sealing up fuel line pipe threads

I think there is a small tube of white paste that is recommended made by Permatex. It is used on NOS systems and fuel systems, rated for high pressure and temp.
It looks like this:
http://www.permatex.com/products/automotive/thread_compounds/a_thread_sealants/auto_Permatex_High_Temperature_Thread_Sealant.htm

BT

 

Almost always, the threads are not where the sealing should be occuring in a high pressure fitting -- unless you are literally using an NPT tapered pipe thread (the threads usually only apply the clamping load to bring the sealing surfaces into contact). Can you better describe the fitting type that you are using, and where you are applying the sealant?

 

Is it possible that the fittings bottomed-out in the holes in the pump before the tapered thread was tight?

Pipe fittings with teflon tape on them shouldn't leak if tightened properly (not over-tightened).

 

I like Tim's thought and Bill's recommendation (if it's a metal-to-metal connection) -- Loctite 565 or 592 are also very similar to that Permatex product (and also should only be used on a metal-to-metal connection).

But I'm amazed that they used a pipe thread -- that makes more sense when the (hard) pipe and fitting are all one piece (and the hard pipe OD is the same size as the tapered thread maximum OD). Is that what you have -- an all hard pipe system (which might have vibration troubles IMO), or is there another joint between the tapered pipe fitting that goes into the fuel pump and a flexible tube delivery system?

 

Which is worth a thousand words

You do have a fair bit of (unsupported) mass hanging off of that inlet fitting -- are you having leakage trouble at all three fittings or just the inlet fitting (your initial post says "I am having the worst time sealing up the pipe threads that go into the pump", but later on "...then I get leaks around the fittings")? If just the inlet fitting, you might try better supporting the free end of the hard structure where it joins the rubber hose from the tank (maybe add something to tie the end of that filter? to the top of the fuel pump motor -- like a hard "saddle" piece of rubber between the body of the filter and the body of the motor and then a band clamp around both) -- could be moving around quite a bit during operation (relative to the motor) and putting a lot of stress on the sealant in the threads of the inlet fitting (and the sealant isn't designed for that) -- just a thought...

PS Can you confirm what sort of fuel pressure you are working with -- is it something like ~3 bar (~45 psi)?

 

Can't fault the mounting of those other fittings so let us know if one of those curing-type sealants perform any better.

 

Man that thing hangs SCARY low .........

 

I have had so much trouble with aftermarket fuel pumps that I would not recommend them.



Ago

 

Just looking at the set-up and how it might be improved...

I would get rid of the 90* blue anodized fitting and the adapters to the filter. Replace it with a fitting like the straight brass fitting that is directly opposite of it. The advantage of the straight fitting is that you can tighten it properly without any regard to orientation. (it kind of looks like you might be over-doing the teflon tape...perhaps in an effort to get the blue 90* to seal AND point up...?). From the straight fitting, run a soft line 90 degrees up and support it with a clamp at the mounting bolt for the fuel pump. Then, attach the filter between the two soft lines...both of which have their own support separate from the pump...

More things would be isolated from pump vibration and movement...it sure can't hurt and will probably help some.

 

Along the lines of what BMW AH is saying, I'd be tempted to dump the whole Mallory setup, and put in an inline Bosch, which is already rated for up to E85, and will probably last until you give the car to your grandkids.

I'd mount it to a frame rail in a cradle with a foam isolating sock to reduce any transmitted noise and put a screen type filter on the inlet and a good filter on the outlet.

Kinsler's prices are a bit high, but you can get a good idea from their website what you need: http://www.kinsler.com/handbook128.html

This pump does 100 L/hr, and it also comes in 165 L/hr and 200 L/hr sizes.
Image Unavailable, Please Login

 

Is the pump solid mounted or is it mounted using those little rubber feet with a stud at both ends? If solid mounted it is shaking those fittings constantly. Rubber mounting would dampen that vibration.

 

Not sure you can get this stuff OTC (as it contains lead), but it works really well with all petroleum products and high pressures...

http://www.gfthompson.com/pipes.html
Image Unavailable, Please Login

 

If someone wants an OEM Bosch fuel pump let me know and I'll see what I can do.


LOTS of (old) Bosch products are NOT sold outside of Germany and/or Europe.

 

Any specific reason that you can't route the return line to the top of one of the tanks instead of the pump inlet?

 

I hope you will make a shield under it the hoses are so low you could get stone damage or anything flying from the road or the track at it.you would feel a lot saver

 

I don't believe so -- aren't the small return fitting port and the inlet fitting port just connected directly together inside that aluminum piece (i.e., same functionally as "T"ing the return line into the inlet line or running the return line back to the tank)?