Question about rebuilding differential bushings

[RoughSilver92]

I am planning on filling my differential mounts with 3M Window Weld, but I have a question about the position of the center related to the outer ring. I had originally thought that they should be perfectly centered, with the middle diameter centered in the outer diameter, and the same amount on both sides of the inner piece sticking past the outer piece when viewed from the side. After removing the bushings I am left wondering if this is correct, though. I notice there are arrows in the rubber portions of the mount, and a mark of white paint on the bottom of the mount when the arrow is pointing up. Any help on this would be appreciated, as I would like to get these things filled since they will take a week to dry!

[RoughSilver92]

OK, then. Looks like I'm going with perfectly centered. The bushings I took out were only a couple mm off center, and I guess that could just be from age and sagging (not to mention being torn). Just need to pick up a bottle of 3M single step primer to get a good bond to the bare metal.

[Crazy_pilot]

If anything I would guess the inner part would be held slightly above center, so when the weight of the diff is on it they pull down to center. I don't think you'll have any worries, the stiffer material should easily take care of any weight/stress.

[RoughSilver92]

Sweet.
And now some pics of the process:
http://img15.imageshack.us/img15/399/0304092330.jpg
The pieces after scraping off the rubber and sanding.


http://img21.imageshack.us/img21/786/0305090012.jpg
Now with the 3M Single Step Primer. Decided to do the transmission mount also. I used the primer on that as well.


http://img17.imageshack.us/img17/8779/0305090030.jpg
Back sides taped. Ready to fill.


http://img14.imageshack.us/img14/9608/0305090057.jpg
All filled. One tube was exactly enough to do these three pieces!
About a week to dry and they should be good to go. Unfortunately, this drying time will slow down my progress on my crossmember.

[sicksubie]

How hard will this be after it sets?

[RoughSilver92]

http://multimedia.3m.com/mws/mediawe...6EVs6E666666--
55-60 Shore A durometer. Stiffer than stock rubber, but not as stiff as the 85 or 90 durometer polyurethane often offered in "race" type mounts. Seems like a happy medium to me, no clunk and no extra NVH (at least thats what I'm hoping).

[svxfiles]

Originally Posted by RoughSilver92

http://multimedia.3m.com/mws/mediawe...6EVs6E666666--
55-60 Shore A durometer. Stiffer than stock rubber, but not as stiff as the 85 or 90 durometer polyurethane often offered in "race" type mounts. Seems like a happy medium to me, no clunk and no extra NVH (at least thats what I'm hoping).

YT and I have been doing this for years, but we use McMaster Carr's
flexable urethane in 60A, 80A, or 94A.
It cures in 48 hours.

[1986nate]

Originally Posted by svxfiles

YT and I have been doing this for years, but we use McMaster Carr's
flexable urethane in 60A, 80A, or 94A.
It cures in 48 hours.

Now you tell him

[RoughSilver92]

http://www.mcmaster.com/#
Flexible Urethane, Shore 60A - 8644K24
Flexible Urethane, Shore 80A - 8644K11
Flexible Urethane, Shore 94A - 8644K18

I've read about that stuff also. For me it was just the ease of access. I see the window weld every time I go to any part store, so that's what I got. Two days is a lot better than a week, though. On the other hand it still would have taken just as long if not longer waiting on the McMaster-Carr stuff to get here, then to dry 2 days. How many mounts can a 1lb batch of that stuff do? If it can do more than twice what I did with the Window Weld, then it would be the better value. If you don't have to use a special primer on the bare metal before using the McMaster-Carr then it's definitely a better value, since the 3M Single Step Primer costs as much as the Window Weld itself. And if you are doing many mounts McMaster-Carr is a really good deal, since you get a NICE price break when you buy the 10# container.

[RoughSilver92]

And you can even get CLEAR 80A urethane from McMaster-Carr. Now that would be cool, clear stiff mounts! Somebody please try this so I can see how it looks.

[Hondasucks]

Anyone know if urethane bushings for say a WRX or any other Subaru will work here? Mine needs them too but I almost don't want to just buy replacements from Subaru if I can get urethane ones...