Teves brake system malfunction | FerrariChat

Teves brake system malfunction

Discussion in '348/355' started by yelcab, Oct 17, 2019.

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  1. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Mitchell Le
    I have a 95 355 with some brake issues and I can use some assistance. This is a Teves system with ABS pump and master cylinder integrated with an ABS valve unit. No longer available and not rebuildable by anyone. This system is identical to Mondial T and 348 so please jump in.

    It started with two symptoms: 1) leaking ABS pump and 2) dragging rear brakes that would go a way if I relieve the pressure in the line at the master cylinder to the rear.

    So far, I have changed the leaking ABS pump, a used master cylinder, and the new regulator in line with the rear brakes. With these changed, I am assuming that the pressure sensors are operational. The problem I have right now is the pedal is very soft after much bleeding with a Motive pressure bleeder and attaching a line to the master cylinder ports and feeding the lines back to the reservoir and pumping the brakes (ignition on) to bleed the master. Then re-bleeding all four wheels with the Motive bleeder (3 times).
    The ABS pump runs for 30 seconds and then shuts off so it seems to be building the right pressure.

    Pedal is still soft. And there is still some sign of rear brake dragging.

    Questions:
    1) would a malfunctioning delay valve cause brake dragging?
    2) would you rebuid the calipers?
    3) I like to check the wirings at the 4 ABS relays. Does anyone have a picture of the wires and their colors at the bottom of these relays?
    4) Any other ideas to get the pedal to firm up?
     
  2. Ferrarium

    Ferrarium F1 Veteran
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    Not sure of this helps here here or is. Does 355 clutch share same fluid? Bleed that maybe if so, air on the line downstream of brakes would make pedal soff if they share same circuit like the 348.

    Sent using FerrariChat.com mobile app
     
  3. yelcab

    yelcab F1 World Champ
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    Yes, the clutch is fed from the same reservoir but with a different line and the circuit is not shared with the brakes. The clutch circuit bleeds fine and is very firm.
     
  4. tbakowsky

    tbakowsky F1 World Champ
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    Sep 18, 2002
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    Hit up the Ford T-bird forums. They used the same set up on the super coupe. Plenty of fixes out there..
     
  5. vvassallo

    vvassallo F1 Veteran
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    You did bleed the master cylinder directly from under the front compartment cover, right? It's a part that is not shared with the 348.
     
  6. Qavion

    Qavion F1 World Champ
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    Not sure if this will help...

    Ferrari F355 Teves wiring diagram
     
  7. yelcab

    yelcab F1 World Champ
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    It's the Teves master cylinder which is identical to the 348. I did hook the Motive to the top of the reservoir.
     
  8. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
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    Not sure if this system needs a scan tool to hold the valves in the ABS unit open to be able to bleed the air out of it. I know on the GM truck ABS units of the mid 90's vintage, you could remove trapped air by taking it for a test drive and putting it into a front and rear ABS skid and then taking it back to the shop and bleed the rest of the air out. I know it sounds a little barbaric, but it did the job. The trouble with some of these designs is the valves are not oriented in in a favorable way to be able to get the air out of them.
     
  9. yelcab

    yelcab F1 World Champ
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    From reading on line at the Tbird forum, I come to the conclusion that ...

    Soft pedal: leaks (none), air in lines (likely), bad master cylinder (possible because it is an unknown unit)
    Dragging brakes: caliper, lines.
     
  10. yelcab

    yelcab F1 World Champ
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    #10 yelcab, Oct 17, 2019
    Last edited: Oct 17, 2019
    There is a suggested way to bleed the Teves master.

    1. Let the pump charge up to full pressure, open each rear lines one at a time 10 seconds each while a helper is depressing the pedal and the ignition is on. Make sure fluid is topped off.
    2. Or, pressure bleed it with minimum 35 psi pressure applied at the reservoir.

    I will try these tomorrow.

    You know, I have always had success with my Motive bleeder and this is certainly not my first rodeo.
     
  11. Ferrarium

    Ferrarium F1 Veteran
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    Do you use the Motive with the ignition on? 35 psi? I read 12 psi somewhere?
     
  12. taz355

    taz355 F1 Veteran
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    Feb 18, 2008
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    Not the same system as my car Mitchell but I also have bled many systems so I thought I was at least quite competent but mine stayed bad until I hooked my Leonardo to bleed the electronics. I bought the motive as you know last spring thinking drawing fluid through the system would fix it. It did not.
    Once I did this with the computer all good now.

    You however have an advantage because as you have all ready identified you have a pump that will engage and pump through these valves.

    If I had your money I would bet you 100 bucks that when you do what you all ready suggested it will fix it.

    Good luck and keep me posted.
     
  13. yelcab

    yelcab F1 World Champ
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    I have never gone higher than 15psi
     
  14. taz355

    taz355 F1 Veteran
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    Did it work??
     
  15. yelcab

    yelcab F1 World Champ
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    I got side tracked and all I did today was to ascertain that the wiring is correct to the four relays.
     
  16. taz355

    taz355 F1 Veteran
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  17. fatbillybob

    fatbillybob Two Time F1 World Champ
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    When I loose a pedal and am very sure I have bleed well I always suspect the master first especially if a lot of work has been done. Often a master sitting will get crud where the pistons so not ride. Then with lots of full stroke bleeding you scratch up the seals with the crud you dislodge from going full stroke and kill the master. A rebuild will fax that. I have on occasion not bled the ABS well. I don't have a tech tool to cycle all the valves. I go out and slam on the brakes carefully and repeat active the abs. I bleed and do it a couple more times. That seems to right the system.
     
  18. yelcab

    yelcab F1 World Champ
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    This is a used master cylinder so there is the possibility of it being bad, there is no way to tell.
     
  19. m.stojanovic

    m.stojanovic F1 Rookie
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  20. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Well if you bench bleed it and then seal the out ports and the piston can be depressed it is dead.
     
  21. yelcab

    yelcab F1 World Champ
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    Did not work. I am declaring this second-hand master cylinder bad.
     
  22. 348Jeff

    348Jeff Formula 3

    Oct 25, 2011
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    When your doing the bleeding (of either brakes or clutch) do you have the ignition key turned enough (I think its first position) so you hear the buzz of the pumping?? I get the feeling a lot of people try and bleed tehir systems without doing this and then dont get a proper bleed? NB should also be on to check the level.

    I just bled my clutch yesterday (and I do same for brakes ) and used a blocked off silicone pipe with a slit in it. By far and away the easiest (and one man way of doing it. Done it this way on my other cars too and never failed to bleed the brakes first time and everytime.

    http://www.clubscuderia.co.uk/forum/showthread.php?45388-348-DIY-quot-Restoration-quot&p=839442#post839442

    Also, you can do and abs test by pressing your foot on the brake pedal and keeping it there and then turn ignition to position 1. After a few seconds you should feel a tremble under your foot and the pedal drop slightly.

    Finally, each caliper has 2 bleed nipples and your suppose to bleed each nipple in order - eg inner first then outer - I cant quite remeber which way - have a google.
     
  23. taz355

    taz355 F1 Veteran
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    Crap. I figured you had it damm
    Do not know your system well but I know I had a brutal time with the newer system until I bled using the computer.
    I know in theory it should have worked even for me by bleeding multiple times etc etc but after about 10 drives, cycling pumps on and off, and about 3 litres of brake fluid I finally broke down and used the computer and then all was good.
    I even used the motive for about 1 litre as well.
    Good luck and keep us posted
     
  24. yelcab

    yelcab F1 World Champ
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    Good news, I took a break. Vented and went back at it. Put the car on jackstands and removed all wheels. Two-man bleed with the key on for the rear brakes and a lot of fluid came out. Motive bleed on the front from all four bleeders. Some air came out from the inside bleeders. And …. pedal firmed up. I am good to go.
     
    taz355, 308 GTB, emac and 2 others like this.
  25. taz355

    taz355 F1 Veteran
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    I knew it
    I knew it
    I knew it

    Nice job
     

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