dickandlois Report post Posted November 29, 2016 I have tried to tie 2 threads together! So here is what I think is the answer for the 3rd fuel filter. The RAI 025RAC10 in line fuel filter or fuel strainer rated at 104 microns was inserted at around the time Bio Fuels cam on the market. So the engineers install it because the braided fabric Rubber fuel lines at the time where not able to handle the fuel mixture and not break down. This screen would trap the rubber partials. Freightliner uses Nylon fuel lines from the tank supply lines back to the curb side rear axle, where a section of fabric wraped line was spliced to the Nylon lines for both the return and supply sides. The supply line is 1/2 in. I.D.(color blue) and the return fuel line is 3/8 in. The same style rubber line was spliced at the same location inside the frame rail in the tightest spot one can imagine. There is a bracket holding both the return and supply lines splices at this location. There is a section of the same style line running from the fuel / water separator output to the lift pump input. Not all the lines are in stock at Freightliner, so one might need to get the length of the lines. There are 3 sections, 2 for the supply side and 1 for the return side. found out that there can be a 50 to 60 day lead time to get these sections of hose. Depending on the connector sized used to make the lines at the time the sections where made up. Solution might be to contact a hydraulic shop and see if they can get the proper inside diameter size line, I.D. is critical - where as O.D. is not. Make sure to match the thread size and style connector to fabricate a replacement with a B 20 rating. The following information was posted earlier, and the why question popped up. The following information hopefully will fill in some of the gaps regarding lift pump failures and the resulting failure of the injector pump. The information offers some suggestions regarding fuel pressure sensor options to maintain the minimum fuel pressure at the input of a VP-44 injector pump. Share this post Link to post Share on other sites
obedb Report post Posted November 29, 2016 That makes sense, but what about the other engines and fuel line configurations? I am thinking about adding the check valve at the tank, fuel pump, and a fuel water separator, then proper fuel line to the secondary filter like Joe did. So look for B-20 rated line? Why are motorhomes less forgiving than big diesels powering large trucks. Had a Series 60 engine mfg date 2000 in my 2001 Western Star with a primary and secondary fuel filter replaced at oil change intervals. Never had to change a filter early. I will take your advice when I do the mods. If we decide on Alaska this year, probably ought to get it done. Share this post Link to post Share on other sites
dickandlois Report post Posted November 29, 2016 Byron, One needs to look at market share for that answer. The ISB series engine was installed in School buses, Dump trucks, Delivery trucks, and other applications. If your unsure of the impact of a problem of Bio on a fleet, then put the filters in the units that would accumulate the highest fuel consumption in the shortest time in a given area as Bio blends come into the market Yes, big over the road trucks travel a huge number of miles, but Bio fuels where phased in over time and you can get regional information on a problem, by what happens in areas with and without the Bio mixture and compare the numbers. Was Bio mixed fuel going to be a big issue and by how much by region, are there hot spots relative to fuel blends or not and if so what was the consumption rate to failure point. Good old base line data. Rich. Share this post Link to post Share on other sites
jleamont Report post Posted December 5, 2016 obedb, the large difference from what I can see is the distance between the tank and engine and the fuel line material. RV manufactures started to use the same type of fuel line product around 2004-2005 while the trucking and automobile industry had been running those materials for 10+ years at that time. Poor pre planning and understanding the new fuel requirements pros and cons I believe were the cause. The RV industry seems to be slow in technology advancements, especially when they are critical, always baffled me. As far as new problems with the diesel fuels are getting worse, we are now removing large clumps of what looks to be salt from our Davco housings. This is carboxylate salt/acid which is being added to the pipelines to prevent corrosion within the pipeline from the ultra low sulphur diesel and the moisture it carries. Its supposed to displace the moisture, the problem is its not blending into the fuel properly, just being suspended and getting caught up in the filters. After it sits it turns back into its original form, salt crystals . You have to wonder what is the long term damage to the engine fuel system from stuff like this being added to the fuel? Share this post Link to post Share on other sites
