressure via the bleeding valve

    But flush the whole system soon and you might be surprised what you find in the fluid.
     
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  11. Jumprun

    Jumprun Karting

    Feb 7, 2012
    175
    Southern California
    Full Name:
    T. Martinez
    Swelled old hoses.
     
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  12. christc

    christc Karting

    Mar 3, 2013
    90
    Germany
    I would agree. My first guess would be old swelled hoses locking up. If I were you I first would change all hoses. They are similar to Jaguar brake hoses and can be obtained at non Ferrari prices. For my Gte I used hoses from MK2 and E-Type.

    Good luck.

    Christopher
     
  13. turbo-joe

    turbo-joe F1 Veteran
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    Apr 6, 2008
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    I think it is not a problem of the hoses. those would be other symptons
     
  14. TTR

    TTR Formula 3
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    Timo
    Romano, I have seen and dealt with this on several vintage cars, including 365 GTB/4s (but not on GTCs) and symptoms on those occasions were pretty similar to what OP describes.

    Of course OPs causes could be any number of other things and without knowing the COMPLETE service history of the brakes on that car, any advise or suggestion offered here is more likely to be just another shot in the dark and more different ones we all offer, more confused OP is likely to become.
     
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  15. llink

    llink Karting

    Nov 18, 2013
    126
    Northern California
    Tommy Yang’s site has a recent blog regarding intermittent brake sticking issues on a 330 GTE. Might provide some insight:

    http://tomyang.net/blog/
     
  16. christc

    christc Karting

    Mar 3, 2013
    90
    Germany
    As I understand the car is with Tom now and he has dismantled the master for new seals
     
  17. christc

    christc Karting

    Mar 3, 2013
    90
    Germany
    Sorry, just realised I was wrong in my last statement. Tom is working on a 330 2+2, but same symptoms.
     
  18. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    Only bled the brakes yesterday: test in a day or two, 'round the neighborhood, so close to home. Hoses look great from the outside, but, like our Coronary Arteries, might be blocked on the inside. (hmmm....maybe time for "cabbage"!). For the moment I'm trying to get some info. Ultimately, the MC might need to be rebuilt, and new hoses, as well. Oh, and, while going down the rabbit trail, rebuild the calipers....probably 600-800 in parts alone and a few hours of labor. <G>

    Christc how do i find out which jag hoses are for my car? thanx. x
     
  19. turbo-joe

    turbo-joe F1 Veteran
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    if you not prefer original look then use steelflex. they need an example and can make as you want
     
  20. christc

    christc Karting

    Mar 3, 2013
    90
    Germany
    Dear Steve,

    I went to a jaguar parts supplier and compared them. If I am right the one in the back was fir a MK2 and the front ones for the E S 1. Let me take a look at the weekend when I am at home. I am sure I noted it down.
     
  21. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    thanx for your efforts Christc. steve
     
  22. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    N.B. this has been X-posted on Tom's website. Gotta hallway pass this afternoon, so I had time to take the car out again, to see if I could reproduce the problem. After about 15 minutes of staying close to home, I could begin to feel the sense that the car was being held back. Got worse as I approached home, and, with the upmost of luck, the car became, as before, absolutely immobile in my driveway! Quickly jacked up the car and found that neither front wheel would move, but both rear wheels were moving easily! Cracked open the main line for the front brakes, and re-tightened....front wheels spun easily. So, the master cylinder is off the car for it's rebuild. Couldn't have done it without a lot of luck and the help of my first assistant, Grover, shown sitting here on this lazy tuchas. s
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  23. steve meltzer

    steve meltzer Formula Junior

    Sep 18, 2004
    809
    with Enzo 8995
    I assume that upon return of the MC, i'll need to bleed it and all 4 calipers. Right? thanx. steve
     
  24. jimlt4383

    jimlt4383 Karting

    Sep 1, 2006
    71
    Yes, bleed master cylinder first then start with the farthest wheel from the master cylinder and work your way around to the closest.
     
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  25. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
    2,981
    Bay Shore, NY
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    Andy
    Oh boy. an opportunity to flush the brake fluid at all four corners! Glad to see you got a solid clue today.
     

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