Downpipe band clamp?

[Big T]

I've got an exhaust leak at the top of the downpipe. Downpipe is in the band clamp, or at least half of it is. The clamp is fully tightened and the lip of the downpipe towards the engine side feels like it's out of the clamp. I've fully loosened the clamp, pushed the downpipe up, held it in place with wood shims, reset and tightened the clamp and end up with the same result: loose downpipe.

This is the second time I've had the downpipe come loose. No doubt due to all the offroading my wife has me do.

Is the clamp stretched out?

Is the inner ring portion of the clamp the same on both sides? I have the threaded end of the bolt pointing towards the fender, but on the firewall side of the turbo.

Where can I get a new clamp?

 

[Big T]

Would this exhaust leak on the downpipe cause a loss of boost?

I'm only getting 10 to 11 psi boost out of the ATT at sea level, where I used to get 14 psi. It's definitely lost some power with this. I always suspect the silicone boots on the intake, but they're really cinched down and not moving. I've checked the crossover and did find a loose bolt on the driver's side and replaced that, but it was not leaking there. Is there anything else I should be looking for?

 

[ak diesel driver]

I got a band clamp from napa for the holset in my work van. there is a myriad of sizes/styles.

 

[bison]

I suggest you take the clamp off and have a good look at it if things are bend somehow.
Could it be the downpipe and exhaust sagged under the cab cause that will change the angle and the flare may not fit square with the turbo elbow and the clamp tapers

 

[Big T]

I suggest you take the clamp off and have a good look at it if things are bend somehow.
Could it be the downpipe and exhaust sagged under the cab cause that will change the angle and the flare may not fit square with the turbo elbow and the clamp tapers

That, not square with the turbo elbow, is what I feel with my hand. I tried to use wood shims between the frame and downpipe to wedge it in place and square it up, then tightened it again. No good. I'll try removing and inspecting the clamp in the AM.

 

[WarWagon]

I have busted the flange off the downpipe before. A muffler shop can weld a new used part on IF they saved some exhaust parts from other jobs that have a flange that size. (Hell is there something I haven't busted/broken/worn out?) It just covered things with soot - no loss of boost or power.

With a mirror is the band clamp bent at all?

Any other kinks or dents in the exhaust from offroading?

Air filter? Damaged fuel lines? Fuel filter? Fuel PSI? Loss of boost is a pre turbo exhaust leak, intake restriction or leak, and mainly lack of fuel. Possible any codes? Possible exhaust restriction.

 

[Big T]

On the loss of boost, I have gone through everything but fuel. It's overdue for a filter change. I don't have a fuel pressure gauge. No codes.

Exhaust has soot trap deleted. Crossover is solid and no leaks.

The silicone boots on the intake are always suspect but they are definitely holding.

 

[Big T]

Alright, pulled the clamp and it's fine and I'm getting incredibly quick at doing it. The outer edge of the downpipe flange has sheared off around 1/3 of the circumference. By loosening the downpipe from the exhaust and shimming it in place at that junction and at the frame, I was able to get it squared to the turbo and cinched back on with the clamp. That said it still rocks a bit in the clamp but there's no up and down slop as before. Still it really needs to be removed and a new flange welded onto it. The exhaust also desperately needs a hanger at the junction of the downpipe and the exhaust. Way too much side-to-side slop there and it will only lead to the downpipe popping out again.

Finally, installed new air cleaner and fuel filter and the boost is back up to near 14 psi. Now back to work on the house in Big Bear Lake, stuffing insulation up under the floor using the crawl space under the house. So much fun.

 

[jmiller]

I used to have a leak at the down pipe after I removed it the first time.

Next time try this:
Use a jack under the lower connector for up pressure and a pry bar to position the the pipe fore / aft / left / right. I can then make sure that the down pipe is evenly centered on the turbo flange. Once its in position, the up pressure from the jack holds it into place. Then I can put the clamp in place and pinch it completely with out any effort.

 

[BigArt]

I am having a somewhat similar problem. I get a "rattle" at idle. When I push on the exhaust I can see some looseness at what appears to be the band clamp. Is there some sort of secret at getting at the sucker? There's not a lot of room. Perhaps pull the inner fender? I've had the inner fender off before when I did the injectors about a year ago. Is there an problem with leaving it a couple of weeks until vacation is over do you think? Truck runs fine, except for the rattle at idle about 50% of the time....

Art

PS: I don't want to steal this thread and can repost if necessary.

 

[bison]

I am having a somewhat similar problem. I get a "rattle" at idle. When I push on the exhaust I can see some looseness at what appears to be the band clamp. Is there some sort of secret at getting at the sucker? There's not a lot of room. Perhaps pull the inner fender? I've had the inner fender off before when I did the injectors about a year ago. Is there an problem with leaving it a couple of weeks until vacation is over do you think? Truck runs fine, except for the rattle at idle about 50% of the time....

Art

PS: I don't want to steal this thread and can repost if necessary.

Removing the air filter box gives easy access to the band clamp.
The rattle can also come from the down pipe hitting the frame or a loose turbo heat shield(put a gloved hand on it)

 

[Big T]

I flipped the clamp so the nut is next to the coolant surge tank:

http://www.thetruckstop.us/forum/album.php?albumid=530&attachmentid=38313

Easier access there vs the other side. You can see where I've lost some of the outer lip on the downpipe to the right. I've got it holding, but it's not the most solid of connections. I'll see if Leroy can get me just the downpipe, install a new one while getting the old one welded up.

 

[BigArt]

I had the truck into a muffler shop earlier today. to see if they could fix it without too much trouble. Because we are leaving for a week tomorrow, etc. They started to go on about removing the inner fender, turbo, etc. :WTF:So, I said no, no, and took the truck home. :nonodno cost). Obviously they don't know much or were pulling a fast one, but I have to admit that the truck was smoking hot at the time, and I'm sure they didn't poke their fingers in there, but... Anyway, after it cooled off and after supper I went and poked around. The clamp is in very good shape, and still in position. But it was so loose that I was able to turn it by hand enough that I could get a 1/4" socket wrench, with extenions, on it. Snugged it right up and took all of 15 minutes. Lucky. I think I'll buy a lottery ticket .

End of story (I hope),
Art