working on a 1975 450 SEL - hard?

[911-450]

How difficult is it to find a competent mechanic for these older MB's? I was at my local MB dealer today and he said that working on these can be difficult, esp the fuel injectors. He said a lot of times the tools needed to fix them are hard to come by. Of course he also said his dealership would do a good job (but things could take more money = time) than I anticipated. I had actually thought working on an older car would be less expensive than a new one. For those who have experience here, what do you think? Thank you!

[UTn_boy]

It always depends largely in the current condition of not only the fuel injection system itself, but the rest of the car, as well.  What good does a perfectly tuned fuel injection system do anyone if the climate control doesn't work, or if the transmission is faulty?  What if it need a valve job? It's no secret that going through the fuel injection system can cost plus or minus $3,000 in parts alone, and a valve job can run about the same, if not, then more....which also will often exceed the value of the car. 

Comparatively speaking, these fuel injection systems were probably one of the most advanced systems in the 1970's with very few people that knew how to service them even when they were new, at least in the U.S. Now, there are even fewer that know anything about them.  Luckily, there are forums like this one that help those out in need. In essence, no.  They're not easier to work on because they're older.....at least to a novice.  To someone like myself, the older ones are more desirable to work on simply because I don't have to buy $50,000 worth of software and special tools to service the newer ones.  Even then, you'd have to constantly upgrade your software and buy new tools every year just to keep up. 

Most dealerships don't have any of the tools needed to do anything on the older ones......even fewer have employees that know how to service/diagnose them.  Consequently, most dealerships will turn the older ones away, or tell dramatic stories like the one you were told.  It's a dealership.  They're not interested in servicing older models or restoring them.  New car sales and warranty/recall work are their bread and butter.     

How difficult is it to find a competent mechanic to work on them?  That's a question I think we'd all like to know the answer to.  The best route is to ask the fellas on here who they trust according to what area of the world your're in.  I'm in East Tennessee, and I know of no one within a 100 mile radius that works on the older ones.  Just be cautious.  Many shops will promise you the moon and claim to know it all.  The end result is usually a set of problems ten times worse than your original problems, and you'll still have the original set of problems, too......after they have your car for 6 months.  When these "shops" see you come in with an old mercedes, they usually assume that you're filthy rich, so they try to take advantage of that, as well.  It doesn't matter if you're a millionaire or not.  Always arrive at the shop with a rather humble outfit and attitude...at least until you get to know them.  Make sure that you know about what the particular job(s) should cost.  One mustn't go by the labor time guides for these cars.  Those time guides are  for when the cars were new and didn't have more than a problem or two at a time.   It takes as long as it takes.  So be expected to be charged hourly. 

Regarding labor, I always try to tell everyone not to go to the cheapest place around.  Those are the ones that will hurt you.  Don't complain about labor rates, either.  If you find a competent expert, then you should be happy to pay their rates, as having them around to work on your car is a convenience to you.  You're paying for their knowledge and expertise.  If you decide to go to the cheaper "shop" down the lane, then expect to have the job done twice, and at your expense.  If you buy your own parts, then expect the shop owner to either decline to agree to use your parts, or expect them to add enough on to the labor to offset what the parts mark up would have been.  Parts mark ups are  20%-30% of what a shop owner brings home in pay.

Last, if you decide to pull the trigger on buying a 450sel, then buy the nicest one you can find.  Don't worry so much about paying a little more for it than it's worth.  Generally speaking, the higher the price, the less that'll be wrong with the car....but not always.  Sometimes people try to sell rust buckets for tens of thousands of dollars just because it's a mercedes.  So if you can't inspect the car yourself, then reach out to the forum to have one of the others look at it for you with their own eyes.  Even if you pay them $200 for an inspection, that $200 is much less expensive than buying an overpriced non-running  W116 that needs everything. 

Always remember, there is nothing more expensive than a cheaply bought Mercedes. 

[911-450]

Thanks that's all really great advice. I'm going to look for a mechanic before I buy the 450 SEL I've been looking at! best, James

[Beastie]

The dealerships will service these cars, and they're meant to. But they don't want to, usually, and they often charge literally ten times more than an independent specialist. If you live close to a big city there is probably at least one old timer mechanic in the area who hoards parts and the specialist tools needed to service these cars. A small shop, loyal customer base, decent prices and good knowledge of the cars, if you're lucky. You might need to get to know owners in your area or check local forums (this forum is based in Australia) to find a mechanic like that nearby. I've found two different mechanics in my area who served their apprenticeships on these cars and have been working on them for 30 - 40 years but obviously your local results may vary wildly.

Your car has the earlier d-jet fuel injection which has a reputation for being more difficult to set up and have running properly but someone who knows what they're doing wouldn't be too daunted by it. Are some d-jet parts NLA? I'm not sure, I have a k-jet.

As UTn_boy said, buy one that is in good shape to begin with unless you want a fixer upper.

[daantjie]

K jet is the way to go. Parts are much easier to come by as this system was installed in millions of cars. Very reliable once sorted.  A good set of metric tools and you can easily get going on doing a lot of the work yourself.

[s class]

Both D-jet and K-jet are black mysteries to most modern generation mechanics.  I started out as a hobbyist trying to get my cars running properly because I was tired of paying 'experts' who were ultimately unsuccessful.  I have invested countless hours in learning the systems and experimenting with them, and the culmination is that I am now one of the recognised few in South Africa who actually can sort out D-jet and K-jet. 

I'm not at all suggesting you need to likewise become an expert, but find that individual near you , who has become an expert.  Someone who really is a D-jet expert will have shelves of good used D-jet parts.  THis is important because some of them are NLA.  If he claims to be a specialist, but has no stock holding, then he isn't really a specialist.  Just MHO. 

[marku]

I keep saying on the forum that Bosch have reprinted their manuals for both systems. They are printed from microfiche so perhaps not the best print quality. I have the D-Jet which is the most complete description and servicing I have found. And not expensive about €29.00 and  well worth having. There is an MB manual which goes in to much more technical testing.

[ptashek]

I keep saying on the forum that Bosch have reprinted their manuals for both systems. They are printed from microfiche so perhaps not the best print quality. I have the D-Jet which is the most complete description and servicing I have found. And not expensive about €29.00 and  well worth having. There is an MB manual which goes in to much more technical testing.

I can also recommend another book: "Bosch Fuel Injection and Engine Management: How to Understand, Service and Modify"
http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/0837603005

It covers D-jet, K-jet and pretty much every other Bosch injection system right up-to KE3-Jetronic.

[marku]

That sounds useful too but the Bosch one I mentioned is specifically for the 116.

[ptashek]

That sounds useful too but the Bosch one I mentioned is specifically for the 116.

Is there an ISBN, or Bosch part number on those books?
The only Bosch book about K-Jet I can find online is the "Gasoline Fuel-Injection System K-Jetronic" technical instruction (Bosch PN# 1987722159), and content wise it's non-brand specific and quite inferior to the book I have mentioned above.

[marku]

No just go to partbob.com and follow the links for the 116. They nearly always have them in German and frequently in English. If they haven't keep looking as they publish them every so often.

[Casey]

D-jet is a much more enjoyable experience to drive than K-jet, IMHO.  It is not as smooth and refined, but feels awesome.  It is also not as efficient with gas.  That said, you're in the US - try to find a 1973 to buy instead of the 1975.  The '73 had smaller bumpers stock and no emissions regulations, so is more powerful than any of the later year 450's at a full 200hp.  Or if you want a K-jet which will give you a more modern, smooth feel and all the newer interior trim redesigns Mercedes did (can't say I'm a fan of most of them though), get a 1977+.  Note that 1980's had a stupid 85mph max speedometer due to US law, and the least power due to emissions regulations - I have a 1979 that I rather enjoyed, though I liked the experience of driving the D-jet more.  That said, while I personally preferred the feel of the D-jet, the K-jet is the one I would pick if I was going to be driving with somebody else who might not be into old cars and wanted to make a good impression.