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Topic: Manual bleeding after r&r lift pump (Read 783 times) previous topic - next topic

Manual bleeding after r&r lift pump

With enough battery, will the system bleed the air out itself (with full filters)?

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding agter r&r lift pump

Reply #1 –
Yes, should not be a problem.  After I replaced our lift pump, I planned to give the "hand pump" plunger a couple pushes, but it was at such a awkward angle that I said "Fergit about it".  Went up front, cranked the engine, and it fired up after only a few extra seconds.  Might run a bit rough initially, but will quickly smooth out.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Manual bleeding agter r&r lift pump

Reply #2 –
Thanks, Chuck& Jeanie. That sorta confirms what the gossip is about these engines. My pump arrived a few minutes ago... Will repost  when things are hooked up again. Gonna leave the seeping at the water separator 'til try to start it to see what happens(very slow leak).

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #3 –
If a leak while sitting at the primary fuel filter, at max fuel demand, it could be a SUCTION leak allowing air into the fuel system.

You really need to address this as well.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Manual bleeding after r&r lift pump

Reply #4 –
Thanks, Brett. I[m green at this and just want to see if things are different with the new pump. Air was observed going back to the filter when hand pump. Looks like wrong way to me and definitely will address leak....I know air should not be there but the direction baffles me. I neglected to notice if it was upon pushing the bulb in or releasing it...

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #5 –
When I'm replacing filters, I leave the secondary filter slightly loose and then use the hand pump until liquid and bubbles appear. Then tighten and it should fire up sooner than using the starter to fill the new filters.

Get the leak fixed at the primary's water separator. You don't want air in the injection system. It won't go away, will just get worse.

If you have a chassis mounted hand primer pump and it does not seem to be working properly, they are not difficult to pull off and then easy to work on. Just need cleaning and two new "O" rings.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Manual bleeding after r&r lift pump

Reply #6 –
Thanks, Pierce. The primer pump is a push button/lever (in a rubber boot ) mounted on the  pump. My nephew just put things back together. Did not pump the pump - hooked the umbilical cord to shore power to charge batteries and we will try it tomorrow. I'll report back after it runs....should it not want to do that - goin' straight to the leak at the primary filter(I know, I know, should do it NOW - but it's HOT out there!

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #7 –
Son just pumped 6-8 times, no start and air bubbles going(with hissing sound someplace?) into plastic bowl on filter, gonna address that next. This was first time to try & starter just used few seconds. Same symptom as with old pump(but no start this time), but now we have a new(?) pump. Stay tuned....

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #8 –
Could there be a failed check valve on the filter housing?  When pumping the hand (primer) pump, fuel might try to flow in the direction of "least resistance".  Without some kind of check valve, that might be backwards, towards the fuel tank.  (This is just a guess...)

If things are working correctly, you should be able to operate the primer pump until you hear the overflow valve "squeaking".  That is the audible sign that the fuel lines are pressurized and the overflow valve is opening to bypass fuel pressure.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Manual bleeding after r&r lift pump

Reply #9 –
Tom Hall has a good page on installing an electric pump to aid filling the filters and starting after you replace your filters. While his is on a Detroit MC-8 bus, it will work on any diesel. You don't need to buy the expensive one way Detroit valve as a couple of inexpensive shutoff valves will work fine along with good fuel hose, not copper. 

Good project when the weather is not so hot.

Tom Hall

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Manual bleeding after r&r lift pump

Reply #10 –
On some really reluctant engines, I crack one of the injection pipes loose about a quarter turn and then turn it over. Once diesel comes out and runs down the injector, tighten it. If the engine starts with the fastener loose, it will run on five cylinders until it's tightened. It won't spray, just run down the injector.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Manual bleeding after r&r lift pump

Reply #11 –
You may need 50 to 75 pumps to prime your system.  6-8 isn't going to do it.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Manual bleeding after r&r lift pump

Reply #12 –
My caterpillar 3126B takes 50 to 60 pumps on the hand pump to become firm and let me know secondary filter is full.
Bill
Wild Bill Colston
1997 Class A Towing 2016 ford F150 XLT extended cab with Golf cart in 8 ft bed or a 2004 Jeep Grand Cherokee
Retired Aircraft Maint Tech A&P Line Crew Chief
Pilots lisc--------Commercial and Multi Eng

Re: Manual bleeding after r&r lift pump

Reply #13 –
thanks Brett & Bill. Just called y our info in to my son - he says gonna go back & pump some more. The air bubbles going back the wrong way still is bugging my mind. I haven't renewed the filters as yet. Don't really know their numbers. I have the owners manual for the 1991 and will take it with me to the parts store...

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #14 –
Quote from: Jim Sizemore –
thanks Brett & Bill. Just called y our info in to my son - he says gonna go back & pump some more. The air bubbles going back the wrong way still is bugging my mind. I haven't renewed the filters as yet. Don't really know their numbers. I have the owners manual for the 1991 and will take it with me to the parts store...
Jim
Jim,

I don't want to be a jerk but the filters along with the belts are the number one priority on any coach. You need to have the part number written down and a spare for both the primary and secondary filters on board. Plus, you need to know how to change them making the least amount of mess and getting it running quickly without any fuss. Lots of Cummins owners on the forum who will guide you along. Nothing worse than getting a load of algae out in the middle of nowhere and being stuck and at the mercy of who ever comes along.

Get the air leak fixed and make sure the hand pump is working. If not, fix it.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Manual bleeding after r&r lift pump

Reply #15 –
Son pumped the hand pump 80+ times today. Activated starter with accelerator pedal not pressed. No start. Pushed  all way down, activated starter again and hit couple times, no run. New filters arrive tomorrow, leaks will be addressed & will update tomorrow. I'm listening, folks, I'm listening... We are just new at this and learning from you. We all will get it going!

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: Manual bleeding after r&r lift pump

Reply #16 –
JIm,

Did you have air pressure in the tanks when you tried to start?  If you have a air throttle, you won't have any movement at the engine throttle lever unless you have about 60-70psi in the air system.  However, the engine should still start even without any throttle movement.

Also, you might have someone stand at the back of the coach and make sure your fuel shutoff solenoid is pulling up when you crank the engine.  I know it doesn't have anything to do with the lift pump and fuel filters, but wouldn't be the first time a completely unrelated problem pops up and causes a no-start condition.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"
 

Re: Manual bleeding after r&r lift pump

Reply #17 –
Thanks, Chuck - shutoff working properly. Learned about that part of things right after purchase, thanks to folks on this forum. Had to clean it up and replace boot with finger from rubber glove. Middle finger was too small so had to use thumb!!

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062