L98 plenum is stuck, won't budge.
Thread Starter
Drifting
Joined: Aug 2001
Posts: 1,550
Likes: 27
From: Minneapolis MN
L98 plenum is stuck, won't budge.
Man this thing is frickin tight. All the bolts are out and it won't move. I have not loosened the runners because I've heard it can be removed without doing that.
Should I go at it with a mallet?
Should I go at it with a mallet?
Drifting
Joined: Jul 2002
Posts: 1,488
Likes: 4
From: Frostburg MD
Re: L98 plenum is stuck, won't budge. (FlyboyZR1)
You removed all 8 bolts? (4 each side?) If it's still stuck, try tapping it upwards from underneath with a rubber mallet, the plenum is kinda wedge shaped.
Team Owner
Joined: Mar 2000
Posts: 83,384
Likes: 88
From: Boston, MA
Re: L98 plenum is stuck, won't budge. (shotchkiss)
Those gaskest can nearly weld the sucker in place over time. You may have to loosen one runner if a rubber mallet doesn't help. Be careful as its only aluminum.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: L98 plenum is stuck, won't budge. (FlyboyZR1)
Remove the TB and tail piece then whack it on top of the snout and on it's top rear as these spots are rather strong. Also the side edges are rather thick compared with the center. You might even try wedging a flat blade in between runner and plenum but go between the runner openings to avoid leaks.
But first double check that all bolts have been removed; don't foreget the two lower ones, one on either side.
But first double check that all bolts have been removed; don't foreget the two lower ones, one on either side.
Thread Starter
Drifting
Joined: Aug 2001
Posts: 1,550
Likes: 27
From: Minneapolis MN
Re: L98 plenum is stuck, won't budge. (scorp508)
Wohoo the rubber mallet did the trick. I hit the thing VERY hard, but eventually it knocked loose! Now if I can only figure out how to get this brake booster fitting off...
Burning Brakes
Joined: Feb 2003
Posts: 1,212
Likes: 0
From: OH
Re: L98 plenum is stuck, won't budge. (65Z01)
I had the same problem the first time I took mine off. Remove your throttle body, and try to loosen the brake booster line too. You can just loosen one or two of the runner bolts on the passanger-side, I found that to be easier. pull it back just a little, then whap it with a mallet a couple times. It will come loose very easy then.
Advanced
Joined: Jan 2001
Posts: 65
Likes: 0
From: eau claire, wi. usa
Re: L98 plenum is stuck, won't budge. (FlyboyZR1)
It doesn't help to reply at this time,since you have it already removed. But. When I took mine loose to replace the EGR, I snapped off a bunch of plastic plugs that were installed to hold the gasket on(I think, maybe stock). Anyway, the plenum didn't want to come off untill I snapped a few of them off and loosened the bolts on the runners. So the trick maybe to remove the 8 bolts at the plenum and at least one side of the runner so it can be pulled apart to see if plastic plugs are in there. Just a thought.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Melting Slicks
Joined: Sep 2003
Posts: 2,775
Likes: 0
From: 1,000,000,001 Posts
Re: L98 plenum is stuck, won't budge. (Sam Lam)
Use a flare nut wrenc (5/8" I think - buy at Sears) and you will not booger up the nut. This comes off easy!
