300 SDL Injection Pump Question

[ses0030]

The injection pump on my 300 SDL had a slight oil leak. It bothered me enough that I pulled the pump and replaced all the gaskets I could find. I put everything back together, started the car, and obviously, I didn't put the bottom plate gasket in correctly since the oil leak was still there and much worse than before.

I bought this part to replace it (based on getting the part number from a parts fiche): https://www.pelicanparts.com/More_Info/0049974640.htm?pn=0049974640

The new gasket was circular when it arrived. I formed it into a rectangular shape when I reinstalled the bottom plate but something didn't work correctly.

Is there a trick to getting the gasket to stay in place? Or a method to test while the injection pump is off the car? I haven't pulled the pump yet to see exactly what went wrong.

[JHZR2]

It’s a square cut Oring, not round. It doesn’t want to sit on the cover really, but the taper of the pump side makes the fit.








At least as important is to ensure consistent even torque at very low levels. Otherwise you could squeeze the gasket out. I used this:

[ses0030]

Thanks for the tips. I meant the shape of the oring was round in the packaging. The oring cut is square as you mentioned.

I'll pull it and see where I went wrong. Might be time to invest in a torque screwdriver.

[JHZR2]

Originally Posted by ses0030

Thanks for the tips. I meant the shape of the oring was round in the packaging. The oring cut is square as you mentioned.

I'll pull it and see where I went wrong. Might be time to invest in a torque screwdriver.

Problem is I’m not sure you cant get it off without removing the pump. Which is a pretty significant pain.

I recall the bolts on mine were just a bit too tight and on the verge of stripping… so I had to pull the pump, which was for the best. For you, I’d try to get a small right angle ratcheting screwdriver in there assuming the pump is installed.

[Diesel911]

Originally Posted by ses0030

Thanks for the tips. I meant the shape of the oring was round in the packaging. The oring cut is square as you mentioned.

I'll pull it and see where I went wrong. Might be time to invest in a torque screwdriver.

The square is the cross section.

You can glue the O-ring to the bottom plate with some gasket adhesive

Note degrease the bottom plate with brake cleaner.

While you don't need the copper particles in it the stuff below is an extremely tacky rubber cement especially if you use it like a contact cement where you coat in your case you would coat the area on the bottom plate where the O-ring goes and one side of the O-ring and let both dry a bit till they are sticky. Carefully press them together and they should stay together and let cure for an hour or so making sure it stays pressed down.

https://shop.boeing.com/aviation-supply/p/401504=CA

Another one is as pictured, gasgachinch. It is a rubber cement gasket adhesive. Not as tacky as the copper coat.

https://www.google.com/imgres?imgurl=https%3A%2F%2Fcdn11.bigcommerce.com%2Fs-b9hlijx30a%2Fimages%2Fstencil%2F1280x1280%2Fproducts%2F945%2F1377%2FACC-C10-5080-2__04972.1601399241.jpg%3Fc%3D1&tbnid=NNKNpdEwCWVgIM&vet=12ahUKEwiCvYP2h72AAxVfOkQIHYZUAzoQMygGegUIARDLAQ..i&imgrefurl=https%3A%2F%2Fwww2.cip1.com%2Facc-c10-5080%2F&docid=Tpl8BvHCGEvaFM&w=1280&h=1280&q=gas-ga-chinch%20gasket%20adhesive&ved=2ahUKEwiCvYP2h72AAxVfOkQIHYZUAzoQMygGegUIARDLAQ

The gasgachinch has an interesting quality. If you take a paper gasket and you apply the gasgachinch and it absorbs into the paper, you can let it dry and recoat it and repeat that as long as it keeps absorbing into the paper and letting it dry between coats. You end up with kind of a rubberized paper gasket. Besure to do the edges of the gasket.

Also at least when it is new the gasgachinch does not easily block off oil passages.

[86Merk]

You best be getting that thing back together. You've got to race me pretty soon ;>)