outbackgeorgia

The only thing I see cracked is the paint. Just my opinion.
Dave

Adk46

I wonder if someone can elaborate on the procedure to "check vacuum". I'm guessing you disconnect the line under the airbox, remove all the packaging from your new MightyVac, somehow attach it to the line, and start pumping – right?

Schocki

Way to complicated . Disconnect one of the elbows on one of the fuel regulators. Hook up the mityvac. Start the engine and check your dynamic vacuum this way.
Connect the elbow again.

If this is ok. Raise the car, hook up the mityvac to the elbow of the tranny shift modulator and check your vacuum while the engine is running. The reading should the same otherwise you'll have a problem.

Leon Speed

Yes. attach a Mityvac to the line going to the gearbox, pump to 5 or 10 inHg and see if it will hold vacuum. Even if it will hold vacuum the test is carried out best directly on the vacuum modulator. Replace the cap on the vacuum modulator regardless of the test result.

To the OP, the most likely candidates for hard shifts are a low ATF level, a vacuum issue or a malajusted bowden cable. Looking at your pictures you probably need to refresh the complete vacuum system. The lines and rubber bits have been on the car for a long time and are undoubtely leaking somewhere. Also replace the blue vacuum valve near the brake booster.

Bertrand Daoust

+1.

Well done Sir!

cambria

Before you do anything, I would take a knife and try to peel the coating. The coating is very thick and will often come off in slabs. Should the crack show below the coating then you are probably looking at replacing the manifold. If that's necessary then a valley refresh should be done. I really think it is a crack in the coating and not the manifold.

carreraclubsport

Hi everybody

Finally tried to peel the coating, and you guys where right, it came off....
Phew, what a relief

Ordered a new transmission modulator valve rubber cap just to make sure, but nothing wrong there. Will have to see if I get hold of a Mityvac or if I just take it to a local Mercedes dealer who can test the rest of it for me.

Will keep you posted, but as you might understand, I don't have the time to go into the garage every day....

@ OTR18WHEELER, thanks for posting, your apology is accepted


Christian

carreraclubsport

Hi guys, time flies....

Got the car to a Mercedes dealer in May where they found several vacuum leaks, one of them under the air intake. Started the removal process right away, with the help of this http://www.928intl.com/repair/intake1b.pdf, but it was first this week I finally got the intake off.
Is it strongly recommended to change the gaskets (part no 928 110 637 02) even though I haven't taken the throttle assembly apart?

I have ordered some of the parts needed, but need some help to find the part no's of 2 different clips. Can anyone please help? Please see attached pictures.

I am also wondering about the vacuum distributing piece (5-way splitter) part no 928 110 441 03. This was the one installed in my car ('93 GTS auto), but it is supposed to have 928 110 441 02 (which is a 7-way splitter) on my auto. I can't see that I have enough vacuum lines to fit in the 7-way splitter!

ROG100

We stock all the clips and you need a 5 way splitter not a 7 way - mistake in the PET

Bmw635

When I bought my S4, it shifted with a loud bang. My friend's ZF specialist shop found the vacuum plastic end inserted into the rubber hose in the trans tunnel along the torque tube, just forward of the trans had disconnected.

The dry rubber hose has splitted end allowing the plastic hose to slip out so they had to cut that section then re-insert the plastic hose using 2 long needle nose pliers.