Solid K frame bushings

Chassis, Suspension and wheels

  1. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    I'd like to find a set of aluminum or polyurethane bushings to replace the old rubber K frame bushings in my Diplomat. It's getting a 360 where a slant six once was, and since it's 450lbs lighter at the moment, now is a good time to change the bushings.

    I would be very grateful if someone could explain to me the safe, proper way of doing this. I'm sure I can figure it out, but any advice would be helpful. Thanks.
     
  2. kramer

    kramer Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    Jul 22, 2020
    Location:
    Vegas
    SlantSixSullivan likes this.
  3. MiradaMegacab

    MiradaMegacab Well-Known Member

    Messages:
    1,718
    Likes Received:
    574
    Joined:
    Feb 27, 2011
    Location:
    Long Island NY
    Tip of the day, drill a 1/8” hole in the frame rails directly in line with the 4 K-Frame bolts. Use RustBuster/ LiquidWrench, inserting the straw into the holes to soak the bolts and more importantly the “captured nuts”.
    Soak your nuts daily, perhaps 3 times a day for a week, this will make bolt removal easy. We don’t like to strip our nuts! Lol
     
    SlantSixSullivan likes this.
  4. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    They usually get soaked a couple times a week, more in the summertime.
     
    MiradaMegacab likes this.
  5. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
  6. M_Body_Coupe

    M_Body_Coupe Well-Known Member

    Messages:
    314
    Likes Received:
    102
    Joined:
    Aug 19, 2013
    Location:
    Windsor, ON, Canada
    Our home-grown FOR SALE item is a great product, a bit spendy (not a remark on the seller's asking price, I think it is reasonble) but the part itself is just a tad more cash.

    If you are looking for something cheaper and are not hung-up on having iron/aluminum pucks in there you can always pursue the POLY approach.

    That is what I installed in my coupe years ago, hasn't been an issue since I tossed these things in.

    Here is a link to Prothane 4-101 kit on Summit ($64) Prothane Motion Control 4-101-BL Prothane Body Mount Bushings | Summit Racing

    or the more expensive Energy Suspension 5.4111 kit ($126) Energy Suspension 5.4111G Energy Suspension Body Mount Bushings | Summit Racing

    Compare them, I think neither one of the kits above come with the mounting hardware (bolts), so that would assume you can re-use yours, and as others have pointed out, that may be questionable.

    However, if you have a little extra ambition and the need to stiffen up the rear suspension a tad I highly recommend the POLY leaf-spring ISO pads, assuming of course that you are staying with the stock ISO clamp setup.

    Take a look at this kit Energy Suspension ($68) Energy Suspension 5.6106G Energy Suspension Leaf Spring Pads | Summit Racing, I tossed these into my coupe to replace the NOS rubber pieces and boy, much stiffer and more controlled ride (as can be expected).
     
  7. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    I'm converting to B body shock plates, an even stiffer setup than poly ISO bushings. Since I'll have extra weight up front, I do want to stiffen the K frame and I believe aluminum/cast iron would be best, however, this is not an all out high performance build so the poly bushings you pointed out would be fine, with an attractive price tag, I might add. Bolts should be no problem, my employer may unwillingly support them (I jest).

    I've read that some people end up having to disconnect the upper control arms to do this job, and that would be fine because I really do need to do those bushings and ball joints as well. I suppose I'm looking for safety tips as well as procedural advice, as I don't want to get hurt
     
  8. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    Just added the Prothane bushings to my Summit cart, so thank you for that. Also thanks to other members who directed me toward some aluminum bushings for sale. With a price difference of roughly $160, it made sense to go polyurethane (for MY needs).
     
  9. BudW

    BudW Moderator Staff Member

    Messages:
    4,579
    Likes Received:
    1275
    Joined:
    Mar 4, 2012
    Location:
    Oklahoma City
    It is not hard to replace the two Right side mounts, with K-frame in car. The two Left side mounts are a bit more difficult – because of the steering gear is still attached to steering column. When the K-frame is unbolted, the steering column will only allow a small bit of movement downwards – less so for the Left Rear mount. A person can then take a saw (hacksaw, Sawsall, etc.) and cut the old rubber.metal mount one out, but it will still be difficult to get new mount in. Sense the engine is already out, I would recommend to either disconnecting the steering column at the rag joint (black rubber donut looking item) – which is not easy to do, or unbolt the steering gear from K-frame (and find a way to support the gear – which is easier).

    On the later method, measure the distance between the fender wells. Screw a couple pieces of 2x4” scraps onto the ends and place your bridge on those fender rails. The exact location is not a major issue. Then take a ratcheting tie-down strap (or something) to support the weight of the steering gear up a bit, then the K-frame will come down enough to remove the Left side mounts after you remove the three steering gear to K-frame bolts.
    86 Underhood m.jpg
    Orange is location of 2x4's and green is tie-down strap.

    This does have to happen because the upper control arm brackets (Chrysler calls them “Support Brackets”) are in the way of the frame rails.
    If you loosened the torsion bars several turns (do this first to come out and last when back together), I remove the four screws (and upper shock nut) that attach the upper control arm bracket (Support Bracket) to the K-frame – that way the alignment is not going to be way off. If you remember exactly how many turns you loosened both torsion bars, then your alignment will be exactly the same as it was before you began.
    With that said, it is always good to check the ride height afterwards and get car aligned afterwards, anyway.

    To me, removing those large upper control arm bolts (to Support Brackets) are a burden and time consuming, where as the 4 bolts (and upper shock nut) are not too bad and just bypass the other.
    77 FSM pg 2-12c.png

    The shock nuts are a different matter. If rusty, it might be faster to break off the upper/lower shock ends or cut 'em off then to unscrew 'em. Aspen 500 has mentioned taking a deep socket (9/16", maybe) and a long extension. Put the deep socket over either front shock nut, then move back/forth and the stud will break off after a bit of work.

    Note: Not counting rust, this would be an excellent time to install new shocks . . .

    If you plan on rebuilding the front suspension, Then I would recommend to remove the entire K-frame from car. Give everything a good coat of paint and stick it back under the car when done. This is one I removed from an '84 Gran Fury.
    20190825_173924.jpg
    I loosened both torsion bars (10 turns, maybe - I can't remember), removed the upper control arm plates (as mentioned above) but still attached to spindles. I placed a floor jack under K-frame (which still held the engine and transmission in place). Raised the front of car up a few feet. Re-bolted the upper control arm brackets onto K-frame, then reattached tires to brake rotors. Then rolled the K-frame/engine/transmission out from under the car. At this point, I still had to have a floor jack under the transmission to roll it around.
    The above picture of that front suspension, after I removed the engine/transmission. I just rolled the entire suspension outside, until I could work on it.

    When I get ready to install the big block(s) into my cars, I will make a Jig so transmission can be supported a bit better. Dropping the front of car down over engine/K-frame is SO MUCH easier than dropping engine down from above - especially if headers are being used.
    K-frame Jig 3.jpg
    This is not an FMJ, but you get the picture.

    BudW
     
    Last edited: Mar 6, 2021
  10. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    Thanks, Bud. I will be referencing this post when I do the job. As always, your detailed instructions are much appreciated.
     
    Kramer79 likes this.
  11. LSM360

    LSM360 Well-Known Member

    Messages:
    358
    Likes Received:
    81
    Joined:
    Nov 28, 2011
    Location:
    Melbourne, Florida
    Aluminum K Frame Isolators: single best suspension upgrade I've ever made.
     
  12. Sub03

    Sub03 Well-Known Member

    Messages:
    48
    Likes Received:
    30
    Joined:
    Apr 5, 2020
    Location:
    Norway
    Borrowing this thread to ask a question: I replaced the pucks on my Aspen with the Summit poly ones. Anyone know the torque I should use on the bolts with the poly bushings?
     
    SlantSixSullivan likes this.
  13. M_Body_Coupe

    M_Body_Coupe Well-Known Member

    Messages:
    314
    Likes Received:
    102
    Joined:
    Aug 19, 2013
    Location:
    Windsor, ON, Canada
    My '80 FSM says: 80 ft. lbs., which is 108 Nm.

    I used the POLY pucks and the factory specs to do mine.

    Keep in mind that the hardware (retaining nuts) hidden on the inside of the frame rail may be rusted and therefore not retaining the sort of strength that it had when new. So I would inch-up on that final 80 ft.lbs. measure and go up in let's say 20 ft.lbs steps: 20, 40, 60 and maybe 70 and finally 80.
     
    SlantSixSullivan and Sub03 like this.
  14. Sub03

    Sub03 Well-Known Member

    Messages:
    48
    Likes Received:
    30
    Joined:
    Apr 5, 2020
    Location:
    Norway
    Thank you M_Body_Coupe, good to know I'm not way off. I read somewhere (FBBO I think) someone wrote 150 ft. lbs.:eek::eek: That didn't feel right so i tightened them to 75 ft. lbs. with regularly check ups.
     
  15. SlantSixSullivan

    SlantSixSullivan Well-Known Member

    Messages:
    122
    Likes Received:
    24
    Joined:
    Nov 21, 2016
    Location:
    East Liverpool, OH
    Just got my poly bushings yesterday. Moving along with this project after three years.
     
  16. MiradaMegacab

    MiradaMegacab Well-Known Member

    Messages:
    1,718
    Likes Received:
    574
    Joined:
    Feb 27, 2011
    Location:
    Long Island NY
    7E1E60E8-C337-46B2-8121-0580738105BD.jpeg
     
    SlantSixSullivan and Camtron like this.
  17. Camtron

    Camtron Well-Known Member

    Messages:
    786
    Likes Received:
    410
    Joined:
    Apr 25, 2019
    Location:
    Here
    When I did mine, I broke the 4 bolts loose with the car on the ground and backed them out about half way.
    Starting at the drivers side, I raised the unibody with a jack until the bolt heads were about touching the K-frame and then removed the two bolts completely on the drivers side and raised the body up a little more.
    That opened up enough space between the K-frame and unibody to get both iso pucks out and install the solid aluminum ones with little effort. Lower the body, thread new bolts in half way and then move onto the passenger side.
    More of the same on the passenger side, the front puck (closest to front end) is pretty easy to get out on the passenger side, not much blocking it at all. The rear puck on the passenger side however, that took a little effort. It’s positioned behind the upper control arm so, I just used a die grinder and cut off wheel to cut it in half and pop the two rubber pieces and sleeve out with a small pry bar.
    Put new pucks in, thread your last two bolts half way in. Lower car to the ground and torque bolts to spec. Think mine are sitting at 80-85ft lbs.
    One thing I did notice is that, the aluminum ISO pucks didn’t want to stay put in their little locating cutouts. The slightest touch/bump will put them out of location so, take your time and double check to make sure they’re sitting correctly.
     
    MiradaMegacab likes this.
  18. Mikes5thAve

    Mikes5thAve Well-Known Member

    Messages:
    496
    Likes Received:
    171
    Joined:
    Mar 3, 2020
    Location:
    Canada
    I'd never imagine unbolting and supporting the steering box is easier then removing 2 bolts from the rag joint. They're pretty quick to remove.
     
  19. BudW

    BudW Moderator Staff Member

    Messages:
    4,579
    Likes Received:
    1275
    Joined:
    Mar 4, 2012
    Location:
    Oklahoma City
    Where as the rag joint bolts are not so easy to remove (even 40 years ago...).
    Pretty much opposite what one would expect.
    BudW
     
  20. MiradaMegacab

    MiradaMegacab Well-Known Member

    Messages:
    1,718
    Likes Received:
    574
    Joined:
    Feb 27, 2011
    Location:
    Long Island NY
    A7DB5468-299C-4262-805C-A8EFDDC3FD09.png