Replacing flex discs - What do I need? - Page 4 - PeachParts Mercedes-Benz Forum

TnBob · #46 04-24-2015, 10:01 PM

Putting a wood block between the jack and the frame is very very commonly done.
Not going to harp on it as you seem to block everything well but ... make sure you block it before getting under it.

Stretch · #47 04-25-2015, 02:46 PM

Quote:

Originally Posted by TnBob

Putting a wood block between the jack and the frame is very very commonly done.
Not going to harp on it as you seem to block everything well but ... make sure you block it before getting under it.

I totally agree with the warning threads you've just started

Naw.. Im only gonna be under there a minute

It really isn't worth it

Ceristimo · #48 04-26-2015, 04:26 AM

I always have two fail-safes when the car is on jack stands, and at least one fail-safe when it's on ramps.
I have the car on stands, with an extra pair of stands right underneath the rear shock mounts (there's no load on them, they're about 1/2 inch from the mount) and rims with long 4x6"s stacked on top that are almost touching the bottom. This way, if the worst were to happen, the car can never drop more then an inch.
Will it damage the car if it happens?
Yes, more then likely. However, I'd much rather crush the car, then crush myself. There's thousands of W123's around, but there's only one of me!

Anyway, with that said, I started work on it the beginning of the afternoon. A buddy of mine unexpectedly came over to join in the fun, so that was cool. It's always more fun to wrench with another person then by yourself.

We first removed the rear part of the drive shaft. The rear flex disc on the differential was super stuck, so had to run to the store to get a short breaker bar. My 36" wouldn't fit, because it was way too long.
We ran into some problems getting the drive shaft to compress all the way, but after greasing the splines a bit and moving it back and forth it went out all the way. The 46 mm small/thin wrench I bought worked very well to loosen the sleeve nut.

So, got the rear end out and realized the carrier bearing was stuck on it. Couldn't pull it off by hand. Ended up going to the car parts store. Bought a 75 dollar bearing puller, pulled the bearing in the parking lot, and brought the puller back 5 minutes later for a full refund. I wasn't cheating the system, the folks at the car parts store were okay with it.

So, got the new bearing on. The old bearing mount was completely ripped to shreds. It seems everything made out of rubber has either failed, or is about to on this car.

Pulled the front end of the drive shaft. I lowered the rear end of the car and got it back on its wheels, then jacked up the front underneath the cross member and put the front wheels on ramps to get enough space to work at the transmission end.
I ended up supporting the transmission with a small 2-ton jack and some lumbar underneath. It went fine, nothing compressed or dented. There's isn't that much weight on it anyway. We removed the support for the transmission, pulled the front end of the shaft, and I put a new transmission mount back on.

The current status is that the front drive shaft is back in place with a new flex disc.

However, the bushing on the rear drive shaft (it sticks out of the middle of the flange) was completely shot (rubber inside torn) and I bought a new one to replace it with.

Here's my question though: How the hell are you supposed to get that bushing out. I tried to knock it out with a hammer, but no go. I heated it up, cooled it down, hit it some more but that thing is STUCK.

Is there any trick to getting that bushing out?

Oh, fun fact! I realized my exhaust is only being held in by one little rubber band thingy, and as the car was raised in the rear it snapped and my exhaust fell. Holy cow, can't believe it stayed on during the whole 350 mile trip from Anchorage to Fairbanks. Ha!

So, now I need to order those exhaust mount thingies as well ( I need four), before I can drive the car.
Oh well.

Anyway, if someone can enlighten me on how to get the bushing out that would be much appreciated.

I'm sure there's a simple trick to it I'm just not seeing.

Ceristimo · #49 04-26-2015, 04:51 PM

Here's a picture of the bushing that I'm stuck with.

Weirdly, the front half of the drive shaft did not have a bushing.

It doesn't go in very far. Roughly only about 1/3th of it's length is inserted into the drive shaft.

Question remains though: how to get it out? Just pulling on it like a madman isn't cutting it...

funola · #50 04-26-2015, 05:37 PM

Make a puller:

Drill a hole large enough for a Phillips screw driver through both sides of bushing. Make a 1 ft dia loop of strong wire retained by screw driver. Rap against the loop with a 1/2 breaker bar to pull it out.

TnBob · #51 04-26-2015, 07:39 PM

Id add..soak in Kroil too.

Any muffler shop should be able to provide you the exhaust doughnuts.
Ebay is good for those too with many offering free shipping.

Ceristimo · #52 04-26-2015, 08:11 PM

@Funola
That is a very good idea! Why didn't I think of that?

I'm a little sore from laying on the concrete floor all afternoon yesterday, so I'm gonna take a day off from the Mercedes, but I'll grab my drill tomorrow and see if your idea will work. Thanks again!

@TnBob
Yeah, I've already located the donuts. They're cheap. It just amazed me that my exhaust was only being held on by one, and that it fell off when jacking up the car. The muffler rocked slightly from side to side and that was enough to snap the donut. Had I driven this car another mile, it would have been dragging on the ground. Which, by the way, at some point in time did happen to the previous owner, judging by the damage on the bottom of the muffler.

SD Blue · #53 04-27-2015, 11:09 AM

Quote:

Originally Posted by funola

Make a puller:

Drill a hole large enough for a Phillips screw driver through both sides of bushing. Make a 1 ft dia loop of strong wire retained by screw driver. Rap against the loop with a 1/2 breaker bar to pull it out.

This method is covered in the Factory Service Manual.

Mercedes Service Manual Source, CD/DVD/Paper

I would highly recommend reading that section as there are several details they cover that will help you with the installation. These driveshafts can be very tricky about vibration.

Ceristimo · #54 04-27-2015, 01:11 PM

For some reason I can't get that program to work. I check Disc 2, pick my car, I find the "removal and installation of propeller shaft", and when I click it I get a "document not found" message on the Startek website.

SD Blue · #55 04-27-2015, 01:57 PM

It's a pdf file so you will need Adobe reader. What I've come across, there must be a timing issue occasionally. Sometimes I can go back and try it at a later time, maybe when it isn't so busy, and it comes right up.

Also, I've heard of strange problems with Firefox and "other" browsers. You might try Explorer if this is the case.

Ceristimo · #56 04-27-2015, 02:00 PM

@SD_Blue
Thanks! Yeah, I tried Firefox and Internet Explorer and have Adobe reader. I'll try again later, see if it works then.

funola · #57 04-27-2015, 02:13 PM

Quote:

Originally Posted by SD Blue

This method is covered in the Factory Service Manual.

Mercedes Service Manual Source, CD/DVD/Paper

I would highly recommend reading that section as there are several details they cover that will help you with the installation. These driveshafts can be very tricky about vibration.

This one http://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Chassis/41-050.pdf ? Where is this method, I didn't see anything about pulling the bushing (centering sleeve)? My idea was based on looking at the pic of the bushing Ceristimo posted and may or may not work. I have never tried it so he's gonna be the guinea pig lol.

Ceristimo · #58 04-27-2015, 02:20 PM

I didn't see it in there either. I do now have a picture of what the factory marks on the drive shafts are supposed to look like. I wasn't able to find them on my drive shaft at all, but now that I know what I'm looking for I'll see if I can find it. I like this sentence:

Quote:

Identification has already been available on propeller shafts prior to August 1982, but not been taken into consideration during assembly.

Little sloppy guys, lil' sloppy...

@Funola
I'd gladly be the guinea pig. I'm gonna drill through the bushing when I get home tonight, and see if I can get it out that way

.

Ceristimo · #59 04-28-2015, 01:00 AM

Ugh! This bushing is turning into a frikkin' nightmare.

Of course, it was only now that I read this topic:
Driveshaft centering bushings ... any magic to removing them?

And there it is mentioned to not replace these things...

I tried Funola's advice:

Drilled a hole, looped some wire, tried to pull it out that way.
I broke the screw driver.

So, did some quick Googling and found this tool called a blind hole bearing puller.

I was able to rent one. It's basically this tapered tool that you insert into the bushing and has a bolt on top you screw in. As you screw the bolt in the fingers on the tool spread out. You then attach a slide hammer and are supposed to be able to hammer it out like that.

I pounded on it with all my strength. The bushing didn't move at all.

So, I have backed myself in a corner here. The bushing was probably re-usable as it didn't look too bad (the rubber was cracked). Now that I have drilled holes through it, whacked it with a hammer and used the blind hole puller on it it's completely mutilated.

So now it has to come out, but I've run out of ideas. I really thought with the puller it'd be easy, but heck no.

Last thing I can think of is call some mechanics tomorrow and see if they have a magic tool to be able to do this.

If not, then what?...

Uuughh! This always seems to happen with me. I get stuck on little things that are super frustrating... I always say I like to work on cars, but sometimes I feel like I'm just lying to myself.

All I can think of now is to apply insane amounts of heat...Just torch it for 15 minutes, but I don't know if that could possibly damage the drive shaft? I applied heat for a few minutes, but maybe that wasn't enough?

renaissanceman · #60 04-28-2015, 01:32 AM

I'd take it to an honest to goodness machine shop -- it might be time to tap out and let someone who has been dealing with stuck parts for many many years take over.

Otherwise, I'd put it in my 12 ton press, heat it with the acetylene torch and press it inward with the press to try to break the bond, and then attempt to pull it.

I hate stuck things, broken fasteners, etc