"Dog-bone" [engine torque strut] rebuild...updated with new content

Discussion in 'Workshop Forum' started by Dr.Jeff, Nov 29, 2017.

  1. zonker

    zonker Just Another FIAT Freak

    Location:
    Sun City, CA
    Great write up on the repair, Jeff. I did something a little different on my '74 - I repaired one side a few years back with a generic napa shock bushing., But when trying the same bushing on my '78 it was too loose to be useful, so be prepared for one replacement diameter not fitting all dogbones.
     
  2. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    That is along the lines of what "SteveG" was suggesting also.

    Back when I did the mod to mine I researched the urethane bushing idea. The problem was nothing I found came close to fitting the stock dogbone strut, so a complete new one would have to be made as SteveG said (which would not be difficult, could even make it with an adjustable length). But I was hoping the solid rubber engine mount would work so I did not pursue the generic urethane idea any further. Plus depending on the "duro" rating, urethane can be too stiff for a road car. I might still have a couple references with the list of available urethane bushings with some dimensions. But they are not well organized or comprehensive, so a bit difficult to navigate.
     
  3. lookforjoe

    lookforjoe True Classic

    I used a shock damper on my old wagon, but that was because the 500AWHP otherwise ripped the lower engine mount to shreds in short order. It generated a fair amount of vibration. I took it apart and actually it relied on a series of different density poly bushes.

    [​IMG]
     
  4. lookforjoe

    lookforjoe True Classic

    Good idea, however those are more rigid that even the mount I have, so more vibration. The bushes with open sections (like the snail mount bushing) provide good damping, that's what I want to add.

    I used the type of bushing illustrated for my Radiator mounting, as they are quite rigid
    :D

    [​IMG]

    [​IMG]
     
    Last edited: Jun 10, 2019
  5. NEG

    NEG Daily Driver

    Location:
    UK
    RevTek used SuperPro SPF0021K for the dogbone in his first video, I wonder if they have lasted....
     
  6. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    For the most part I agree with Huss, urethane bushings are too firm for a street car (as suspension or eng/trans mounts). However some of the urethane bushing manufacturers offer a range of duro ratings to choose from. The softer ones are actually quite compliant, you can easily squeeze them with your hand (with the bushing not installed in a race). But I have not tried any of those softer duro ones on a vehicle to see how they feel, so I have no idea if they are soft enough to be good for regular driving without too much vibration transmitted. However I doubt you are likely to find a selection of duros for universal bushings(?). So it would have to be a part that fits another vehicle, and comes in different firmnesses, and fits in the dog bone.
     
  7. AKimball92

    AKimball92 True Classic

    I talked to Dominic (I believe his name is) about the video. I saw the vid and wanted to copy his directions. I still have the bushings and might yet follow through with his given his experience and review after some miles.

    Hi Andrew,

    The bushing fit fairly well, there definitely was not 10mm of space between the bushing and dogbone housing, maybe closer to 5mm (2.5mm each side).

    To fix this, I used an polyurethane sealant all around both mounts (in the air gap between bushing and housing) which has secured it 100%, there is now zero movement and the bushing should last forever.
    I didnt get a chance to show that part in the video, the part you see in the video is before I added the sealant.

    I did a big search, could not find a bushing closer to the size for our dogbone as its not just the OD that needs to match, but the ID for the pin, and the width of the bushing. I found the superpro bushing to be withing 5mm of all the measurements (ID is exact) which is pretty good.

    Dom​
     
    Mark likes this.
  8. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    His mention of the urethane sealant brings up another option that I don't believe we've discussed. On other forums it has been quite popular to take stock engine mounts or other various rubber bushings and fill any/all voids with a urethane sealant (windshield glue seems to be the most common). With the stock dog bone bushings the void is actually large but located inside the metal housing (round tube). So I'm not sure the best way to fill that void with the adhesive. But it should make them much more durable if someone can think of a clever way to do it.

    3m-08609-400.jpg
     
  9. Rod Midkiff

    Rod Midkiff True Classic

    Location:
    Eugene, OR
    I found this image on facebook showing a modified dog boon mount.


    Capture.JPG
     
  10. PaulD

    PaulD Paul Davock

    Location:
    Kitchener, Ontario
    Here is a photograph of the solid mount I made, and the modified stock unit I made when I found the solid mount to transmit too much vibration for me:

    DSC_0221.jpg


    The bushings in the dog bone are the ones that Jeff recommended, only they I expanded them greatly when I pressed in the larger steel center bushings. They fill the full cavity, are very stiff and have held up well so far. Not many miles and one track day on it, so I am not sure about longevity.

    Paul Davock
     
    Dr.Jeff likes this.
  11. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Paul, I can see that those inner sleeves are much thicker and push the insert much further out. That not only fills the outer metal cases better, but also compresses the rubber to make it more dense in the available space. Very interesting. Even with the stock inner sleeve I enlarged the center hole in the rubber to fit it in. Did you open up the hole any, or manage to press the thicker sleeve into the smaller hole into the rubber as it came?
     
  12. Daniel Forest

    Daniel Forest True Classic

    Location:
    Montreal,Canada
    Paul,
    If you want to sell the solid one, I'm interested. I'm already using a solid one and I was looking to modify it to be able to adjust the length.
     
  13. Mark

    Mark FIATFREAK

    This is what I have on my car and it’s been working fine with no objectionable vibrations.

     
  14. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    The SuperPro SKF0021K in the referenced mod by Dom is a rear suspension trailing arm bushing for a 124 Fiat. I recall the suggestion of using a stock 124 rear arm bushing in the past. But it sounds like they are actually too small and require the use of urethane adhesive to hold them in the metal cylinder?
     
  15. Mark

    Mark FIATFREAK

    The metal sleeves on the stock 124 trailing arms are for 10mm bolts; not 8mm like on the X1/9 dog bone. That’s why they won’t work.


     
  16. PaulD

    PaulD Paul Davock

    Location:
    Kitchener, Ontario
    Yes, I did enlarge the center hole of the rubber, I do not remember the size. Note that the bolts are 1/2 inch so the steel insert part is bigger too. It expanded the rubber quite a bit when I inserted it.

    Paul
     
    Dr.Jeff likes this.
  17. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    Here's how I do it...

    I use an SPF020 bush. This is the GREY bush shown in the pic. SPF021 is the green bush, the yellow and blue bushes are both spf155's but the yellow is old production, the blue is new production and duro 70 rated supplied with the steel sleeve.
    20190613_120641.jpg
    20190613_120702.jpg

    I think the SPF020 is a better choice. While totally crap for their intended application as a suspension bush in a 124 (they are an EXACT copy of the rubber original, so when the OE steel sleeve is press thru the bush effectively locks solid) they work great as a replacement "dog-bone" bush for a 128 / X19

    Take to the edges of the SPF020 with a hand held grinder (I mount mine in a vice, I don't like to use my bench grinder for plastics/alloys) a bit like this, it's not rocket science, just so it goes in a little easier.
    20190613_122138.jpg
    20190613_122148.jpg

    To get the old bush out of the torque rod, press out the centre steel sleeve
    20190613_122326.jpg
    20190613_122337.jpg

    make sure you clean the sleeve up, they are usually a bit rusty.
    20190613_123909.jpg

    next step is to remove the old rubber bush from the arm, pretty simple, bang an old screwdriver thru the top, and twist it out...

    20190613_121050.jpg

    original bush next to the SPF020 and SPF021
    20190613_121223.jpg

    next step is to simply by hand slip one end of the slightly modified SPF020 bush into the torque rod end, it should be a snug push thru the hole... I usually run a hand file around the inside of the steel bush ID to make sure there are no rough edges... and rubber grease is always a good thing.
    20190613_122914.jpg

    next step I actually forgot to take a pic of, but it makes the job much much easier... slip the inner steel sleeve into the urethane bush...in this pic it would be in from the right hand side... but ONLY PUT IT IN ABOUT 1/3 OF THE WAY.

    then put the whole lot into the vice again with some appropriate sockets and give it a squeeze.
    20190613_123258.jpg

    after a bit of jiggling, you'll get this....
    20190613_134535.jpg

    now the bush is actually a tiny bit too wide, so take to it again to trim it for length with the angle grinder...
    20190613_134905.jpg

    20190613_134946.jpg
    20190613_134955.jpg

    I've done this a few times so it took maybe 20 minutes from start to finish including stopping and picking up my phone to take the pics.

    SteveC
     
    Last edited: Jun 13, 2019
    nichol01, PaulD, lookforjoe and 3 others like this.
  18. NEG

    NEG Daily Driver

    Location:
    UK
    Thanks for taking the time to post the procedure, but the bush you show being inserted is marked SPF020 not 021 or am I misunderstanding?
     
    fiatfactory likes this.
  19. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    lol... lucky I had nice clear pics of both... yes you're correct ...typo on my part...SPF021 was the previously mentioned bush used by someones else, I use an SPF020...

    SteveC
     
    NEG likes this.
  20. NEG

    NEG Daily Driver

    Location:
    UK
    Phew, I’m not senile yet! Thanks Steve!
     

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