How do you guys adjust a new modulator. I replaced a leaking vacuum modulator and now I need to adjust it . I replaced it because it was leaking trans oil. This is a photo of the old one. The new one is different. It has the black rubber cap on it. Thanks, Doug.

 

Carefully remove the black rubber cap - don't violate as it is needed to hold vacuum. There is a small 'T' key that is used to turn CW or CCWise, and fit back in the notches. See pg 3.3/3 on the link.

https://brandon314.files.wordpress.c...ull-manual.pdf

 

This might help you also.

https://rennlist.com/forums/928-foru...-pressure.html

 

'...The WSM also suggests driving at 140 kmh (or 50 kmh if 140 is going to be tough). After talking with a bunch of MB techs, turns out none of them do this - all check pressures at idle and stationary. So that's what I did.'

Would be curious to hear what Greg Brown would say about measuring the modulating pressure while not under load.

 

Will this gauge work to measure the vacuum modulator's pressure?

 

Your gauge scale is right for checking modulator pressure. Just need to have the right head and/or adapters to attach to the measuring port.

 

Thanks everyone. I've been trying to stop the Trans leaks for sometime and now it appears (I hope ) that this just might be final fix. I will get the proper adapter to mate the hose to the port tomorrow and give the adjusting a go!

 

Best Wishes.
Just be sure your ATF level is appropriate.

 

Subtle difference when under load, so I always check on my dyno at 140kph.

However, since the adjustment is just to get things close and then adjust to personal preference, idle is probably close enough.

 

This is now good to know.

 

Maine, I've been keeping a eye on the level since it has always leaked and I just topped it off and now that is right . Thanks again all.

 

I bought this kit. Worked very well. It contains all you need.


https://mercedessource.com/store/61x...ssure-test-kit

 

Thanks ihoe.

 

Well ,I hoped to get a fitting to connect the gauge to the port ... No luck. Ihoe,I'll be ordering the kit you suggested. Thanks for the heads up on that.

 

Two questions..... the new vacuum modulator is different than the one in the photo in the first post .It has the black rubber cap. So, does the plunger that worked for the old modulator work for the new one? The plunger fits in a "hole" in the modulator. The new modulator has a flat piece of metal and no depression.
The other question ... what values do I set the modulator? Is it 4.2 bars?