1982 300D Turbo

Today I accidently broke two lines that connect to the "tube" (for lack of a better word) that leads out of the brake booster. These two lines are connected to the vacuum system and enter the "tube" about 6 inches from the brake booster. The plastic on the ends of the lines that connected it to the "tube" were very brittle and they simply broke off. The only thing I can notice now is that car does not shut off without pushing on linkage. What I'm wondering is what these two lines do and if car is driveable while broken? I have only run engine, haven't actually driven car since I broke them. Thanks for your help!

Yep, we've all done it.

Working anywhere near those plastic nipples is an invitation for disaster.

You must replace the entire line, either from Fastlane (this site) or the dealer.

You can drive it without those connections. You'll have to shut it down by hand and either the climate control or the door locks won't function.

The leaks should not be of a magnitude that will affect the brakes, but, just check the pedal on the first drive to be sure.

This is want you broke:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41WR17NPKS&year=1982&make=MB&model=300-DT-001&category=All&part=Booster+Vacuum+Hose&appChassis=_any

The small vacuum connections feed everything except the brake booster, which is feed by the big line. The broken lines will affect the engine shut-off, the transmission modulator (very hard shifts), the door locks, and the HVAC dampers. Driving it shouldn't do any damage, but you will not like how it shifts. Also, be careful of the brakes because you have a leak in the booster line.

Thank you for the help, I'm ordering a booster vacuum hose this week. Do you suppose I can find the lines that connect onto this in the store as well, because they have broken plastic nipples too. Thanks so much!

The rubber lines that are used on a M/B are 4mm. The standard rubber hose in the McParts stores is slightly larger at 3/16" and won't fit very well on the nipples.

Better to get the hose from this site, or the dealer.

The plastic Tecalan line is also 4mm tubing and it's available from this site or the dealer.

What other parts have broken nipples? Can you describe them or show us a photo?

Can't get photos unfortunatley. But the plastic lines that should normally be connected to the booster vacuum have broken plastic at the end. Then still connected to the hose is the other half of the plastic nipple.

So half of the plastic nipple still connected to booster vac. Other half still connected to the rubber lines. Can I just pull the broken half out of the rubber lines and then use the same lines to connect to new booster vacuum thing?

Thanks!

As long as the connector is still intact, just remove the broke piece and reconnect it to the new hose when you install it. I think I'm on my third booster hose now.

Awesome, thanks!

You can........but.........I'd advise that you do yourself a favor and buy some 4mm vacuum hose and replace those lines. They are 23 years old and the rubber is far from pliable. The vacuum system starts leaking around the connections due to the poor fit from the old hose.

Probably a good idea. It's good to have some vacuum extra hose around anyway.

and I would caution you IF you are continuing to drive with these vacuum "nipples" that are "T'd" off the large Vacuum Pump-to-Brake Booster line... IF you are still driving the car:
(1) be wary of how the brakes are performing,
(2) By all means try to temporarily reconnect the vacuum hoses to the broken off "T" nipples, and
(3) IF you canNOT reconnect the hose, then use some duct/"duck" tape to plug up the large vacuum source line [ your broken off "nipple" ]... this to conserve vacuum for use by the brake system.
(4) Try a local foreign auto parts store [especially if it specializes in VWs] and you should easily find a meter of metric vacuum line.

Regards,
Sam

Just put a dab of RTV on the broken nipples if you're concerned about the leakage (I'm not). Duck tape isn't going to prevent air passage across the broken nipple.

... and " Error on the side of Caution " is second nature to me... so let me state for the record:

(1) IMHO ANY person who is confident enough about their DIYer abilities to seriously consider working on their own car should be able to quite effectively apply a little sticky "duck tape" to stop a vacuum leak at a broken "T". After all this is a vacuum, not positive air pressure!

(2) Regarding the use of "RTV", a semi-liquid silicone based adhesive sealant, you should be careful to NOT allow excess RTV to be sucked into the vacuum line so this most likely means the sealant should be applied sparingly and allowed to dry thoroughly [~24+ hours] before starting the engine and creating a vacuum in the line. Otherwise you might suck enough of the RTV into the vacuum line that would restrict the passage of vacuum to the booster and braking system... the very last thing I for one would want to happen to this FORUM participant [ " banjoread " ].

(3) To repeat myself "...be wary of how the brakes are performing..." and if there are ANY signs of degraded brake performance, do NOT operate the vehicle beyound your ability to safely bring it to a stop... at least keep off the freeway and higher speeds !

I happen to be in the midst of communicating with and trying to get MBZusa to address MBZ's intent of incorporating a restricted orifice into the design of these "T"(s). Believe me when I say that I am not holding my breath while I wait for a response. When "SAFETY" is the issue, corporations tend to in general clam up and with an automobile manufacturing corporation I think this is doubly likely to happen in today's global economy!

Retired CSP... be safe,
Sam