Clam shell gaskets???

ZeroGravity58

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Mar 23, 2008
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So long start short I was out having fun with the kids and got on the truck pretty hard. When i let off i heard a pop and now the truck won't build boost. All the boots are fine, so I pulled the piping off the y bridge and with the truck running I can put my hand over the y bridge and completely cover it and the truck keeps on running. I can hear it sucking air but I can't find it. Has anyone ever blown the gaskets out of the clam shells?
 

ZeroGravity58

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Mar 23, 2008
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They are silicone but has anyone had any problems with them? Its hard to see but whatever it is it's a huge leak. Truck won't build any boost. I can't feel anything if someone revs it up alittle but I can def hear it. I really don't feel like pulling the entire topend apart
 

ZeroGravity58

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Mar 23, 2008
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I checked all around the y bridge, I hear it coming from the pass side next to the turbo. I can't get my hand in there to confirm with all the piping for the twins. I do know one thing if I got to pull this thing apart the stock turbo isn't going back, maybe a 68 in it's place along with a 100 or 125 overs. Then when I blow it up everything is done except the bottom end :D
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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either hook it to shop air and start spraying with soapy water or tear into it and find the issue. no use speculating on here. its pretty clear cut
 

ZeroGravity58

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Mar 23, 2008
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either hook it to shop air and start spraying with soapy water or tear into it and find the issue. no use speculating on here. its pretty clear cut

I know this, I was just seeing I anyone else has had this problem. I've been under the hoods of more Duramaxs then I care to think about and have never seen this problem.
 

clrussell

pro-procrastinator
Sep 23, 2013
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If it’s a stock non welded bridge I’d put money on the horn being pushed out.

Unless you have a hole like my old lly had lol
 

zakkb787

<that’s not me...
Sep 29, 2014
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When I put my lb7 back together I didn’t get enough RTV on the intake runners so one leaked. I still built boost but had a nasty squealing sound under heavy boost. Work your way to that. Go to Lowe’s and make you a cheap pressure valve with a cutoff and a pipe cap and hook the compressor to it. Sohould be able to tell where the air is escaping. You may have a loose runner that was fine at stock boost but the twins blew out the silicone.
 

ZeroGravity58

Well-known member
Mar 23, 2008
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When I put my lb7 back together I didn’t get enough RTV on the intake runners so one leaked. I still built boost but had a nasty squealing sound under heavy boost. Work your way to that. Go to Lowe’s and make you a cheap pressure valve with a cutoff and a pipe cap and hook the compressor to it. Sohould be able to tell where the air is escaping. You may have a loose runner that was fine at stock boost but the twins blew out the silicone.

This is what I'm thinking also. The y bridge is a sdp two piece bridge I just put in about 2 or 3 months ago. I unbolted the kneck since it's a two piece y bridge. I can hold my hand over the y bridge and completely cover the whole. The truck keeps on running and I can hear it pulling air from the pass side clam shell. I've never seen the silicone push out but my luck it probably has :( I never even thought about a runner working itself loose. the twins have been on for about 10k miles but you know how that goes...
 

Ne-max

I like turtles
Nov 15, 2011
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I've never had the clam shell rtv blow out. That grey acdelco sealant is tough. Now 2 piece y bridges I see all the time. Never had good luck with them.