W124 - which repairs first? - PeachParts Mercedes-Benz Forum

smharr4 · #1 05-10-2006, 07:42 PM

I had an offer come into my inbox about a free spring checkup at one of my local dealers, so I made an appointment and took my car in earlier today.

An hour later, I had a list of items that they found wrong with the car - my question is, what should I fix first, and what should I fix myself, and what should I leave to the dealer (their quotes in brackets afterwards):

Rear differential L & R axle seals leaking ($700)
Power steering gearbox is seeping
Front flex disc cracking ($235)
steering shock leaking ($190)
oil leak from timing cover/head gasket ($1200)

So, what should I do first?

Pete Geither · #2 05-10-2006, 07:45 PM

Look out,,, you will get a ton of advice on this issue.

glenmore · #3 05-10-2006, 08:19 PM

The steering dampner you can do yourself for ~$25. Two bolts off, two bolts on. I have yet to do a flex disk but I think they are straightforward.

glenmore
1991 300CE
2000 C280
1990 LS400

Jackd · #4 05-10-2006, 08:28 PM

OK, I'll go first
Rear differential: Mine has been seeping for years but never actually saw the oil level go down. If it is only slightly oily, don't do it now.(or ever)
Same for power steering gearbox.
Front flex disc cracking: That would be a priority. This problem generally result in drive train vibrations. I'd do it now, it is relatively cheap.
steering shock leaking: Do it now but not at $190. Buy the part at the right place for about $50.00 and any half bright rookie mechanic student can replace it less than 15 minutes.
oil leak from timing cover/head gasket ($1200). How have they diagnosed the faulty head gasket? These engine are leakers (front top timing chain cover), very rarely from the head gasket at this location. Get a second opinion on that one. How much oil does the engine uses?

xenawolf · #5 05-10-2006, 08:40 PM

The l&r rear axle seals- rear axles complete are $150.00 rebuilt then labor $700.is reasonable if the axles are rebuilt as needed, not just new rubber boots installed.
Power steering- check the gasket on the resovoir its a few dollars & anyone can install it. I did this and put in some stop leak in my sec and now it does not leak at all. It previously leaked about a half pint every week or two. I know some will scoff at stop leak(i did too).Savings-$600.00.
I would fix the flex disk first to make a long story short,then steering shock(a $50.00 Part). Then see if you could have the engine cleaned, change the oil often with 20-50.(worked on my (1991 300e 4-matic) try to isolate the leak or simply have the head retourqued along with the timing cover bolts. However, someone once told me retourqing the head could actually make it leak more, although this theory has yet to proven (to me anyway). It really depends how much you want to spend. Hope this helps.

smharr4 · #6 05-10-2006, 08:42 PM

Pete: I want all the advice I can get, which is why I asked. I know there's master Mercedes mechanics on here who aren't looking to just take my money, and are willing to give me a fair idea of what's what. By the same token, there's seasoned DIYers who are willing to share their experience of what they've done.

Glenmore: I found a Stabilus steering damper at fastlane for under $40, sounds like it's an easy fix.

Jackd: I have noticed some vibrations in the car that I initially attributed to collapsed motor mounts and/or a slightly warped rotor. I did know that a cracked flex disc can cause drivetrain vibration, but as I already had a collapsed motor mount I attributed the vibration to that instead

The service advisor did say that he couldn't tell if the leak was from the timing cover or from the head gasket. I did have a new head gasket installed in August of 2005, so I'm suspecting (hoping?) that it's the timing cover. It's not using a lot of oil, I've only added 2 quarts since December and the car is driven 20-30 miles daily.

softconsult · #7 05-10-2006, 08:51 PM

First of all, I would not let the Dealer do anything. You already have some good advice. I doubt steering shock is leaking. They are less than $50 bucks and if you can slide under your car with a ratchet, it takes about 10 minutes max to replace.

On the differential seal, I believe they are talking about the pinion seal. This is not a do it your self thing. It can weep for a long long time. I had mine done a while ago. It wasn't much dollar wise.

Flex disk, absolutely get this fixed. Not a pleasant prospect if your car is not on a lift. Let the local MB shop do this.

Oil leak is probably front timing cover seal. Cheap fix, but again my opinion, let the shop do it for you. A bit tricky.

Someone in the thread mentioned re-torqing head bolts. No, no . Bad advise. Do not do this. He doesn't understand that the bolts are stretch bolts.

Steve

smharr4 · #8 05-11-2006, 12:05 AM

Can the timing cover be resealed on the M104's without pulling the head? I thought I read that was possible on the M103's but not the M104.

Replacing the flex disc has moved to the top of my list, I've already called a local independent shop to see if they can do the work. I'll be asking them to look at the rear differential seals for their opinion while the car is up on the lift.

What procedure is the replacement of the steering damper outlined in? I've been browsing section 46 of my shop manuals and nothing is standing out as being obvious.

Pete Geither · #9 05-11-2006, 05:31 AM

Most of the "needed" repairs sounded oh so typical for a dealership, that I knew you would get a lot of good advice here. You are right,,, there are a LOT of great people here who will never steer you wrong and probably save you a lot of money.

gmercoleza · #10 05-11-2006, 08:59 AM

Quote:

Originally Posted by smharr4

Can the timing cover be resealed on the M104's without pulling the head?

What's your DIY skill level? I've done this job. I'd say it is fairly easy and would take all of 4 hours. Look up parts on FastLane, I think you just need the U-seal which is something like $30 along with the black sealant, either the MBZ or Loctite (do a search - the debates have the makings of another oil thread).

89-300ce · #11 05-11-2006, 10:17 AM

Check to see if the differential vent is plugged. If it is plugged your seals will leak when the differential heats up and builds pressure.

Jorg

jim16671836 · #12 05-11-2006, 11:49 AM

STEERING DAMPER...Just get the car up on jackstands and the steering damper(shock) can be removed with 2- 17 mm wrenches..... sometime you will need a short pipe to help break the nuts(bolts) loose.... just 2 bolts with nuts... usually the nuts are a lock nut and no washer....

Flex Disc...They are pretty easy to remove... Remove(about 8 small fasteners) the cover plate from the drive shaft and check out the bearing first(try shaking the driveshaft with your hand(up, down and sideways out near the center of the drive shaft) and if the bearing/rubber need replacing you can remove the whole driveshaft.... This is one of causes of vibration... Next take out the bolts that go thru the flex disc(6 of them with lock nuts and maybe locktite on them)... you will have to use 2 wrenches... I use a rachet with socket and a open/box end wrench... Just rotate the driveshaft as needed to place the bolt/nut in a workable position..I also use a pipe for a breaker bar.... then you use a crowbar to get the flex disc out

You can use brake part cleaner or oven cleaner to help clean the area on the engine that is leaking oil... then after you make your 20 mile trip inspect the engine and find the leak... Normally it will be the valve cover or the timeing chain cover.. You will probably find that both are leaking... I would do these repairs myself...... If it is the head gasket then I would keep on driving the car and adding some oil... maybe the car has enough value to you that you are willing to spend what it will take to fix the problem?????

I also think that if the front rear end seal is leaking that you can also fix it while you have the car up on jackstands.... But that is another story... I don't have a lift just jackstands and a couple of jacks and I would do all I could to keep the dealer from doing any of these repairs...Jim

lkchris · #13 05-11-2006, 12:23 PM

Quote:

Originally Posted by Jackd

Front flex disc cracking: That would be a priority. This problem generally result in drive train vibrations.

I've heard also that if it fails when driving, it's likely your airbag will deploy due to proximity of a sensor. That is, even more expensive.

lkchris · #14 05-11-2006, 12:25 PM

Quote:

Originally Posted by Pete Geither

Most of the "needed" repairs sounded oh so typical for a dealership, that I knew you would get a lot of good advice here.

OTOH, if you went away with no recommendation to fix a leak what would you think?

Poster could ask same "priority" question at the dealership, too, and probably get similar answers as here.

E550 · #15 11-02-2008, 05:27 PM

Quote:

Originally Posted by Jackd

OK, I'll go first
Rear differential: Mine has been seeping for years but never actually saw the oil level go down. If it is only slightly oily, don't do it now.(or ever)
Same for power steering gearbox.
Front flex disc cracking: That would be a priority. This problem generally result in drive train vibrations. I'd do it now, it is relatively cheap.
steering shock leaking: Do it now but not at $190. Buy the part at the right place for about $50.00 and any half bright rookie mechanic student can replace it less than 15 minutes.
oil leak from timing cover/head gasket ($1200). How have they diagnosed the faulty head gasket? These engine are leakers (front top timing chain cover), very rarely from the head gasket at this location. Get a second opinion on that one. How much oil does the engine uses?

I have 2000 E320 purchased new with 74K. Recommendations by SA after FLEX Service. Rear Flex Disc Cracking, Front Lower Control Arm Bushings Cracking. Other recommendations Air, Fuel Filter, Spark Plugs and all Original Brake Fluid needs replacement.