Curious for knowledge

Discussion in 'A boatload of fun' started by Steelride16, Mar 11, 2018.

  1. Steelride16

    Steelride16 New Member

    Hey, I am working on a 1970 Buick Lesabre. I would like to replace the speedometer cable and heater core. Whats the issue? I am a little new to working on classic Buicks and embarrassingly enough I dont know how to remove the instrument cluster and am too nervous to start picking at it as I dont want to break anything. And if I could get hints on replacing the heater core that would be useful as well. I want to learn, I just need pointers. Also the fuel gauge has never left E since I bought the car. It has a 25 gallon tank and have been told it doesn't use a float so how would I repair the fuel gauge so I can read my fuel levels like normal again? Those are the 3 main issues with the car.
  2. Nailhead Ronnie

    Nailhead Ronnie Life's 2 Short. Live like it.

    You need to find a service and chassis manual. I had to buy one recently beacause life is hard with out them. Check online for a used one.

    Wish I could help with more.
  3. john.schaefer77

    john.schaefer77 Well-Known Member

  4. TrunkMonkey

    TrunkMonkey Well-Known Member

    A manual is almost as good a friend as a dog.

    Nothing like a real flesh and blood (OK, pulp and ink) manual you can mark pages, flip back and forth and get a job done. This internet stuff is fine for "browsing", but having the ability to go back and forth, mark pages for "random access as needed" during work, troubleshooting or whatever, is gold.

    Second to that, are friends, both in the flesh and "imaginary" to help you over the sticky spots.

    To address the three things you mention.

    1. Speedo cable. Connection to the speedometer at the back. Lay on your back and flashlight. It is a knurled cap that is screwed to the back of the speedo. Routed down and through the firewall to the drivers side of the tranny at the rear of the housing. You unscrew both knurled caps, pull the old cable sheath, stuff the new one and route/fasten it the same way in reverse.

    2. Heater core is going to be some work. The housing for the core is "split" on both sides of the firewall. You remove all the bolts holding the heater box inside the passenger compartment, and the blower housing on the engine side of the firewall, with the heater hoses disconnected, along with the heater box/vent control cables, and then the heater core is removed from the inside of the heater box after you get it out of the car. Then reverse the procedure. There are some tricks, you will find that help, from removing the inner fender well on the passenger side, to cutting an access hole in the fender well so you don't have to pull it, as well as leaving out the one or two bolts that otherwise require pulling the fender well.

    3. You have a sender in the tank, and the gage. The sender is a rheostat (variable resistor) that is between 0-90 Ohms. At one position, you are reading "E" on the other end of the resistor (float arm position) you are full.
    You need a ground, at the sender/tank. The tan wire that runs from the sender in the tank, the the back of the fuel gage, and power to the gage, and ground for the gage.
    So, there are three things that can be wrong. The gauge is bad, the sender is bad, or the wiring is bad.
    There are ways to test each of these.

    First thing is to make sure all connections are clean and tight. (ground and power).

    Then disconnecting of the tan wire at the sender/tank, and touching it to ground, the indicator should drive to "E". with the ignition switch in the "run/on" position. (here is a good bit on the operation;

    Using an Ohm meter on the sender is almost always requiring the sender to ber out of the tank, so you can articulate the float from one end to the other, but you can test the wire and the gage in place first and rule them out.

    Most of these things, are simple "one thing at a time" and systematic and logical progression.

    And until you gain experience, you might do some things that are redundant, or "simplistic" to other's with experience, but you also will be building skills and knowledge along the way.

    Those last two things are more valuable than all the tools and best guesses, when you have nothing but your wits and experience. And those will let you solve things you have no knowledge or experience in, when you cannot ask someone for help.

    Hope that helps. :)
    john.schaefer77 likes this.
  5. john.schaefer77

    john.schaefer77 Well-Known Member

    I prefer my paper one by far. Just put the link in case the OP needed it quick. Rock auto carries the manual in electronic and paper form. Good price too

    Part# 70BSM $38.79
    TrunkMonkey likes this.
  6. 69GS400s

    69GS400s own amusement ride!

    I call the factory Buick service and chassis manuals "The Bible" for my car.

    When I bought my 69 GS 25 years ago,they were the first thing I bought .. I then spent a whole summer of weekends at a friend's lake house reading them cover to cover ..
  7. TrunkMonkey

    TrunkMonkey Well-Known Member

    I hope my reply did not come across as a criticism. It was far from that. :)
    john.schaefer77 likes this.
  8. flynbuick

    flynbuick Super Moderator Staff Member

    Read Jason's thread on diagnosing issues with fuel gauge readings. Yes, your tank has a sending unit with a type of float. There may be no reproductions, but you can send your tank sending unit to Tri Starr Radiator for a rebuild. Your problem could be as simply as a faulty ground wire connection outside of the tank. So, follow the steps Jason laid out first rather than taking a guess.
  9. john.schaefer77

    john.schaefer77 Well-Known Member

    Not at all. I am in agreement. I personally use the electronic version when I just need a page to take out to the job and not worry about destroying it.

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