Engine/Transmission (1998.5 - 2002) Leaking fuel connections

[Wolfgang]

I don't know if this is the right place for this but here goes.



I installed a boost gauge to use as a fuel pressure gauge. The problem is I can't get the fittings on either end to quit leaking. I do have the petcock on the VP44 side but as soon as I turn it on the fittings in the cab start leaking. Has any one seen this problem and come up with a way to seal the threads that diesel fuel won't affect

 

[Vaughn MacKenzie]

Wolfgang, I did the same thing as you, mechanical gauge in the cab. I used Gasket Maker (not sure of brand) to give it a good seal and haven't had any trouble.



Teflon tape does not work that well, it is not diesel fuel rated and seems to deteriorate.



When you redo your connection you have to absolutely remove all residue of diesel from you fittings before applying the sealant/gasket maker. Use something like brake parts or carb cleaner.



Mine has held fine for 30K now.



Vaughn

 

[illflem]

What type of line and fittings are you using?

If you are using boost tubing with a ferule and tightened it too much the ferule will distort and leak. You will have to get a new ferule, cut the old one off and redo not so tight. If you used a pipe thread fitting Permatex #2 works best for sealant. Make sure it is the same thread type on both sides, some AIN fittings will screw onto pipe fittings but won't seal.

 

[Wolfgang]

It is the plastic bosst tubingI will replace the ferrule and do as Vaugh suggests. Vaugh is there any chance the gasket maker is made by permatex.



Thanks guys

 

[illflem]

If you are using a ferrule type fitting no thread seal is necessary, the seal isn't on the threads but is in the compression between the fitting and ferrule. Like I said just don't over tighten, a half turn past finger tight is plenty. If you think it may loosen from vibration use some blue or green wicking Loc-Tite on the threaded part of the compression fitting.

 

[Wolfgang]

OK I'll try that first. Thanks Illflem