How I may have killed my 740 (more info)

Discussion in 'Volvo 740' started by jimb, May 3, 2006.

  1. jimb

    jimb Guest

    Fellow aficionados of the Brick

    In an effort to remove the crank sensor from my 1990 740, I broke the
    mounting ear off the engine (transmission).

    While tapping the sensor to rotate it in the mounting hole to free it
    up I hit the mounting ear.

    Casting is designed with a very thin wall around the bore that the
    sensor fits in and hence broke directly across the bore. I am actually
    surprised at how thing the casting is.

    Does anyone have any ideas about how to repair?

    Pulling transmission is possible but certainly not convenient.

    Has anyone else run across this?

    All this an I hope the diagnosis of the original problem is correct.

    No spark, no injectors, seemingingly open sensor (infinite
    resistance).

    ************************************
    I forgot in the first post:

    740 Non-Turbo
    5 speed
    Regina/Rex systems
    ************************************

    TIA

    jimB
     
    jimb, May 3, 2006
    #1
  2. I am just about to do a clutch job on my 99' V70 T5 and I plan to take the
    engine out instead of disconnecting the transmission in place. Judging from your
    experience this may be a good idea, right?

    -Peter
     
    Peter Ziobrzynski, May 3, 2006
    #2
  3. Unless I have a mistaken idea about how the piece is broken, it sounds like
    a job for JB Weld, a steel-filled epoxy. The repair area doesn't have to be
    exceptionally strong and won't exceed the 450F temperature rating of JB
    Weld.

    There are a few considerations. The mating surfaces have to be scrupulously
    clean - use brake cleaner or alcohol. When the epoxy is applied it will try
    to invade the threaded part of the casting; you should be prepared to deal
    with that. A tap would work, or if there isn't room to do that you can wax
    the threads of the crank sensor and run that in and back out before the
    epoxy sets.

    The finished product is surprisingly strong.

    Mike
     
    Michael Pardee, May 4, 2006
    #3
  4. jimb

    User Guest

    Since the two screws that will hold the new bracket in place are
    concealed by the bell housing, the only way to replace it is to R&R the
    transmission. :-(.

    Bob
     
    User, May 4, 2006
    #4
  5. jimb

    James Sweet Guest


    Hmm that could be a little tricky. Can you drill a hole through the
    broken piece on each side straight into metal still on the engine? If
    you can do that, then tap out the holes in the engine and ream the ones
    in the broken piece a bit larger you could screw it back on.
     
    James Sweet, May 4, 2006
    #5
  6. jimb

    jimb Guest

    totally different car so I couldn't say.

    I was working on the ignition and did something hasty.

    this is an in-line drive car.

    jimB
     
    jimb, May 4, 2006
    #6
  7. jimb

    jimb Guest

    I held my camera behind the engine and took some pictures.

    I see that the bell-housing has a relief for the nuts that hold the
    bracket.

    I assume that you are telling me that there isn't enough room to get
    the nuts and bracket off as I had hoped?

    TIA

    jimB
     
    jimb, May 4, 2006
    #7
  8. jimb

    User Guest

    Yup. Wanna see the t-shirt?

    Bob
     
    User, May 4, 2006
    #8
  9. jimb

    jimb Guest

    Bob,

    I was thinking of just pulling the transmission back by a bit.

    Put some longer bolts in a couple of the holes to keep everything
    lined up.

    I am a designer and I was amazed at how crappy the part is. Also how
    fused the sensor was in the hole.

    Maybe JB Weld with a reinforcing plate is the answer.

    TIA

    jimB
     
    jimb, May 5, 2006
    #9
  10. jimb

    jimb Guest

    Mike

    thanks for the tip!

    I had never heard of JB Weld; you're the second person to suggest it.
    sensor is not threaded in so it shouldn't be an issue.

    jimB
     
    jimb, May 5, 2006
    #10
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