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348 (Rear) Brake pressure stuck - not hoses, nor calipers

Discussion in '348/355' started by Lifeboatboy, Jul 7, 2020.

  1. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    My 1994 UK spec. 348 Spider is suffering from seized rear brakes, holding pressure that it won't release.

    Thinking it was the 26-year old hoses, I had some bespoke ones made by Goodrich, but after replacing one (so far), the problem persists. It's not the calipers (they release and open manually). When they're open, I turn on the ignition, depress the brake once...and that's it, they're locked solid and won't release again until it's done manually.

    There's no visible pinch in the brake lines that I can see in the engine bay (neither rubber, nor the metal hose following the chassis), and there's no sign that I've smashed the undercarriage against anything, but it's clear that the pressure is being held somewhere between the pedal and the pads.

    The only thing I can think to do now, is to try to locate the fault by removing the trim under the bonnet, disconnecting the Hydraulic Control Station, and hoping that it doesn't fix the issue. Because by current estimates, the HCS is about $10K, and at least if disconnecting that doesn't suddenly release the pressure, 'all' I have to do, is find the pinch between the front and the rear.

    Anyone have any ideas?

    If there's a solution to this somewhere else on here, please would someone cut and paste it so I can go and have a look?

    Thanks in advance.
     
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  3. Ferrarium

    Ferrarium F1 Rookie
    Rossa Subscribed

    Jul 28, 2018
    3,522
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    Eric
    If you pop the bleeder open does fluid gush, how do you know its holding pressure vs caliper sticking? I assume you have to pry them open with a screw driver or something but it could be jammed/corroded pot? The whole unit used is about $1200.
     
  4. ferraridriver

    ferraridriver F1 Rookie

    Aug 8, 2002
    4,122
    Bay Area Calif.
    Full Name:
    Dave
    Had that happen on a Mercedes once, it was a master cylinder check valve failure.
     
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  5. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    No, fluid doesn't gush out. I put plenty of pressure through a manual pump into the brake fluid reservoir under the bonnet, and waited... Took ages to get anything through at all. To open the calipers (when the engine was off), it was easy.
     
  6. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Hmmmm... will check - thanks
     
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  8. Ferrarium

    Ferrarium F1 Rookie
    Rossa Subscribed

    Jul 28, 2018
    3,522
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    Eric
    So pressure is not in the lines at the brake caliper? Odd if the brakes are stuck in rear one would think there would be pressure in the lines. Problem may be upstream not allowing fluid back into system when you release pedal. Good luck.



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  9. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    10,955
    San Carlos, CA
    Full Name:
    Mitchell Le
    You need a new Teves master cylinder, NLA, and if you can find a used one, it's $$.
     
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  10. Ferrarium

    Ferrarium F1 Rookie
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    Jul 28, 2018
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  11. allandwf

    allandwf Karting

    Aug 27, 2011
    237
    Scotland UK
    I also had this on another car, as mentioned, it was the master cylinder cap vent in my case.
     
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  13. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Thanks Ferrarium. I know. I’m confused. But cheers for the support
     
  14. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Bollo**s!

    I rather preferred @Ferrarium’s reply at $150, versus yours @yelcab at $1500 :-( But seriously, both of you - thanks chaps.

    I’ll go through what we Brits call: “...some f*****g careful problem isolation”, and then accept that in all likelihood, I’m going to to become the benefactor of some reassuringly expensive, completely invisible metal.

    B*******s.
     
  15. Ferrarium

    Ferrarium F1 Rookie
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    Jul 28, 2018
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    No brake light or codes I assume? If so I myself am the replace things before the break guy, and a shop will likely just start removing and replacing parts and give you a huge bill so if I was in your shoes right now I would put SS lines on (easy to do lines are old anyhow) , replace the master cylinder (if its not leaking it will its old and its cheap to do) , put in new accumulator (xref delco its cheap) and a new ABS pump (also cheap with jag xref) which are all sitting in a box for me brand new so its easy to say so understand that, and then take a look at cleaning out or replacing these items that could have blockage before jumping to a new control station. Those last 2 items are interring seems like a check valve of sorts?

    139375
    101394
    134597
    136313

    https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348-1989-1992/brake-system-with-antiskid.html
     
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  16. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Mate - I understood the first 3 lines...:). Ok, I’m out of my depth and will stop even trying to wish I could sort this. I’ll show my best mate (also my mechanic) what you’ve kindly shared. And hope we can sort it without me resorting to selling myself.

    Thanks so much. Really appreciate it.


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  17. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    10,955
    San Carlos, CA
    Full Name:
    Mitchell Le
    I had that very same problem last year. Rear brakes locked up. If I crack the rear line at the master cylinder the brakes would release. In my case, even the ABS pump was leaking which doubled the trouble and the fun because one cannot troubleshoot the system until the pump works to build pressure. In the end, it was replacement of the NLA pump and NLA master cylinder, and Rebuilding the brake calipers, and changing the rear brake lines did the trick. It was a bruising crush to the bank account. And it pissed me off so much that I recommended another Fchater to commercialize his bracket kit to make the Jaguar pump work with the Ferrari 348/355 chassis.

    Get this: a used Ferrari pump was $900 with no warranty that it works. The same jaguar pump was $150 but it tilts the other way (right hand drive mount) so the kit makes the pump fit the Ferrari kit.

    Oh, it took 4 months to try rebuilding, sourcing, looking, trying, and finally found the pieces that work.
     
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  18. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    FFS. And they said the Middle East conflict was a big deal. Cheers @yelcab Eemind me to ping you when I need to replace my dust caps hahahaha
     
  19. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,966
    Milton, Wash.
    Full Name:
    Jeff B.
    Are both rear brakes (left and right) locking up at the same time? I ask because I once had a problem with the rear brakes on my 348ts, at about 50% wear on the pads, where the pads could go slightly crooked in the caliper when the brakes were applied, and would fail to retract fully. New rear pads (very easy) permanently fixed that particular issue, no hydraulic problem at all. I remember wondering if perhaps the old pads were aftermarket, and the metal backing plates for them were too small, causing the misalignment.

    Also, have you checked to see if the parking brake shoes are worn to the metal and have destroyed the drums inside the rear rotors? There have probably been dozens of cases where the cars have been driven with the parking brake applied and significant damage done, unseen until the rotors are removed for inspection.
     
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  20. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Ah now this too, has been on my mind @Miltonian. I’ve been wondering about the repeated mentions on other 348 brake threads ref alignment.

    My pads are ok, but definitely suffered due to the heat I generated when I took it for it’s test drive on June 1st (because they were locked against the drums). I haven’t seen discs glow like that since the night racing at Le Mans. I thought it was cool. My mechanic was less impressed.

    Genuinely I don’t know, and same for the shoes. But my mate is brilliant and has looked after my irresponsible toys from Esprits to 911s to my 348.

    Thank you. I’ll share all of this with him. He treats my car better than I do most of the time, and he’ll kick my a**e if I just spend money without checking all avenues.


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  21. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,966
    Milton, Wash.
    Full Name:
    Jeff B.
    Interesting. Have you or your mechanic yet attempted to remove the rear rotors? They can be a bear to get off unless you can get the adjusters slackened. If the discs were glowing if may have been from heat generated via one or more locked handbrakes. Either driven with the handbrake applied, or the friction material broken off from the metal shoe and wedged where it don't belong.

    If this IS the problem, it should be considerably less difficult and less expensive to repair than anything in the hydraulics.
     
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  22. A348W

    A348W Formula 3

    Jun 28, 2017
    1,578
    North Wiltshire, UK
    I just had new handbrake shoes fitted as part of my major. I recall the mechanic saying the dust can build up and bind the rear discs.

    If you take the rear pads out of the Rear callipers, are the discs still binding? If so; do as suggested above; it’s the handbrake shoes binding.
     
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  23. A348W

    A348W Formula 3

    Jun 28, 2017
    1,578
    North Wiltshire, UK
    If you end up needing pumps etc; I recall redbay cars had some... I think.
     
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  24. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Thanks gents. Will update in the next week or so. Not because I’m not uber-keen to resolve it - just that he’s got some unreasonable distractions I call ankle-biters, that seem to be his alternative to my car. Who knew...?


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  25. m.stojanovic

    m.stojanovic Formula 3
    Silver Subscribed

    Dec 22, 2011
    2,223
    Malaysia - KL
    Full Name:
    Miroljub Stojanovic
    When using a pressure bleeder, you still need to pump the pedal to operate the control valve (inside the MC) for the rear brakes. If you don't move the pedal, there will be practically no flow to the rear brakes as the mentioned valve will be closed.

    As to the rear calipers binding, you did not mention whether they are Teves or Brembo. One of the Teves rear calipers on my 1991 348 started binding, not to the red heat as I discovered it early. I first thought of rebuilding it but, as I could not find seals for it anywhere, I installed good used Brembo calipers and never had the problem since (~5 years now).

    I would not immediately jump on spending huge money for the MC which may not solve the issue. Better to go step by step. As suggested, try first with new pads at the rear. If it solves (temporarily) the binding problem, it would then mean that the binding is caused by the calipers themselves - the pistons getting skewed and stuck when they come further out with somewhat worn (thinner) pads.
     
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  26. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    #24 Lifeboatboy, Jul 10, 2020
    Last edited: Jul 10, 2020
    L&G, update on my situation, and a chance to thank you all again for the help, tips and advice etc. I mean it - this forum blows my mind with the help and encouragement it offers people. @m.stojanovic @A348W @Miltonian @yelcab @Ferrarium

    I removed all the interior bonnet trim so that we could get to the hydraulic control and master cylinder etc. Because whilst in an ideal world I'd follow the 'replace before it breaks (no pun intended) policy', there's a balance between that and the affordability aspect.

    This morning we changed both SS hoses anyway (as recommended, and I'd already bought them), and still no joy. We removed the brake pads (I'll replace them anyway as part of sensible due diligence), and found that the pistons move freely and as they should. The calipers seem absolutely fine, but again I think given the extreme heat I generated when the issue presented itself, I'll send them away for a thorough refurb. I don't want to run the risk of the interior parts having been damaged, and the parts that stop the car seem fairly important - even to a luddite like me.

    Then we went back under the bonnet, and I held my breath as we released the pipe connecting to the Master Cylinder. I figured: if upon separating the pipe from the MC, the pressure suddenly released the calipers, it identified the MC as the culprit retaining the pressure. We were surprised at how far the metal brake pipe protrudes into the MC, so that even upon undoing the nut - allowing air into the bottom and thus fluid to drip out - we couldn't actually get it out far enough to be free. No matter. As a frogman, I know enough about pressure that even 10 bar (145 PSI) should have been enough to open the gills at the back. Nothing.

    The pump works fine (whirrs away nicely), the interior is nothing short of immaculate (no drips, no corrosion, no degradation), and even after more gentle on/off on the pedal (with the ignition on), we couldn't identify any discernable change.

    Next we followed another suggestion i.e. to flush the pipe with fluid. We ran a good 3 or 4 litres of new fluid through tapping the brakes to get flow, and there's clearly no issue there, so my mechanic was getting really frustrated and antsy. As much as he doesn't want me to spend $10K on replacing the MC, the ABS pump and all the bits and pieces around it, he's also my best mate and a conscientious bloke, so complex brake systems aren't something he'll 'learn along the way', where it potentially puts my life at risk.

    We agreed that a crushed metal pipe might be the issue, but how? No bumps in the road last time out, and anyway - if the pipe was crushed somewhere, surely the flushing would have been strained, not free flowing?

    Then I mentioned to him what you guys had said about "some sort of valve", which was about as helpful as I get.

    He decided to try to find it, and traced the pipes from the discs around the engine bay, and stumbled upon it. He climbed underneath and released the side nearest to the brakes. Hey presto! The calipers released.

    Which left us desperately hoping that if we put pressure back into the pipes, and released the other side (nearest the front of the car), and the same thing happened, we'd have identified the valve as the issue. Unfortunately it's really fragile brass and without a strong set of mole grips to hand, the spanners were just rounding the valve. We sprayed it with WD40 and have left it to soak.

    He's back with me on Tuesday (with all of his toys), and we're just praying that we've found the problem.

    For what it's worth (in case anyone in the UK is having similar problems), Eurospares haven't got one and they're no longer available new (even at £1700), so if that is the cause, it'll be a quest to source one. Also, please note that they advised me that the part number on mine (as one of the last RHD European 348 Spiders), it's identical to the 355 but different to earlier TS/TB/Spiders, so getting the part number on the valve is critical.

    Of course at this stage we're still guessing, but the diagnosis we've gone through all points towards the valve on the front side.- exactly as @m.stojanovic referenced to @Meister on a parallel thread (https://www.ferrarichat.com/forum/threads/brake-troubles.624947/). So apologies if I've come at this from a different angle, but seemingly (potentially) with the same problem, but please know how much you folk help.

    I'll let you know how I get on next week.
     
  27. Lifeboatboy

    Lifeboatboy Karting

    Sep 12, 2012
    52
    London, UK
    Miro, how do I know which sort they are? I’ve had the car since 2004, and the single previous owner wouldn’t know a caliper if it slapped him around the face :)
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