Hydraulic system seals

[SAJanesick - Bellsouth]

I recently lost a seal where the high pressure hose attaches to the hydraulic pump.  According to the VagCat board drawings, there appears to be different size seals depending on which hose is attached.  I've matched the size, but I am concerned about the O-Ring composition.  The seal that blew out was a reddish orange seal versus the darker brown seal that is used on the hose from the hydraulic reservoir.

Since it was over the holidays, I just picked up a generic O-Ring assortment from Harbor Freight and indeed found the right size that seems to be sealing with no apparent leaks.  The O-Rings are black and package states that they are made of  Nitrile and resistant to oil, grease, etc.

Does anyone have any experience of using black Nitrile O-Rings within the hydraulic hoses fittings?  I've been told that Audi often uses very specific O-Rings of different color and material for different applications.  I have not gone to the dealer yet, but I could still get by there today or tomorrow.  In the meantime, I travel with wrenches, O-Ring assortment, towels and as much Chf11s as I can get my hands on - just in case.

Also, I'm looking at having the hydraulic pump rebuilt by LARES http://www.larescorp.com/index.html up in Minnesota.  From what I can tell, they look like they know what they are doing, but I thought I'd check to see  if anyone has any prior experience with them.

Thanks,

            - Steve Janesick
              sajanesick at bellsouth.net