Broken drivers side motor mount.... I JB welded it yesterday UPDATE: it lasted a week lol

So my 2010 has been clunking for years due to the drivers side motor mount being broken. So finally yesterday I jacked up the engine and got some of the faster drying JB Weld and the mixing attachment and squirted a bunch into the motor mount in the broken area and set it back down. Today no more clunking. I didn't feel like replacing the stupid motor mount. Will see how long it lasts.

Uh, OK, I guess that's one way of dealing with it, lol

Keep us posted

robgreg75 said:

So my 2010 has been clunking for years due to the drivers side motor mount being broken. So finally yesterday I jacked up the engine and got some of the faster drying JB Weld and the mixing attachment and squirted a bunch into the motor mount in the broken area and set it back down. Today no more clunking. I didn't feel like replacing the stupid motor mount. Will see how long it lasts.

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Fingers crossed! My guess is that one good jolt in reverse and it'll pop loose.

Geotrash said:

Fingers crossed! My guess is that one good jolt in reverse and it'll pop loose.

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IDK man, depending on what type of JB he used and the qualities of the mount, sometimes this stuff is more durable than the surrounding material. I think you are right though, even if it bonds well, it will likely shear due to the differing qualities between the two materials.

I just replaced my driver's side mount, and minus the constants (jack up truck, remove wheel, remove wheel liner, remove steering shaft, remove manifold heat shield, jack up engine...) I could probably do the job 5 minutes faster.

Geotrash said:

Fingers crossed! My guess is that one good jolt in reverse and it'll pop loose.

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Reverse just puts it in compression. What would be the real test would be pulling a heavy load.

If you have a tune with no torque management and or tow or punch it form a light, it should last at least .0023 seconds.
Dive like a baby maybe a few months.
Its not that bad of a job, do it once (Hummer) and be done.

I've used the JB Weld, on my brother in-laws Toyota Pick Up, and it's still holding. If you prep the surface correctly it just might last quite awhile. But personally, I would just use it as a quick fix. Just something to hold until I could get it fixed properly. Because if it fails it's going to be at a time when you can least afford it and least expect it. Remember...Safety FIRST!!!

gpracer1 said:

If you have a tune with no torque management and or tow or punch it form a light, it should last at least .0023 seconds.
Dive like a baby maybe a few months.
Its not that bad of a job, do it once (Hummer) and be done.

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bill1013 said:

I've used the JB Weld, on my brother in-laws Toyota Pick Up, and it's still holding. If you prep the surface correctly it just might last quite awhile. But personally, I would just use it as a quick fix. Just something to hold until I could get it fixed properly. Because if it fails it's going to be at a time when you can least afford it and least expect it. Remember...Safety FIRST!!!

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I know I need to do it right, wife is driving it so it might last a while but it won't last forever. It has been clunking for years so not like it is a big deal if the JB weld doesn't work it is not going to ruing anything. I just figured for $10 it was worth a shot. Not like I am against working on cars I rebuilt the transmission in this one after the torque converter lock failed and metal got in the tranny, that was over 70K miles ago and the motor mount was already clunking then I just forgot about changing it when I had the exhaust already out and could have jacked the motor up high.

robgreg75 said:

I know I need to do it right, wife is driving it so it might last a while but it won't last forever. It has been clunking for years so not like it is a big deal if the JB weld doesn't work it is going to ruing anything. I just figured for $10 it was worth a shot. Not like I am against working on cars I rebuilt the transmission in this one after the torque converter lock failed and metal got in the tranny, that was over 70K miles ago and the motor mount was already clunking then I just forgot about changing it when I had the exhaust already out and could have jacked the motor up high.

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That clunking is a steel pin that works like a chain link to limit the separation of the two halves of the mount. Repeated collisions of this pin against the rest of the mount wear it thin and it'll eventually break. Mine was clunking for a year or so after I bought it, I have no idea how long prior to my purchase it was bad. When I replaced the mount, the pin was worn and starting to bend. Once that broke, there would be nothing but the dryrotted rubber shell of the mount holding that side of the engine down. It would rip apart like snapping an old rubber band the first time I punched the throttle or towed anything heavy. This puts a lot of torsional stress on the tailhousing of the trans. I've seen tailhousings cracked from a failed engine mount.

As for your J-B Weld fix, I would've squirted some urethane or similar in there. It's actually a common practice in racing to inject the voids of stock mounts with urethane to solidify them for better torque control. There are various levels of firmness for urethanes so they're not all like the super hard aftermarket polyurethane mounts. J-B Weld is solid, but if you lowered the engine down before it cured, that pin inside the mount is resting on a bed of rubber. So it shouldn't transmit very many vibes. The J-B Weld being above the pin and filling the upper half of the cavity is "stiff-arming" the pin/upper half of the mount from travelling upward during accelerating. If there's no upward movement at all, then it might not crack as everything is absorbing and transferring the forces together. I'd consider it a viable way to buy time.