Before I commence this guide, I shall briefly present my credentials on how I gained knowledge of this model. I had a background of engineering and design in the 1970’s and on the launch of the W123 I became firmly committed to buying one. Certain it was to be a pinnacle of achievement for the Daimler-Benz company, I bought my first, a humble 200 in 1979 and due to it’s superb looks and features, was often asked if I would hire it for weddings etc. This grew into a full-scale business, with eventually 4 Mercedes delivering many hundreds of brides all over South Wales. As you can imagine a need for my own source of parts and maintenance soon developed as all my cars needed to be presented in ‘Show Condition’.
During this period I became actively involved in the Mercedes-Benz Club of Britain, eventually becoming their Regional Section Leader for Wales and enjoyed the friendship of many other enthusiasts whilst organising events all over the U.K and overseas.
By the late 1990’s the W123 model was becoming a little neglected, but many of us felt its design virtues were never surpassed. Consequently, after a suggestion by me, I formed a section of the club devoted entirely to this model; and a helpline regarding technical quires and advice on ownership and parts. I had been buying type W123 cars for a number of years for dismantling, mostly for my own vehicles. This soon grew into a full time business, when many of the U.K. dealerships changed hands. I was offered vast amounts of stock, including parts for both newer models as well as the earlier ones.
I now have a full time dismantling business, hold large stocks of ‘New’ obsolete parts for all models and import service items direct from the suppliers to the factory from Germany. Although I often have various vehicles and parts for all models, the W123 series car is my ‘core’ business. It’s the model I consider my first love, I have driven, serviced, dismantled and restored to concours condition every model in the range. To give you some idea, I bought over 30 W123’s last year (2003). Consequently the W123 has become something of a life-style for me, I regularly share my extensive knowledge, with up to 20 calls a day on the W123 helpline. There is hardly an area of this vehicle, which has not been touched upon by someone on our club helpline. This coupled with the knowledge that I have supplied every single part for this model from the smallest screw fixing to complete engines and interiors. I am often remorseful of the many good vehicles I have dismantled but find great satisfaction in the knowledge that my help has kept another W123 alive!
‘ W123’ is the serial number for this particular model. ‘W’ stands for wagen (car in German) and 123 is purely a series number, not always running in order. On the front cross member, of all Mercedes cars is a small vehicle identification number (V.I.N.) where this number is stamped. On all W123 models these first 3 digits indicate the model of the car the digits that follow indicate specific details of the car, e.g. size of engine, petrol or diesel, automatic or manual etc. It is important you understand the use of this number, especially when ordering parts, as there are vast differences between the models although they will all be known as type W123s. I will separate the vehicle into areas of detailed analysis for the prospective purchaser.
Body shell
There are three main body types, saloon, coupe and estate although there were a few rare versions for specialists, ambulance, hearse etc.
The W123 was produced at a time in the mid to late seventies when not a great deal of attention was paid to rust proofing, and also because of the huge demand for this model most of the early cars from 76-80 were not as well protected from the elements as they could have been. In 1980 and to the end of it’s life the model was given better wax protection for cavities, plastic liners were fitted to the front wheel arches and better weather-strips were fitted to doors and screens etc, it is this reason that the later cars have survived better.
All cars have mild-steel bodies but unlike SL models the coupe version does not have any alloy panels etc.
When looking at your prospective car start from the roof. If it has a sunroof, fully open it and stand on the sill and peer in for signs of rust and blocked drain holes. Sunroofs are very prone to rusting if not serviced regularly, and needless to say are very expensive to remove and replace. Particularly avoid cars with rust around the aperture of the sunroof door. Next check all the shut lines of the car for accident damage and poor panel fit. Non-original panels never fit properly, especially front wings and bonnets, and are very much inferior to the original ones.
On Coupés pay particular attention to any damaged chrome trim on windows and doors also check all the rubber door and window seals. If they are cracked or perished replacing them with new ones (the only option) will be very expensive. Obviously pay attention to the paint colour and condition and do not consider buying any other than an original colour, colour changed cars are worthless. Examine the front and rear wings for rust on the arches. N.B. W123, were never fitted with chrome wheel arches, these are add-ons, usually to conceal rust or poor body repairs, and in fact make them worse by trapping in more dirt and moisture. Front wings are bolt on panels, rears, are far more difficult to repair properly. Tailgates on estate cars need particular attention. The struts can fail with age, not a problem, easily replaced, but the bottom lip of the door and around the rear screen are prone to rust caused by water leaks, it is difficult to repair and very expensive. Used ones in A1 condition are hard to find.
Check bumpers for damage or rust, remember the coupé bumper is made up of three pieces and therefore much more costly than a one-piece saloon bumper. Estates models have rear bumpers that contain fog and reversing lights. Model 280E also has a three piece bumper. U.S. spec cars have much larger bumpers capable of withstanding a 5m.p.h. shunt.
Try to look underneath the car, rusting often starts around jacking points and also front box sections and chassis leg. The rear of these cars is very strong, sometimes corrosion can start near rear wishbone mountings. If car has been wet inside examine floor pan for softness as water enters sound deadening material and is trapped until rust comes through the floor.
Open bonnet and examine inner bays for rust and repairs done around suspension legs. Look behind headlights as small drain hole is underneath, often blocked and causing rust. Push bonnet stay catches forward and place bonnet in vertical position. Check spring on bonnet hinges and area for blocked drain holes, water should escape down into wheel arch. Look at battery tray, as it’s a favourite place for severe corrosion on R.H.D. cars. If rusty examine bulk head behind, as front roll bar is mounted there, and in bad cases can detach from bulk head.
Always look for corrosion in difficult to repair areas. E.G. Around front and rear screens, these will require screen removal for repair and again is very expensive. The W123 body-shell is immensely strong, but remember even the youngest of these cars is 20 years old, and although many have survived few of them do not need some sort of bodywork. Always bear in mind that this is the most difficult to repair and restore correctly and consequently the most expensive. Any restoration of these vehicles using cheap non original panels and trim is a total waste of time and money, as they do not fit correctly and are vastly inferior quality wise. I am constantly asked about these factor replacement wings, etc. my answer now, is simple, I think they are a good £20.00 worth because I couldn’t make one and send it half way around the world for that, and show a profit. That it wouldn’t fit, and is rolled out of sheet steel with a large scrap content, is irrelevant, you get what you pay for! With all the body repairs, remember the old adage, ‘do it once and do it right.’ Finally choose a car with a colour that you like, and is easy to look after. Silver metallic and gold’s are always difficult paints to match after 20 years, and would usually require a total respray to colour match repaired areas.
Mechanicals
Again all products of Mercedes-Benz during the 70’s were of the highest quality in design and durability. Engines in the early cars 76-80 were carried over from the previous W114/115 models and were noted for their longevity and quality, unfortunately their fuel consumption was not high and their performance not great. The model 250 had a redesigned engine only found in the W123 called M123. ‘M’ stands for motor, but this engine equipped with twin choice down draught carburettors by Solex was not a success, and was discontinued when the new cross-flow engines ‘M102’ were introduced in 1980. The twin cam ‘M110’ in production for the whole of the W123 production produced a superb 185 later188 B.H.P. from just under 2.8 litres and was a high performer. Later engines from ’83 had various economy devices to help increase fuel economy.
M102 engines are good performers if a little fragile and need regular oil changes. I suggest 4000 miles if you want to make the engine last, and in 230E guisé produce 135B.H.P. Cam chains are often neglected, 60,000 miles is enough as it is a simplex design and works fine if properly maintained, but was later changed to a dual (duplex) design in the W124 with bigger oil filter in 1987. Original equipment cam chains should only be fitted and are made by company ‘JEWIS’.
Diesel engines are in option of 200 to 300 turbo, again carried over from previous models. They were primarily built for the huge European taxi market. Consequently performance is not their forte, although the 5 cylinder and 300 turbo model has adequate performance. Turbo diesels were never available R.H.D.
If considering a diesel car do take every opportunity to, test drive it first as some diesels are very slow in comparison with modern models. In their favour is the fact they are almost bombproof if regularly maintained, and are far more reliable than any petrol option. Mileages of over a quarter of a million miles with no major rebuilds are not unusual.
Gearboxes are again of two types, early auto’s and later more economical ones, also manual boxes are 4 speed and later 5 speed. None have any major flaws but high mileage auto’s with imprecise gear changes are to be avoided, check history on car and see if any auto box has been serviced regularly.
Drive trains prop-shaft couplings are difficult to examine without getting under vehicles, when driving the car, apply power down hill, and lifting off abruptly will indicate if the prop-shaft is loose in mountings, quite common.
There is not enough room to list every possible engine defect other than to pay attention to the oil pressure gauge, it should always read full from cold, and should not drop back too rapidly from full when hot or be reluctant to climb. Listen for harshness in the engine and any undue knocks or rattles. Mercedes-Benz engines are usually very quiet in operation unless worn, also examine for blue smoke on tick-over, likely cause is worn piston rings, if only on overrun usually valve guide stem seals or guides.
The fuel injection system is very reliable but does not like lack of use. Fuel pump and filter are located under rear of car, often poorly maintained and all pipes rusted, although still working. Fuel tank on estate cars need special attention as they are often damaged and filler necks rust badly. This is also compounded if non-original tow brackets are fitted. Original one fits behind rear bumper and into special fittings in chassis legs made by company ‘ORIS’ self-levelling suspension system on ‘T’ series estate cars, works on engine driven hydraulic pump and reservoir in engine bay. It pushes fluid to rear shock absorbers with control unit fixed to rear anti roll bar by movable bracket, as car is loaded bracket moves down allowing increased hydraulic fluid to enter rear shocks and car will rise to compensate. Nitrogen spheres are also attached to maintain back-pressure.
If the car examined sits too low or too high or is very bouncy when driving the self-levelling is not working. This system must be surveyed and repaired by a proper technician who is familiar with the system and can test pressures with the proper testing gauges and equipment. Another area of great concern are steering boxes, most of them are now greatly worn and allow too much play in the steering and fail annual safety tests. New ones are very expensive, and second hand ones in good order are now very difficult to find. Shock absorbers and steering dampers if original on the car should now be changed as a matter of course.
Radiators are mostly of the aluminium type and are now starting to crumble and fur up inside. When replacing only fit original type as I have seen many poor copies, which have caused engines to overheat. Original ones are BEHR or NISSENS of Denmark. Brakes are discs all round with additional handbrake shoes on rear. Calipers are starting to show age and are beginning to seize through lack of use, main suppliers are; BENDIX, early cars and A.T.E. on later ones. All pads and discs are interchangeable on all models.
The exhaust system is very important and is made from high quality heavy gauge Metal Aluminumised and containing the correct back pressure design, very important to fuel injected engines. Original supplier is; ‘Eberspächer’ which fit underside of car perfectly. Main dealers also supply exhausts now, by a company called ‘Roth’, these are new to me and I suspect are a budget version, personally I would recommend staying with Eberspächer. Very important also are ignition systems on these cars. Cheap factor lead sets and distribution caps etc, will only cause problems. O.E. suppliers are Bosch and Beru. When examining a vehicle always check if original equipment has been fitted in servicing. It’s a good guide to tell you if the car has been looked after properly by someone who cares or otherwise.
Electrical fittings such as wiper motors, window regulators and motors rarely give much trouble and I have hardly ever replaced them, unlike the later models produced which regularly fail. Coupes present some problems with their unique window design and also ‘T’ series wash wipes can also fail. Both of these are usually caused by poor maintenance.
Interiors
This is an area that you should be particularly concerned about when viewing a vehicle.
There are four types of interior, and unlike the body and mechanical parts some of the trim is no longer available.
The four types are cloth, velour, leather and M.B.Tex. Early cloth interiors up to 1980 have a pronounced check design and vinyl on the seats squabs and backs, with a central cloth section. This was changed to a herringbone pattern; before the final full cloth covered seats appeared in 1982 also with a redesigned seat back allowing more rear legroom.
Velour interiors were more expensive and are similar to Draylon in texture but are actually nearly all wool and were very expensive to produce. Sadly they suffer from colour fade and tend to wear away more readily.
Leather interiors are very rare in W123 series cars although there are more coupes and late model ‘T’ series cars with this type of interior than any others. M.B.Tex is short for Mercedes-Benz Textured Punctured Vinyl and is very hard wearing almost indistinguishable from leather and is easy to wipe clean, and personally is my favourite as I find it very comfortable. The main problem area in all these interiors is usually the driver’s seat. This is the one that receives the most use so after 20 years the majority will have worn through covers sometimes exposing the horsehair pad underneath. The main area of concern is the spring base underneath, most of these have broken springs and cause the base to collapse, the cantilever type design collapses when only one spring wire is broken. This makes for a very uncomfortable seat, and I have often seen these bases stuffed with all manner of objects to maintain their height and composure. But I’m afraid telephone directories, lumps of foam, and pieces of wood will not help. The only remedy is a replacement spring-base. I have fitted and supplied more of these than almost any other item, so common is their failure. There was also a special lowered seat base available for the coupes, these can also fail and are not available from main dealers anymore. A big problem is that even if the seat cover is available it will no longer match the colour of the interior that has faded due to sunlight. Good second hand covers are the answer, but are difficult to find and match. Pay attention to any damaged vinyl in the interior especially on the dashboard and the centre console, again the only remedy will be replacement. I particularly dislike holes drilled to accept mobile phones, which was common practise in the 1980’s. Give the steering wheel a good squeeze and feel if it has gone soft, many are also worn smooth, it’s also a good indicator of how many miles the car has really covered.
Finally check that all the accessories and switches work and all the instruments are in full working order, examine, all the lights for damage and also front headlights for reflector corrosion giving a duller light than normal. They also suffer from condensation if the seals are perished.
I hope this article is of use in your prospective purchase, there are finally two main things to remember when buying a classic Mercedes, which the W123 undeniably is. See as many as you can, and buy the best example you can, even if it is the most expensive as restoring one can cost much, much more. Regular monthly articles are produced by yours truly in the Mercedes-Benz Club (UK) Gazette.
Mark Cosovich
April 2004