They need more like a Harley vibration, solid mounts in a Tahoe would just be just a tease.
Broken Motor Mounts
- Thread starter osidesurfer365
- Start date
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Meccanoble
Full Access Member
UPDATE!!! The H3 is NOT broken. The 4 bolts that connect mount to the engine are all gone!! Heading to Home Depot to find similar bolts. Any specific torque for these bolts? I'm sure I tightened them right before but I know I had trouble fitting in. I think I will keep the H3's in and return the solids if possible.
Meccanoble
Full Access Member
Can anyone confirm the size bolt? I think all 7 are the same but would like to be as much prepared as possible.
Metric for sure.. I'm thinking M12 thread. But not sure. Make sure you get
Grade 8 or better.. Gm uses the grade of 10.9, 12.9 kinda stuff.. I know it's
the Good Stuff, so only go with the high grade strength. I would use something
on the threads that go into the block- maybe a teflon paste to keep them from galling
and seizing into the block
Grade 8 or better.. Gm uses the grade of 10.9, 12.9 kinda stuff.. I know it's
the Good Stuff, so only go with the high grade strength. I would use something
on the threads that go into the block- maybe a teflon paste to keep them from galling
and seizing into the block
Meccanoble
Full Access Member
Teflon paste? Is this similar to the stuff like red or blue that keeps the bolt sealed?
Not sure on the bolt size or thread pitch. Service manual states mount-to-engine bolt torque is 37 ft-lbs and they don’t specify use of thread lock but I wouldn’t use anti-seize or “Teflon paste” because that might help them to vibrate loose. If you are worried about electrolysis or having the bolts seize in place I would use blue Loctite. It accomplishes the same thing along with being a medium strength thread locker which will help them hold.
Meccanoble
Full Access Member
I'll probably just do without any. I have red but i think you recommended blue for a reason. I see grade 8.8 in the stores based off websites. I hope thats good enough.
Might be best to use the ones i currently have on the engine and the new ones on the body....?
iamdub
Full Access Member
M10x1.50x20mm long
Use blue thread locker (Loctite, etc.) if you want. It's not a convenient place to fit a torque wrench but I've always torqued 'em down by hand as tight as I could get 'em in that area- about 2.75-3 solid grunt's worth of torque. Never used thread locker and never had any come loose.
20mm length isn't so common and you're likely to find 25mm or 30mm. Thread one in by hand and if it bottoms out, take it out and grind a few millimeters off the tip. You may wanna pick up an M10x1.50 nut to have on hand in case you need to grind the bolt down. Thread the nut all the way down on the bolt before you grind it. I recommend you use a flap disc and grind a slight taper into the edge of the tip. I just put a slight 45° on that edge and it's fine. No need to round it over or sharpen it to a point. When you're done grinding, removing the nut will act as a tap to fix and clean up the threads. You could always pull one outta the other side and take that with you to the hardware store for reference.
Aim for grade 10.9, but 8.8 will be fine.
Glad to know the H3 mounts are still good to go!
Meccanoble
Full Access Member
I am not familiar with grinding or any custom work involving bolts
. I dont even have a grinder. If I cant find locally, i'll have to go to dealer on Monday. Looking for a link to send. I see zinc bolts. If I spray them with paint built for high heat, will that help in any way?
iamdub
Full Access Member
I am not familiar with grinding or any custom work involving bolts
No painting of any kind is necessary.
Here's some at Home Depot: https://www.homedepot.com/p/Prime-L...Hex-Head-Cap-Screws-10-Pack-9114719/310516216
Apparently, 20mm is actually a standard/common length. Maybe they're just always out of stock when I shop for them. They're out of stock at my local Home Depot. Get 20mm and you won't have to grind anything, just screw 'em right in, with or without a little thread locker if you want. You could stick something in one of the holes, and hold your fingernail on it to mark the depth so you'd know if a 25mm bolt would work in case the 20mm isn't available. Don't have a metric ruler? Just know that one inch is 25.4mm. So, if you have right at an inch of depth or a little more, then you can use a 25mm bolt. You could always use a thick washer to space it out if it comes to that. I'd get washers anyway. It's just four bolts in four holes- nothing complicated.
I'm sure any decent local hardware store (Ace, True Value, whatever mom-and-pop store is close to you, etc.) would have what you need as well. No need for dealership visit or cost, if they even have them in stock.
