I was going through an old posting about changing the stem seals and I believe that I need mine changed in my 87 300E 165.000 miles. Just after about a week of smooth running it started missing so I pulled all of the plugs and the 5th one was definetely oil fouled so I figured with all of the miles its time for a valve job. But reading the posts it looks like the seals can be changed without pulling the head and is alot cheaper than a valve job, can you guys give me alittle more info on the process of changing the seals I would really apreciate it.

thanks
flrydr

Remove valve cover
remove sheet steel oil sprayer bar (2 screws, plus one of the rocker arm bridge bolts)
remove plugs
remove rocker bridge #1
pressurize #1 hole
(MB has a good tool to remove valve springs BTW)
compress valve springs and remove springs (has regular type of valve keeper, a split collar type)
remove valve stem seals, DON'T scratch the stems!
Install seals, these should be put in a container of fresh oil prior to starting the job. seal with DARK colored spring goes on the INTAKE side, seal with BRIGHT colored spring goes on EXHAUST side. Be sure to use the plastic shield that is supplied with the kit, they go on the valve stem and prevent the seal from being damaged when sliding over the valve retainer grooves. Shove them down onto the guide, you should feel a slight "snap" when they are all the way down. Reinstall everything, making sure the valve spring keepers are on before removing pressure form the #1 hole. Move on and do the same thing with the rest of the holes, pressurizing the next hole only after removing the rocker bridge. Reinstall the bridge after you are done with the valve stem seals to keep correct tension on the cam. DON'T remove ALL the bridges at one time, only ONE at a time, you can crack the cam otherwise. The engine may rotate reverse when you pressurize the cylinders, so after you have done all the pressurizing I recommend rotating the engine by hand about 1/2 a crank rotation clockwise. The torque spec on the rocker bridges is 21 nm. On the oil spraying bar, be sure to clean (deoil) the 2 retaining screws and use loctite thread locker when reinstalling. Real light torque, I think just 5nm. When remving the rocker bridges be real careful to NOT lose the small cup shaped spacers on top of the valve stem (under the rocker arms).

Gilly

Gilly, thanks... it looks like you have done a few of these before not sure if I want to go in there and attempt but there is a real good MB mechanic nearby so I might go and see him.

thanks again
flrydr

Does your user name mean FL rider, as in a hog?

Gilly

Gilly,

Regarding your comment, please explain how removing all bridges can crack the camshaft. Don't they all get removed when overhauling the head?

Another related question that I have raised previously in posts regarding head work on the M103 (and similar engines). Just when should the cam bearings be torqued down? Before the head is installed (and head bolts torqued) or after? I have raised this question due to concerns with any slight distortion of the head when torquing the head down possibly damaging a previously installed and torqued camshaft. My instincts suggest it would be preferable to install the camshaft after head bolts are torqued.

Your thoughts on this would be appreciated. Thanks,

Greg

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

Hi Greg
This is because the timing chain tensioner generally isn't removed for just replacing the valve stem seals. If you remove all the bridges without removing the tensioner, the tension on the cam sprocket can cause the rear of the cam to come up and lead to damage to the cam or bearings. Because the procedure I outlined doesn't call for repositioning of the crankshaft during the operation, but relies solely on air pressure, you have to have a very good dependable source of air pressure. It also acknowledges that the crank could turn backwards during pressurization, which would make me feel better having the tensioner left in place (keeping the timing chain fairly tight due to the internal spring). But again I would insist on using a socket and bar to rotate the crankshaft in the normal direction about 1/2 a turn before attempting to start to ensure the tension on the chain is correct again, in case it DID move backwards.

I would recommend torquing the camshaft bearings/caps any time before the tensioner is installed. On or off car I wouldn't worry about, as long as there is no tension on the cam sprocket.

Gilly

PS another advantage to removing one rocker arm bracket at a time is this way you can more easily manage the hardware that is being removed, such as getting the brackets back over the same valves, and also those small cup shaped spacers on top of the valve stems DO come in different thicknesses (2 or 3 thicknesses, I think 2) so you want to make sure to put them back in their original places, and again doing 1 at a time makes this less prone to goof ups.

Thanks Gilly,

Your procedure for replacing the valve stem seals makes perfect sense. My question regarding when to torque the camshaft bearing caps was one that I had wondered about ever since doing the head on our 300TE over three years ago (long before I discovered these forums). At that time I torqued the cam bearing bolts after the head bolts. The car is still running perfectly today (without so much as an oil leak) so I must have got that job right! Thanks for putting my mind at ease.

Greg

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

I have used the above procedure to replace the valve stem seals on two of my M103 cars. My '92 300e went from using 1 quart in 750 miles to less than 1 quart between changes (3000 miles). My '88 260e improved a little too but still uses about 1 quart in 1500 miles.

When I worked on my cars I brought the piston to TDC just as a precaution in case something went wrong so I wouldn't drop a valve into a cylinder. With the piston at TDC the valve only drops about 1/2" before hitting the piston.

I did it like this: When applying air to the cylinder I was working on, I rotated the crankshaft a little past TDC and put a ratchet and breaker bar on the cranshaft pully to keep the engine from turning. Going past TDC causes the crankshaft to turn clockwise against the ratchet (yes, this is the direction to loosen the crankshaft bolt but it is torqued on so tight you don't have to worry about that).

Also be very careful not to drop any of the little valve cups or keepers because it appears they could go down an oil drain hole and disappear into the engine. I tried to keep the drain holes covered with a small rag.

Gilly, Yea your right it stands for FLH as in 1978 FLH Electra Glide, you must ride also cause most people have to ask what the FL stands for. I had the bike for about 5 yrs 80" motor built by a tech at Arlen Ness, light weight rods, pistons, Jims Lifters, blocks, Andrews BH Cam,S&S oil pump, dyna ignition (getting old) S&S Shorty E carb, Thunder Header, Just rebuilt tranny with Andrews gears, and I call her "Squeeky" cause of the worn shock in the rear.

flrydr

Yeah, Ya don't live 42 yrs in Wisconsin without picking up at least SOME Harley lingo. Both of my bro's ride Hogs, I got a Beemer, but I also have lots of friends into Harleys. We can ALLLLL get along!

Gilly

How long should this job take for an experienced person?

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1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz

I would only add: be sure to remove the little plastic guide/shield after each new seal is installed. The ones I had were very clear plastic & easy to overlook.

It make the valve keepers fit funny.

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Norm in NJ
Next oil change at 230,000miles

The job took me about 2 or 3 hours, only because I was being extra careful.

Removing a small part that disappears down one of the oil passages would add considerably to the time required.

1) Anyone care to post info on the cheapest/most effective valve spring compressors to use for an M103. (I would love to get a mercedes tool but they seem kind of expensive for a DIYer like me.)

2) What are any other essential... or particularly usefull specialty tools for this job?

TIA

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-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Very careful indeed! At some point in the past someone dropped one of these into my engine. They are called ball sockets. Years later the little sucker beat its way through the oil pump screen and locked up the oil pump, shearing the drive gear off the front of the pump.

Only a miracle let me shut down the engine soon enough for no harm to be done, and that was after I heard it start rattling and knocking. I removed the pump, found the problem, cursed the perpetrator, replaced the pump and all is well.

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2012 E350
2006 Callaway SC560