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Smoked my brake reservoir!

Discussion in 'Mondial' started by blownfuse, Jan 7, 2020.

  1. blownfuse

    blownfuse Karting

    Jul 16, 2012
    97
    Campbell, California
    [​IMG]

    1988 3.2 Cabriolet with ABS

    Had been sitting for a while with electrical issues. I replaced the main board with a nice repro from G.T. Car Parts and most all was well...

    Decided to replace all the fluids before driving it again, and bled both the clutch slave and four brake calipers with fresh DOT4 fluid.

    Upon starting the car & pulling out of the garage, a great cloud of smoke came from under the front hood, along with an acrid metallic smell. Looks like I smoked something. How do I diagnose this? Don't want to install a new part & smoke it as well.

    Also looks like my only option here is to replace the entire "Hydraulic Control Unit" as I'm not seeing any part # in the schematics for just a reservoir. Would love to hear if there are any other options.
     
  2. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Seems you have to find first the reason why your reservoir got a court circuit. Has something to do with the replacement of your fuseboard? or switched some wires at the reservoir? or other thing.
    Guido
     
  3. blownfuse

    blownfuse Karting

    Jul 16, 2012
    97
    Campbell, California
    Yeah that's my first look. I was able to start and run the engine without incident a few times before this happened, so it must've been something that happened during my brake fluid flush & refill.

    I did use a Motive Power Bleeder on the reservoir, pumped it to 10 PSI while I bled the calipers. Wonder if that broke the sensor that ended up smoking itself. Ugh.
     
  4. yelcab

    yelcab F1 World Champ
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    Wait, what component was producing the smoke? That first. A picture would be nice.
     
  5. mike32

    mike32 F1 Rookie

    May 13, 2016
    2,759
    Uk
    Are you sure this is electrical . Any chance you have damaged the AC piping and the smoke is actually fridge gas.
     
  6. moysiuan

    moysiuan Formula 3
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    Nov 1, 2005
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    Yikes. To be clear, you changed the board and it ran fine, then separately you did the bleed and only after that the unit smoked? Is there some obvious melted connector or some sign of what on the brake unit might have shorted? Hard to imagine a brake bleed causing this. Do you still have the main board, might be a failure/short in the main board. Did any fuses blow?
     
  7. blownfuse

    blownfuse Karting

    Jul 16, 2012
    97
    Campbell, California
    You are correct, it ran fine until after the bleed... I'm also dumbfounded that a bleed would cause this.

    I don't have the old main board as I was required to trade it in as part of the refurb process. The new main board is a modern etched PCB, so failure is very unlikely.

    No blown fuses. Next steps, barring any newfound wisdom, are to trace the circuits with an ohmmeter and see if there are any shorts therein.
     
  8. yelcab

    yelcab F1 World Champ
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    Before you do that, remove the connector underneath that hose, inspect the pins to see if something caused to burn. Did you use a pressure bleeder with a bad gasket that may have caused a leak at the reservoir cap when you did the bleed?
     
  9. Wade

    Wade Three Time F1 World Champ
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    Crazy question based on ancient memory... there are two different fuse boards for the 3.2 (ABS and non-ABS), did you get the correct one?
     
  10. blownfuse

    blownfuse Karting

    Jul 16, 2012
    97
    Campbell, California
    Pressure bleeder is like new. Been using it to service my Porsches as well. Same cap size & threading, interestingly enough!

    If there was a leak, it wouldn't be able to hold pressure -- as measured by a gauge on the bleeder. I checked that gauge throughout the process to ensure there was no leaks.

    That's a great question. I called G.T. Car Parts and they said the same board was used for all 3.2 variants as well as 328 and Mondial T variants. They did offer to take the board back for testing & inspection, but I'd like to get some more clarity on that before I go through the work of removing & shipping it...

    If there are in fact two different fuse boards, where would we see that difference manifest? The schematics and wiring diagrams I have don't show a different board for ABS vs. non-ABS models.
     
  11. spicedriver

    spicedriver Formula 3

    Feb 1, 2011
    1,945
    Were you refilling the reservoir ? Perhaps some fluid got spilled onto that area.
     
  12. Wade

    Wade Three Time F1 World Champ
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    Well, they should know since they've been in the business much more than I.

    But before you remove it for testing, step back and do an analysis of when the "smoked" problem occurred. In other words, after you replaced the fuse board and before tackling the ABS, how well did everything work and for how long?
     
  13. theunissenguido

    theunissenguido Formula 3
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    Like GT parts is mentioning....the same boards for mondial QV, 3.2 and mondial t (with or without ABS !). Even the same as 328....
    Guido
     
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  14. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    By the way, the reservoir is not available as a unit, it comes with the Teves master cylinder which is NLA. Brian (Spider355) has a bunch of used ones that may or may not work. I also have one if you are interested.

    I think you have a problem with the ABS system from the looks of the burnt hose/connector. If it were my car, I would remove the connectors to the master cylinder, turn the system on, and start looking at voltages.
     
  15. moysiuan

    moysiuan Formula 3
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    Brake fluid on an electrical board or connector can cause a short. Maybe some fluid seeped into the connector and that was enough to cause the problem?
     
  16. yelcab

    yelcab F1 World Champ
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    not can, WILL cause a short.
     
  17. moysiuan

    moysiuan Formula 3
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    This abs system was also used on some Lincolns of the 1990's. There might some diagnostic ideas on the Lincoln web sites. eg. http://www.thelincolnmarkviiclub.org/phpBB3/viewtopic.php?t=6041
    ABS unit failures on Mondials seem to be very rare, so there is not as much creativity in parts crossing that is documented, but I would bet the Lincoln units have many similar parts.

    There is also a Ferrari manual on this abs system with all the electrical tests to be done to diagnose problems. You should be able to confirm if the unit is still ok despite being smoked, or narrow down what part of it may have been damaged.
     
  18. moysiuan

    moysiuan Formula 3
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    A fuse or relay burning out might have prevented the short from damaging the unit itself. Things may still be ok, and just a short from some fluid dipping into the connector. At the least need to inspect carefully and rule out if anything non technical and possibly obvious caused the problem. Check the fuses and relays that are relevant to this system, and relevant white plastic the connectors at the fusebox for signs of burn/problems. The fuse board itself may not be the failure item, but maybe one of the connectors was disturbed and or bent a pin or something relating to how things were reassembled.
     
  19. moysiuan

    moysiuan Formula 3
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    Here is a link regarding the 348 that used the same system, some parts and rebuild sources etc. if it comes to that.
    http://www.my348.com/
     
  20. blownfuse

    blownfuse Karting

    Jul 16, 2012
    97
    Campbell, California
    Thanks for all the resources! Have a rainy weekend ahead so plenty of garage time for me and my junior assistant.

    Knowing the effects of errant drops of brake fluid, I was VERY careful not to spill a bit when refilling the reservoir. My guess is that the pressure may have forced fluid through old, brittle plastic into whatever sensor burnt itself up.

    No connectors were touched as part of the service, aside from those going into the relay board. I replaced Ferrari's "duck bill" relay board connectors with .187 female spade connectors in the process, for better mechanical & electrical performance. (And, yes, I was VERY careful to ensure I preserved the ordering of all ~75 circuits going through the board. This was a months-long project with tons of documentation & testing before the battery was reconnected.)

    The dash has separate lights for "ABS" and "Brake failure". The former light goes out after the self-test. The latter remains illuminated after running.

    I'll have to chase this down, any idea where one might find it? Will try the procedure outlined at my348.com in the meantime.
     
  21. moysiuan

    moysiuan Formula 3
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    I have the manual, the problem is it is a larger than letter page size so hard to scan each page on my scanner. I will give it a go with some of the electrical test procedures.
     
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  22. moysiuan

    moysiuan Formula 3
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    I also have a 1988 3.2 Mondial with ABS, and have done a pressure bleed with my Motive bleeder from time to time, so it certianly is a relatable issue you have surfaced.
     
  23. moysiuan

    moysiuan Formula 3
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    I had to use a compression app to get this small enough to send, hopefully it is clear enough for you. I scanned the electrical diagnosis section trying to get the English segments even though the whole pages don't fit. The rest of the manual deals with the system description, and the pressure testing diagnostics.
     

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  24. moysiuan

    moysiuan Formula 3
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    This is a manual for a Jaguar that used the same system, might be helpful to understand how the whole system works.
     

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