W126 91' 560SEL Laundry List of Potential Headaches

[lordworm]

Hey Gang, I picked this up recently and got a list of stuff to do from my local shop as a part of the state inspection. They sent me a really thorough report which I thought was cool but also made me realize the vehicle isn't as "tip-top" as I initially thought. It runs and drives great but I think it could be better with some TLC.

I figured I could log my adventures with the car here as I am not familiar with the car and some of you might get a kick out of it. I chose Tech Help instead of Long Term Builds because I could actually use some of your wisdom with this, and it's not a restoration or build. Typically when I need to do work on a car or bike I can find a bunch of information on youtube and such but this particular car is a bit more exclusive I guess.

Here is my current list of issues not in a particular order:

Brake Pads and Fluid refresh.
Brake pedal FEELS like the car needs new pads but the inspection report showed pads still have plenty of life, only issues are that the rear pads are wearing more on the inboard pad and the reservoir was showing high levels of moisture. So my plan is to replace rear pads and do a fluid exchange on whole system with some fresh DOT4.

High Idle when in N or P.
This is apparently a common issue, I likely need to replace a rubber hose or clean/ replace the idle control valve. Only troubleshooting I did was spray some brake cleaner around the hoses while it was idling to see if I can get the rpms to jump but didn't find anything. So I guess I pull the ICV next and clean it?

Fuel Level sensor
The fuel gauge in the dash stops at about 1/4 tank and will sit there until E light comes on, then the car will run out of gas shortly after that. My guess is that I could find the float/sensor mechanism in the trunk and inspect/clean it to ensure its actuating fully. I know these systems are generally pretty simple but from what I've seen so far on this car I wouldn't be surprised if they over engineered the crap out of this component for no reason.

Parasitic Electrical Draw and Intermittent Short to Ground
Whew, fuse 15 is blowing with some relation to the curtesy lighting system. There are times when the short is active and a new fuse will insta-blow then there are times when everything is fine. Previous owner had installed a killswitch on battery, when I saw it I prayed to myself it was for winter storage purposes but I think I am discovering the real reason why. I will follow up with a post on this alone with what I have found and how I tested it

Rear Dif Oil Leak
There is oil residue on the pinion shaft seal of the rear differential. My guess is to replace the seal, not sure how involved it is or how high I should make this on the priority list. First thing I might do is try to check oil level in the dif and top it off if needed. Photo attached

Oil Leak Possibly From Valve Cover
Inspector reported seeing oil residue running down the passenger side cylinder head and bell housing. My plan is to change the valve cover gasket on that side and try to clean up the residue to see if that fixes it

Power Steering Hose and Fluid refresh
The steering is really stiff and I think it could be improved. I've heard these cars have really smooth steering. Existing fluid is dark ATF and I inspected the filter in the reservoir which was pretty filthy. Inspection report also mentions seeing a leak at the hose going from the power steering cooler to the steering gearbox, they recommend replacing that hose and cleaning off the pump assembly to see if the leak is coming from there. I bought a URO replacement hose and some official power steering fluid from benz.

Hydraulic Fluid Refresh
The rear suspension certainly needs some attention. When driving it can be pretty loud going over bumps. This SLS is a bit overwhelming so I figured I could start with some fresh hydraulic fluid and filter as the existing reservoir is low and dark in color. If that doesn't help then I will dig deeper.

Trunk Seal
Water is getting into the sides of the trunk when it rains. You know those little buckets on the left and right side of the trunk behind the tail lights. They get damp and I am assuming its the trunk seal. Before I buy the rubber I want to get out there with a hose and just double check its the trunk seal and not the tail light assembly housing as that also looks like it might have cracks in the seal.


As a part of the inspection they also found that the dual fuel pump/filter system under the trunk was leaking fuel in multiple places and needed an overhaul. I agreed to have them do it with despite it costing me a 1/4 of the value of the car but it seemed like the type of job that should be done properly with factory parts. So 6 new hoses, two pumps, a filter and some other components and hardware later; the vehicle doesn't smell like fuel anymore!

Ultimately the body is in great condition and it drives wonderfully. I plan to drive it to work (short commute) a couple times a week and use it with the family on the weekend so I want it to maintain it as a comfortable classic ride. The kids love the amenities of the back seat (don't tell them about the cig lighters).

I am linking images from a third party site because the photo upload function is pretty limiting.
https://imgur.com/a/pcMmSwm

Sorry about the wall of text, if anyone has any recommendations please share.