How To Replace C5 Motor Mounts
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,305
Likes: 516
From: Gilbert, Arizona Currently Own: 1998 Coupe YouTube: My Corvette Life
How To Replace C5 Motor Mounts
This process may very slightly depending on your exhaust setup, but I hope this can help some of you DIYers.
TORQE SPECS:
Sub-Frame (4) 21mm @ 81ft-lbs
Motor Mounts (2x2) 18mm @ 37ft-lbs
Front Sway Bar Bracket (4) 13mm @ 43ft-lbs
Front Sway Barend Links (2x2) 18mm @ 53ft-lbs
Lower Shock Mount (2) 13mm @ 21ft-lbs
Upper A-Arm (4) 16mm @ 48ft-lbs
Intake Manifold (10) 8mm @ 44in-lbs 1st pass, 89in-lbs 2nd pass (SEE TORQUE SEQUENCE)
Fuel Rail (4) 10mm @ hand tight
Throttle Body (3) 8mm @ hand tight
Brake Line Bracket (2) 10mm @ hand tight
Exhaust - depends on your setup
TORQE SPECS:
Sub-Frame (4) 21mm @ 81ft-lbs
Motor Mounts (2x2) 18mm @ 37ft-lbs
Front Sway Bar Bracket (4) 13mm @ 43ft-lbs
Front Sway Barend Links (2x2) 18mm @ 53ft-lbs
Lower Shock Mount (2) 13mm @ 21ft-lbs
Upper A-Arm (4) 16mm @ 48ft-lbs
Intake Manifold (10) 8mm @ 44in-lbs 1st pass, 89in-lbs 2nd pass (SEE TORQUE SEQUENCE)
Fuel Rail (4) 10mm @ hand tight
Throttle Body (3) 8mm @ hand tight
Brake Line Bracket (2) 10mm @ hand tight
Exhaust - depends on your setup
Last edited by Chris Draper; Aug 4, 2020 at 11:05 AM.
Melting Slicks
Joined: Dec 2018
Posts: 2,647
Likes: 1,381
From: Orange County, CA
Thanks for sharing! I have motor mounts in-hand so this is really useful for me.
Have you tried removing the intake manifold with the fuel rail still bolted on? I've had luck doing so, and find that it's one less spot for debris to possibly enter. Also a small bit less work, of course.
Have you tried removing the intake manifold with the fuel rail still bolted on? I've had luck doing so, and find that it's one less spot for debris to possibly enter. Also a small bit less work, of course.
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,305
Likes: 516
From: Gilbert, Arizona Currently Own: 1998 Coupe YouTube: My Corvette Life
Thanks for sharing! I have motor mounts in-hand so this is really useful for me.
Have you tried removing the intake manifold with the fuel rail still bolted on? I've had luck doing so, and find that it's one less spot for debris to possibly enter. Also a small bit less work, of course.
Have you tried removing the intake manifold with the fuel rail still bolted on? I've had luck doing so, and find that it's one less spot for debris to possibly enter. Also a small bit less work, of course.
Melting Slicks
Joined: Nov 2016
Posts: 2,305
Likes: 1,581
From: East Metro (Twin Cities) Minnesota
St. Jude Donor '21
Good vid thanks for posting!
Question. I saw what the old vs new in the video looked like - and they did appear to be worn for sure.
Have you had a chance to drive the old girl post new mount install and get on it & break the tires loose a time or three? What I am getting at is I think a lot of people that think they have wheel hop actually have a little excessive engine flopping around on soft 20 year old mounts - so instead of wheel hop they actually have engine flop.
What say you?
Thanks,
Toys
Question. I saw what the old vs new in the video looked like - and they did appear to be worn for sure.
Have you had a chance to drive the old girl post new mount install and get on it & break the tires loose a time or three? What I am getting at is I think a lot of people that think they have wheel hop actually have a little excessive engine flopping around on soft 20 year old mounts - so instead of wheel hop they actually have engine flop.
What say you?
Thanks,
Toys
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Moved over to the C5 Tech section.
Thread Starter
Drifting
Joined: Jun 2004
Posts: 1,305
Likes: 516
From: Gilbert, Arizona Currently Own: 1998 Coupe YouTube: My Corvette Life
Good vid thanks for posting!
Question. I saw what the old vs new in the video looked like - and they did appear to be worn for sure.
Have you had a chance to drive the old girl post new mount install and get on it & break the tires loose a time or three? What I am getting at is I think a lot of people that think they have wheel hop actually have a little excessive engine flopping around on soft 20 year old mounts - so instead of wheel hop they actually have engine flop.
What say you?
Thanks,
Toys
Question. I saw what the old vs new in the video looked like - and they did appear to be worn for sure.
Have you had a chance to drive the old girl post new mount install and get on it & break the tires loose a time or three? What I am getting at is I think a lot of people that think they have wheel hop actually have a little excessive engine flopping around on soft 20 year old mounts - so instead of wheel hop they actually have engine flop.
What say you?
Thanks,
Toys
I have several friends with FD RX7s and one of the main causes for whee hop in those cars is a bad differential bushing that is basically directly above the rear axles and diff, similar to the C5 trans mount.
I have not had a chance to drive the car yet. I’m still in the middle of several other projects, but I’ll report back when I can.
Last edited by Chris Draper; Aug 7, 2020 at 01:30 AM.
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Melting Slicks
Joined: Nov 2016
Posts: 2,305
Likes: 1,581
From: East Metro (Twin Cities) Minnesota
St. Jude Donor '21
Interesting theory, I can see where that may be true. I can also see the transmission mount being the cause for wheel hop.
I have several friends with FD RX7s and one of the main causes for whee hop in those cars is a bad differential bushing that is basically directly above the rear axles and diff, similar to the C5 trans mount.
I have not had a chance to drive the car yet. I’m still in the middle of several other projects, but I’ll report back when I can.
I have several friends with FD RX7s and one of the main causes for whee hop in those cars is a bad differential bushing that is basically directly above the rear axles and diff, similar to the C5 trans mount.
I have not had a chance to drive the car yet. I’m still in the middle of several other projects, but I’ll report back when I can.
It is clear that GM never intended to have the tranny mount provide much if any twisting resistance.
The aftermarket ones do, but even a new GM wont provide much. Wonder what Tadge would say about the aftermarket diff mounts. Wish I could ask him.
Please do report back after a few hard rips as to if you notice a more solid feeling with the new motor mounts. I have used poly mounts on other vehicles in the past and the N/H/V issues made me change them back to stock in a hurry.