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Both Front and rear motor mounts are liquid filled, the big bulky front
didn't surprise me too much, but the fact that there was a pocket of oil in the
rear motor mount did surprise me....
Mine used to have liquid in them, I am awaiting pourable Urethane to put in the hollow void that used to contain the oil to stiffen the mounts.
Okay so which is it? seems like you have hard proof of them being liquid filled, but then I have heard on this list of people saying Gen III's didn't use liquid filled mounts.
Are there any special recommendations or precautions for dealing with installing new liquid mounts then?
or Scott can you give us a play by play of your pourable Urethane treatment. what, you make some sort of temporary mold around the mount or is that not necessary? I am not sure of the properties of U., does it harden/gel up or will it stay liquid?
I knew the mounts were either hollow or had liquid in them. Since the MTX driveline is going to have more jarring stresses than the ATX does I am doing everything I can to more rigidly hold the driveline in place.
I took a drill and drilled holes in both motor mounts. I did the front first as I knew that it had give in it but was a solid piece with no visible exterior holes in the rubber, I was hoping to find it have some kind of void in it that I could fill. Sure enough about a cup of oil came out. So for kicks the rear mount clearly has space in it around the sides and the top, but I wasn't so sure about the bottom. Employing the drill there revealed the same thing (except much less fluid as there isn't that much space to fill)
There is obviously open space around the sides and top of the rear mount that will also get filled. Pourable molding Urethane is available in various cured hardness levels but isn't exactly the cheapest stuff around. It is a two part epoxy like approach, and I will pour / squeeze it into the openings of these mounts (I have degreased the inside of them as best I can, and am letting them dry out now), I'm thinking I need to go by myself a cheap frosting thing like the cake people use so that I can fill it and squeeze it on into the mounts.
I've gone for a urethane that has a Shore hardness rating of 80. A Car tire is about a 70 on the same scale, so this is a touch harder than that. Hopefully it doesn't end up too harsh, but if motor mounts are my biggest problem then man the rest of it must be working well. I'll have about 20 minutes to work with the mix before it starts to set, full cure will take 48 hours.
How about high temp hot melt glue? I would think this would work as long as
you get some that is rated above 300F. I know where this can be gotten cheaply.
When it hardens it still has some flex and is almost indestructible.
Are there glue guns for the commoner that get hot enough to melt it? I
thought most glues guns were about 220 or so. To get a 300 degree hotmelt to
flow well inside the entire mount I would think you would need to heat it to 400
or so, and then getting all of it in there through any reasonable size opening
before it sets up would be another challenge. Is there some tooling that would
make this possible that I don't know of? If we could move about 1 cup of hotmelt
(remaining fluid during that minute - maybe by baking the mount prior to the
process) in 60 seconds or so this woudl be a possible and cheap solution.
The TPR may be an option for fabricating completely new mounts.... I may end up there for the tranny....
One of the beautiful things about the pourable Urethane is that the shrink is les than .0005" per inch when it sets (so shrink is .05% during hardening); that along with the luid properties which reduce air entrapment still make it a shining star. 20 - 30 bucks for a pound (not quite a quart) of it however woudl be a drawback if this would be done frequently by many or with any volume.
So I took some pictures of the de-liquefied mounts, I'll send pics of them after filling them as well Obviously the holes are where I let the oil out. Each mount got two holes (one on each side) so I can get the air out as I fill it.