I was over at JHunt's yesterday evening and he was finishing up the last of the glowplugs on his '95 E300. Many of them were stuck and he's come up with an innovative solution to remove them using hydraulics without removing the head. I thought is was really slick... Literally!
Here's a few pictures of the process:
First the pre-chamber ring is removed:
Next, the pre-chamber puller is installed:
The original design puller makes it easy to crank them out:
Next, the pre-chamber pocket in the head is plugged with this Delryn plug and honed a few seconds with a brake cylinder hone to ensure a smooth finish and seal:
The custom made hydraulic fitting is then inserted into the head:
The pressure is pumped up to around 2000 PSI with a modified injector pop tester filled with oil.
After a turn of the glowplug, it slides right out!
The tool can also be pumped up and left for a period of time and the glowplugs will literally push out by themselves.