1972 M130 Oil Leaks - fuel pump adjustment screw

[haris]

Hi All,

Hope you guys are keeping well in these ridiculous times.

Quick intro: car is a US LHD 1972 W108 280SE with an M130 engine. The car has been imported into the UK.

The car has left a few drips before but after using the car a bit more often it seems to be getting to a stage where it is ridiculous amount. I've tried to clean the bottom with a pressure washer but need to go over it again with a bit of degreaser. I got a load of pictures as they will obviously tell the story a lot better than I can describing them.

I seem to have 3 main areas that seem really bad

1. I noticed a drip always at the front of the sump on a particular bolt, I believe it's the front crankshaft seal. I haven't driven it much but it doesn't seemed to have leaked since being cleaned.

2. Left hand side of the engine with, the side with the injection pump. This seems to be the worst, I can see a drip hanging off the adjustment screw, this seems to be the main leak leaving big quantities of oil.

3. There seems to be some weeping around a particular bolt which I'll take out and replace the washer for.

Any tips for tackling the adjustment screw, I tried to search on here but couldn't find anything. Is there a rubber gasket or o-ring underneath? Anything I should be wary of taking it apart?

Your help would be appreciated.

Thanks

[col320ce]

I'm not sure is this will be contributing but some mechanics put oil for modern cars in and it finds leaks. I use 20w/50 mineral oil.
Make sure the engine is off if you ever adjust the fip thumb screw.

[Charles 230SL]

.....Left hand side of the engine with, the side with the injection pump. This seems to be the worst, I can see a drip hanging off the adjustment screw, this seems to be the main leak leaving big quantities of oil....Any tips for tackling the adjustment screw, I tried to search on here but couldn't find anything. Is there a rubber gasket or o-ring underneath?

hello Haris, I replaced several O-rings in my (R11) fuel injection pump a few years ago, one of which was the seal on the adjustment screw. Attached are a couple of Bosch diagrams I referred to when I had the pump apart and one shows the governor section - the diagrams probably won't apply to your pump but they'll give you an idea where the seals and o-rings are. A seal kit for the fuel injection pump on your 280SE should be available from Bosch. You'll need to remove the pump and open the governor section to replace that o-ring on the adjustment screw/knob.  https://www.sl113.org/forums/index.php?topic=24659.msg177310#msg177310

[mrfatboy]

I just replaced the o ring on my 280sl FIP idle adjustment screw because of a leak there also.  You need to remove the big hex nut. I had a modified socket to do the job. About a cup of oil will come out.

Once out you will see the tiny black o ring that will need to be replaced. I don’t remember the size.

[Pawel66]

Also: each time you do the adjustment, pull the adjustment screw a little outwards. Helps seal it.

[haris]

Thanks for the help, those diagrams are especially useful.

Yup I did think more modern oil might be a contributing factor, it has 10w40 in it I believe.

@mrfatboy which big hex are you referring to? I have two small bolts either side of the adjustment screw which hold a metal plate to the pump.

[haris]

Any ideas where I can search for that seal with Bosch?

[Pawel66]

The two small bolts solution is on newer pumps - you are lucky because it is 10min job to get there. Just place some piece of cloth underneath as oil may drip out. You take the plate with adjustment screw out and replace the oring.

Which seal are you after? The seal for adjustment screw is a generic oring - you will get it in any parts store. Set of seals for Bosch FIPs are available at ebay, you just need to know which kit, e.g.:  https://www.ebay.com/itm/Dichtungssatz-Bosch-F026T03029-f%C3%BCr-PES-6-KL-Pumpe-Mercedes-250-280-300-SE-SL-SEL/282503703660?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[Shvegel]

It also looks like your input rod seal is leaking (Where the linkage attaches)  You cannot replace that seal without extensive knowledge and equipment.  The positioning of that shaft is part of the adjustment process of the pump so if you mess with it the pump will need to be calibrated.

[haris]

OK Update,

I took the plate off and gave it a good clean. I found no o-ring on the adjustment screw bit just a conical metal bit which seats in a countersunk bit on the plate (I forgot to take a picture). Am I missing something there?

Also does someone have the dimensions of the larger O-ring so I can order it online since nothing is open here at the moment.

I thought I had fixed it but instead of oil hanging off the edge if the screw it is now dripping straight down.

I'm also going to try 20w-50 next time.

[Pawel66]

I had oring on the adjustment screw. I replaced it and it stopped leaking.

On the FIP spare parts list this plate with adjuster screw comes as an assembly.

The seal between plate and housing, I know only PN is 1420206005. It is difficult to search Bosch catalogues these days...

[Benz Dr.]

Any ideas where I can search for that seal with Bosch?

Modern oils won't make your engine leak unless it already was. I use 15 W 40 for most oil changes in the shop. I use 10 W 40 synthetic in my own car.

[Pawel66]

Here you have ebay search results. I see that Vintage Europarts are selling the FIP kits, maybe they have the oring or orings you need:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=F026T03029&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=Dichtungssatz+Bosch+F026T03029+f%C3%BCr+PES+6+KL+Pumpe+Mercedes+250+280+300+SE%2FSL%2FSEL

I have a box with assortment of orings in the garage, so it was not difficult to find a replacement. You can most likely measure what oring/orings you need approximately and order several sizes of them to be on the safe side. Or order a set containing sizes close to the one that you may need.

I cannot find the dimensions of the 1 420 206 005 anywhere...

[Shvegel]

That "Conical metal bit” might be a petrified O-ring.  4.5 ID X 1.5 mm cross section or what is also referred to as a JIS S5.  It stretches over the end of the adjustment shaft.  No need to unscrew the shaft from the adjustment wheel.

[jim 56]

I have the same car.The adjustment screw on the FIP has a small "O" ring between the spring and the slotted head.

[wwheeler]

Be careful what O-ring material you use. Some O-rings are meant for water (most hardware stores) and some for oil. But not both. All rubber is not the same.

Do yourself a favor and buy a Viton (FKM) O-ring and you will not have to do this job again. Viton is far superior in oil than standard Nitrile.

[haris]

Thanks for the help everyone

The bigger o-ring is 30mm x 2.5mm for anyone else tackling this in the future

No longer leaking from there anyway, next step clean the engine and replace the valve cover gasket and adjust valve clearances.

Will have a think about whether I feel up to tackling the crankshaft seal or whether I just give it to someone else to do.