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Knee action suspension

Discussion in 'The Hokey Ass Message Board' started by fej70, Apr 30, 2012.

  1. fej70
    Joined: Apr 8, 2012
    Posts: 6

    fej70
    Member
    from Minnesota

    Has anyone kept their original suspension with a V8 swap? looking at putting in a chevy 305 and keeping the knee action suspension.
     
  2. 39 All Ford
    Joined: Sep 15, 2008
    Posts: 1,531

    39 All Ford
    Member
    from Benton AR

    Not really an answer, I read up on rebuilding a knee action setup several months back, seems like an "involved", but rewarding project.


    From what I read, I don't think that the 305 would prove too much for this suspension.
     
  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,908

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Exactly what are you referring to as "knee action' suspension? Your avatar appears to be a '41/'48 Chevy and if that is the car in question, it does not have "knee action". Those cars, and most if not all GM cars of the period, had shocks incorporated into the upper "A" arms.

    The actual suspension system that introduced Knee Action was on earlier models, around '36 or '37/'38 and was derived from a French design and is a massive hunk, with trailing arms to the front wheels. I doubt that is what you have.

    If you have the '41/'48 style integrated shocks, they can be rebuilt, but it is my opinion they are not very effective even when working correctly, but better than not working. It may be possible to fit tubular shocks by providing a mount on the lower control arm and an upper mount on the frame and just using the upper "A" arms as.......well, upper "A" arms.

    Ray
     
  4. TagMan
    Joined: Dec 12, 2002
    Posts: 5,938

    TagMan
    ALLIANCE MEMBER

    "Knee Action" is the name Chevrolet called the Dubonnet front suspension. It was Chevy's first stab at independent front suspension and combined a shock absorber & spring in one housing. They work well, but had a poor reputation for leaaking oil. When the units ran out of oil they failed and most people then changed over to a I-beam axle or just junked the cars. I have them on my '37 coupe and rebuilt them to use modern lip seals. They don't leak now and perform well, but they are heavy. They were first introduced in 1934 and were used thru 1938.
     
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  5. fej70
    Joined: Apr 8, 2012
    Posts: 6

    fej70
    Member
    from Minnesota

    My mistake, I thought it was considered knee action. Its a 41 2dr town sedan. Looking to make a driver. If fabrication is needed to the original suspension then it might be worth going for a weld in IFS.
     
  6. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 23,746

    Jalopy Joker
    Member

    depends on what level of ride and handling you will accept. installing upgraded shocks nothing like switching entire front suspension. your ride, your $$
     
  7. OoltewahSpeedShop
    Joined: Oct 18, 2007
    Posts: 3,104

    OoltewahSpeedShop
    Member

    One of my buddies has a '34 Pontiac straight 8 with the Knee Action suspension. It's decent at best. I'm sure the 305 wouldn't weigh what the original engine does. When we do the V8 swap on his car it will be getting a Ford type front suspension and crossmember with transverse spring.

    It's a cool ass car, but the drivetrain and suspension have to go.... 45mph doesn't cut it.
     

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  8. TagMan
    Joined: Dec 12, 2002
    Posts: 5,938

    TagMan
    ALLIANCE MEMBER

    Come to think of it, Chevrolet might have called their independent front suspension "Knee Action" even after they discontinued the Dubonnet system. Try Googling "Knee Action"and see what you find.

    BTW, some people also call the regular old shock absorbers "Knee Action", but that's a misnomer.

    Pontiac did have the Dubonnet system, too, during the same years as Chevy. I also recall that using a Pontiac Dubonnet on the Chevy would lower the front end a bit.
     
  9. fej70
    Joined: Apr 8, 2012
    Posts: 6

    fej70
    Member
    from Minnesota

    It's a cool ass car, but the drivetrain and suspension have to go.... 45mph doesn't cut it.[/QUOTE]

    That is what I thought of. I want a driver, but a driver that can keep up with todays traffic.

    Is there other options other than MMII, within in a moderate price range? not looking to go cheap, I don't mind paying for quality, just dont want to break the bank.
     
  10. fej70
    Joined: Apr 8, 2012
    Posts: 6

    fej70
    Member
    from Minnesota

    Where did yhou find the kit to rebuild them? or did you make a kit on your own?
     
  11. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    pasadenahotrod
    Member
    from Texas

    Probably the Pinto/Mustang II units would be your best choice in IFS. So many options for brakes, bolt patterns etc., now available.
    Pinto 73-80, Mustang II 74-78.
     
  12. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    Your suspension is fairly strong. The manufacturer would have specified greasing every 1,000 miles. The original springs are very soft. The shocks are under-damped for the original springs and WAY under-damped if you go to stiffer springs. I know it is possible to increase the damping of these units, but I have never done it. If you don't want to try it yourself, there are people who specialize in working on these shocks. I remember seeing a car where the original shock was retained as a control arm, and a tubular shock was added. Damping and spring rate aside, the biggest down side of this suspension is its geometry. Years ago tires didn't last very long. Because of that, whether necessary or not, GM decided the most important thing was to minimize sideways scrubbing of the tire as the suspension went up and down. That results in camber changes that are not very good for cornering. The wider and/or stiffer the tires, the more that is so. Something to think about; because of frame flex, there is only so much benefit to be had from stiffer springs, shocks, or sway bar. You reach a point where any additional upgrading is mostly negated by the frame's low stiffness.

    It's pretty standard practice to swap in more modern suspension. I have seen quite a few cases where I don't think that was really necessary. It comes down to what the car is and what you want it to be.
     
  13. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,908

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Chassis Engineering bolt in Mustang II based suspension (or weld in Fatman/Heidts, etc.) is probably the easiest and cleanest install for your chassis. The only other fairly simple is Jaguar XJ6/12/XJS, but it may be too wide for your application.

    I would avoid the Nova/Camaro clip method. A rear steer version, narrowed a bit COULD be done cost effectively, but done right is a lot of work.

    I have always liked the '41s............nice looking cars IMO.

    Ray
     
  14. silversink
    Joined: May 3, 2008
    Posts: 912

    silversink
    Member

    I kept them on a 1948 International after putting in a 350/350 combo. The old 6 weighed as much as the chev combo, I do 55-60 and it rides just fine. I'm not saying it wouldn't ride betterwith tubes, but I also kept the stock springs which are stout enough that the shocks aren't flexing that much. I rebuilt them for the lip seals and no leaks here.
     
  15. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    [​IMG]

    This 34 Chevy was built in 64(ish). A low mileage one old lady car. A master, it came with a knee action and replaced it when it was built with an early Ford straight axle, cross spring and split radius rods.

    [​IMG]

    This is the knee action that was a sort time (34-38) not very successful attempt at independent suspension.
     
  16. OldBuzzard
    Joined: Mar 8, 2008
    Posts: 878

    OldBuzzard

    You might check into a '49 - '54 front end. It should almost, if not directly, bolt in. It appears that they switched from the upper a-frame/shock thing to a more normal type a-frame with a tube shock.
     
  17. TagMan
    Joined: Dec 12, 2002
    Posts: 5,938

    TagMan
    ALLIANCE MEMBER



    No, I tore them apart, tossed the packings, made new bushings, sleeved the shaft and machined the housings to accept lip seals. The biggest challenge was mounting the housings on the mill - they were a real PITA.

    I did this about four years ago and have put approximately 15k miles on the car with no leaks.
     
  18. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    [​IMG]
    I'll always remember my 47 Chevy woodie wagon that I drove up to Cumberland. During the rod jousting I was able to get the front tires off the ground on the third bounce by coming off the line and stabbing the clutch at the top of the lift off. When it reached bottom I let out on the clutch after it would go back up I repeated the process until the front tires were finally air born.. My buddy was bouncing around hanging out of the RR window with a pool cue. We cracked the glass but it still worked. We didn't win anything. Who could wield a pool cue under those circumstances? We sure did have fun with the dry shocks that did nothing to reduce any of the the bounce!!!....but the crowd loved us!:D
     
  19. OoltewahSpeedShop
    Joined: Oct 18, 2007
    Posts: 3,104

    OoltewahSpeedShop
    Member

    That is what I thought of. I want a driver, but a driver that can keep up with todays traffic.

    Is there other options other than MMII, within in a moderate price range? not looking to go cheap, I don't mind paying for quality, just dont want to break the bank.[/QUOTE]

    Like I said before, we have no intention of going with an IFS unit. The Ford type front setup is what we are going to use with a DROPPED STRAIGHT AXLE.

    No Mll around here... Ever.
     

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