Oil under accelerator pedal???

2003 W900. We have replaced the rubber and insulation thinking at some point some oil had been spilt. Degreased and cleaned the entire floor. We can not find a leak anywhere. The oil has since started to come back. You see it on the heel of the pedal and it slowly saturates the area around it. Where do you guys think this could be coming from?? Any ideas? Thought oil in the air system but have since changed the dryer and compressor. Truck has over a million on it and is in great shape. This is driving the us and the driver crazy. Thanks

 

Mr Haney. Our thoughts also. We did have quite a bit of oil in the system. Have tried for a while to get all we could out. After the putting in new fan clutch bearings it looks as though we have gotten it out. Have not checked the foot valve but we are not losing any air either. I believe the oil psi gauge is electronic. Didn't get a chance to pull the dash today. Two of our hands broke some studs off a W900's breathers so spent a while making and welding on new studs so we could finish the service. Had three trucks to service, all had loaders. Before that had a rattle on a western star, found a broken alternator tensioner bracket...welded it back together and reinstalled, rattle went away, then came back right before backing the truck out of the shop. Suspected fan clutch bearings and it was. Rebuilt the fan clutch. Then a wheel seal got in the way. There is always something to get in the way of what you "thought" you needed to do. lol.

 

If I have time this week I'm going to pull it up. He is leaving in the morning to go to Iowa with a load of poles. Should be back Thursday. If not I'll have to look at it next week. Been like this a LONG time. It is getting worse though. Will keep you updated.