Brake booster line p/n - W140 300SD
 

Everything was going great. Just finished replacing belt tensioner lever and pulley, belt, water pump, fan clutch - with some spot cleaning thrown in (oh the filth). "Oh look that vacuum line is split, I'll just snip it and push it back on" ... the *&^%$ nipple on the brake booster line non-return valve broke. Why oh why did the Mercedes engineers invent their on vocabulary, why not call it a check valve. Hmmm, I'm digressing

Anyway I am having a hard time coming up with a part number for the line from the vacuum pump to the brake booster with a check valve in the middle that also T's off to the key operated engine stop valve. The closest I can find on EPC is 140 430 07 29 but the EPC description is INTAKE MANIFOLD TO BRAKE BOOSTER ASSEMBLY which just doesn't sound right. Mine looks suspiciously like:
http://www.peachparts.com/shopforum/...ter-image.jpeg

If someone knows the p/n for a W140 1992 300SD, vin WDBGB34E0NA039946, I would appreciate it.

Normally I can find what I need. I remember looking for this when I first got the car because the check valve had that white-ish color that some plastics get when they have been sitting around in the heat too long, but I couldn't find it and gave up because it was working.

In the interim, I'll plug where the nipple broke off and T in somewhere else for the stop valve or just open the hood and push the lever.

That was an awfully long post for a p/n request - maybe it was the beer after coming in from working in the heat/sun.

thnx,
Bill

You can temporarily tap into the VCV vacuum supply. Even permanently.

Sixto
98 E320s sedan and wagon

Any guess why they decided to tap off the brake booster line for the shutoff supply? Capacity? Re-using parts from previous generations of the OM603?

Brake booster vacuum line p/n - OM603.971
 

Just to tie this off ... I can confirm that 140-430-13-29 is the correct p/n for the brake booster vacuum line that goes from the vacuum pump to the brake booster for a '92 W140 300SD OM603.971. Until this purchase I have been very happy with my local dealer parts department; even though EPC said it fit my vin they wouldn't guarantee it and had no comment on how often EPC has been wrong. Anyway guess I was being a little paranoid.

Initially I connected the shut-off valve to the other vacuum supply and that worked just fine but I decided to bite the bullet and replace the whole line. Glad I did as the check valve on the original didn't seem to have as positive an action as the new one. Not really sure why the check valve is there ... Keep a brake booster leak from compromising the rest of the vacuum system? Now I'm getting 23" vacuum tee'd into the vcv supply - it was just 17" so I'm happy

I think it's the other way. The check valve preserves booster vacuum in case of a pump failure or engine stall.

Sixto
98 E320s sedan and wagon

Yep you are right - after I posted that I remembered that it checked flow from the pump to the booster.

silly me.