Cummins engine - the turbo clamp leaks air

[CountryFit]

A month ago when i was in Eugene, I heard an abnormal rattle sound from the engine area when i was driving, granted no PacBrake activation when needed. Upon further inspection, I noticed the exhaust pipe connecting to turbo was hanging on the air; the clamp was lost on the road. I checked with Cummins and then Country Coach, because it's manufacturer's part. But CC said they didn't have the clamp.

Finally I got one for 4" from Napa. I put it on, but wasn't feeling too confident as I was able to tighten it to the very end. That means it's a little too big. But no choice at the time, at least I connected it and the sound was gone and I could continue my trip. I immediately ordered another John Deere Clamp fit 3.75" - 4" on Amazon. Yesterday the new clamp arrived, I flipped up the bed, the existing clamp was loose already.

The new clamp's short!! It won't make the full circle, about 1.5" short. The bolt won't reach out of the sleeve so I couldn't put the nuts on. Went to Home Depot and got a longer bolt and put on.

Now I have a problem, hope somebody can tell me... When engine is running, it puffs out large volume wasted air from the clamp. I felt it with my hand around there. Is there a gasket or something between the contact surfaces that I missed? Please advise!! TIA.

[NHRA225]

You need a T-Bolt Turbo Clamp -- available most Places.
I'm not aware of any Gaskets other than the Hose to your Turbo .

[Dsmullen]

I would head to a Freightliner or cummins outfit and get a really heavy duty clamp with a heavy spring loaded tangent bolt to tighten it on. $15 bucks each but you can rely on the fix. I had a stressed clamp break off on a trip and used two cheap clamps side by side till I got the Freightliner good one. I have lost turbo boost twice now. Not fun and zero power.

[dennis45]

Originally Posted by CountryFit

A month ago when i was in Eugene, I heard an abnormal rattle sound from the engine area when i was driving, granted no PacBrake activation when needed. Upon further inspection, I noticed the exhaust pipe connecting to turbo was hanging on the air; the clamp was lost on the road. I checked with Cummins and then Country Coach, because it's manufacturer's part. But CC said they didn't have the clamp.

Finally I got one for 4" from Napa. I put it on, but I wasn't feeling too confident as I was able to tighten it to the very end. That means it's a little too big. But no choice at the time, at least I connected it and the sound was gone. I immediately ordered another John Deere Clamp fit 3.75" - 4" on Amazon. Yesterday the new clamp arrived, I flipped up the bed, the existing clamp was loose already.

The new clamp's short!! It won't make the full circle, about 1.5" short. The bolt won't reach out of the sleeve so I couldn't put the nuts on. Went to Home Depot and got a longer bolt and put on.

Now I have a problem, hope somebody can tell me... When engine is running, it puffs out large volume wasted air from the clamp. I felt it with my hand around there. Is there a gasket or something between the contact surfaces that I missed? Please advise!! TIA.

Cummins will have the correct part. If it were me, I would remove the PacBrake assembly, clean, check and lubricate it with High Temp Lube. Take the assembly and your engine model/serial number to your local smiling Cummins Dealer (could be a truck repair shop) and get two new clamps and a new gasket for the Turbo side. These are two different clamps. The one next to the turbo is wider than the outlet side to accommodate the turbo flange and gasket.
Cummins will also be able to supply the lubricant. If you do it with the right parts, you'll only have to do it once.

[Mr_D]

Need to know if it's a half Marmon or full Marmon joint. The patent application spells it Marmon, but NASA papers say Marman.

www.jacobsvehiclesystems.com/files/support/docs-pdfs/025726A.pdf

[dennis45]

Originally Posted by Mr_D

Need to know if it's a half Marman or full Marman joint.

http://www.jacobsvehiclesystems.com/...fs/025726A.pdf

You are spot on Mr. D. When I replaced mine, they had difficulty grasping this information until I took the Brake Assembly and set it on the counter.
Not all parts people are able to read. They are Paint by Number.

[CountryFit]

Thank you all for the fast responses!!

Originally Posted by NHRA225

You need a T-Bolt Turbo Clamp -- available most Places.
I'm not aware of any Gaskets other than the Hose to your Turbo .

The clamps I bought were all T-bolt with V-Band. Those were specifically designed for turbo.

Originally Posted by Dsmullen

I would head to a Freightliner or cummins outfit and get a really heavy duty clamp with a heavy spring loaded tangent bolt to tighten it on. $15 bucks each but you can rely on the fix.

Freightliner closes in weekend. I went to Peterbilt earlier. Their Clamp is heavy duty just like the John Deere's I bought, but the 4" one is way bigger than my 4" flange. Don't know why their 4" and Napa's 4" are all bigger than my 4" (Peterbilt's is even bigger than Napa's). See my size:

Originally Posted by dennis45

get two new clamps and a new gasket for the Turbo side. These are two different clamps. The one next to the turbo is wider than the outlet side to accommodate the turbo flange and gasket.

Dennis, did you mean there is a gasket for the turbo side? That is what I have been wondering. I called Cummins when I was in Eugene, I will go Cummins Pacific in Bay Area to find out. I'll take the other side clamp out, so to clean the PacBrake, one stone two birds.

[CountryFit]

Originally Posted by Mr_D

Need to know if it's a half Marmon or full Marmon joint. The patent application spells it Marmon, but NASA papers say Marman.

www.jacobsvehiclesystems.com/files/support/docs-pdfs/025726A.pdf

Thank you much, Mr D!! You always have the right documents and are always hitting the nail on the head!! Salute!!