M103 timing cover reseal + chain guides
 

Hey guys,

For my 300TE:

Recently switched to Synthetic and my front (lower) timing leak that I had a little leak on has gotten worse. Its not bad, but its leaking more now so its time to do it. Doing my standard research and everything, order parts, then get it done with lots of pictures as always :) Planning to do it in about a months time once school is over.
Did a search and can't find much on the lower case...tons on the upper, but that was a piece of cake. Lower looks much more involved.

1) MB sealant or Hylomar?

2) I am considering doing the chain guides too...anything particular I need to know about this? Should I replace the chain tensioner or leave it alone? I've read the chains are basically bulletproof, so I plan to leave the original chain in...just replacing the guides.

3) http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Engine/103/01-2100.pdf
Manual states I need to remove radiator and swivel power steering pump out the way. Is this really necessary??

4) Anything else I should consider replacing while doing the job? I have a new fan clutch bearing bracket ready to go too.

Thanks guys

1) mb sealant is made by loctite . see post#2: http://www.peachparts.com/shopforum/tech-help/145246-confused-about-mb-sealants-engine-mating-surfaces-loctite-5900-permatex-right-stuff.html


2) you’ll need a special tool to lock the crankshaft pulley/flywheel, cause the bolt is torqued pretty high. Although in the link, a forum member mentions that bolt torque = 250-300lbs I double checked my Haynes manual which claims that it should be at 300Nm or 221lbf ft.
see post#8: http://www.peachparts.com/shopforum/tech-help/129996-crank-shaft-bolt-removal-m103.html

3) CHAIN: ive also read that the chains are pretty durable, but I would definitely check it to see if there is any stretch(supposedly 5degrees =max.).

Good luck cant wait to see the write up

If you plan on removing the lower timing chain cover, it's the perfect chance to replace the front main crankshaft seal.

Reinz has the same sealant as does Loctite, just purchase whatever you can find for the best price.

The tool to lock the flexplate is pretty inexpensive for the M10x and OM60x.

Cannot comment on the radiator removal for the W124, I had mine out on the 300SEL when I did the top end this past winter. I just replaced my front main, super easy and now no oil leaks! I was not in the mood to pull the front cover. Check the stretch of the chain while in there, no easier time to drop in a new chain.

Reinz is $10....OE MB is $20, which should I go with?

I have ordered both the regular crank seal and repair size seal just in case.

----

Do I NEED to remove the belt tensioner assembly? I cannot tell if it actually gets in the way or not?

Also where can I find one those locks inexpensively?

ps2cho, on a 104 engine you need to remove the belt tensioner assembly to replace the fan bearing bracket. Suspect that it's the same process with a 103 engine.

Removing the radiator will certainly provide significantly better access, even when replacing the fan bearing bracket. I left the radiator in place when replacing the fan bearing bracket on a 104 engine, and it increased the degree of difficulty significantly.

go with the genuine mb gasket, since this is a pretty big job and it would not be fun to have to do it again.

victor reinz: from personal experience, bought a valve cover gasket 2yrs ago, and it now leaks oil to spark plug holes.

a couple of other people that had problems with VR gaskets: http://www.peachparts.com/shopforum/tech-help/315782-m116-lower-oil-pan-torque-victorreinz-gasket.html


EDIT: forgot to mention that i replaced the front crank seal about7yrs ago / 30,000 miles ago with genuine MBseal , and it is still holding up well.

Actually when I did my 260E's fan bearing bracket, I did not remove the belt tensioner...

That's why I am curious as to why I need to? I guess I will figure it out when I get in there, but I always like to know what I am gonna need to do ahead of time. Its easier for planning and parts purchase.

Will go with OE MB. Thanks. I guess when in doubt, go OE is a good rule.

Half way mark!

Found pieces of the guide rail bracket missing, so I decided I needed to do it, but the rail connected to the tensioner was not bad at all...Replaced it anyway since by now I will need to recheck timing.

Oil pan gasket broke off. I do NOT want to drop the pan, so plan is to carefully cut off the section and use the MB timing gasket sealant carefully. I cannot see a reason why this will not work. Worst case, if it leaks, I'll change it next time I change the oil.

Here are customary pics!

I cracked the main crankshaft pulley bolt using the starter and a breaker bar against the frame. Worked like a charm. One click and it popped right off!

http://www.w124-zone.com/downloads/p...er/timing1.jpg
http://www.w124-zone.com/downloads/p...er/timing2.jpg
http://www.w124-zone.com/downloads/p...er/timing3.jpg
http://www.w124-zone.com/downloads/p...er/timing4.jpg
http://www.w124-zone.com/downloads/p...er/timing5.jpg
http://www.w124-zone.com/downloads/p...er/timing6.jpg
http://www.w124-zone.com/downloads/p...er/timing7.jpg
http://www.w124-zone.com/downloads/p...er/timing8.jpg

Make sure to tighten crank bolt to specs , if it comes loose IT WILL DAMAGE CRANK AND PULLY

Change the oil pump chain tensioner slide while you are there too.

Unfortunately I do not have that slide...
At 115k miles on the clock, I am not worried...I had no plans to even replace those guide rails, but since I had to replace the straight one, the chain had to come off slightly so I went ahead and did whatever I had in my parts box.

I will make sure its tightened to spec, thanks! I hope my torque wrench goes up to 300nm!! LOL.

Ugh looks like my torque wrench only goes up to 250nm...

Is there a calculation so I can figure out how much more it would need to reach about 300nm?

All done! Found my TW went up to 250ft/lbs so I was good.

Locked crank at flywheel with prybar which worked a charm.

Pics:

http://www.w124-zone.com/downloads/p...er/timing9.jpg
http://www.w124-zone.com/downloads/p...r/timing10.jpg
http://www.w124-zone.com/downloads/p...r/timing11.jpg
http://www.w124-zone.com/downloads/p...r/timing12.jpg

I locked the crank using the flywheel and a pry bar carefully. Worked a charm!

Hey Ps2cho, You still around?
 

Hey Ps2cho, I know this is a fairly old thread, but I hope you're still around.
I have to do the same job on my daughter's 190E 2.6. I came across this thread and had a few questions if you still remember!
First, How did you make out with the sealing of the oil pan? did the sealant hold up? If it happens to me, I'm going to splice in the front piece of a new gasket with some sealant and only have to worry about it leaking at the splice cracks.
Second, In your pics it only shows the balance and hub attached together. Did you remove them that way or did you take off the pulley and balance first? Was it hard to pull off?
Third, was it hard to torque the bolt down? weren't you worried about breaking teeth on the flywheel or some other damage.

If Ps2cho isn't around or misses this, I'd welcome any other input from someone who's done this before!
Thanks

Well, I got it done. Although I still have to get hold of a torque wrench that goes up to 220 Ft lbs (about 300Nm) to tighten the bolt.

To break the bolt I made a simple holder from a 2" wide x 1/4" thick x 15" long aluminum bar. Two 3/8" holes drilled at one end that are spaced apart the distance between two of the crank pulley bolt holes (2 1/2" on center, which will leave a hole between them) and about 1/2" from the edge of the bar and a 1/2" or so from the end of it. between the holes I cut a half circle arc to allow the 27mm socket to freely turn. Doesn't have to be neat, just as long as the socket can fit in there. I secured it to the hub/balance with two 1.5" M8 bolts with 3/8" spacers (Steel bushings from the hardware store) since I left the balance on the hub. After it was bolted to the hub/balance i used a Jack stand to support it horizontally. With a three foot pipe over my 1/2" breaker bar the bolt came off easily.
The hub came off very easily with a puller. Best of all it could be put back on by hand and some gentle nudging. The Haynes manual said it would be necessary to heat it up to about 120° to be able to fit it back on, but that certainly wasn't the case.
Before I attempted to pull on the lower timing cover I tapped it all around with a mallet until it sounded hollow everywhere. It slipped right out with no damage to the oil pan gasket at all. Lucky I guess.
With the cover off the guide rail and two cable ties around the chain/cam sprocket to keep the chain in place and a finger firmly on the chain on the underside of the crank gear (to keep the chain in place there as well) I manipulated the tension rail out on the left side to have room to angle the chain away from the workings, wiggled the sprocket off the cam and with some difficulty managed to get the guide rail backing out of the case (always keeping my finger on the chain under the crank gear. Manipulated the new one in and set the sprocket back on the cam making sure the chain is taut on the guide rail (intake) side.

the bottom of the rail should be secured first. one of the rail pin holes will be oval which helps the installation.

Hope this info helps someone else.
Thanks

I just wanted to add that I've heard from several sources that using the starter method to break the bolt is effective and very easy. I guess you should make sure you just break the hold and don't let it turn very much!
For me, I already had the holder made from taking the hub off another car years ago and the holes on it just happened to line up perfectly. And I just wanted to do it the way I' was already somewhat familiar with.

The tool to lock the flexplate or flywheel for the M103 is about $26. Not sure why you would use a starter and risk breaking something when the proper tool is so inexpensive.

PS2 Just one thing did you put sealer on the bottom bolt that holds the tenssioner bracket to the chain cover .This is a major oilleak problem if you dont seal the bolt head .

Hit Man X, I kind of feel the same way about jamming something in the flywheel. I guess besides the expense of the tool, though not much, plus the shipping, you'd have to wait 3 or 4 days to get it. If you needed to get it done you may not want the down time. Also, your in there for a reason, probably a reason that's already costing you a bit. Between using the starter and blocking the flywheel, it's just about a coin toss comfort-wise for me.
I really admire the ingenuity of the starter trick though! I think guys who are inclined to work on cars just have a bizarre compulsion to try crap like that :)

Optimusprime, I'm pretty sure Ps2cho would know about that. He's had the timing covers and bearing bracket off these engines many times. I'm guessing he has two or three timing cover O-rings laying around in his toolbox.
Thanks for mentioning it for readers who may not know!

I read all i could before i did my m103 and no place did it say to re seal the bolt head .Only by chance i came across it on another mb fitters class i was at .And only normal wahers on the bolt . But i hope it helps someone .

Same here. I read all I could and never came across it. I don't think there was anything in the Haynes manual about it either. When I took apart the top end of an M103 the first time, the O-ring must've fallen to the ground without me seeing it. When ordering parts, there was a "timing cover O-ring" listed, so I ordered one even though I didn't recall taking one out.
When I had everything just about together, I realized I still hadn't found where that O-ring went. There were still a few small round gaskets and seals left over from the head gasket set, pretty much just for different sensors and plugs on the head that didn't pertain to my application but sure enough there was an O-ring exactly like the one I ordered!
I poked around on the forum but never got an answer, so I went to the MB dealer and by going through exploded views with the parts guy we found where it went.

If you look at Ps2cho's pictures you'll see it still in the extra large bolt hole in the timing cover under where the fan bearing bracket was bolted, like you mentioned, behind the the arm of the tensioner bracket. I use sealant there along with the O-ring to be thorough.

No leaks at all -- just do as I did. Its been almost 4 years and 60k and not a drip so it worked perfectly.

Wasn't worried about the flywheel as I had it locked in really well if I remember correctly.

wanted to report back that the entire timing cover is spewing leaks after 2 years...multiple locations.
I'm going to have to re-do the job as its making a mess on my driveway and the block is smothered in oil from it.

I'm going to try a different sealant this time and see if it lasts longer. Looks like I used the Victor-Reinz sealant...won't be using that again. Maybe I'll try whatever the best Permatex stuff is.

I picked up a tube of the MB stuff, ran me about $40. I have a PN if you want it.

Looks identical packaging to the stuff I used by Victor-Reinz EDIT: "Sorry it was Reinzosil" by Victor-Reinz...are we sure its not the same stuff?

https://images-na.ssl-images-amazon....1v8MEumZxL.jpg

I could not tell you. I opted to go for the OEM goop this time around versus the VR stuff. I have Reinzosil here at the house, box is different than the OEM stuff. I have not opened the OEM stuff yet to reseal the timing covers, I will report back as soon as my head studs are here.

002.959.45.20 is the part number.

FWIW, OE head gasket by Elring is smoother than the aftermarket Elring available. I doubt the MB stuff is the same as the stuff by VR.

ps2cho, do yourself a favor and use the black MB sealant. It's worth every dollar. Sealing a timing chain cover is not a job you want to be repeating every 2 years.

For others doing this job .Refitting the fan bearing bracket back in place .A lot of people refit the bolt that holds the serpentine belt tensioner back with out any sealer on the head of the bolt Then find that oil will leaks out through the threads of the bolt and bracket . Only just read this post , so i was to late to post it then

After reading my old posts, I remember I never did the lower oil pump chain guide so I'll likely get that replaced this time around. EDIT: oh wow dealer is only $9 for it. Probably cheapest part I've ever seen!

Also ordered the KTC flywheel tool so I can lock it for a one-man job.

Many parts arrive today so I'm going to try and get going on more work!

Flywheel tool worked a charm:

Here's the culprit spot its leaking from. Going to be a tad more liberal in that area this time around, using Genuine MB sealant.

http://w124-zone.com/downloads/photo...%20cover/3.jpg

http://w124-zone.com/downloads/photo...%20cover/4.jpg

On replacing the serpentine belt tensioner bracket to the front case, did you use a sealant on the back and front of the bracket ? In the manual, it said not to replace this without doing so .Oil can leak from that area if sealant is not used.

As far as the manual states, the only one that needs sealant is for the bolt that goes through the middle where the small O-ring is, shown above -- the lower right fan clutch bearing bracket bolt. It just says to coat that bolt in sealant.

more info. on chain tensioner guide rail, please
 

I'm doing a head gasket on my '88 M103, and would like to change out the plastic guide (tensioner side). BUT...I don't want to pull the lower timing case, if it can be avoided.

Yesterday I spoke to a mechanic who owns an independent (mostly MB) shop, and he said that I could remove a bolt in the lower timing case cover--the one just to the left of the crankshaft nose, presumably--and pull out the banana-shaped guide rail.

I interpreted him to be saying that I DON'T have to remove the lower cover to change the guide rail. Does this seem right? He may have been confused about whether I already had the cover off. I'd rather not do everything else to pull the lower timing case cover, if it can be avoided.