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D4 fuel transfer pump

D4 fuel transfer pump

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Haus
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Is there a new number for 1F5471 (the seals)?

I'm chasing both diesel leaking into the crank case and also trying to improve fuel pressure.

I'm hoping a new bypass spring will help with fuel pressure.

Paul.

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Fri, Jun 12, 2026 8:56 PM
jdunbar
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Location: Friant, Ca.
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I have the same lift/ transfer pump as you. I'm dealing with low fuel pressure as well. 5 psi running.

Diesel engine runs perfect though...so far. Don't want to cause any other issues so far have....

  1. cleaned inside and out. It was locked up with tar from old diesel. Still seemed hard to spin by hand so may clean again.

  2. checked bypass spring and plunger. Stretched spring.

  3. replaced filters

  4. replaced gauge

I also need to crack the injector lines every time i start. Hoping fixing fuel psi will help. I'll post results.

D4 6U Caterpillar Dozer

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Wed, Jun 17, 2026 1:05 PM
Blue0xEF
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Location: Eastern Oregon
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Haus - Have you checked the atmo' drain on the injector pump housing? Mine was plugged solid in the pump casting and the adjustment access was full of what smelled like diesel (but if it was it was ugly). If there's diesel in the access area of the pump the seal between the pump and the fuel filter tower might be where your crankcase contamination is coming from.

jdunbar - If you're getting air from the bleed valves every start and no leaks then I'd be looking for a crack in the lift pump casting and/or at the plumbing between the lift pump and the tank. Time to magnaflux the pump casting? Sounds to me like it must be sucking air from somewhere.

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Wed, Jun 17, 2026 3:23 PM
edb
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many moons ago I wrote up a detailed post on replacing the packing type seals on these pumps, the packing change material but I m not sure if the P/No changed at this time--feel it did not--I stand to be corrected

.

In said article was plans for the old named tamping tooling so we can make our own--NOTE the new packing MUST be pressed to squash them against the housings--if you tamp them as with the previous packings then the new style ones will be destroyed--there were pictures if such in said article.

Yeah, well, sorry about multiple scan loadings--phft.

Cheers,

Eddie B.

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Thu, Jun 18, 2026 1:29 AM
d2gary
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I used edb instructions to replace packing and it worked perfectly

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Thu, Jun 18, 2026 2:34 AM
Haus
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Thankyou all for the advice!

Jdunbar - I plan to check the spring and expect that I may need to replace. Seems it is still available and looks like I can get one in Aus for ~$30.

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Fri, Jun 19, 2026 10:30 AM
Haus
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BlueOxEF - I haven't checked those drains yet. I don't see any weeping/dripping when it is running. Perhaps that means the drains are blocked.

Thankyou very much for the instructions edb! I'm a few hours away from the tractor and can only get there every month so I have time to have a go at making those tools between now and when I get there next.

d2gary - did you use the tamping tool? I'm assuming that the tool is still helpful for pressing the seals (even though the new type seals don't need tamping)??

I can't find 1F5471 through Cat, but I can find what seems to be a replacement for it 5M6038. I think I'll take a guess and get some of those.

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Fri, Jun 19, 2026 10:49 AM
d2gary
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I don't remember what I pushed the seals in with. I probably had something laying around the was close enough, but it is important to press the seals in. If you look up my thread D2 going in the shop, on page 33 are some pictures of the pump rebuild that might be helpful.

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Fri, Jun 19, 2026 12:26 PM
Haus
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Ok thanks, I had a look. Great info there. I'll have to refer back to that page.

Paul.

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Sat, Jun 20, 2026 4:28 AM
Haus
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I had a go at making the tamping tool and the others you posted edb.

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Sat, Jun 27, 2026 9:19 AM
Haus
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Turned out better than I expected.

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Sat, Jun 27, 2026 9:22 AM
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