If its got a metallic luster I think you found your problem. It should be a 70 durometer Buna oring. Take the size that 911 gave you to the BMW M/C shop or any hydraulic shop and they should have it . Second to the smallest in a metric oring kit.

70 is the hardness and buna is the material its common. Hope this helps.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

When I used to see the O-rings in a kit was back between 1975-1980. At that time they did not appear any different than just a black O-ring.

The O-ring I got from the BMW Dealer is just a Black O-ring.

If your O-ring came with the kit no matter what color it is it should be the correct one.

__________________
84 300D, 82 Volvo 244Gl Diesel

What companies metric O-ring kit?

__________________
84 300D, 82 Volvo 244Gl Diesel

Way back 1975-1980 when I worked in a Fuel Injection Shop all of the Bosch inline Fuel Injection Pump Lift/Fuel Supply pumps can be rebuilt. Bosch makes kits for them as do a bunch of other companies.

The parts of the Pumps also used to be available separetely.

While not much happens to the Lift Pumps that stops them from working I have seen:
The Pump Piston stuck due to Water in the Fuel causing Rust that tool hold while the vehicle sat unused for a time.
Piston stuck due to dirt in the Fuel.
Water in the Fuel rusting through the little thin Valve Springs in the Pump
The big pump spring breaking due to fatigue
The pump Push Rod breaking (I saw 2 in 5 years)
If the vehicle has not been used for several years I have seen gummy dried Fuel keep the pump Valves from seating properly.
Sometimes the Valve seating area becomes pitted or rusted as well as the seating area on the Valves themselves becomes worn.

__________________
84 300D, 82 Volvo 244Gl Diesel

Hercules Bulldog is the Mfg. I pick them up at the hydraulic shop that rebuilds my cylinders. They make standard , metric , Japanese Etc. They have a huge master catalog they ship out for free.

The most common O-rings are the buna the black ones. Two durometers 70 for most mobile applications 90 for static applications (boss type fittings ) . Viton would be the brown ones high heat and special apps but they're a PITA they cut / nick real easy.

Everything seems to be throwaway nowadays these kits have saved me more than once.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

Thanks for the info.
Those kits do savey you a lot if trouble and inconvenience.
I have 2 Harbor Freight standard US size type kits and a Metric one that cost less than $8 from Auto Zone.
The Auto Zone kit does not have the Lift Pump O-ring but it does have 24 of the Oil Filter bottom Stem O-Rings and the Lower Fuel Filter Bolt O-ring sizes.
I have not seen it yet but in their ad Harbor Freight is now selling a Metric O-ring kit.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

the original poster has a 240, can anyone tell me if the Oring is the same size in my 83 w123 300d turbo?

if so I need to do this repair also..

__________________
1983 W123 300D Turbo
2000 F250 7.3 Powerstroke

To the best of my knowlege they are the same sized O-ring. Also it is the Size I used on my 84 300D Lift Pump.

If you are not leaking Diesel into your Crankcase Oil or as some have claimed that a leak there can also cause you to suck in the Crankcase Oil into the Lift Pump. You do not need to change it.

If you have decided to buy the Supply/Lift Pump kit (and the kit does not come with the O-ring) because you are having problems with you Lift Pump I would change O-ring since the Pump is alreay apart.

I changed mine only because I though I was begining to get some Diesel Fuel in my Crankcase Oil. I found that when I checked the Dip Stick my Oil level had risen slightly when I would have expected it to go down slightly.
So I change the O-ring and that fixed it.

__________________
84 300D, 82 Volvo 244Gl Diesel

Thanks to the forum I just completed my rebuild of my lift pump.

Just sharing an enhanced pic and somewhat blurry closeup of the location of small o-ring mentioned in previous posts, along with a couple of sources for them.

I used a dental pick to remove the old o-ring and installed the new one using a chop stick as I didn't want to nick or damage the new o-ring using a metal tool. I can say I did notice a difference an increase in the feel (or drag) of the shaft when the new one was installed - glad I did it while I was rebuilding the valves.

I have about 80 extra o-rings...if you would like a couple (two!), PM me with an address, I'll send them to you for free while they last. Peachparts can source the rebuild kit for the valves.

Attached Thumbnails

     

__________________
1985 300D 172,110mi and goin' strong

Thanks 300dOwnder for bringing this helpful page up, and the additional info. I saved a copy for the future.

I removed the lift pump on one of my W123's since that seemed the simplest way to remove the old white hand primer. I recall having to work slowly w/ a 10 mm box wrench to get some of the 3 mounting bolts off. I may not have had my 10 mm ratcheting wrench then, or might not have fit. I took the outlet fittings off to inspect and don't recall any difficulties like mentioned here (minimal rust in CA). Since then, I read the best way to remove the white primer is to just bash off the plastic to get at the bottom nut, assuming you aren't trying to save it.

I don't think I've seen this thread before either.

Bit of reference marking going on

Here's a link to a M pump fuel pump rebuild I did

Refreshing the fuel pump on an OM617 (European spec – non turbo)

(I'll link this thread in that one and the circle of life will be complete...)

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!