870 timing actuator

[Blott4]

I'm guessing the actuator shaft should not look like this. Looks like there was threads there that hold the redish purple plunger thing but they are now gone. The only reason I took this apart was the truck had a slight skip when idled up to 900rpm and this actuator was leaking i think through the connector. Can these actuators still be gotten brand new or am i going to have to resort to cummins reman?
2005 cm 870 446k miles, 15k hrs bought truck used im assuming these are original they are the older o-ring style seal to ifsm. This is the only one ive taken apart so far.

[Rawze]

maybe this helps...
ref: http://rawze.com/forums/showthread.php?t...619#pid619

[Blott4]

I read through that article and tested the play at .002 with dial indicator. What I haven’t found is any pics of the piston (the reddish thing) removed from the plunger shaft (has triangular flats milled onto round shaft). Seems like I read someone had found a few loose pistons which lead me to believe there should be threads on the plunger shaft. When I disassembled this actuator the piston wasn’t held onto the shaft at all. Also wondering if the reman will be any better as far as plunger play. I do feel a step when I push the plunger down into the bore. I reassembled and truck runs ok as it did before but I can see the fuel weeping out around the electrical connector so I’m pretty sure the actuator is cooked.

[Rawze]

(02-26-2022 )Blott4 Wrote:  I read through that article and tested the play at .002 with dial indicator. What I haven’t found is any pics of the piston (the reddish thing) removed from the plunger shaft (has triangular flats milled onto round shaft). Seems like I read someone had found a few loose pistons which lead me to believe there should be threads on the plunger shaft. When I disassembled this actuator the piston wasn’t held onto the shaft at all. Also wondering if the reman will be any better as far as plunger play. I do feel a step when I push the plunger down into the bore. I reassembled and truck runs ok as it did before but I can see the fuel weeping out around the electrical connector so I’m pretty sure the actuator is cooked.

Sometimes reman actuators have more than normal amount of play in them where they polished the shafts up. It is mostly the step wear that gets into them that makes them not allow an accurate amount of fuel thru them.