Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector - ZR-1 Net Registry Forums

Erik · 08-11-2022

I've got a nasty vacuum leak at the dual connector. The metal hose doesn't seem to want to go deep enough into it to seal properly. If I push it in, maybe an 1/8 to a 1/4 inch more, it seals up. but as soon as I release it, its starts moaning again.

The connector is a new one from Jerry. Any suggestions to make it work?

Erik · 08-11-2022

Hopefully this video will help makes some sense of it. The leak is LOUD. You can easily hear it from inside the car.

https://youtu.be/srgYMdTxs1A

A26B · 08-11-2022

Frequently, when the original connector failed, it was replaced with a hose on each pipe. The hose wall thickness required spreading the aluminum tubes/pipes apart to make room for the 2 hoses. Works for hose, but the pipes are no longer parallel. The connector holes are parallel. Forcing it onto the pipes without straightening back to parallel, can result in distortion of the connector & a vacuum leak.

Remove the connector & see if the pipes from under the plenum are parallel to each other and align properly to the spacing of the connector.

Erik · 08-11-2022

Quote:

Originally Posted by A26B

Frequently, when the original connector failed, it was replaced with a hose on each pipe. The hose wall thickness required spreading the aluminum tubes/pipes apart to make room for the 2 hoses. Works for hose, but the pipes are no longer parallel. The connector holes are parallel. Forcing it onto the pipes without straightening back to parallel, can result in distortion of the connector & a vacuum leak.

Remove the connector & see if the pipes from under the plenum are parallel to each other and align properly to the spacing of the connector.

Thanks, Jerry.
I have a backup new one also, so I can swap that one in.

Is there any recommended way to bend them without breaking them? The long metal tube that comes from the back of the plenum does seem to be angled in a way to keep it from seating well. Is it adjustable also?

Erik · 08-11-2022

Out of curiosity, as this is a huge vacuum leak, what effect would it have on the operation of the engine?

Young1 · 08-11-2022

High idle.

08-11-2022	#1
Erik Join Date: Nov 2016 Location: New Brunswick Posts: 953	Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector I've got a nasty vacuum leak at the dual connector. The metal hose doesn't seem to want to go deep enough into it to seal properly. If I push it in, maybe an 1/8 to a 1/4 inch more, it seals up. but as soon as I release it, its starts moaning again. The connector is a new one from Jerry. Any suggestions to make it work? __________________ 1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy

08-11-2022	#2
Erik Join Date: Nov 2016 Location: New Brunswick Posts: 953	Re: Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector Hopefully this video will help makes some sense of it. The leak is LOUD. You can easily hear it from inside the car. https://youtu.be/srgYMdTxs1A __________________ 1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy

08-11-2022	#3
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,391	Re: Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector Frequently, when the original connector failed, it was replaced with a hose on each pipe. The hose wall thickness required spreading the aluminum tubes/pipes apart to make room for the 2 hoses. Works for hose, but the pipes are no longer parallel. The connector holes are parallel. Forcing it onto the pipes without straightening back to parallel, can result in distortion of the connector & a vacuum leak. Remove the connector & see if the pipes from under the plenum are parallel to each other and align properly to the spacing of the connector. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

08-11-2022	#5
Erik Join Date: Nov 2016 Location: New Brunswick Posts: 953	Re: Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector Out of curiosity, as this is a huge vacuum leak, what effect would it have on the operation of the engine? __________________ 1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy

08-11-2022	#6
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 891	Re: Fixing Vacuum Leak at 1990 Dual Plenum Vacuum Connector High idle. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.