Hello y'all, I drive a 2003 Mercedes 500sl that has a whopping 9900 miles on it. Im aware that miles take its tole on parts but so does time. I am aware that the abs and hydraulic roof system have been rebuilt by the dealership in the last 3 years so I don't have to worry about that. what I am worried about is all the other plastic and rubber parts that are 20+ years old. if so what should I change or keep an eye out for mechanically and asthetically. furthermore I thinking of using either techron or bk44g in the fuel, which would be better? finally the leather in the footwells is beginning to sag what would you recommend to fix or at least slow this.

Start with this: Get it up on a hoist and check all the suspension bushes. They crack and turn to mush with age, not miles.

Are the engine mounts shot? They're hydraulic and they leak. Look for brown fluid near the mounts.

ABC hoses? Probably due for replacement.

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Others may suggest more places to look...

the suspension was gone through by the dealership a couple years ago along with abs they replace everything. so that brown fluid was the engine mounts, are they hard to replace.

I bought my 2004 SL600 three years ago with only 21,000 miles on it. Same as you, "age" things were my concern. Car came from Florida and I think it was stored for 10+ years in a garage by an unfortunate widow.
For "age" related maintenance, I have:

• Replaced the ABC suspension accumulators and pulsation dampener
• Replaced the engine mounts (when I swapped to the AMG engine)
• Replaced tires, just this year when they reached 5 years in age
• Replaced the plastic lever in the shifter
• Replaced all vacuum lines and radiator hoses (as part of the engine swap)
• Replaced the conductor plate in the transmission
• Fused the BCM to prevent it potentially catching on fire
• Replaced the fuel pump and filter

Since I have a hoist at home, I can easily check things. The suspension bushing all look perfect; no record of every having been replaced. All ABC hoses look good.

About the only current problem I have is that the roll bar activation hydraulic piston is leaking. My roof has the tell-tale ripples in the weather stripping indicating a front piston leak, but it is not leaking now; must have been fixed previously.

You mentioned that the dealer rebuilt the "abs" system. Technically there is no "abs" on these cars. The suspension system is called the "ABC" system and the braking system is part of the "SBC" system.
If you can get more info what what was done, that would be helpful.

As I don't have a SL500 I cannot answer the question of how difficult it is to replace the engine mounts.

sorry, I ment ABC was rebuilt by deal due to leaking and the previous owner believe the dealer could do it best.

why did you replace fuel pump and conductor plate?

the suspension was gone through by the dealership a couple years ago along with abs they replace everything.
Really? Let's see the list of work done...

So that brown fluid was the engine mounts, are they hard to replace.
No. Mounts on the 500 require no more than these steps:

• Car up on four axle stands or hoist
• Have face licked by hound while you unplug both oxygen sensors
• If your exhaust is two piece, undo the union (about half way down under the car) and each side below the manifold
• If you have a one piece exhaust (US cars) undo both sides from the manifolds, disconnect the rubber mount half way down and let the exhaust hang, supported
• Remove bolts from top and bottom of mounts (top needs 16 mm offset wrench - it's essential - order from Amazon or eBay)
• Jack up engine about 1 inch with a soft piece of 4x2 wod on the jack - one side at a time
• Throw ball to the dog
• Wiggle the old mount out
• Wiggle new mount back in
• Throw ball again
• Put everything back together.

Here is the wrench Tom mentioned:

The M275 engines often have misfire codes causing limp mode. After replacing all the typical parts - spark plugs, coil packs and ignition transformer- the next suspect is the fuel pump. This did cure my misfire codes, but perhaps not directly related. After swapping in the AMG engine and ECU it was running pig rich. I finally traced that to a bad fuel pressure sensor which was allowing 110 psi fuel pressure. I doubt that happened exactly during the engine swap; likely contributed to previous misfires. Also, I would not trust a 20 year old fuel pump.

The MB 5-speed 722.6 transmission often has the conductor plate fail over time because it is plastic and its sensors sit on plastic flaps which loosen up over time. Also that day the weather was bad and I wanted to "play" with the car. And I a very comfortable working on automatic transmissions. I also bought a spare ABC valve block and swapped it in to confirm it was good.

Besides the "age" maintenance I mentioned about, I have bought spare parts such as the roof pump motor, additional cooling lines, the three SAMs and most other computer modules. (Except for the hyper expensive BCM). I like and plan to keep this car.

Use contact cement to glue back sagging leather.
The order of things I would replace on an old 500SL is:
Oil Mobile 1 Synthetic 20,000 mile formula, and filter
Spark Plugs
CPS (Crankshaft Position Sensor)
Brake Fluid – Service Booklet says every 20kmilesThen check if need replacement:
Air hoses cracked or leaking
Serpentine Belt has excessive wear, cracked or missing bits
Brake Pads worn down – to reduce brake dust, replace with ceramic pads
Windshield wiper blades streaking windshield, visibly hardened or damaged
Tires – replace worn down to wear bars; balance ride wobbles shakes vibrates
Batteries – Accessory rear, starter front – won’t hold a charge
Clear all drain hoses. See:

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First Service Items:
Clean and preserve external seals – retractable roof, doors, trunk, hood
Leather Seats+ clean and protect
Interior plastic+ clean and protect
Exterior plastic – Mother’s Back to Black aerosol = longest lasting plastic restoration
Roof Trunk & Hood pivots Lubricate (Dry Lube is good)
Exterior Paint = Clear Coat wash then orbital buffer compound then polish, then ceramic quartz polish – 9H Mr Fix - Auto Ceramics Coating - is pro quality
Wheels clean brake dust off, polish the clear coat, then ceramic quartz polish coat
Tires clean off brake dust+, Shine – Meguiar’s Ultimate Instant Shine = best non greasy

Next, if it ain’t broke…
If it runs rough, coil packs and/or maybe ignition wires, both if diagnosed problems
ABC Hydraulic Suspension – replace 4 accumulators, rebuild both valve blocks with new seals – when experience problems typically u see red ABC visit workshop light on dash, and/or corner sags

On my 2003 SL500, replaced all heater hoses and heater valve under the windshield wipers, heater hoses for heated washer fluid, hoses to REST electric pump.
Date codes on old hoses, made in 2000 and 2001. FYI