OldBeaver

Primary Fuel Filter Bypassed

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I just discovered that the primary fuel filter is bypassed.

I am the 3rd owner and the previous owners were not aware that it was. At least that is what they told me.

 

I did replace that filter as well as the secondary.

I wanted to ask all the experts here before reconnecting the lines if there is anything I should check first.

Given that the previous owners do not know the reason for the bypass I can only hope that it was done due to the filter getting clogged while on the road and then forgotten.

 

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wolfe10   

Please tell us WHAT brand, and if you now it what model primary fuel filter you have. That may help us understand why it was bypassed.

Some, such as the Winn system were very prone to leaking air into the fuel system.  Parker/Racor has a supersession kit to replace the Winn system.

I am a big proponent of two filter systems.  Primary with 10-30 micron element, then lift pump, then secondary filter (2 micron for Caterpillar).

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All the filters that were on this motorhome when I bought it were CarQuest.

The one in question was 86406 - premium fuel water seperator.

I do not know what the brand the base is but it looks aluminum. The filter is a screw on canister with a drain nipple.

 

I installed corresponding Fleetmaster filters.

10 micron for primary and 2 micron for secondary.

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wolfe10   

If just a plain aluminum filter base on the primary, I can see no reason at all for bypassing it. The Winn system also has clear plastic part that was prone to leaking-- doesn't sound like that is what you have.

Like your choice of primary (10) and secondary (2) micron elements.

Do you have the Caterpillar 3208 engine?  If so, do you have a manual primer pump on the secondary fuel filter?

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Yes it is a Cat 3208 and the secondary has the priming pump.

When I replaced the filters I read the thread on filter replacement. I did not know about the pump so I followed the advice I believe that you gave about filling the filter using the outer holes and installing them wet. 

 

Whoever the mechanic was that maintained this RV for them is someone I would never use.

While the primary filter looked like it has been changed regularly (although it is bypassed) the secondary was very old. I would say over 10 years old based on the dirt and rust (and it's a California RV).

The oil filters were on so tight that I snapped the oil filter wrench trying to unscrew them. Even after 2 full turns they were still too tight.

 

I will head to the RV later today to do an ATF change. I am putting in Shell's TES 295 version of it.

I will also reconnect the primary fuel filter while I am there.

I have only driven it once after the purchase - to get it home. A trip of about 1000 miles.

Yesterday was the first time I drove it since doing an oil change and replacing the fuel filters.

Seems to me that the RV has quite a bit more power. It got up to 60 mph about the same as my van.  Fairly quickly. It was lot more sluggish before.

I cannot even imagine how clogged that old filter was.

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wolfe10   

With Caterpillar manual primer pump on the secondary filter housing, you can install both filters DRY.  Then unlock the primer pump handle (turn counter-clockwise) and pump.... and pump.... and pump.  It will go from very easy (air) to very hard all of a sudden as whole system is liquid instead of air.  Push pump handle all the way in and turn clockwise to lock.  Be sure to do last step!

If the pump does not work-- if not been used in 20 years, they are available at any Caterpillar dealer and replacement is just the two bolts and the O ring.

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The pump does work. 

I used it to prime when I changed the filters...but it took me a while to figure it out.  It was a bit of an adventure. 

I installed the filters dry and started the engine. It was running horribly. I started researching and saw all the posts about wet filters and the pump. Not knowing what the pump looks like and because it is not visible from the back I assumed I did not have one and took off the filters and filled them with diesel.

The engine would not start. Back to research. Found the procedure and drawings of the pump in my maintenance manual.

So I pumped until the fuel come out and then try starting the engine. I think it took about 3 tries at priming the system.

Once the engine started running it was fine.

 

I sharing so that the next guy can learn from my mistakes like I have learned from others'.

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wolfe10   
1 hour ago, Erniee said:

I never install filters dry- priming a series 60 Detroit would be a nightmare

Yup, there is NO "here is how to prime all diesels".  Totally depends on how the engine and chassis maker designed the fuel system.

Best advice-- follow what is in your owners manual.

We have owned coaches that recommend installing dry (i.e. there is some means of priming) and some that required pre-filling the filters.

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Brett, 

Any more advise on the Racor set up. It was drawing air from day one. While n AZ last year Dave Atherton told me to change it to CAT set up. I like the Racor unit cause I can see fuel and whether it has or is drawing air, and it has a purge set up. I took the bowl apart and cleaned, replaced the 4  O-rings. It is still drawing air. I replaced the Gates fuel hose to the pump on the front of the engine as it was full of fractures. There is one other hose, I believe a return to the tank hose from the hard plumbed giszmo on the right side of the C12 up high middle of the engine that is badly fractured but not leaking or weeping. This has no connection to the primary Racor. Could the body joints of the Racor need disassembly? I have in clue what the seal is inside. 

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wolfe10   

Bill,

Racor did have a series of fuel filters with a very high failure rate-- yes, the ones with the clear plastic cylinder with O rings.

The do have a supersession to address the issues with the original design.

I also have no problem with replace your primary filter with a "plain" Racor with clear bowl.  That is what I would do.  And make sure your Caterpillar secondary fuel filter has the Caterp8llar manual primer pump.

 

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obedb   

Bill/ Had Racor fuel/water separators on my trucks starting in 1977 on a new Peterbilt  352 large bunk Cabover. Had no problems with them other than in 1977, the filters were not readily available because the unit was quite new. Learned to keep several spares after crawling up Donner often times on the shoulder.🙄 Always had the plastic bowl and had to quickly break (by lifting the lid) the vacuum to get water and crud to drain out. It was my primary filter. Have even changed filters on the side of the road a few times. Easier on a truck though than a motorhome.

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wolfe10   

Bill,

Go to the Parker/Racor website and input your model number.  May be OK, or may be superseded because of excessive issues.

If superseded, then you decide if you want to do it.

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Thank you Brett, I will do that in the AM

Byron, what you had was very different from what was done and superceded in the late 90's. I like the idea and the way it presents itself but I have to solve this air induction to  the fuel problem and now...bad for the big boy C12.

 

B

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obedb   

Bill/ I used Racor products until 2004. Then I bought my last truck with a series60 and spin on primary and secondary filters. Things worked well so I never installed a Racor.

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jleamont   

Bill, what micron spec do you need? I have a case of Fleetguard FS1015's and the base for it, they have the clear bowel on the bottom. I have no need now with a Davco on the primary side

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Joe,

I have made a change and have changed the primary filter air and water purge pump unit out. I spent hours messing with it. Turns out a problematic setup with a common issue of sucking air and I could not figure out where it was coming from. I called Parker/Racor and had a 15 second conversation before the tech realized the problem and directed me to the replacement. Not bad as I was expecting double the $300 it cost. I then ordered a half dozen upgrade filters, 3 times larger from ADF Diesel in Montreal, Canada.  Their price was half of what they could be purchased for in the  states, go figure. The same price differential with the original filters. Joe the filter I am using is a Racor R125 S, Red 30 micron. I was told a long time ago that since diesel is a dirty fuel, the the most important filter on a diesel is the fuel filter and to change it every 20 thousand miles or every other oil change. Oil in the 2003 F350 7.3 Powerstroke stays nice and clean and at 214,000 that is great. It certainly cannot hurt. I have some recently purchased Racor S3230 red 30 micron filters available for the old style unit that now need a home.

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