injector pump fitting leaks on 4020

susandiane · Dec 31, 2020

One of the injector lines is leaking a little at the Standyne pump. The banjo fitting is tight as I dare make it. Do I need to replace the two washers to stop the leak? Anything else? What would they torque to? Thanking you in advance and a new year of joy and happiness to everyone out there!

Glen D Anderson · Dec 31, 2020

In the event you are unable to get it to seal with new OEM washers and tightening the bolt to approximately .5 ft/lb shy of breaking it off you can use these washers from Dipaco Diesel.

They work great!

David G · Dec 31, 2020

Agreed, use softer washers.

Dieseltech · Dec 31, 2020

I prefer the Delphi 5936 332C mild steel line washers. The black Stanadyne 16225 are EXTREMELY hard, and don't always seal well. Use two Delphi washers, seat the bolt then go 1/2 turn more and you're done.

SVcummins · Dec 31, 2020

I used aluminum washers on mine never completely sealed but it was a million times better than when I started

Dieseltech · Dec 31, 2020

NEVER use aluminum washers on Stanadyne/RoosaMaster DB, JDB, DC, and JDC injection pumps. When the line banjo bolt bottoms out due to thin washers, OR one dropped steel washer the the hydraulic head WILL seize, and WILL break the drive shaft. You can get away with it on the CB and CD pumps, but those seldom last long anyway. I just got a 1970 4020 Powershift that still has the CB pump on it.

SVcummins · Dec 31, 2020

I don’t know what pump I have but it has studs up through then an acorn nut on the top new acorn nuts new washers and a lot of work on the lapping table and it was as close as I could get them to sealing

Dieseltech · Dec 31, 2020

That's the CB pump, thinner washers won't kill that pump like the D series pumps. My 4020 has that POS pump on it too, surprised it's still working..

SVcummins · Dec 31, 2020

Mine has been trouble free for 18 years it came on the replacement engine when I bought it

4520BW · Jan 1, 2021

I use copper sealing washers on mine. They are the same thickness as the steel ones.

SVcummins · Jan 2, 2021

I found less leaking without going quite as tight as the spec
calls for. Are those nylon washers ? I tried some carbon fiber
washers and they worked great for about 20 minutes

Glen D Anderson · Jan 4, 2021

If you're asking about the washers in the picture that I posted, the outer ring is steel and the inner ring is teflon I think.

The outer ring provides containment for the teflon seal while acting as a stop for the bolt. Same principle as the bonded washers used on BSP hydraulic fittings.

I had a set of injector lines on a late model 4020 that proved impossible to seal. Tried new steel washers, new bolts, parts antiseptically clean during assy, multiple times, with no luck. Even tried copper washers to no avail.

Put in the Dipaco washers at a fraction of the applied torque to the bolt and they haven't leaked a drop since. Think that was about 5 years ago.

(quoted from post at 19:18:34 01/02/21) I found less leaking without going quite as tight as the spec
calls for. Are those nylon washers ? I tried some carbon fiber
washers and they worked great for about 20 minutes

injector pump fitting leaks on 4020

susandiane

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Glen D Anderson

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David G

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Dieseltech

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SVcummins

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Dieseltech

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SVcummins

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Dieseltech

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SVcummins

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4520BW

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SVcummins

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Glen D Anderson

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