The Mercedes R107 – Five Things You Need To Know

The very first Mercedes-Benz SL graced the world in 1952. Born of a desire to create an accomplished race car, the ‘Sport Light’ moniker was apt considering the aluminium and magnesium frame weighed just 50kg. The original racer was paired with a 3.0-litre straight-six engine borrowed from the Mercedes saloon of the period. After stirring up some healthy interest following a string of strong race finishes Mercedes decided a road going version was the right way to go, eventually paving the way for the focus of this feature: the R107.

Two years later the 300SL Gullwing Coupé and 190SL roadster were revealed at the New York Motor Show and the SL model line was born. Never one not to take an opportunity to make a statement, Mercedes debuted the first ever car to be produced with gullwing doors. It just so happened to be the fastest production car of the period too. Mercedes had essentially launched the most iconic car of the ‘50s, laying the groundwork for decades of SL iterations to follow.

Later, in 1957, a larger-engined roadster hit the market equipped with the straight-six from the coupé and a slight power boost as a result, upping it to 225bhp. By the time 1963 rolled around, the SL had been completely redesigned and thanks to an unusual hard top roof design, the W113 earned its now famous nickname: ‘Pagoda’.

The SL generation in question here is the Pagoda’s successor, the R107. Whilst replacing the W113 was never going to be an easy task, the R107 went on to be the best selling SL model of all time. Launched in 1971, it enjoyed an 18 year production run resulting in more than 230,000 SL Roadsters. By then, the engine line-up had expanded and there were some tasty options to choose from including the 280, 300, 350, 380, 420, 450, 500 and 560 although the 560 was never made for the UK market.

Whilst the V8 engines make the SL a bit more sporty, it didn’t really live up to its Sport Light heritage. It’s a little on the weighty side so it’s better suited to open top cruising. But that’s not necessarily a bad thing. In fact, from a classic ownership point of view, the R107 is pleasingly over engineered and stands the test of time admirably, as long as you find one that’s been diligently cared for that is, and these five things are a good starting point.

Body and chassis

You heard it before we even said it: rust. Obviously, for any car from this era rust is a concern and buying something that’s rotten through will break your heart worse than it’ll break the bank. Pre 1976 models didn’t have great rust protection from the factory so earlier examples need going over with a fine tooth comb. From 1980 wax cavity injection was used but after 1986 shells were galvanised so you should have an easier time with these.

Water tends to sit and causes the bumpers to rust from the inside out. Have a good feel inside the bumpers to see how they’re faring. Another common place for this to happen is the bulkhead. If the air intakes by the windscreen are blocked this could be a sign that the bulkhead is corroded. Unscrewing the heater blower’s plastic cover allows better access to assess the state of the bulkhead.

Engine and transmission

The R107 has a beautifully comprehensive engine line-up including some straight six examples and of course, a healthy choice of V8s. The 500SL was the largest, most powerful engine sold in the UK so if a noisy eight-cylinder is your thing then keep an eye out for one of these. The 560SL never made it to the UK during production so any over here will be from the US or Europe. Be wary of American imports, especially from ‘wet’ states – the variable climate and conditions out there make it more likely something will be suffering with hidden rust.

Listen carefully on a test drive, the V8s can have a noisy tapping at the top of the engine. An oil change may be able to remedy this but new rocker arms might be the solution for engines that have seen heavier wear.

An odd one maybe, but the radiator is largely unprotected on the R107 so it’s prone to stone damage. Check for leaks, and overheating during a test drive. As always, if the owner has warmed up the car before you get there, walk away. A cold start is needed to get a good idea of the engine condition. Blue smoke when it starts could be a sign of worn valves which have a lifespan of around 70,000 miles. If any accompanying history shows the valves have been changed, also check the cam chain and tensioner were seen to around the same time.

Suspension, steering and brakes

It goes without saying, steering is a key component to pay attention to. Test driving lots of different R107 examples will help weed out the ones with awful feedback. If the steering feels a bit loose it could be down to the steering box. Over time its adjustable nature can be more of a hindrance than a help and in some cases it can move too much, making the steering feel a bit woolly. Sometimes this can be fixed by adjusting the box but it might be beyond the point of saving. Even if a fettle improves the feel it’s likely to be a temporary fix before the box needs a full refurb but a refurbished box will be significantly cheaper than a brand new one. If it needs replacing it’s worth doing the steering damper at the same time as this can wear over time too.

You can never rely on the fact that the previous owner didn’t fancy themself as a racing driver so it’s a good idea to look over the brakes. With the R107 it’s unlikely brake wear will be from reckless driving, instead, the passage of time is the most likely culprit. The R107 has disc brakes on each wheel that can screech, grind and catch under braking pressure if they’re on the way out. Over time they can warp and brakes are degradable components anyway, so account for new discs and pads as a matter of course. They’re an essential part of the car, obviously, so we’d advise budgeting for brakes no matter what model you’re looking at unless very recent service history evidences they’ve been replaced.

A floaty, smooth ride is the goal for an R107 so anything less might be a sign the suspension could do with some care. Rattles and knocks are pretty good indicators that something’s awry but approaching a speed bump too quickly and clattering over it might be a symptom of the driver rather than the car. If you suspect the suspension needs some attention it might be the anti-roll bar links which are an inexpensive fix but will lead to an MOT failure if not addressed. Otherwise, shock absorbers, coil springs and control arms could be the culprit of any uneasiness or funny sounds so get underneath and have a nosey.

Interior and electrics

Roadsters are prone to water ingress after a certain age thanks to old seals and sills. On the R107 this mainly shows up in the carpets and the boot. It’s not the end of the world straight away but this could lead to rust patches if the vehicle has been sitting like that for a long time. Again, a rusted bulkhead can cause problems. If you find any water or damp spots, take a good look over the hood for any obvious signs of wear. If the vehicle is still paired with its hard top, check this over to see how healthy the window seals look and check the structural integrity of the roof.

The central locking system runs in a vacuum that can leak. If someone was really determined to nick the car then it wouldn’t matter either way but dodgy locks get very annoying very quickly so for the sake of your sanity, it’s something to keep an eye on.

Parts

Fortunately, if something does need replacing, the R107 era is well supported by OEM parts and after market options. Also, thanks to large production numbers over the years, there are plenty of SL specialists around like the SL Shop, for instance, if you’re not comfortable doing the work yourself. It might save a lot of time to enlist the help of a specialist for some jobs and it’s always good to have a backup plan anyway in case you uncover something that has been royally fudged by a previous owner.