How to replace engine mount inserts/isolaters/bushings? Is fire necessary?

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MRGTX

MRGTX

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Before my new engine goes in, I am seizing the opportunity to replace the rubber inserts in my motor mounts with urethane pieces. I am working on the '73+ 340/360 style motor mounts that connect the engine block to the K member.

It seemed like a very straight forward job and I didn't anticipate any problems...but these pieces appear to be molded into the bracket in an unexpectedly tenacious fashion. Even after trimming away as much of the material as possible, They resisted the press to the point of bending the sheet metal slightly. They're probably salvageable but to be on the safe side, I have another set of used motor mounts on the way (which will also benefit from the new inserts).

So before I mess up another set of mounts, what's the right way to get those out? I'm sure a torch would do it but I'm hoping there is a trick that will help avoid melting/burning and the associated smoke and mess.

Thanks!

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Drill a series of smaller holes around the perimeter then pull whats left out
 
Maybe dissolve rubber then cut collar (Blue) then air or hammer and chisel along (Red) to dent it in.. Then bang it out
Also maybe check ends for any tack weld .

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Maybe cut out enough section with a coping saw so you can collapse the remaining?
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If you're going to install urethane replacements, I don't believe you want to remove that outer shell.
 
I believe those inserts are pressed into the mount. Rock Auto sells the whole assembly and there rather inexpensive. 65'
 
Thanks to all for the suggestions so far...
Just to help clarify, this is what the replacement pieces look like...so the idea is to not remove or destroy the tube that contains the stock bushing.


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The idea of using acetone isn't one I had thought about. I don't know for sure that the stock pieces are made from natural rubber but it may be worth a shot.
 
Plymouth 65 said:
I believe those inserts are pressed into the mount. Rock Auto sells the whole assembly and there rather inexpensive. 65'
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Are those rubber mount though? Not poly?

In 1997 I completely filled all the air voids in the rubber mounts with Silicone from a caulking tube. Was suggested by Rick Ehrenberg in Mopar Action magazine. It was sort of a compromise between a poly mount or solid mount and a factory rubber setup.

been in there since ‘97. My guess is the silicone lessens the movement. And since they don’t move as much they’ve lasted a long time. … I have brand new replacements on hand waiting for these silicone filled ones to go bad.
 
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Yes, the one's I purchased from Rock Auto were rubber. On street cars I don't use poly mounts on anything but the transmission mount. 65'
 
Plymouth 65 said:
Yes, the one's I purchased from Rock Auto were rubber. On street cars I don't use poly mounts on anything but the transmission mount. 65'
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I used a torch and heated the outer shell until the were loose enough to pull out. Then cleaned up the inside and the new inserts went right in. I left the shell in the mount. It didn’t take much heat to get them out.
 
44067gtdart said:
I used a torch and heated the outer shell until the were loose enough to pull out. Then cleaned up the inside and the new inserts went right in. I left the shell in the mount. It didn’t take much heat to get them out.
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So it's not necessary to actually burn the material...this is encouraging.
 
Street driven cars ride much less harsh with rubber mounts. The engine mounts really don't effect the ride so it's builders choice. 65'
 
Ok, guys...just one more request to see if I'm missing anything.

I set one of these new mounts into a vice (careful not to bend it of course) and held the propane torch on the tube and the rubber itself. Using a chisel, I was able to carve away about 40% of the rubber after what seemed like a damn long time. It's still not out and I have another one to do. This will work eventually but it just seems like it shouldn't be this hard.

When you guys have heated up the mounts, how hot did you get them? Glowing? I'm not sure propane is the most efficient way to do this but I am hesitant to get the mounts that hot anyway.
 
Post #12 He said he heats the outer tube and pulls it out. I personally have never done it.
 
Kendog 170 said:
Post #12 He said he heats the outer tube and pulls it out. I personally have never done it.
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Right. I was hoping for more specifics or another method all together. I have already expended quite a bit of propane without much to show for it.
 
MRGTX said:
Right. I was hoping for more specifics or another method all together. I have already expended quite a bit of propane without much to show for it.
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Heat the outer shell and it will begin melting the bushing where it contacts the shell. Use oxy/acetylene torch if you can. If not, try MAP gas with your small propane torch.
 
I just built a fire and my fire pit, and throw them in there, retrieved them the next day.
 
I stuck one of the mounts Right into my garage propane heater and let it sit there for a few minutes. Flung it out into the snow to put out the fire and just pulled the rubber out with a pair pliers.

The first one took about two hours of heating and cutting, heating and cutting. The second one took five minutes.

Thanks to all for the input.

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sireland67 said:
Good job, you were just over-thinking it.
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Guilty as charged. :D

I have no special mechanical inclination only a desperate love for my Dart, Mopars in general, and driving as much as possible. I’m full of motivation but I’m trying to figure out all of this stuff in isolation aside from the input I get here. I am so grateful for this forum and the input.
 
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