Have not tried yet because the plunger once dry doesn't move in the barrel smoothly. Not sure if there is a trick to getting it right?

The plunger should not be an issue if it extends under pressure. You and your dad or a friend can plug up all of the outlets with your finger tips and use some compressed air at the inlet.

I build a number of heads and the "old" stem seals are always "free" but still work. The new stem seals always hold tight for the first few hours. I use Viton on the exhaust side. I suspect you are fine if you can pull the plunger or make it move with 50 psi.

That said...you MAY need to make an adjustment to the CO/idle screw as the O-ring frees up.

Well I was concerned over it because the one I just received back from CIS Flow Tech -- the plunger moves freely, but I did notice that the whole unit had a film of grease, I was just wondering if this is the grease that is used to keep it moving freely when not under pressure.

I'll be able to test my rebuilt one in about a month, so I'll report back soon. I'm excited to test it out, but gotta move out of where I am living first.

Grease or oil has never helped make my valves slide through new seals the way they slide through old ones.

Options are:

The rebuilt FD reused the old O-ring
duxthe1 is correct and the O-ring used in the rebuilds is not the same as your HF version

Either way, how could it matter? (Rhetorical)

The plunger does not come in contact with the o-rings though...so it should make no difference?

The o-rings are on the outside of the barrel....

I would not be *too* concerned with the plunger. It will behave completely different when the fuel system is pressurized. I have pulled a lot of FD's from junkyard cars, and the static plunger behavior varies from car to car.

Fair enough. I'll just wait til I get it tested in the car.

Old thread but it needs an update.

Are you changing the big black rubber part that goes between the upper and lower part?
or you are just re-using your old one?

I did my the FD rebuild twice, once on my 3.4 AMG and once on a freind 420 SEL and didnt face those problems.

Plunger reassembly
 

Hi,

I saw the brilliant pictures g the 560 bosh KE-Jetronic Distributor with the nut which hold the plunger and barrel in position. I took mine appart and did not record the position of the nuts. You got the outer ring nut which holds the barrel in place and then the innter one with the rubber seal which screws inside the outer nut. You can set the inner one deeper of higher into the out one. What should be the correct position.
For example i presses the inner nut (the bruubr ring side) as far as it would go into the barrel and then turned the outer one over it till t seated on the distributor housing. one can however with a screw driver turn the inner one out again. (Hope I made sense here)