Replacing Injection pump check valve seals.

[alpina]

The  thread below give details of a making a tool to remove the Injection pump check valves. In the thread you can see the seals on the check valve as it is being removed.
So my question is can the seal be replaced without removing the valve ? with a pick tool for example.  Everything runs perfectly only I have notice a very slight external fuel leak
on the no 1 fitting where it screws into the pump.  Just debating whether it is a job i want to tackle. best regards DM.
https://www.sl113.org/forums/index.php?topic=15754.msg108365#msg108365

[alpina]

Anyone know if it possible to remove just the seal ?  or does the check valve have to come out  to get the seal out. Meaning we will have to
many a tool to remove the valve.
All thoughts welcome
cheers DM

[ja17]

It is very difficult to remove the seals without removing the check valves. I use a fine thread metric fitting used on Mercedes air suspension cars of the era to remove the valves. It is exactly the correct thread to screw onto the valve and extract it from the injection pump. There are lots of other ways to do it.

[wwheeler]

If I remember correctly, the seal looks like a plastic washer. A new one goes in easily but a used one has been compressed between the fuel fitting and the valve. Compressed meaning both the ID and OD of the washer have expanded to the cavity dimensions and create a seal. It is difficult to remove because of this newly created press fit.

Removing the valve acts to pull the seal out. I suppose you have nothing to lose trying use a pick to remove as long as you don’t scratch things up. The fittings need to be torqued to the spec and forget what that is but somewhere around 20 ft.lbs. The reason being you need enough compressive force to compress and seat the sealing washer.

[alpina]

Thanks Wallace i guess that makes sense. I will look at making a removal tool. I have found a BMW brake fitting below that has the M12x1 thread. it is also only 4 euros direct from BMW.
just need to get a M12x1 bolt the thread in the other end. Do they just pull out?
best regards

DM

[wwheeler]

Yep, just pull out. The plastic washer will come with it. The seal is there to direct the pressurized fuel from the piston into the fuel line via the check valve. Shouldn’t leak on the outside. The check valve’s job is to hold fuel going into fuel the lines going to the injectors. Should hold fuel in the lines after the engine is shut off.

[alpina]

Well I have made a tool to pull the check valve. The connection is a BMW brake fitting with the M12 x 1 thread, plus some aluminium tubes I had around the garage. Hopefully it will work okay.  There is no sign of any external leak since the garage tightened the fitting to the right torque, No1 was looser than all the others causing a slight weeping of fuel.  I have replacement seals and now a tool if needed.