Went out to cut the studs of my hpfp stud kit so future cam follower replacements will be easier when removing the hpfp. Cut 6mm off, got them re-chamfered, and installed using a homemade stud-driver.
Then I decided to look at the APR hpfp piston seals and pulled out the piston. I saw slivers of rubber just inside the hole with the piston removed. I took the seal out and it was in bad shape. I found a VITON o-ring that will work until I order and receive the proper type quad-rings: https://www.amazon.com/Sterling-Seal-XP75VIT012X10-Viton-Black/dp/B01F0HFH6E/ref=sr_1_11?s=industrial&ie=UTF8&qid=1510820276&sr=1-11&keywords=viton+quad-ring
Got any more pics / info on that process? Just wondering if I should do the same with my Loba as it's done quite a lot of miles now.
No, no pics. I have 83k miles on my APR HPFP kit...and, why I was just curious.
LOBA looks to use the oem nut collar like Autotech does. They give you a larger pump cylinder, a spring, and the dual sized piston in order to reuse the oem nut and end cap. Their piston has two sections of different diameters in order to do so. The smaller goes into the oem nut collar:
http://www.loba-motorsport.com/img/img-07.jpgI would not recommend removing the seal before knowing what to replace it with, or even if you can. For example, Autotech and LOBA uses the oem nut collar and it has a press-in seal inside. Integrated Eng. and APR make their own. So all seals inside may differ. It may get damaged attempting to remove it and then you're F'd. I realized that before beginning and decided F-it, I'm going for it. I used one form my hook and pick set to remove the seal. It was shredded badly, so I temporarily installed a VITON o-ring size-012 (3/8" ID - 1/2" OD). Used small wooden dowels to install it into the groove inside the nut-collar where the piston goes back into. New VITON quad-ring ordered and will install when received.
APR confirmed the seal material today, saying "Flouroelastomer Polymer"
After doing more measuring, seal type determining, and ring seal reading...I mean, a ton of reading. Especially Chapter 5:
https://www.parker.com/literature/O-Ring%20Division%20Literature/ORD%205700%20Parker_O-Ring_Handbook.pdf...I found, if needed for an APR HPFP(all brands differ as they are custom made); use VITON 75D quad-ring:
https://www.amazon.com/Sterling-Seal-XP75VIT012X10-Viton-Black/dp/B01F0HFH6E/ref=sr_1_11?s=industrial&ie=UTF8&qid=1510820276&sr=1-11&keywords=viton+quad-ringSize-012 Quad-Ring dimensions; sec;1.78 ID;9.25 OD;12.81
This is a 2.5tfsi by APR, but it's the best image and angle showing the seal I speak of and where it goes...seal #1 goes inside position #2:
