72 Buick Skylark - Convertible top getting weak.

Discussion in 'The Bench' started by bcoyour, Apr 19, 2016.

  1. bcoyour

    bcoyour Member

    Does anyone have suggestions on why my 72 Skylark convertible top would be getting weaker (going up and down). For reference it used to be very zippy both up and down. Then after sitting over Winter as it normally does, the next year it was noticeably weaker and very sluggish both up and down. I popped off the back seat and check the fluid level, which was fine. Also, the lines had no visible leaks. One of the cylinders looks kind of grimy, It appears to have been leaking at some point, though the fluid was not low.

    Any thoughts on if the pump / motor could be just going bad, or if the cylinders should be replaced? Also, what would you grease / lubricate the hinges of the convertible top with?

  2. mrolds69

    mrolds69 "The Cure"

    It's hard to say what the problem is. The motors usually work or not, although I suppose there could be burnt windings or dirty brushes in it. One guess would be high resistance in the electric circuit someplace. The motor needs lots of juice. It's always better to raise or lower the top with the car running. The manual says to use a dripless oil on the hinges, HTF stuff...but it's still around.
  3. yachtsmanbill

    yachtsmanbill Well-Known Member

    You need to put a pressure gage on the pump to isolate whats what. Its either that or the cylinders are gonners. Oiling the hinge points with a drop or two of 5W20 oil from an oil can may ease a situation that's just tired. Keep an rag handy to wipe up any drippage. I don't recall what the pump pressure should be, but if its tired as well, theres rebuild kits or exchanges available. ws
  4. BrianinStLouis

    BrianinStLouis Silver Level contributor

    I thought I remember reading the pump pressure should be ungodly high....more than 300 PSI.

    I have the same problem. I've bought a pressure gauge but a leaky exhaust manifold has kept me at the other end of the project.
  5. TORQUED455

    TORQUED455 Well-Known Member

    My 72 convertible had a slowly declining enthusiasm for going up and down. I replaced the pump/motor asm for some reason other than slow-motion (leaked or something) with a new one from Hydroelectric in Punta Gorda Florida. That didn't change the speed of up and down. A few years later, one of the cylinders leaked badly and fluid ended up on the ground. I replaced both cylinders with new ones from Hydroelectric and now the top has been faster than I can remember in over 30 years! Although the cylinders were grimy, I never added much fluid over the years.

    You could have a voltage drop to the pump/motor asm, a faulty pump/motor asm, faulty cylinders, faulty lines or a binding frame mechanism. I'll vote for cylinders.
  6. DeeVeeEight

    DeeVeeEight Well-Known Member

    Check for pinched or kinked hydraulic lines.
  7. bcoyour

    bcoyour Member

    Thanks for all the suggestions! I'll try out some of these ideas once I get some time to spend in the garage. I'll report back with my findings.
  8. pbr400

    pbr400 68GS400

    For what it's worth, it doesn't sound like the pump. Mine worked fine for two or three years of regular use, then like a switch was flipped went to running at about 50% and tripping the breaker halfway up. That was a pump failing.
  9. cstanley-gs

    cstanley-gs Silver Mist

    FYI, a pump from an 80's Chrysler Lebaron is the same - just switch the reservoir covers so you have the correct mount on that end. (electrical connection is different but still two wires, easily modify the pump to match)
    Lines are the same too.
    I can find them sometimes in the local yards and have never paid more than $10 for the pump
    I often wondered about the cylinders but I never did try them.

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