Cracked rear diff bushings - refreshing with window weld

[idosubaru]

The rear bushings are cracked - 3 of the 4 support areas have cracks all the way through and the last one is very close to being all the way through.  But the bushings are all intact, all rubber is still there, All the cracks are gapless and tight. 250,000 mile Tribeca but the diff/bushings are exactly like EJ/EZ and even EA even.

I'm going to clean the bushings out and fill all of the areas around the bushing material with 3M window weld and see how it goes. 

Clean with brake cleaner or something else?  Brake cleaner is said to be safe for rubber/bushings.

Has anyone done this?  I've seen posts about making bushings or filling in good bushings to stiffen them up.  But not much of anything on just filling in existing bushings with this stuff. 

 

[nvu]

I've done a couple, it's okay if you want to do it on car.  More than likely you'll need to soap and water to get the grime off.  Brake cleaner or acetone is fine. mainly to get the water off.

[idosubaru]

20 hours ago, nvu said:

I've done a couple, it's okay if you want to do it on car.  More than likely you'll need to soap and water to get the grime off.  Brake cleaner or acetone is fine. mainly to get the water off.

Excellent.  Did you do it to compensate for the bushing failing or performance?

The diff blew up so it’ll be removed and easy access. 

[nvu]

They were all dirty or cracked bushings, definitely failing state. I've only went with window weld if was too lazy to take things apart, though nowadays window weld is pricier than getting replacement bushings.

I did have one that needed extra stiff bushings, so used concrete leveler.  Needed to make molds to pour it in, but it completely filled the voids after some days of curing.  It was definitely close to solid, had to tap it in with mallet.  Car already had stiff cusco style transmission and engine mounts, so a little more noise from solid diff mounts isn't an issue.  It was $7 at home depot.

[azdave]

You have little to lose trying to save those bad bushings but I've not had much luck with that Sika product. I found that after a few years in use, the material became gooey and broke apart. I've had better luck with 3M Window Weld. I have also used that same SIka self-leveling to fill driveway cracks and the UV exposure and heat pretty much destroyed it after about 5 years of exposure. Now I'm digging out the broken, sticky bits and having to seal all the driveway seams once again with a better product (I hope).

[idosubaru]

11 hours ago, nvu said:

They were all dirty or cracked bushings, definitely failing state. I've only went with window weld if was too lazy to take things apart, though nowadays window weld is pricier than getting replacement bushings.
 

 

$30 a tube no kidding. cutting the bushings out and pressing in new ones sounds terrible but you’re probably right. this is closer to a farm truck than long term daily driver so, time being money, I’ll probably try window weld for the learning experience. 
 

ha I’ve got that same sika flex in my garage. Fascinating never consider using it for bushings. 

[nvu]

4 hours ago, azdave said:

You have little to lose trying to save those bad bushings but I've not had much luck with that Sika product. I found that after a few years in use, the material became gooey and broke apart.

Good to know.  It's only been a little over a year for me.  I'll check on it every once in a while and report back.

[idosubaru]

6 hours ago, nvu said:

Good to know.  It's only been a little over a year for me.  I'll check on it every once in a while and report back.

I dug out two SIKA bottles I already had, if they're still good I'll try them.  Thanks again.