Exhaust brake Questions

[TGeorge]

My 2006 M 1078A1 with c7 Acert is fitted with what I believe is an air actuated exhaust brake (see photo)

What is the "normal" position for the air cylinder when the engine is idling? Extended or retracted?

I can't for the life of me get the rotary shaft to move *at all* I'm curious if this could be the source of my reduced power.

TIA, Tobin

 

[TomTime]

My 2006 M 1078A1 with c7 Acert is fitted with what I believe is an air actuated exhaust brake (see photo)

What is the "normal" position for the air cylinder when the engine is idling? Extended or retracted?

I can't for the life of me get the rotary shaft to move *at all* I'm curious if this could be the source of my reduced power.

TIA, Tobin

Photo?

 

[TGeorge]

Photo?

Oops! Apparently you have your clairvoyance tuned down today. Try this:

 

[Ronmar]

Looks retracted/off to me. If you start the truck, and with the transmission in N, set the ex brake switch to the warmup position. That should apply air to the cylinder and extend the cylinder/engage the ex brake butterfly to load the engine and warm it up faster…

you could also remove that braided airline, and apply air to that end of the cylinder to extend it.

 

[TGeorge]

Looks retracted/off to me. If you start the truck, and with the transmission in N, set the ex brake switch to the warmup position. That should apply air to the cylinder and extend the cylinder/engage the ex brake butterfly to load the engine and warm it up faster…

you could also remove that braided airline, and apply air to that end of the cylinder to extend it.

Great Info. I've already tried injecting shop air into the "extend end" of the cylinder, no joy, stuck fast. The good news is it is stuck open, not shut. Thanks a bunch. Time to soak that mess in a bucket of penetrating oil. I'm going to start it up as you describe, and loosen that JIC fitting and see it I'm getting air at the cylinder too.

 

[Lostchain]

Great Info. I've already tried injecting shop air into the "extend end" of the cylinder, no joy, stuck fast. The good news is it is stuck open, not shut. Thanks a bunch. Time to soak that mess in a bucket of penetrating oil. I'm going to start it up as you describe, and loosen that JIC fitting and see it I'm getting air at the cylinder too.

Just pull the front and rear E-clips and take it off the shafts, then you can test it with the warmup button for function check. My unit was also seized when I got it, but squirting high temp lube and working the butterfly valve got it back to smooth after a while.

 

[TGeorge]

Just pull the front and rear E-clips and take it off the shafts, then you can test it with the warmup button for function check. My unit was also seized when I got it, but squirting high temp lube and working the butterfly valve got it back to smooth after a while.

Thanks. I pulled the two marmon clamps and took the entire unit to the work bench. Seized completely. Penetrating lube, big hammers, large rosebud torches and almost my entire vocabulary would not get things turning. I drilled out the retaining set screw, and drilled a 7/32 hole through the blind boss on the side opposite the bellcrank. Then I was able to press out the shaft with a large arbor press. Nasty rusty mess. Wire brushes and scotch brite. Then the shaft need a visit to the chiropractor as the removal process left it a bit bent. Tapped the hole in the boss for 5/16 x 24 Reassembled with some PTFE lube (no idea if that will work long term, but it was the only "HI_TEMP" fucka doo I had handy. Now it works great.