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1993 500SEL
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Discussion Starter · #1 · (Edited)
Hello everyone. I currently own a W140 1993 Mercedes 500SEL. I'm a student and this is the first car I've owned. I have no experience or tools to work with cars. However I have been lurking here for quite a while, so I'm willing to learn.

I have owned the car for about 4 months. I bought the car because it was 4700$ and I kinda took my chance with it. Recently, the car started to develop an unusual sound when driving, especially when going over uneven road or bumps. The sound sounds like a a bumping noise of something hitting something. It comes from the passenger side. It comes on whenever the car shakes/vibrates, not just going over bumps. I suspect it is a part of the suspension system, but I cannot be sure.

This is the main problem with my car that I want to fix ASAP. I can only show what this sound is really like by having the person sitting inside the car.

(The history of the car since I owned it:
The car has been sitting undriven for a long time before I bought it. 2 Weeks later, I did an oil change, and over mechanical inspection at my indy. The result was the engine and transmission condition were good. However the previous owner didn't even change the oil filter, it was very dirty. I suspect they never changed oil much either. One side of the front brake caliper is stuck with the disc, causing the car to pull to the left side (like an alignment issue), therefore the whole front brake caliper, disc, pads were replaced ($1200CAD job).

Then alignment & balancing was done at Kal Tire because I get steering wheel vibrations at 60-80 Km/h. However they made the steering wheel vibration even worse after balancing, and therefore lost 1 customer forever.

Then I rotated the wheels X cross, and the steering wheel vibration is 90% gone.

Good driving for a while.

About 1 month ago, changed oil again to flush out the old dirty oil. I replaced the rear hydraulic structs with normal shock absorbers, because my mechanic found the right hydraulic struct to be broken, and therefore the rear structs needed to be replaced. However, these structs are very expensive, so I chose to replace them with normal shock absorbers. I brought my car back to my mechanic to double check if he the job properly, and he found no problems.

Then the steering wheel vibration happens again, and I re-balanced at a different place, improved a bit. After rotating wheels again, much improved

Had my mechanic to check suspension, nothing found.)


The car has some minor issues (since I bought it, didn't bother to fix them because I was quite busy):

1. The air conditioner is not cold enough.
2. The closing assist function of the trunk lid does not work. I have to close the trunk lid using fair amount of strength, otherwise the trunk handle doesn't retract in and trunk does not lock.
3.The closing assist function of the doors work for 2-3 days only if I reset the closing assist pump by pulling fuse #9. I don't know if its air leak in the system, bad sensor, too high shut-off pressure, or other causes.
4. The odometer is stuck. It does not roll at all. Dealer quoted me around 1000$ for a new instrument panel with digital odometer + labour. I thought maybe the gears need lube so I didn't let dealer fix it. This has to be fixed before my next emission inspection is due, which is Feb 2011.
5. Driver side rear window doesn't work.

The car shows signs of a minor accident. The gas tank cover is slightly off-position, and a rubber tube is needed to prevent it from closing all the way in. The front part of the right front fender is cracked and broken. I can't tell whether the previous owner had the wiring harness done or not.

I'm located in Greater Vancouver Region. I've been to the Vancouver Dealer on Boundary Road, but their attitude was not friendly when I asked them to do a computer diagnosis for me, and YES they refused. Do you guys know any very good W140 specialist who are able to fix the problems I listed? Thanks in advance.

Here are some pictures of the car:
 

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1995 Mercedes-Benz S420 (W140), 1997 BMW 740iL (E38), 2011 C300 Luxury (W204)
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Congrats on your acquisition. I encourage you to buy a basic toolkit, that has the most common sockets, pliers, ratchets, screwdrivers, etc.

Your trunk might need to be adjusted, there are adjustment screws. It shouldn't be that hard to close, especially if your pumps are all working etc. It seems like the latch isn't engaging to close.

The pumps related to the door closing assist could be diagnosed. With a simple toolbox and careful reading, you should be able to tell whether you need a new pump or should be able to fix the problem. Its not difficult if you are good with following instructions, and handy. You're a guy, I'll assume you're handy.
Heres the link. Credit goes to Brett for the fine article.
V12 Uber Alles, Getting to know your Closing Assist Pump in a W140 Mercedes Benz, an article by Brett Allison

Your rear window not working: When you push the open/close switch, do you hear a sound at all? Motor sounds? If you do hear a motor sound, motor is fine. Regulator might be bad. It is a pretty easy fix, for the average DIYer. Regulators are fairly cheap on eBay.
Here is the link, it isn't that great of an article but it should work.
V12 Uber Alles, Replacing the Rear Window Regulator in a W140 Mercedes Benz

I am also a college student, also bought the car less than a year ago, my first car too. Also not a mechanic, but I'm handy and a fast learner.
My first "mechanical" work was performed on my W140 aswell (aside from basic maintenance, tire rotations of my brother's corolla).

I started off on the Window Regulator replacement. It was also my driver's rear window regulator that went bad. I followed the instructions, the only thing was I needed a rivet gun to put in new rivets. I bought one from Ace Hardware, and then returned it after using it. They were cool about it, there was no signs of use. You could do that, or you can just use bolts and nuts. Rivets are much harder to put in though. Just follow the instructions, took me 2 hours in the dark with a flashlight. One warning, be very careful taking out the wood piece in the door panel, also be careful ripping the cover sheet.

I started my DIY projects with the window regulator mentioned above. I then started to learn more thanks to these forums and the good sources on the internet. I then was able to change my spark plugs, spark plug wires, MAF sensor, one headlight unit, one headlight lens, replaced cluster bulbs and dash vent control bulbs. Also learned how to properly detail the whole care, with the right stuff and tools.

I started in the same spot as you, only with less money I bet :)
So, be eager to learn, don't be scared, thoroughly do your research before starting a DIY project. Of course, if you have any questions, come to these forums and ask away! We don't judge.

I am still learning, soon migrating to doing DIY that involves lifting the car up ie suspension work, diy motor oil/tranny change, maybe motor mounts/flex discs. I just don't have the equipment to do tackle these tasks yet. If you read about the horror stories of having the right equipment, it gets scary being under a 2 ton beast.

I hope this gives you some encouragement. If in doubt, ask here, go to an Indy. But, before you go, always do some research on your problem so you don't get ripped off. Good luck!
 

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91 500SL, 93 600SL, 95 S600 coupe, 97 S320, 99 ML430, 2003 CL600, 94 SL600, 97 Kawasaki 1100 STX
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Try AC recharge with dye to find leaks. Pay attention under the car next to transmission. Evaporator drain tubs go there and if you see green dye you need to replace your evaporator. I had that problem and drove about a year adding freon in the system to get cold AC. Check AC dryer sight glass for bubbles. If there are any, AC system is low on gas.
Odometer issue might be a cluster failure. If you need to pass inspection, take out the cluster, disassemble it, and move mileage manually. It's a crazy fix but way cheaper than $1000 cluster :)
Rear window motor might be bad, thus window doesn't work. Take out door panel and apply 12 volts to the motor to see if it works. If it doesn't, check window switch. ( I assume you checked fuses already).
Trunk can be adjusted. There are adjustment screws in the trunk lid. Take out lid covering and look for bolts that hold lock. Make that lock extend out more.
That might be your close assist pump issue (pulling fuse 9 to reset the pump). I had close assist pump failure. It was high pressure. Opened the pump and lowered the pressure. (search forums for more info on pmp pressure adjustment. Fairly easy to do)

Congrats on your purchase and good luck.
 

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1993 500SEL
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Discussion Starter · #4 ·
Thanks for the replies.

I can DIY closing assist pump and rear window, as I've read the instructions. And I will try to take off the trunk link carpet cover and see what I can do with the trunk latch. However I'm not familiar with AC system, but it's OK for now. I'm fair busy with schoolwork, so I have priorities when it comes to fixing problems with my car.

The major issue now is the annoying bumping/hitting sound whenever the car shakes e.g going over unsmooth road. The road condition in greater Vancouver here is pretty bad. Thus I hear the sound all the time while I drive. My friend keeps telling me that this sound is normal. He told me when he lowered his car (1995 Honda Odyssey), he got a similar noise. In this case, I am sure that the sound in my car is unusual. My friend pressed down on the car for me while I sat inside when the car is not running, and I could hear this same sound. This sound is a little bit similar to the sound I heard when the rear struct suddenly broke, but a lot less loud.

I will need to fix this soon, because I fear if I leave it, I could cause serious damage to my suspension (I believe) and any problem caused by this will be harder to fix in the future. Could this be an improper shock job? Thanks a lot.
 

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1993 300SEL (Sold) 2007 X5
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My advice would be not to drive the car with the front brake(s) sticking.

You can easily grab a 2nd hand cluster to replace your current one. Just make sure it's from a V8 W140 and it should be the same. There are some issues swapping between analogue and digital if it's not the exact part. The other option is to contact MBcluster.com who repair and refurbish clusters for a lot less than the dealer's charge for a new one.

In terms of changing your rear shocks be sure that they rerouted the fluid lines - they run in tandem with the power steering pump and if not changed round the pump will run dry. Also you might note that your car is sitting a bit low in the rear - that could be that it's parked on an incline or that they didn't change the rear springs when they did the shocks - they are different.

The clunking sound could well be the swaybar links - it's pretty common - you could fix the brake calliper which is sticking while you're in there doing the links.

Most of the issues you're having are relatively cheap and easy to fix if you're frugal with your money and use 2nd hand parts where you can. I maintained a W140 on a student budget for four years during university, it is possible.

Congrats on the car.
 

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93 300se,92 300se,93 600 sel,92 500 sel,79 500slc,02 1.8t bug,01 a8,01 s80 t6,96 bmw 740il,86 rx7
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I have a old cluster you can have. The odo is in working order. You can transfer the odo out of my cluster into yours and have parts. Your welcome to it. I can set the odo for you if you like. Just find a diy on here about the cluster and replace the guts. Your for the taking.
 

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1993 500SEL
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Discussion Starter · #7 ·
@:NZ_Benz

The front brake sticking has been fixed already. As for the sway bar link, I've let my indy check it already but he said it's O.K. However, now I have a sudden desire to DIY. I'm fairly busy M-F but have time at weekends. There is a rental vehicle lift shop specifically opened for DIYers near my place for around 20$/hr. I can go there and work on my car myself. However, I might need instructions (w/ pictures preferably) on sway bar links. As for the shock job, I need to check as well.

@phamilton01: I will take out the cluster and check to see if the odometer needs lube or has stuck gears first. This way I can get hands-on experience with pulling out the instrument panel. Maybe you could keep the cluster for me for a bit longer perhaps? And How much are you asking? Thanks.
 

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2003 Mercedes S320 CDi (W220)
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Congratulations on the purchase, I am sure it will provide many hours of pleasure ((and ain)

I look forward to reading about your progress.

Shane
 

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Congratulations on your W140. You are obviously separate from the pack,as most students are looking at a used Japanese car and Mercedes is not even on their radar. Your interest in DIY inspires me to look at that myself,as I want to keep my W140.

I am from N. Vancouver, attended UBC in the seventies.Vancouver is a totally different place now as you know.

I am fortunate in that my daily driver is a 240D,which has been in our family since almost new (originally bought at the Vancouver MB dealer as a year old demo).The diesel is incredibly reliable, with no power features, so maintenance is minimal.

Totally the opposite to my W140, which is showroom new with only 109K miles, and no issues except the intermittent door lock failure on right front passenger door.

Your car should be running incredibly quiet, with no vibration. I have run mine up to 110 mph for a few miles on a remote undisclosed section of I-15, and the ride was like I was doing thirty.Absolutely no vibration.

One source of parts I have discovered is www.adsit.com

Again, keep us posted. Forget about the a/c this year;you can work on it during the winter or next Spring. It is also a good idea to decide if you want to just get your indy to do some of the jobs just to get them done, and do diy on others.

By the way, if you want a DVD of the original W140 service manual, it is available from Mercedes Benz but there are not many left. I just bought mine online through Mercedes Benz of Anaheim (formerly Caliber Motors). The parts manager there is Mike Gutierrez.
I also bought a magnet (it has a part number) to insert into the AT housing next time the fluid is changed; it collects any metal fragments generated in the automatic transmission.
The newer S models have it built in, but my 93 does not have it. Since I am just past the 100k mark, it is time to change the transmission fluid, and I am going to put synthetic in and place the magnet.
 

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1993 500SEL
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Discussion Starter · #10 ·
@NZ_Benz:

After re-reading your post, I thought I've might've missed something. The struts use the power steering pump to pressurize the line. Now my struts were replaced by shocks. The shocks are similar to these: (1st one in the link)
1993 Mercedes-Benz 500SEL - Shock Absorber Rear - BUY 1993 Mercedes-Benz 500SEL - Shock Absorber Rear
Did you mean that I need to make sure the fluid lines do not hang around loose so the fluid in the power steering pump don't dry out?

Yes, the rear springs were not changed, and the rear is now lower than before. Do I need the correct spring height for the shocks? Were the original rear springs meant to be used only with hydraulic struts?

@AZMT123

Originally I didn't realize my car is quiet, because I had no comparison with other cars, as I drive my car daily. However, once I sat in my friend's car a bit of time, and then drove my car, I suddenly felt that I was flying: it was so smooth compared to his 1995 Odyssey. My car has a bit of vibration from time to time at various speeds, but is smooth in general. The vibration is caused by improperly fit/balanced tires or possibly a bent rim I believe. I will have to go to a tire shop to check this in the future.
 

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'98 E300, '10 GL350 Bluetec
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Welcome. Where in Van are you?

For alignment, spend the extra $ at MB; they do it right.

You need springs from a car without the hydraulic suspension (SLS)

PM me your contact # and we can chat; I may have more info.
 

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91 500SL, 93 600SL, 95 S600 coupe, 97 S320, 99 ML430, 2003 CL600, 94 SL600, 97 Kawasaki 1100 STX
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I forgot to mention about my odd vibration problems. Upper control arm bushing was bad. It checked out to bee good on the lift but had a bit more play on one side than the other. I replaced them and vibration was reduced A LOT. I still had slight vibration but that was due to older tires.
 
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