Replacing the Frequency Valve and Return hoses
Taking advantage of the cooler weather these past few weeks, I decided it is time to replace the 3 remaining fuel lines with my previously purchased DeloreanGo braided stainless steel replacements. Doing so will relieve my concern about the condition of the old lines, especially the high pressure side of the FV. Plus, I will have all 13 lines new and matching. I will post my steps/things learned here as I couldn't find a specific thread on these hoses.
Here is a picture of the original hoses:
http://dmctalk.org/attachment.php?at...5&d=1548142478
Here are the parts ready to install:
http://dmctalk.org/attachment.php?at...6&d=1526429617
They are:
1) long high pressure FV hose (102400)
2) short low pressure FV line (102395A)
3) return hose (102359SS)
I made some slight changes to ensure these hoses will match my other 10 hoses, and I'll detail these here as well.
Most notably, the M12 banjo AN/JIC fitting on the return line had a blue anodized finish (as they are aluminum). I believe they also have a black anodized finish version. To make it match my black and silver color scheme, I stripped the blue finish off with oven cleaner, and polished it to better match the silver fitting finish on the rest of the lines. The same can be done to the black fitting.
Here is a close up of the finished fitting. After soaking in the oven cleaner for a few minutes, I rinsed it off, and sanded the rest of the anodized finish off with 320, then 1000 grit sandpaper. Next I polished it with a dremel mounted buffing wheel and rubbing compound. Finally a hand polish with Mother's Mag and Aluminum polish to a mirror shine:
http://dmctalk.org/attachment.php?at...7&d=1526431465
To be continued...
Return Hose Removal continued
Quote:
Originally Posted by
Jonathan
Whoo hoo Dana! Great thread! I need to do this myself... but am waiting for the weather and temperature in my garage to go back UP, lol. After you sir...
Attachment 59140
Thanks Jonathan!
-------------------
Return Hose Removal continued:
I separated the 8mm cutting ring/”Olive”/ bulk ring (106980) from the metric tube compression adapter (106994) . I applied needle nose vice grips in the rear part of the cutting ring and used a 17mm wrench to turn the adapter clockwise against the cutting ring. As before, try to focus your movement axially, (avoid lateral forces).
http://dmctalk.org/attachment.php?at...7&d=1548158849
After a couple tries while adjusting the tension on the vice grips (tight enough to grip, but not tight enough to deform the ring/tube), I had success. Here are the parts separated. I read that the metric compression fitting can be re-assembled assuming that the tube and fitting parts are not damaged. Mine were is great shape, so I gently cleared the burrs off the cutting ring with 1000 grit sandpaper and used carb cleaner on a shop towel to remove any debris. I also learned that it is recommended that you use a light assembly oil on reassembly which I’ll detail later.
If you have to cut the olive off to start with an undamaged tube, you can get a new cutting ring, DMC has them (Bulk Ring- 106980 ). A new swivel nut is part number 106981 .
Interestingly, after the fitting was removed, I needed to put the adapter in a vice and use a 14mm wrench using a large amount of force to remove the -5 SAE 45° flare fitting on the OEM return line, so I seriously doubt this could have been removed in the car without damaging the hard line.
http://dmctalk.org/attachment.php?at...8&d=1548159205
Assembling the New Low Pressure hose:
The low pressure hose is mostly braided SS but has a short piece of rubber hose. I see that you can now optionally send DeLoreanGo your FV and have it permanently fastened to the hose (like OEM). It's good to have choices. After some thought, I would still choose this configuration as it will make FV replacement or maintenance easier. However, this rubber hose needs to be fastened securely. I took some measurements of the width of the fuel injection clamp versus the length of the barb on the frequency valve to ensure that I positioned the clamp in the center of the barb. I figured that details matter here:
http://dmctalk.org/attachment.php?at...0&d=1548764432
Same process for the other side:
http://dmctalk.org/attachment.php?at...2&d=1548764862
I torqued the clamp to spec ( 13 in/lbs in this case), and used blue Loctite on the threads:
http://dmctalk.org/attachment.php?at...1&d=1548764675
After a trial fit, I optionally chose to use a longer rubber piece of fuel injection hose (4 and 3/8 inches), to more smoothly route around to the braided Stainless Steel hose. When I shopped for the longer hose, I selected Gates Barricade GreenShield Fuel Injection rated for 225 psi - vastly overrated for this use, but it gave me peace of mind. I found the 1/4” (0.25 inch) diameter of this hose was very slightly smaller than the 7 mm (0.27 inch) hose that came with the kit. This meant a tighter fit on the 2 barbs.
Here is the low pressure Frequency valve hose all assembled, torqued and thread locked:
http://dmctalk.org/attachment.php?at...3&d=1548805045
^ I also fastened the M12 60° cone inverted flare adapter to the FV. I applied a light assembly oil to the threads and the concave seal surface. The torque spec here is 7 - 15 ft/lbs. Considering I read that a leak free seal should be achieved with the minimum spec, I torqued it to 8 ft/lbs. That will allow more range to tighten if it should leak during testing.
Appendix: Heat Shrinking the Hoses:
One other thing, and as mentioned, I bought these hoses previously before DeLoreanGo began offering pre-wrapped hoses. So I wrapped the return hose myself and wanted to show you how easy it is:
I found an appropriate size black semi-rigid plastic heat shrink tube with integrated glue for the job. It was 3/4 inches which fit over the swivel nut and reduces down to half it's diameter, 3/8 inches, which is the OD of the hose.
http://dmctalk.org/attachment.php?at...6&d=1459477295
Cut a length slightly longer than the area you want to cover.
http://dmctalk.org/attachment.php?at...0&d=1548809432
Then use a heat gun on a low setting and start at one end. Use one hand to hold the hose and at the same time the other end of the tube. Use the other hand to wave the gun close, but not touching the HS tube. Only do 1-2 inches at a time, going around the circumference of the hose.
Watch the un-shrunk end to ensure it doesn't shrink in length or get twisted while soft. Mine tended to want to shrink lengthwise so I gently tugged the HS to stretch the soft portion and maintain the original length. Don't overdo the stretching.
Here is the heat shrinking in process :
http://dmctalk.org/attachment.php?at...1&d=1548809599