Oil Leak - Fuel Injection Pump

[bkfitz]

It appears engine oil is somehow dripping from the bottom of the throttle mechanism on the FIP.  Any ideas?

Thanks!

[Charles 230SL]

This message string shows a similar leak from those 2 bolts on the FIP. The bolts run into the governor oil reservoir and the threads could be leaking: https://www.sl113.org/forums/index.php?topic=36959.msg270404#msg270404. You can remove the bolts and seal the threads without removing the FIP. 

[bkfitz]

Thanks Charles that's a helpful thread.  It looks like maybe those bolts allow for some adjustment of the linkage arm position?  Any risk of removal and reinsertion with thread sealer?  It almost looks like mine has some crush or locking washers on it, is that typical?

What about the 'top leak' it must be coming from higher up no?

(Attachment from Joe Alexanders FIP tour thread)

[ja17]

Caution!!!! You should never disturb the stop adjustment of the accelerator linkage on the IP. This adjustment can only be set by having the injection pump re-calibrated on a factory injection testing bench.

[bkfitz]

Thanks Joe that's what I worried about!  Can they be removed and replaced one at a time without the 'armiture' moving?  Should I just live with this slow leak?  Any idea where the upper leak could be originating from?

Thanks!!

[ejboyd5]

Thoroughly clean the area to determine the source of the leak before taking any action.

[bkfitz]

The two 'lower' bolts running through the linkage stop don't seem to run completely through the body of this model FIP as noted above if the videos below match my USA '68 280SL.  The upper throttle shaft does however seem to run through.  Perhaps there is a gasket or seal in there?  I'm thinking I had better live with this leak

See (fasincating) videos below.

https://youtu.be/pzoWqeuVFG4?t=269

https://youtu.be/ZXLFY5UQE7I?t=300

Model Number of FIP in videos:

[Philippe VIARD]

I had the same problem of leakage in the 2 screws. Depending on the pumps, the screws can communicate with the inside of the regulator. Unscrew one screw at a time, clean and degrease the thread before applying a sealant.

[wwheeler]

There is a shaft seal on the arm. That is most likely where the leak is coming from especially if this has never had a rebuild. Seals get hard with age and weep. As far as I know, only way to replace the seal is with a full rebuild. I am with Joe, I wouldn't touch those bolts. They adjust the stop for the fuel arm. If that gets off, the linkage will never adjust correctly.

I have a small oil weep from the pump mounting gasket. I will fix it one day. But for now, i just give the area a quick wipe after a drive. Not that big of a deal. If your engine runs well, I wouldn't touch it and get a towel.   

[Philippe VIARD]

To bkfitz,
My FIP is type R25 and the regulator 1/34R
The regulator was changed because the metal part of the regulator supporting the small air filter was broken.
I had witnessed the disassembly and removal of the pump regulator by C Beck Etoile 67 Sélestat. The pictures below show that the 2 regulators are different at the level of the 2 screws. In one case the holes are terminals so no leakage possible (original regulator), in the other case the holes communicate with the inside of the regulator (new part set up) and therefore risk of leakage. What I got.

[Charles 230SL]

Depending on the pumps, the screws can communicate with the inside of the regulator. Unscrew one screw at a time, clean and degrease the thread before applying a sealant..

That's what I did on my R11 pump; unscrewed one bolt at a time, cleaned/degreased, applied thread sealant and reinstalled. That's been a few years ago and the bolts haven't leaked a drop since. BK, looks like you've got a later pump so as Philippe noted, your bolts don't penetrate the oil reservoir. To replace the seal on the shaft you'll need to remove and disassemble the pump, and then recalibrate it. The shaft seal is #22 (highlighted) in the attached file. I agree with JA17 and Wallace and wouldn't attempt to replace the seal unless you plan on a full rebuild and recalibration of the pump.

[bkfitz]

Thanks all, this group is incredible!

[bkfitz]

UPDATE: Looks to be leaking from shaft seal on the arm:

https://youtu.be/7Pd617RsGU0

I confirmed my IP is the original PES 6KL 70 B 120 R 20 Y so I presume that the housing is the same as the R22 Y in the FIP restoration video which means those two bolts do not seal oil.

I'll live with it until I can have the FIP rebuilt.

Thanks again!

[mdsalemi]

Brian,

Unless it's leaking a LOT of oil, AND your car isn't running right (due to the need to rebuild the FIP) I'd live with it a LONG while.
There's almost always something leaking somewhere on a car 50+ years old. I was dry for the longest time after all my steering components were changed but now noted a small leak at the oil pan...

[bkfitz]

Thanks Michael I agree.  Car is running pretty good and the leak is slow.