I have a leak where the 17mm banjo bolt attaches the clear line to the side of the IP just above the lift pump. It all started 6 months ago when I started using HPR diesel. I replaced the two crush washers at the bolt with aluminum washers, and it helped but the leaking would only stop if I had around 30% or less of HPR in the tank. I've been leak free for the past 5 months, then all of a sudden that bolt started leaking again last week and there was no HPR in the tank. I've tried replacing the crush washers with both aluminum and copper with no luck. I've also replaced the plastic line and bolt with good ones I pulled from a yard.

I don't want to torque it down too hard and risk stripping or cracking the pump. The only thing left that I can think of is going to the dealer and getting a new clear line and washers.

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'81 300SD

I suspect you have a micro crack in the plastic line.

Remember the system operates at a vacuum so it will suck air and not leak fuel while the engine is running.

After you shut down, the crack will leak out and if it is behind the line it will be easy to blame the banjo bolt.

New lines are relatively inexpensive and should be replaced on principle if you don't know when they were replaced last.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

The leak occurs while the engine is running. After about 30 seconds of idling, the area around the banjo bolt is wet with fuel. By the time I've driven a mile or so the fuel has leaked onto the lift pump and the oil line for the IP.

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'81 300SD

I was looking at a pic of an IP and evidently there is a threaded steel insert cast in to the Fuel Injection Pumps where the Banjo Bolts screw into. I think it is possible that the Steel Insert could have become loose in the Fuel Injection Pump Housing.

Inspect the Banjo Bolt closely for cracks between the holes.

If it was me I would degrease the whole area with Brake Cleaner and get out an Magnifying Glass and a Light if needed and have someone start the Engine and pin point exactly where the leak is coming from.

On person has had the O-ring between the Element and the Fuel Injection Pump Housing leak. That means the leak would be under the 13mm Nuts (don't remove the 13mm Nuts without instructions on marking the Element position).

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84 300D, 82 Volvo 244Gl Diesel

I cleaned the entire IP with brake cleaner and a rag, used a light and mirror to discover that the leak is coming from under one of the shims on top of the pump. I think that I've seen a thread our two on changing those seal washers. Is this a simple DIY, or should I take it to a shop? I don't have the most accurate torque wrench.

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'81 300SD

I got a hold of the crush washers from a Bosch dealer and replaced the ones on ports 2 and 3 since that's where all of the fuel was coming from. The leak has slowed down a little bit but is still drenching my lift pump after a short drive. Could I have torqued down too much? Removing the delivery valves required a lot of force so I went close to 40 Lbs.

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'81 300SD

You used the torque wrench to do the removal?

Concerning the Delivery Valve Holder being tight there could be just a little rust on the threads and also who knows what a previous owner did.

The issue with removing an Element to change the O-rings is that the Shims that you see time the Element to the Camshaft inside of the Fuel Injection Pump and rotating the Element changes the Fuel amount that the Element puts out.
That means if you don't get the element back exactlty in the position it came from then your Fuel adustment for that element is going to be incorrect.

Is it a DIY Job. That is hard to say. In the one thread I gave instructions on how to mark the Fuel Injection Pump (MW Fuel Injection Pump) so the Element has a really good chance of going back to where it belongs.

I would not try that with the Fuel Injection Pump on the Engine becaue you need to scribe/scratch your marks exactly and the Element needd to go back in exactly and that means you need to get your Eyes up close.

Shops generally don't want to do a partial job on things because they are expected to warrant their work. I have seen that on the TV small calims court shows. The Judge told the Mechanic that if the customer was not going to allow them to do the job correctly then the Mechanic should refuse to do the job. The Mechanic got stuck with having to warrant the work.

So that leaves either getting a good used Fuel Injectin Pump or having a complete rebuild on the Pump.

Personally I would try to repace the O-rings myself and if that did not work try a used Pump.

Note that it is also possible for the Delivery Valve Holders to develop cracks in the threaded area but it is not common.

There is 2 O-rings under each element. One at the top and I have been told there is another at the bottom.
I believe in the thread where the guy did the fix himself he posted the part number of the Gasket Kit for the MW Fuel Injection Pump.

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84 300D, 82 Volvo 244Gl Diesel

No, I used a braker bar. My 15mm wrench wouldn't cut it. I have the old style torque wrench with a needle and I doubt it's accuracy.

Let me know if you can find the thread with the instructions.

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84 300D, 82 Volvo 244Gl Diesel

I came across this link and will try again tomorrow with a new torque wrench and a little extra effort to clean the valve. The torque is 30lbs. , correct?

Delivery valve still leaks Turbo 617

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'81 300SD

I would not torque it till you are sure of the torque; not I don not remember the torque.

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84 300D, 82 Volvo 244Gl Diesel

I just checked the engine service manual.

617 is 40 - 50 Nm

615,616 is 35 Nm

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'81 300SD

Even at the correct torque, the leak is as bad as ever. I can't spot the leak coming up at the threads of the valves, but it seeps badly under the shims on the edge of the pump. There's a local shop familiar with these cars that I'll take it to this week and hope for the best.

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'81 300SD

You might not believe what ended up being the fix. After I put back all of the 5/16" bolt clamps on to the lines, I decided to turn the engine over and see if the clamps made a difference. Well yeah, they make a huge difference. The leak is gone. When I was putting the lines back on to the delivery valves, I didn't think the clamps would matter because the engine and pump are vibrating in unison. Now I'm wondering if this has been a wild goose chase and all I had to do in the first place was just torque those clamps down harder than what they were.

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'81 300SD