Air checking 904

[72Dart360]

I put together a 904 with transbrake. The front drum has a bleed off hole drilled in it. The issue I have is when air checking the front clutch air is coming out the pump. I can hear the piston move but im not sure about the air leakage. This is my 1st build with a drum that has a hole drilled in it so I'm not sure if this normal or not.

 

[70aarcuda]

you are going to hear come bleed off ...pour some trans fluid into the hole where you shoot the air ...it should help the seals contain the air...

is the trans fully assembled or still apart on the bench?

 

[TrailBeast]

Some air will get by the rings on the pump stator when you pressurize it.

 

[72Dart360]

It's assembled on bench. Has Teflon seals on stator. I will give the fluid a shot.

 

[340dartley]

one thing that helps sometimes is air checking it out of the case. You can place the front and rear clutch packs in the front pump on the bench and air check through the pump. Sometimes easier to find problems that way.

 

[DusterW2]

It's assembled on bench. Has Teflon seals on stator. I will give the fluid a shot.

When air checking Teflon seals, you will always hear some air leakage. Did you pack them in the groove with assembly grease? Seals are designed to have fluid pressure to help seal. Also, with the 0.062" bleed hole for the transbrake release, you'll also hear some air leakage.