Author Topic: 84k30 Motor Mounts  (Read 430 times)

Offline KamperBob

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84k30 Motor Mounts
« on: June 03, 2024, 07:50:37 PM »
I'm replacing motor mounts on my 1984 k30 with 6.2 diesel. Getting them out was tricky. The engine could not be raised enough to slip them out due to interference. So I removed the frame brackets. That involved heating/bending a box wrench to hold the bolt heads tucked up inside those brackets on top. The rearward of each pair of bolt has a brake line blocking a socket from just grabbing the bolt.

The puzzler's on the passenger side engine bracket. On the rearward side (where the long bolt goes through the motor mount) instead of a round hole it's an open slot. To me it looks like a Bubba Mod not stock. Please feel free to correct me if GM did that on purpose. The service manual sketches indicate round holes not an open slot. I'm sorely tempted to weld it closed unless anyone can give me a good reason to leave it slotted. TIA


Offline Mike81K10

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Re: 84k30 Motor Mounts
« Reply #1 on: June 03, 2024, 09:00:10 PM »
Someone cut that slit, should be closed. You can find used ones on eBay. The bolts for your motor mounts (if like mine on an 81 K10) goes through the top side and nuts go on the bottom side which would eliminate your problem with the brake line being in the way.

Don't use the one that was cut because it defeats the purpose of the mount. Some probably did that because they had trouble lining up the bolt hole and did not take the time to do it right.
« Last Edit: June 03, 2024, 09:02:50 PM by Mike81K10 »
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin

Offline KamperBob

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Re: 84k30 Motor Mounts
« Reply #2 on: June 03, 2024, 11:51:39 PM »
Thanks Mike81K10. The motor mounts themselves were not a problem. The frame bracket has 6 holes. Of the 2 top bolts the rearward one is partially blocked on the inside by the brake line. It follows the frame rail back on the inside then makes a right angle turn out to the front wheel. The bent wrench solved it nicely. I'm probably not making it clear with words. I'm done today. Left that passenger side mount off to do the welding in the morning when it's cool. We're hitting 90s now in SoCal. I'll try to get better pictures tomorrow. Just to clarify the problem and solution. In case someone else encounters similar issues later...

Offline JohnnyPopper

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Re: 84k30 Motor Mounts
« Reply #3 on: June 04, 2024, 08:55:30 PM »
Wow! Those were shot out!
Noise transfer to the frame should be greatly reduced.
Amazing how cruddy these trucks get down under...
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline KamperBob

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Re: 84k30 Motor Mounts
« Reply #4 on: June 04, 2024, 11:59:42 PM »
Fixing the slotted out hole in the passenger motor mount "engine bracket" wasn't that bad. It pays to keep a bucket of cut offs. That gave a head start of making the right "jigsaw puzzle piece" to fill the slot. The filler piece was welded into the bracket and ground smooth on the sides. Then the passenger side engine bracket was reinstalled. So far so good.

Offline KamperBob

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Re: 84k30 Motor Mounts
« Reply #5 on: June 05, 2024, 12:05:29 AM »
That's when I finally understood why Mr. Bubba slotted out this bracket. On the driver side the new motor mount just sat in there pretty as you please. On the passenger side, however, the through bolt holes didn't line up. There was interference between the engine bracket and motor mount "tabs" such that only about half the bolt diameter was clear through. Rather than hack the bracket I just fixed I trimmed the motor mount tabs instead. Then it fit like a charm.

Offline KamperBob

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Re: 84k30 Motor Mounts
« Reply #6 on: June 05, 2024, 12:14:44 AM »
It all went back together. First the engine bracket (again). Then the motor mount.

I was more careful in these pix to capture the holes in the frame where the frame bracket bolts. There are 6 bolts. One is down low on the vertical part of the C channel which can't be seen in this view because it's blocked by the bottom horizontal portion. Of the two bolts through the top horizontal portion of the frame the forward one is partially hiding behind the motor mount in this view. The rear of those 2 holes is the one that really needed a bent wrench. Just under it in the vertical webbing of the C channel frame you can see the brake line going out to the passenger side wheel.

Finally the frame bracket was reinstalled.

Offline KamperBob

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Re: 84k30 Motor Mounts
« Reply #7 on: June 05, 2024, 12:17:20 AM »
One other note. I removed the starter to better access the passenger side motor mount brackets. Now that the motor mounts are done I get the second return on that investment. Access to fix the missing bell housing cover, which is a separate topic.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=39726.msg333749
« Last Edit: June 05, 2024, 12:29:37 AM by KamperBob »