Flex disk replacement W107 DIY??
 

Has anyone seen a DIY anywhere on flex disk replacement? Specfically I have a 1982 380SL which needs new flex disks.

Most of the postings on this forum end with "took it to an indie" - which I might do - but am interested in how complex the job is. I have stands and a trolley jack but no lift.

Thanks

I did it over a pit and it took a solid day. Much harder than a sedan because you really have to monkey around with the driveshaft to get it out so that you can get to the center support. Buy German parts so you don't have to do this ever again...

How to do it. Remove exhaust system. Remove transmission support. Unbolt disks. Unbolt center support. Remove as unit. ( IIRC I had to jack up the engine to get the DS out)

Yuk, this sounds a lot nastier than on my 300SD, for example.

I also am considering a transmission swop as I have a leaking tranny front seal and a slipping clutch pack. Sounds like it would make a lot of sense to do both jobs at the same time.... and I would probably have an indie do it given the complexity of the job.

RL

Yes, much harder than on a 300SD, but the same basic drill. Ten pounds of s**t in a five pound bag. IIRC there a long plate welded in the tunnel on the R107 whereas on the sedans it's basically open.

Of course....if it's just the flex discs, then the prop shaft is telescopic.

No need for complete removal.

BUT.....if you are replacing the flex discs, then I would do the hanger bearing at the same time.


FLEX DISC INFO - Benzworld.org - Mercedes-Benz Discussion Forum

Nobby - these are great posts in Benzwolrd, thank you

No problem.

I like this forum but benzworld is a little more active.

this is not easy and requires a pit or lift, also some exactness so as not to disturb balance, the carrier bearing R/R is a good idea.
Not for the faint of heart but not many things on the SL's are :)
I think my carrier bearing could be going south on mine, but I will not attemp the R/R until I can schedule a lift to use.

I have a pair of used but like new flex disks from a 560SL on my ebay sight.

Good advice, but limiting.

I don't have a pit, lift or helper. But I managed to re and re the manual trani which necessitated the removal of the propshaft, exhaust.....among a host of other things.
I had my SL 20 inches up on sturdy jackstands for 2 months. A lift or pit would have been nice but 95% of us don't have access to that..

the entire program of work on the 380SL
 

I think I have found an indie who is willing to work with me on this. He seems to be of the right mindset as he has an immaculate Triumph TR6 and a 1960's Land Rover.

Here's the entire program of work:

- badly leaking transmission front seal
- suspected oil leak in engine rear main seal
- diff oil seal leak
- beginnings of cracks in flex disk
- time to replace all flexible brake hoses
- front control arm bushings beginning to age
- do the transmission mount when we're in there
- replace that bearing thingy on the prop shaft while we're in there

It seems to me that I need access to the facilities of an equipped garage and skills beyond mine to do this program of work. The engine still runs fine!;)

Question - while we're in there with the tranny pulled, is there anything else we should look at? The car has 115,000 miles on it (US vehicle imported to Canada).

Some days I want to throw this one away and buy a different 380SL, but I could have exactly the same sort of issues with a new one. Comments and thoughts on where I am headed are welcome as this will be an expensive set of repairs. These little buggers are much more complex than my 300SD but the wife loves the car :rolleyes:

As for the transmission, you may find that it's the front pump seal that is leaking not the torque converter seal. I would change that, or at least have one ready. Could do the output shaft since you seem to be trying to fix all the seals. All the servos have seals as well, but if they don't leak now, I guess they will be good.

Seems to me if you are doing control arm bushings you are opening up the whole front end rebuild can of worms...ball joints? subframe bushings? Motor mounts?.....

I don't know if other problems with your 380 have been addressed. As it is a U.S. model I have to ask if the timing chain and gears have been replaced or serviced recently.

Front sub frame bushings all done and ball joints in good shape on the front end. Unfortunately we did not do the control arm busings at the same time.

The power plant is in great shape and was upgraded about 10K miles ago to a twin chain etc. It was a single with 100K miles on it when I bought the car - living dangerously.

Then all is well on the engine.
Nobby has a great post about welding the sub frame reinforcement and replacing the bushings.

It sounds like you are doing the right thing, drawing a "baseline" on the car and replacing rubber and consumables before they fail. No question, it will cost less and your enjoyment of the car will be higher than doing things as they become obvious. I did many of these things on both of my cars and I have gotten (knock on wood) 70K of relatively trouble-free miles out of that work. If you don't plan on keeping the car forever, document everything and save the receipts; you will get back a good percentage of your dollar.

Wow, very few people have done this; the parts new alone are quite expensive, never mind the labor.

Yes, I have to say that these cars are a money pit compared to my 300SD. Everything seems much more complex than the w126 body as it's all crammed into a smaller space and the design of some elements (flexdisks, front suspension components for example) did not properly consider the need for major future maintenance when these cars were designed!

help help on transmission seals
 

Ok, I need some very BASIC help here on seals. Ive R&R'd tractor transmission but up to now - thankfully - I've never had to tangle with an automatic other than doing basic fluid and filter changes on the bottom.

The tranny is leaking fluid at the front. I assumed it was a front seal (which is a round seal on Fastlane) and I've also been warned to get a front pump seal (which looks like a big o-ring) in case that's the issue.

Someone also mentioned a torque converter seal but I can't find a one of them on Fastlane or competitive parts sites. Is a torque converter seal and the front seal the same beastie?

Thanks!

The torque converter seal or front seal on Fastlane is this:

W0133-1634133

This thing looks sort of like a wheel bearing seal and seals the neck of the TC where it slides over the input shaft of the tranny.

The pump seal is:

W0133-1642641

As you said , it's huge O-ring. The front pump fits into the front casting and this keeps it from leaking.

You MIGHT also need a W0133-1635036, front cover (paper) gasket. I honestly can't remember...I did a 722.3xx and part of a 722.1xx and my memory is fuzzy...


I hope you have a transmission manual- there is a 722.3xx factory manual floating around somewhere and an exploded parts diagram

This is really useful, thank you. I do have the manuals on CD and will start the laborious job of going through all the PDF's to find the right file for the transmission manuals - the index uses an ancient version of flash which no longer works.

Unfortunately access from Canada to the online parts and service manuals at MB USA seems to be blocked. You are referred to the Canadian site, only to find that MB Canada does not provide a parts or service online service. Arghh!

Overall doing the tranny front seals and the flexdisks does not sound too bad if I work with this indie I've found. I may wait on the control arm bushings until I am around an experienced MB indie as prior experience of that job sounds very useful. This all started because my trusted local Mercedes indie closed down and there is not a reasonable local alternative ...

I am off to check out Benzworld as there seem to be more "hands on" 107 posts over there and the old CD manual set. Will report back as the job progresses. Need the weather to warm up some more....

RL

This thread got me motivated - this junk came out of my driveline. Rear engine mount was squashed and weak. Front disk faked me out because the rear side looked good; when I got it out the front side showed the most damage (cracks, cord showing). The center bearing was as you see it. The bearing was just resting in the collar of the mount which is amazing. The rear flex had minor cracks that were most visible which is what made me tackle this job.

Lessons learned:

1. Remove the exhaust system from the exhaust manifold. I tried to pull the resonance damper and mid section - wasted 3 hours fighting that.

2. Be careful when you press the center bearing onto the rear propeller shaft in front of the U-joint. I over did it and damaged the bearing; Do Over!!

The job took 8 hours but I wasted half that with a blank stare learning and thinking.

OK , now that you know how, can you come over and do mine :) PLEASE

While you are at it, I'm only maybe 1/2 hour away...

While you are at it, I'm only maybe 1/2 hour away from meltedpanda...I have two.

I would love to help but it's too nice to leave ABQ right now; hardtop is coming off today. I will be a good wingman on this forum when you decide to tackle it.

I know it is tough for some to find access to a pit or a lift, as Nobby has said, but it sure makes the job quicker. I use the auto hobby shop at Kirtland AFB. The lift I used was a drive up that had front and rear auxilliary jacks that slide on rails. This made it easy to lift the transmission and make numerous up / down lifts at the rear axle. Bring some wooden boards to pad the transmission pan. (Chassis Service manual instruction)

The job calls for a 46mm open end wrench to work a collar at the mid-point. That was a tough item to find - I bought and used a 15" adjustable wrench. The bolts on my new flex disks use 10mm allen heads in lieu of 19mm hex. You will need a snap ring plier to R&R a snap ring in front of the protective cap on the center bearing (I forgot mine and was lucky enough to borrow one). You will need a gear puller to remove the old bearing from the forward spline of the aft prop shaft (I brought mine but it was too small - again lucky enough to borrow a bigger one). Bottom line - plan and load up the right tools for the job; I thought I had this covered but NOOOOOOOO!

I didn't intend to write so much but figured it was better to get it down before I forget it. After reading this, you probably don't want me anywhere near your cars.

LOL, no you are still welcome. Frankly the lack of a lift has kept me from this job, I need to do the carrier bearing

I didn't have too bad a time when I replaced my disks with just jackstands. I just made sure that I had them solidly placed. But my creeper had roken a plastic wheel mount, so I used a large piece of cardboard box. It was pretty easy to slide around on, and the security of having the driveway to work against was helpful, I didn't have to worry about breaking another creeper.

Scott

I almost think that lieing on the garage floor doing this work gave me more leverage and kept me from having my arms above my head.
Maybe because I've done it all my life, but I don't have any problem working under a car that is securely on jack stands.

My project too is very much alive. I am just moving more slowly than some of you other guys. :)

I had the car up on a lift this week and surveyed the work to be done. I think my transmission flare may be vac related as it goes away under hard acceleration, so I need to do some testing. Also it looks like the rear cover on the diff has an oil leak and I am trying to decide if I can get it off without having to drop the rear axle. Looks like it is not too bad a job to remove the diff mount....

I am extemely busy for the next couple of weeks so expect updates when I get more time to tackle the beastie.

Obviously I can't see it from here......but generally the covers don't tend to leak.
It's usually one of the 3 rotating shaft seals that leaks and then the oil migrates to the lowest point.

But if you are taking the cover off, take a pic for all to see.

Further, you might take the opportunity to clean the breather at the top of the diff.

Project moving ahead -380SL transmission & drivetrain
 

Next steps on Monday are to do the flexible brake hoses and replace the rear brake shoes. The front hoses look rough and the rears are of unknown age so I'm just doing the lot to be done with it.

I am troubleshooting the vac system before pulling the transmission.

Question: I have found the vac line that travels across the back of the engine, goes into a banjo bolt in the back of the right manifold and then transforms into a metal line that goes down to the transmission. Does anyone know the correct vac on this line as it would be easy to insert the Mityvac into the union just "upstream" of the manifold banjo bolt and measure it?. I have been unable to find the answer to this on my 107CD or on the ATMSG manual for the 722.312

I think vac or a bad modulator valve are at least part of my issues. I disconnected said vac line and the 2/3 flare got a little better. No change on the 3/4 flare.

Troubleshooting vac line to modulator valve
 

Continuing to troubleshoot shift flare issues, I put a Mityvac T in the vac line as indicated by the arrow in the attached pic. This is up in the rear driver's side of the engine compartment.

At idle I had a steady 18 inches of Hg vacuum, which dropped slightly when I revved to 2,000 rpm. Is this about right?

I then switched off and separated the line and tested with the Mityvac. The line going into the bulkhead behind the brake booster held vac for over a minute with no problem. The line heading for the intake manifold banjo bolt would not hold vac - no doubt due to all the air in the manifold?

I am concluding next step is to test the modulator valve on the transmission... if anyone can comment on whether I am on the right track ... please do so...

make sure your shift linkage is adjusted properly.
not sure you have the smae set up , but give it a look
http://www.peachparts.com/shopforum/sl-forum/297416-modulator-adjustment-old-steel-type.html

Thanks Ron. I am probably going to replace the vacuum modulator valve and then have a go at adjusting it.

The 380SL has a bowden cable to the transmission, not a rod. The bowden cable influences the shift point from my reading, but not flare or the "abruptness" of the upshift.

If the modulator valve does not cure the problem then I am on to a Superior spring kit. Oh joy ......

Monday night update
 

A good day today. Replaced the flex brake hoses and rear brake linings. Topped up the differential oil level, removed and cleaned the breather and found the source of the diff oil leak (I hope). The bolts holding the seals on each side of the diff, where the driveshafts exit, were quite loose. I tightened the bolts as best I could with a conventional 15mm wrench and I hope that does the job.

The diff oil level plug was in quite tight. I used a 16" breaker bar on a half inch drive 14mm allen bit and I still had to use a framing hammer as a pursuader.

Now all I have to tackle are

- exhaust hangers (trivial)
- flare on 2/3 (not too bad) and 3/4 (more severe) shifts, start with the modulator valve
- leaking transmission fluid from front of transmission, likely torque converter and/or front pump seals
- suspected oil weep from rear main engine seal
- replace flex disks when tranny out
- replace all engine belts
- replace fan clutch
- sort vac system as suspect its mis-plumbed
- sort fast idle
- test aux fan
- remove trim and get it painted
- new softtop and assorted softtop seals
- finally., new front torsion bar bushings

Simple to maintain, these cars? It has to be a hobby ... :)

yup, simple, but complex, fun but no fun , easy and hard, all at the same time - just enjoy the journey..:)

Improved transmission flare and fast idle!
 

:)

I replaced the two check valves on the attached 380SL vacuum diagram. #17 check valve was open both ways and looked like the original part. #26 was missing. Ahem! You have to take the air filter housing off to get at #26. #17 is just underneath the air filter housing at the front and can be extracted and replaced with a long set of forceps or needle nose pliers.

Fast idle has dropped from 1400 rpm to 1050-1100 rpm. Still not to spec but better. Way better.

Transmission flare has disappeared as well. Need to test drive it again to double confirm but was behaving well yesterday. Modulator valve was replaced at the same time.

I could not understand the configuration of part #26 from the diagram on EPC or the shop manual and had to try it both ways round!

Still have to pull the tranny to fix the seals but this is progress at last.

progress ... yes, indeed, progress
 

So, some progress on the project

- replaced horns as one inop and the other sounded like an expiring sheep!
- dropped transmission, replaced torque converter and front pump seals, AT filter and gasket (of course), rear transmission mount and flex disk. Oh yes, and the rear main crankshaft seal which was beginning to leak engine oil.
- replaced and tweaked modulator valve which eliminated 2/3 flare and reduced but did not eliminate 3/4 flare. Superior spring kit may be in our future?
- got the high idle down from 1400 to 1100 rpm, still work to do there
- replaced front sway bar bushings. As usual this turned out to be more complex than expected as one of the mounts was bent back - suspect PO must have hit a high curb. Friendly body shop fixed the issue for me.

I have to admit that a transmission shop did the transmission job for me. I just did not fancy doing that without a hoist.

We're off on a road trip next week in the 380SL from our home in the north Okanagan, BC down highway 97 as far as Portland. Stopping around Leavenworth, WA to do some hiking. You may get a 911 at some point!

Thanks for all the help guys.