Having replaced all of the old servo hose, I can hear a leak from the servo take off point on the manifold. I've taken out the plastic elbow which has a taper thread, but not readily identifiable as it is the wrong pitch for BSTP, although the major diameter is about right. The take off is to the rear of the manifold, so a pig to get a look at to measure and check the thread. Do these manifolds come with a standard tapping for the servo take off, or has the PO most likely done a DIY job (i.e. could be anything)?
The VHW centre manifold section looks like it's tapped out as standard, it's just hard to measure the thread when it's round the back of the manifold. The plastic fitting has probably just been made to fit (it did include a quantity of thread tape and mastic on the threads when I took it off) rather than being the right thread, but if I buy brass, I need to make sure it's right. Edit: VHW part showing tapping. http://www.vwheritage.com/vw_spares...hop.product_pID_141619_lang_EN_country_GB.htm
They said the fitting is included. My guess is that they have no idea about the thread, which after some research looks like the US version of a taper BSP (NPT), and that the crappy plastic take off is probably what comes with the manifold.
Yank BSTP, taper thread. 18 TPI, which matches the crappy plastic elbow I have, vs. 19 TPI for the BSTP version. Since the EMPI stuff is from the US, it makes sense they would use the US thread.
Thread is NPT, but BSTP is very close and the guy at Pirtek sat they are interchangeable at this size. I got a 1/4 to 1/2 BSTP male to male adapter and then a 1/2 elbow with barb and swivel fitting. Both in steel and they fit securely and airtight, until the plastic POS that came with the manifold.
