DIY Pages. Overview of current pages with links. W123 basis.

[BoostnBenz]

These pages were intended to focus mainly around the W123 chassis (240D & 300D) but I'm sure many things are quite applicable to the W126 chassis as well.

Legal Disclaimer: By opening any of the following pages you agree that I am not to be held responsible for any actions or implications made in the instructive sites. They are merely meant to be a guide, there are other ways to do things and there are things which can be very dangerous if done incorrectly. NEVER assume anything, if in doubt ask! Safety is the #1 concern, there are more Mercedes out there, there aren't any replacements for you or your loved ones.

Main Page

Chassis:
Front suspension rebuild:
Front suspension rebuild leads to another page of links, which include rebuilding the idler arm, upper control arm, and lower ball joints. I have not yet finished the page for the sway bar bushings but the link for it remains, followed by the CS (coming soon). I didn't do the lower control arm bushings but in the near future I'm sure I will. All of the previously stated items can be done without a spring compressor using the methods stated in the instructions.
http://www.peachparts.com/Wikka/W123FrontSuspension

Fuel tank removal:
After accumulating an algae problem Dave Morrison created this page to inform us how to remove and clean the fuel tank in a W123.

Fuel tank sender removal:
The fuel sender page is quite a simple one as the task is quite simple as well!

Renewing steering feel:
This page has a simple breakdown of solutions to help eliminate that steering wheel play and make it feel like new again.
Steering:

Replacing Rear Subframe Mounts:
Here Richard Easley covers how to replace the rear subframe mounts in a W126, the W123 mounts are probably quite similiar.


Drivetrain:
How to replace the CV boots:
I go into almost terrifying detail here on how to rebuild your own CV boots. It does take some more specialized tools than the normal garage has but for I created the page for those of us sick of getting bad rebuilds or just would rather rebuild their own for a fraction of the price.

Remember flare, is when the transmission seems to go into neutral between shifts and the modulator can only be as good as the signal that the IP bleeder valve on top of the injector pump is.
Here is a page with quick descriptions of the vital parts involved in shifting adjustments along with some pretty decent pictures to go with them.
This page is yet another one dedicated to adjusting the transmission, it mainly focuses on the vacuum aspects of shifting which is vital to having proper shifts.

Basic transmission adjustment:
Gives a quick overview of modulator and bowden cable adjustmens. Also links to a page on troubleshooting tranmission related vacuum system problems.



Exterior:
How to change that broken power antenna mast:
Whether your power antenna mast has either got stuck in a position it shouldn't have or is bent, as long as the motor is good you can easily change out your antenna mast using these instructions.

Brake Light Modification
Looking around it seems that most of the accidents these Mercedes are due to getting rear ended most likely due to very poor brake lights. Fortunately most Mercedes in Europe had “rear fog lights” which leaves a blank spot for 2 more brake lights. OldNavy created this how-to to help make your Mercedes that much safer.

H4 European Light Upgrade (W126)
One doesn’t realize how poor the USdot lights are until they finally experience European code lights. E-code lights is what every country not in North America are mandated to use, they have a much more efficient reflector which means more light on the road and not in other drivers’ eyes.

Headlight Relays & Upgrades:
If you think your factory lights are pretty good well you haven't seen anything yet! I've tried a few different things but ended up with european code lights for both the looks and excellent lighting they create at night. The factory DOT lights just didn't cut it. If you insist on keeping the US factory look there are replacements out there for the round 7" headlight which can be just as great if not better than the full headlight assembly replacement. On this page there is a pretty good run down on how to rewire the headlights such that they get the highest possible voltage to put out the most light that they can. I'm not positive but I believe anything over 80W low beams and 100W high beams should be rewired using this method. There are also good tips in there about rewiring the fog lights so they can be turned on with the parking lights rather than just with the low beams.

Getting the electric sunroof to speed up:
Sunroofs are excellent but when they are working to slow or are making bad noises they aren't so nice, here you will find information on how to speed up that slow sunroof. I have a pretty good feeling that almost all of you reading this have at one point in time had a problem with your sunroof being to slow. Most of this is caused by people using the wrong grease, use only the Mercedes slide grease!! No matter how good you think your grease is, in time it will gum up and make your sunroof stick again.


Interior:
Resoldering Climate Control:
This climate control unit (CCU) or automatic climate control (ACC) is quite the Achille's heal of our MBs. They can also be quite interesting to troubleshoot the problems. There are many different failures which root different problems. Such as if the center vents quit then there are good chances it is that vacuum pod that needs to be replaced. But if your fan quits and doesn't come on with defrost thennew brushes probably won't fix it. However if you hear rapid clicking then perhaps resoldering the climate control unit will fix your problem.

Cruise Control:
A nice series of sites about fixing that inoperative cruise control units. There are pretty good chances with a little work you can get it going again.
Cruise Amp Repair:
Resoldering Cruise Control:
Troubleshooting Cruise Control:
Brake Light/ Cruise Control Myths:

Clock Repair:
Richard Easley covers how to get an non functional dash clock working again in this DIY page.

Brightening your dash backlighting:
In a nutshell if you remove the cluster, take out the two bulbs which light the dash and clean them and the area the bulb lights you may notice quite a significant increase in light output at night. It tends to get dirty in there over time and as it gets dirty the light doesn't transmit as well, some people just clean it, others have painted it white or a chrome like color to help the light travel down the plastic lens which sends it to the gauge faces.



List continues below!

[BoostnBenz]

Interior: (cont'd)
Repainting gauge needles
This page helps you make that old cluster (set of gauges) look like new again by painting the needles which started off orange and faded off to that bright yellow they now are. Also while in there I highly recommend cleaning the trip odometer off, by lightly pushing the reset button as you roll the trip odometer around to clean it off. Another good fix while having it out would be to get that non functional odometer working again by roughing up the shaft the plastic gear spins on.

Wiring Seat Heater
If you want to install a heating element in the seat of your W123 or similiar Benz this may be worth a glance. Mercedes was good enough to allow space in the fuse panel for the seat heaters but it takes a little work getting things to work out.

Rebuilding Seats (Coming Eventually, unedited pictures up)
When it comes time to recover your seats, replace the spring, or if you just want to add lumbar support then perhaps this page will be beneficial to you.

Conversion to Electric Vacuum Pump Powered Locks
82-300td walks you through a conversion from the motor powered vacuum pump our W123s came with from the factory to the electric vacuum pump systems that the W126s came with. No more having your locks only working a few times between running the motor. If you are interested in this for keyless entry may I suggest getting a system with power lock actuator which is installed on the power door and uses the current vacuum system to unlock the other doors.

Odometer Repair
Diesel Giant provides an excellent writeup on repairing a broken odometer with some good photos of the task. Scroll down to find it.


Installing Evaporator Box
Having some really bad A/C issues not due to the climate control or just lack of Freon? Perhaps this page created by Dave Morrison will be of some interest then.

Ignition Switch Troubleshooting
Negligence can lead to some bad problems and this may be one of them, if the key doesn’t turn right once or twice it’d be best to save your time and change it while you can. The tumblers get sloppy then out of the blue they stop working, if the tumbler can’t be turned then the vehicle must be towed to a Mercedes dealer and they’ll have to drill it out at a very high expense.

Refinishing the wood in your Mercedes
Unfortunately in time the finish seems to crack and fade, if you're tired of looking at this and not willing to big money to have it redone then perhaps this page is your answer!


General Maintenance:
Accessory belt replacement
This page will help you change your belts by locating those tensioners, the bolts that need to be loosened, and tips on tensioning and detensioning the systems.

Oil & Oil Filter Change
Bill Makemson created this page to help you change your oil with the correct procedure. As Larry Bible always says, change it hot and change it often.

Power steering filter and fluid change
Herbert Rocha wrote this article so you will know the easiest way to change the power steering fluid and filter. Rather than sucking the fluid out of the reservoir and changing it little by little it is recommended to remove the return line and let the pump empty the old fluid into the waste container.

Servicing the Rear Brakes
Alan Phillips makes changing the rear brakes easy by walking you through the procedure with this page. This is also quite applicable to the front brakes with a few minor complications.

Repacking Bearings
If a quality (synthetic) grease is used the wheel bearings should be packed every 40-50k miles, if a lesser quality grease is used then perhaps they should be repacked every 20-30k miles.


Motor:
Replacing Glow Plugs
Sean Roland walks you through troubleshooting and replacing the glow plugs. The GPs can be tested by using an accurate multimeter from the body of the GP to the center stud shouldn't exceed 1.0ohms of resistance.

Injection Pump Timing Adjustment for 617 Engines
Richard Easley talks you through timing the injection pump with no special tools. In my opinion this isn't a very accurate way to set timing, in the near future I'll create a page on using the injection pump locking tool to set the timing.

Repairing Monovalve
This page created by Philip Fox goes through the steps in repairing a bad monovalve. Generally the monovalve is repaired rather than replaced because a new monovalve is very expensive, but a rebuild kit is generally around $30 which isn't very bad. A bad monovalve is famous (or lack thereof) for the heat working at slower speeds and rpms but not at higher speeds even though the water temperature is still up.

Replacing the Turbocharger Oil Return Tube Seals
on Mercedes-Benz 617.952 Diesel Engines
I hate oil leaks, at this moment the only oil leak I have is actually from the turbo return seals so I'll soon get to follow this page created by Richard Easley, perhaps I'll make one of my own with pictures as well.
http://www.peachparts.com/Wikka/OM617TurboDrainTube

Adjusting Wastegate Spring
In time the spring which controls the boost pressure fatigues from the heat and repetitive cycles, what does this mean to you? Well rather than the car going 0-60 in 13 seconds like it did from the factory it may be significantly worse. The factory boost is about 13psi so if you have a lot of mileage on your vehicle and never set this before you're probably running a little bit less than this. I hear of down to 8psi on quite a few cars. So if you conclude your turbo pressure is to low then this page by Stu Ritter should come in very helpful.


Vacuum:
Checking Boost Sensing Lines
And Overboost Sensing Switch for 617 Engines
Well the boost lines and overboost switch have made themselves famous, in a negative manner, for causing poor performance and lag. When the boost lines clog up the IP doesn't know your turbo is running so it doesn't send the extra fuel in, which results in little to no added power. The overboost switch sometimes gets in the way of the signal, some people have bypassed it all together but it is there to help you in case the wastegate goes uncontrolled.

Rebuilding the Vacuum Pump on the 617 Engine
Our vacuum pumps last quite well but one part failure in it may cost the whole part to quit working. Richard Easley made a very nice page full of good pictures on how to rebuild your old pump. Rebuild kits can be had for far less money than what it'd take for a new pump.

Vacuum system Tuning (transmission)
While I can't say this is a perfect document as I don't think it goes into enough depth in some areas and to much in other areas, it is also the best transmission adjustment article that I know of. As a quick reminder, flaring is when the transmission free revs between shifts.

Vacuum System
Very simple page here of my vacuum system and some nice factory vacuum diagrams to help troubleshoot, provided by Peter Schmid transmission shop.

Troubleshooting the vacuum to the door locks
IceSailor takes you through the step by step sequence to find your vacuum leak at one of the doors, the trunk, or the fuel filler door. Follow it carefully, fix that leak, and get your door locks working again.


Valve Adjustment
While I don't agree with Jamie that you need the tools for the valve adjustment job, I do agree it makes it much easier. Valve adjustments can help smooth out the idle, bring back a little performance, or just plain help keep the car's performance upto par. I'm not sure what Mercedes' specification on doing it is, but I would suggest somewhere between 30-50k mile intervals.


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If you know of a good W123 or W126 related page, wrote a page, or want to write one send me an email.

[jake1222]

BoostnBenz,

See if you can put something in there about all of the drains that are in a W123. It seems that every one that I have looked at lately (shopping around for another one) the PO doen't understand where the water is coming from, including the drains from the sunroof and under the hood.

BTW; Great job and keep it up as long as possible.

[BoostnBenz]

Great suggestion, I'll make sure to do that in the near future.

[P.E.Haiges]

BoostnBenz,

How about a page on how to replace rear wheel bearings.

P E H

[BoostnBenz]

I can't say I've ever had to do that on either of my W123s. The closest I'll come to that (hopefully) is covered in the CV boots page, removing the axles.

[N8Scafe]

Hey Boostn, I just want to let you know that I'm eagerly awaiting the seat rebuilding DIY. No pressure...

[BoostnBenz]

Ok, I haven't touched this page in a while now. I guess it is time to finish off the current links and update the ones I've added. Thank you to the people who've given me extra links, advice on the site, or better pictures. Thanks for the support, the site has been getting over a thousand visits per month since I started it, it is now somewhere around 1700 per month! I don't have much to add to it right now as the MB is just purring along at the moment being, but just so you know I haven't forgot about it!

I hope my new thumbnail idea is working out better for people, makes it look a little fancier as well. I will probably be making some more slight cosmetic changes to the site in the near future.

[BoostnBenz]

Not much new, I just wanted to say if you send me a zipped folder your message immediately gets erased. I'm pretty sure most of the things I get are just spam but I have things sent to my DIY email account in zipped folders from time to time. As you may or should know virus detectors can't really look into zip folders until it is to open, to late.

[kmaysob]

the 83 300sd does not start out in 2nd. i have argued this everytime i mentioned a problem with 1st gear. it starts out in 1st.
have a great day!

Hi,
I just bought an 82 300CDT with 124k miles and wonder if you could help me out.
I am looking for the window "wipes" the weatherstripping on the outside for the front and rear windows. Any source you know of?
Also the ignition cylinder...hard to turn, want to replace it but how do I get it "keyed to doors?"
Also how do I test my Aux fan? I have not seen it run, and my temperature guage stays at just above 80. So Maybe it is not gettting hot enough?
Also fuel economy is only 16mpg? any suggestions greatly appreciated.
Thanks

[BoostnBenz]

Congrats on the purchase, they make very nice vehicles. Not that this is really the spot to put questions, but here are your answers;

I don't quite understand why Fastlane would list something for the front windshield seal for a 83 like mine but not for a 82 like yours. I never noticed if the pre83 W123s had a different trim around the windshield but I'm sure someone here may have a better answer for that. I don't recall offhand anyone really doing the front windshield themselves but I do recall several people replacing their rear windshield seal. It is about a 2-3 hour project and is quite helpful to have a second person.

It is a part that you'll just have to succumb to your dealer for, they will use your VIN and key it to your car. Last I heard it costs somewhere around $90 for a new tumbler keyed by MB, you can actually get a blank version for around $30 at parts places like FastLane, but again it isn't keyed to anything specific. I've talked to a locksmith or two in hopes of getting a spare tumbler but they refused to touch it, they seemed a bit sore at the fact mercedes doesn't share any information with them.

Which fan are you referring to? The engine fan is ran on a clutch that once the fluid hits a certain temperature it kicks in, sounds quite a bit like a turbine going. It has to be running quite warm for this to happen, probably near 100*C if not in excess of. The second fan is the fan for the A/C, it is triggered by that system unless the car is in risk of overheating. It sounds like your thermostat is working well, if it drops below 80*F while driving it normally means it is a weak spring but it sounds like yours is in the ideal spot.

That is very poor mileage, have you noticed anything inherently wrong? Excessive smoke during normal acceleration? Any fuel leaks? Have you checked the brakes for drag? Have you tried any sort of injection system cleaner (like diesel purge)?

Thanks for the comments.
I guess I was not real clear... its the seals for the Driver, Passenger, and two rear windows, (the little seal next to the glass on the outside) hope that exlains it better

The fan is the electric one on the front of the radiator, I was told it only runs when two things occur
1. a certain temperature occurs (don't know how high)
2. When A/C is on.
I drove it for a 100 miles one day, and still no fan action
I have looked for fuel leaks, can't find any, but my next attempt was going to be an additive.
Oh and no real sense of drag, or any thing wrong. I bought the car from the second owner for $2,790. (long story on price specific :p .

thanks, again.
Joe

[Breckman99]

BoostnBenz, I thank you! You have inspired me to refinish my own wood! This is something that I usually would not take on (wood work that is). At the moment I am just finishing up stripping the finish off a couple of test dash pieces.... I will post some pictures of the progress soon! (looking real good so far..)

[BoostnBenz]

I'm glad it can be inspiration for you, just trying to give back to the community I that I've learned a good deal from. Actually on the topic of wood mine still looks like the day I did it. There have been a few different suggestions for other finishes such as a type they use for kayak's and another that is used on a commercial bar. From what I hear all have been quite successful.