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Regular Maintenance Procedures


This section describes regular maintenance procedures that our members recommend each car owner to perform on a regular basis. Where necessary additional detail may be provided or linked to in different sections of this Technical Manual.

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Regular content

Workshop and tools

How to remove damaged or stuck screws

When a screw is stuck, or the head is damaged, it may be very hard to remove the screw. The following are tips from the experts on how to remove such a screw, in the order you should attempt the methods. Don't try drilling out the screw as the first resort. The problem with drilling is that these sheet metal screws can be too hard to drill and the drilll bit simply moves off to the side of the screw and drifts into the softer body steel or simply ruins the drill bit.

  1. First use a dental pick to clean the rust and dirst out the phillips head of the screw. Your first effort is the most important since the head of the screw will damage after a failed attempt.
  2. Next try impacting the screw with a blunt end punch or drift. The impact jars the rusty threads loose. Use a good quality phillips screw driver and also tap it into the screw head with a hammer (again to jar the threads loose and seat the driver). Impacting the screw first is very important.
  3. Before you engage the screwdriver tip into the screw head, dip it into a can of coarse lapping compound. This will help cancel out the tendency of the screwdriver tip to ramp out of the screw head.
  4. You can get a very nice smaill impact screw driver. I got one at Harbor Freight which holds standard interchangeable hex screwdriver bits. Some of these bits I have specially modified to engage damaged screw heads. The interchangeable bits are inexpensive and I discard them when they show any signs of damage or wear.
  5. (Variation on the theme): Get a bit holder adapter and attach it to an air hammer. Then use large vise-grips to apply torque while the air hammer taps away at it. This worked for someone on the door sill trim strips.
  6. If you fail to remove the screw at this point, get a dremel tool. You can get very small cut off wheels for these (they are about the diameter of a dime and are very thin), you can then cut a slot in the damaged head of the screw. It now becomes a "slotted screw" and you can hopefully remove it with a slotted screwdriver!
  7. (Alternative at this point): JB Weld an old screwdriver to the screw head after making a clean slot for it to sit in.
  8. If this fails, carefully finish grinding off the head of the screws with the dremmel and remove the part it holds. Try removing what is left. If you still fail, grind the screw off flush, drill it out or "pop" it through the metal with an automatic center punch.

An alternative trick is to place a small washer over the remains of the screw and then TIG weld the screw to the washer. Repeat if necessary with a larger washer and then a nut. Usually the heat has freed the seized screw and it will happily unscrew with the use of a spanner on the nut. This welding trick almost always work. However if it is a very small screw and you do not have a tig welder or do not weld you are stuck.

Safety and environmental matters first

Conversion tables

Where to find conversion tables and other detailed technical information (liquids to use, torque settings, tolerances, service intervals, etc).

Filling Capacities

Maintenance Procedures

Most elements of a major tune-up / service are listed in the original owner's service booklet which came with the car's books when new. This "E" service at 30,000 mile intervals is a tune-up and service procedure. The "EZ" service at 60,000 miles is a major tune-up and service.

A customer once asked me what the "E" stood for in "E service"? I replied. "E stands for the condition of your wallet when finished, Empty!" The fifty or sixty procedures involved in the service along with the parts can be somewhat costly. It is no wonder that many "E services were never performed.

Naturally performing part or all of the work yourself can be very worthwhile in savings and knowledge gained. Proposal: there is a logical sequence of procedures which may vary, from person to person. This is only a starting point which can be altered or added to as needed. Once we finalize the list we can describe the factory procedure, list the specifications, list the parts needed, list the tools needed, and give personal insight and experiences.

Many from the group can research their own literature and contribute. A summary can be written and placed in the file. Feel free to make suggestions and relate your own experiences on the subjects. This will take some time and work. Many listers can contribute and help research in their own literature. Factory manuals are very informative however the factory training literature and service bulletins are hard to find and full of good information also. Many aftermarket manuals offer condensed information that is described in simpler terms.

We should focus on procedures done with common inexpensive equipment and tools available to most of the list. Much of the information is already available in the archives and just needs to be organized into a usable format. The "EZ" Service / major tune-up:

  • record important car numbers VIN #, motor #, distributor #, transmission #, differential ratio.
  • Check and clean all fuses.
  • Check charging system output.
  • Change main fuel filter.
  • Check pressure and output of the electric fuel pump: the delivery pressure with the ignition on (minimum terminal voltage at the pump of 11 volts) at a point "behind the fuel filter" should be 0.8 to 1.1 atm. I would check it on each side of the filter just to see what the difference is.

Discharge pressure (with a dummy plug on the fuel line) behind the fuel overflow valve on the injection pump should be a minimum of 1.3 atm. The output rate at this same location should be 1 liter in a minimum of 15 seconds.

  • Remove and examine spark plugs.
  • Check the engine compression and record.
  • Remove valve cover and re-torque cylinder head.
  • Examine timing chain, tensioner and chain guides.
  • Meter spark plug wires and ends.
  • Examine distributor and test vacuum advance and centrifugal advance springs lube as specified.
  • Replace ignition condenser.
  • Replace ignition rotor.
  • Replace the distributor cap.
  • Check the ignition voltage.
  • Adjust valves on a cold engine.
  • Examine valve seals.
  • Install spark plugs and re-install valve cover with new gasket if needed.
  • Replace air filter.
  • Set static ignition timing.
  • Set dwell.
  • Set ignition timing with strobe timing light.
  • Check and adjust all engine linkages.
  • Check constant idle solenoid.
  • Replace injection pump air filter.
  • Check cold start solenoid on injection pump.
  • Check starting valve on the intake manifold.
  • Set idle.
  • Set injection pump idle mixture.
  • Replace power steering filter.
  • Jack up or lift car to drain fluids.
  • Replace oil, filter, check all seals.
  • Replace coolant.
  • Check all hoses.
  • Drain transmission and replace fluid. On automatics drain the torque converter also and replace the transmission filter and pan gasket.
  • Replace rear differential fluid and check rear axle boot.
  • Replace all engine v belts.
  • Check front suspension for wear.
  • Check drive shaft.
  • Lubricate chassis.
  • Note any fluid leaks.
  • Check for any loose bolts.
  • Check brake pads, rotors change brake fluid.
  • Replenish front wheel bearing grease.
  • Rotate tires.
  • Check exhaust system.
  • Check battery.
  • Check windshield washer system.

Recommended Maintenance list

FWIW, here is the list for my 280sl that I have hanging in the garage that I've compiled over time using MB literature and info from the forum. Specific parts may not applicable to your car. Produced by awolff280sl (Andrew Wolff)


  • Brake fluid: ATE super blue racing/ate typ 200(amber)(dot 4)(alternating flushes)
  • Clutch fluid: Ate super blue racing/ate typ 200 (amber)(dot 4)
  • Oil: Mobil-1 extended performance 15-50 synthetic, add ZDDP 6.5-7.0 ltr = 6.9-7.4 qts
  • Power steering: MB
  • Differential: Redline 75w90 GL-5 synthetic gear oil 5.3 pts
  • Transmission: Redline D4 synthetic atf 1.4 ltr = 1.5 qts
  • Coolant: MB + water wetter + water pump lube 12.5 ltr=13.2 qts

Every 3000 miles

  1. Oil and filter (incl. Oil cooler) change, wix 51348 & add zddp new copper crush washer (NOTE: this is for the spin-on filter adapter)
  2. Front & rear suspension - grease
  3. Driveshaft & spider - grease
  4. Brake fluid top up
  5. Clutch fluid top up
  6. Coolant top up
  7. Belts alt: Xl7355 (napa/gates) a/c: Xl7480 (napa/gates) ps: MB 006-997-09-92 (Note: for alternator mounted low and rotary compressor)
  8. Tachometer cable - lube
  9. Speedometer cable - lube

Every 6000 miles

  1. Transmission fluid change, new aluminum seal 007603024100,14mm Allen, fill to hole
  2. Differential fluid top up to bottom of plug hole
  3. Power steering fluid top up
  4. Front axle bearing caps change grease
  5. Rear axle bearings grease (zerks)
  6. Lube linkages, doors, hood, trunk
  7. Spark plugs- clean or renew. NGK bp6es .034, nickle anti-seize/dielectric, 20 ft/lbs
  8. Ignition timing check
  9. Idle - check
  10. Steering linkage joints check for wear
  11. Clutch pedal free movement (1/2) - check
  12. Brake pads check (carbotech: Front ct-45 1521(vented rotors); rear ct-31 1521)
  13. Brake hoses check (cox racing)
  14. Clutch hose check
  15. Fuel filter/seal replace Mann P707+MB seal 1009970040 (MB 0004776415 = filter+seal), 14mm stubby wrench
  16. Rear axle breather clean, 19mm wrench
  17. Tires check & rotate, alloy torque 81 ft/lbs

Every 12000 miles

  1. Spark plugs ngk bp6es .034 replace nickle anti-seize/dielectric 20 ft/lbs
  2. Air filter clean
  3. Transmission fluid change, sealing ring 007603024100
  4. Power steering fluid top up
  5. Differential fluid change hot: Redline + bg multigear concentrate
  6. Front wheel bearings clean, repack with fresh grease, adjust
  7. Parking brake shoes adjust
  8. Alignment & steering angles check
  9. Valves adjust (cold engine); valve cover bolts:3-5nm
  10. Valve seals examine
  11. Timing chain - check the cam index mark @ tdc for chain wear
  12. Timing chain tensioner/chain guides/rails examine
  13. Cylinder head retorque (warm engine, coolant cap off, in sequence)
  14. Injection pump air filter replace
  15. Power steering fluid filter - replace 000 236 00 55

Every 30,000 miles

  • Shock absorbers
  • flex disc-check
  • rotor, distrib cap
  • exhaust hangers-replace

At 100,000 miles

  • Change timing chain

Every 6 months

  • Wipers - change rubber & lube


  • Coolant flush and renew
  • Brake fluid - renew (bleed in order: RR/RL/FR/FL)
  • Clutch fluid - renew
  • Power steering fluid - suction off and renew

Tinkering tips

Note: from Old Yahoo section. To be distributed to appropriate places in this Technical Manual.

Will says: I use latex rubber gloves to keep the grease from under the fingernails. Get them at the pharmacy in boxes of 100 or mail order. The latex gloves I use are from Microflex, 1-800-876-6866. They seem to have several types of gloves. I use the Powergrip. See if they will send you samples of various sizes. Too big a glove is flopping around and gets in the way, too small a glove and you are forcing the hand to work against the glove and it will make your hands ache at the end of the day. You will have to buy a minimum of a case of gloves. But I use them for everything from cars to yard work to house painting. I used to get the gloves from my local pharmacy, but the Microflex gloves are better and half the price. Also, I have tried vinyl gloves and they are not worth the trouble.

I've heard mentioned (maybe Will Samples) that we have to be careful about letting our cars be hoisted from the wrong places on the frame. Trouble is I can't find anything in the literature about the correct locations to lift from. Has anybody got the lowdown on this? How about from the floor and the locations of jack stands? Is it acceptable to lift from the oilpan or the subframe, with a floor jack, on these models?

Jacking in front must be under the front axle in the middle just behind the small oilpan. In the rear, it should be under the differential. Stands can be placed under the body where the car's jack normally goes.

Got a question for some of you old car nuts out there. I am taking a car out of 9 years of storage this weekend and having it towed to my home. It's not been driven since being stored. Can you guys give me an idea of what some of the initial problems will be in getting the car started? Fuel? Oil? Water? Coolant? What do I need to do initially? I saw the car last weekend and it looks pretty good. Now it's time to get it running and sell it. The car is my father's who is unable to use the car.

Chuck Gale says: To start, you will need to replace all the fluids. Don't fool with any old fluids, replace the oil, coolant, transmission and brake fluid now and get it over with. Don't forget that the air filter is probably an oil bath unit. Think about repacking the wheel bearings and greasing the steering column and gear shift too.

The gas is where you could have the real problems. Gasoline, when left for long periods of time, will turn into glue. It can build up in the gas lines, carburetor and even the tank. I would pull, clean and re-gap the plugs, and add a few drop of oil to each cylinder before replacing the plugs.

When you try to start the vehicle, quickly make sure you have oil pressure and look for leaks. Properly stored, these old cars should be up on blocks and the gas should be completely drained from every part of the vehicle. If you are lucky you will not have to replace the tank, lines and carburetor. If not, be prepared to spend some real money.

Inspect the tires for cracks and check the fan belt(s) as well. Don't fool around with old rubber, just replace anything that is sub-standard. Once you have the car running, drive it around a bit and see how the suspension feels. You may want to crawl under and check the rubber bushings and while you are at it check the spring rate and the shocks.

A good lube job will do wonders as well, but be on the lookout for leaky grease nipples and slave cylinders. Push down on each corner of the car and see if it bounces up and down. If it bounces more than once, have the shocks replaced. Stand back from the vehicle, way back, and see if it is lower than it should be and if it's lower on one side. Typically sprung springs will show up on the drivers side first.

Age will also show up in brittle upholstry and body rubber in places like around doors, etc. The worst problems I've had were related to the deterioration of old gas.

Bernt Damm: I would worry lots about the brakes, brake lines, hoses and brake fluid. Also, I would try and turn the motor over by hand to see if it has seized itself in place due to moisture going into the exhaust and intake manifold form the air.

Be also careful that the valves actually open and close and that the ones that were open for all those years have not become stuck open. That could be serious when you try and start later. If it turns, Change the oil and filter. Take the tappet cover off and pour some oil over all the moving components.

Also make sure that the tanks and fuel system is cleaned out and operational. Replace porous rubber hoses. Drain the coolant and replace. Replace the plugs, check the point gap and rough timing. Get a good battery. Make sure there is good fuel where it should be. Maybe use a can of quick start if necessary and spray onto the intake for a few seconds.

Push the button (or key) and coax it to life. That is really my favourite part, starting something that has not run for a long time. If it takes, immediately check for oil pressure and if it does not come up within a few seconds, shut down! Once it starts and sounds happy, you can worry about servicing the rest...

I recently had a problem on my 230S (same transmission as W113) with the gears not going in. This got worse to the point of no more gears. It wasn't the hydraulics and the clutch worked but was sticky somehow. I suspected the spigot shaft bearing in the flywheel.

I decided to do the job and pulled out the motor and gearbox. I always do it like that since I don't have the right equipment or a lift to be able to take out a gearbox alone from under the car. Upon disassembly, I found that the clutch plate had oiled up. I then found that there were traces of red oil in the bell housing.

I stripped the gearbox to replace 3rd gear synchro ring and in the process also replaced the front and rear seals as well as the top lid gasket. Next, I cleared off all the oil and upon cleaning,

I noticed oil behind the flywheel too. I took it off and found that oil was leaking from the rear crank seal (famous rope seal) too. I decided to replace that and had to strip down the motor. In the motor, I found metal shavings in the oil pump screen and also a lot of grooves in the main bearings. I subsequently decided to find out where these metal parts came from and stripped down the top end too.

Upon removal of the pistons, I found that some pieces were missing from the compression rings and on one piston, the ring had broken and doubled up on itself. It was still running like that! Needless to say I ended up having to overhaul this whole motor and all I wanted to do was fix the clutch.

I also had to get another flex disc because there was nothing left of the old one except rope and fragments of rubber. The rear engine mounting also fell to pieces and I had to replace that too. Furthermore, all 4 screws of the thermostat housing broke off because they were corroded in place. I had to get another housing.

One of the banjo screws on the water pump (they hold the little bleed pipe in place) also broke off and I had to get another water pump too. Upon reassemble I found that my newly sealed gearbox had made a spot of red oil on the garage floor where it was lying for the past few weeks. Investigation revealed that the leak came from the reverse gear pin and nut on the side of the box. So, I had to fix that too.

All in all, this was one hell of a clutch repair! It is just as they always say, once you start with these cars, it never ends. I now have carburetor problems on this vehicle and the drag link has developed play...

Question: Is it possible to drop the motor and Trans from the underside of the car? Or must one remove it the conventional way? I am planning on starting the restoration of my front suspension and motor and I am looking into the different paths to get this all done.

Walter Klatt: that's the beauty of the front crossmember and subframe system. A carry over from the Ponton series where they had a system where a few bolts and all the hoses and wires were disconnected and the entire drivetrain could be dropped from below.

You need to consider the steering linkage to the column and the hoses for the brakes. There were a few shots of an immaculately restored engine with tranny complete with the ancilliaries and front suspension assy. a while back. A member of our group has them on his website of his gold metallic SL restoration. Sorry it has been a while since I've seen that website. Also if you look in Lawrence Meredith's SL book, you'll find a few pictures of the same.

Pete Lesler: this in my opinion is the only way to go. I have done it this way about five times now. No fear any longer of chipping the paint. You will need to get the front of the car fairly high. I slid the entire subframe/engine assembly without the wheels attached under the car. You will need a fairly experienced person to help.

I can't remember all of the steps, but in removal, first jack up the engine under the subframe so it appears stable. Then you need to disconnect all of the brake lines first, then the Idler arm from the body. There is another locating rod just behind the idler arm that must also come off.

I would then remove the trans mounting plate after remove the big bolt to the rear engine/transmission mount. Then disconnect the flex coupling, sliding the driveshaft down and way from the transmission yoke. Next step would be to slide the steering arm off the steering shaft. Then release the front sway bar links from the subframe, not the body. Last step would be to release the sub frame mounts.

The the entire assembly should be free to lower from the engine bay. I may have some of these steps out of sequence, but it should be apparent when you start which step follows in order. Now it would be wise to replace all rubber mounts including flex disk at this time.

Comment: An inexpensive and handy alternative to the OxyAcet. set is a "tiger torch". Puts out serious heat, when you need something more than the little BernzOmatic torch. Attaches to a regular propane BBQ bottle, and only costs about usd $20,-.

Dan Caron: You have to get the metal to the glowing level to have it hot enough to release two ferrous metal components. With aluminum it's much more difficult to get the proper amount. On lighter pieces I set the torch to give off black smoke and coat the aluminum part first.

As I heat the part the black area will turn gray before it gets too hot. If I'm trying to get a stuck cap screw out of an aluminum housing like a thermostat I only heat the screw and carefully turn it with a 1/4 drive ratchet while it's still hot.

On a collar or ring I only heat one area really well which seems to concentrate the heat and break it loose. Anything under 13mm should have 1/4 inch drive tools only. You can avoid a lot of breakage by using the right tools and not forcing things apart.

Question: Does anyone now where how to hook up a jump start switch to the starter on a W113. The starter is below the manifold and I want to crank over the starter to ajust the valves and set the ignition points. I have a unit but cann't figure out how to hook it up or to what, other than the battery hook up?

At least on the automatic, the point of connection is the neutral safety switch.

Remove the protective cover to the wiring harness that serves the neutral safety switch, exposing the 6 connector wires in the harness.

Connect a wire to the positive terminal of the battery and assuming the other end is an aligator clip, *temporarily* clip the other end of the wire to a plastic part on the car--do not let a wire attached to the battery "float" in the engine area unless you ground it to a rubber/plast part. Looking at the wiring harness on the neutral safety switch as if facing the front of the car, the top right connector in the wiring harness is the connection point.

Take the aligator connector (see step 2) off the rubber insulator and touch the end of the wire coming from the positive point on the battery to this terminal on the neutral safety switch to "bump" the starter to get the cam lobe to the proper position for adjusting valves.

Naj: I prefer to turn the engine manually with a 27mm socket on the crank bolt.

Walter Klatt: Also if I may add, remove the high tension coil wire from the coil so you don't accidently start the car. I know it won't start at this point, but never know if a fluke or something...

If one connects a wire to the positive terminal of the battery, that wire is hot and if it grounds (touches metal in the engine area), it will spark and potentially short out some component on the car or ignite fuel vapor or do other bad things. I have a gold mark on my battery hold down where my college ring touched the positive terminal of the battery and also touched the hold down-this grounded the positive terminal and actually melted gold from my ring to the hold down!!! (I swear I am not making this up!!!)

I have a simple question. How do you manually rotate the engine in order to for example get the points up on a lobe. I assume that you use a socket on the bolt in the center of the crank shaft pully. If that's how it's done, what size is the socket. I don't have anything that fits, and I haven't found any metric sockets larger then 19mm on the shelves of the Sears and Auto Parts stores that visited.

On the automatic tranny, hook a wire to the positive terminal of the battery. Remove the terminal cover to the neutral safety switch. There are 6 terminals. As if you are facing the car, touch the wire to the top right (I think) terminal on the neutral safety switch. This will bump the starter. Someone please correct me if I have the wrong terminal on the NS switch.

Joe: Tom and Jeff have two good suggestions in previous posts. I use both frequently. The other option as you described is to use a 27mm socket on the crankshaft bolt. A 1 1/16 inch socket will also work just fine. I sugggest using a 1/2" drive. You can sneak this socket along with a short extension up from below.

Work the rachet handle from below if needed. This is a preferred method when installing a new timing chain or precise rotation for distributor set-up etc. Whatever you do don't forget to remove the tools before cranking the starter. If all the spark plugs are removed, you may also be able to turn the engine with a wrench, using the 22mm (7/8") power steering pump pulley nut.

Can I fit other Mercedes model parts?

On the 230SL engine and trans exchangeability - Basically, motor and gear boxes from other MB do fit, best coices are the 220 250 and 280 SE (W 108/111) from the same building period. Not everything fits. You always have to change the motor mounts, they have to be from the SL.

Attention is necessary when you want to use a manual transmission from a steering colum shifted car, the upper lid of the gear box is different. The engines of the 250 SE (M 129) and SL and 280 SE and SL (M 130) are basically the same, however the 230 SL has a unique engine (M 127 II) that was not used in other MB cars. However, you can always distiguish between SL engines and others by the first six digits of the whole engine numbers:

230 SL engines start with 127.981

250 SL engines start with 129.982

280 SL engines start with 130.983

Have you tried that boneyard search engine? It's pretty incredible. Here's the link:
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