Flex disk replacement W107 DIY??

[nobby]

Originally Posted by 300sdToronto

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.

[300sdToronto]

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.

[300sdToronto]

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...

[meltedpanda]

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

[300sdToronto]

Originally Posted by meltedpanda

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 ......

[300sdToronto]

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 ...

[meltedpanda]

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

[300sdToronto]

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.

[300sdToronto]

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.