Cleaned Banjo bolt - vac hose keeps blowing off going down road - Fix? - PeachParts Mercedes-Benz Forum

willrev · #1 04-07-2005, 09:03 PM

I removed the banjo bolt from back of intake manifold and cleaned and reinstalled. When I tried to remove vac line from it, so brittle it broke off. Cut off piece still on nipple and tried to push back on. Would not go far down on nipple and keeps coming off going down highway. Hose is hard and brittle.

Suggestions? Is this hose supposed to be that brittle? Thought of heating up and softening it and pushing it on nipple.

MS Fowler · #2 04-07-2005, 09:14 PM

If I understand, that is not a vacuum line. Well, it is vacuum some of the time, but as soon as the turbo spools up, it becomes a pressure line. You are talking about the line to the ALDA, right? You need to make some kind of a positive connection to keep it from blowing off when the tubo starts working.

boneheaddoctor · #3 04-07-2005, 09:15 PM

The rubber hose should not be that hard that it cracked on you....it will be hard to push in without a litle soapy water to lube it. Buy bulk vacume line and replace it....there should be spring clamps holding it on.

tangofox007 · #4 04-07-2005, 09:44 PM

Once that plastic line gets brittle, it is nearly impossible to get it back on the hose barb. (It's hard enough with new line.) I just bought a new line with the banjo fitting attached. $9.25 at the dealer.
For future reference, removing the line from the banjo fitting is asking for trouble. I just disconnect the line at both ends. Soak the fitting end in solvent, then blow it out from the opposite (valve) end.

boneheaddoctor · #5 04-07-2005, 10:30 PM

I missed that................I didn't notice he was taking the barb off of it......its new hose time .........................

#6 04-07-2005, 11:02 PM

Quote:

Originally Posted by MS Fowler

If I understand, that is not a vacuum line. Well, it is vacuum some of the time, but as soon as the turbo spools up, it becomes a pressure line.

I'd hope it wasn't MUCH of a vac line

Johnhef · #7 04-07-2005, 11:49 PM

Had one a few weeks ago where the line had broken off and they fixed it by reattching the hose to the barb with rubber vacuum line.

I took it off, heated the line with a heat gun and it slid right on.

lrg · #8 04-08-2005, 12:25 AM

Use a short length of small diameter rubber vacuum hose to hold the two pieces together. Mine broke right at the end of the barb like yours and I just used about 1" of soft rubber hose pushed over each end to hold them together. If you get the hard plastic lines butted up against one another the soft hose just holds them in place and can't collapse under vacuum. I used that for over a year before I got around to replacing the hose. (The old hose is too brittle to reattach properly, eventually you'll need a new one.)

dieseldiehard · #9 04-08-2005, 12:53 AM

I replaced my cracked hose with small rubber hose (like vac line) for the whole distance and it held up OK. I believe I used hose clamps on the ends.

Johnhef · #10 04-08-2005, 07:10 AM

Did someone say vacuum??

#11 04-08-2005, 08:19 AM

Quote:

Originally Posted by Johnhef

Did someone say vacuum??

I pointed this out eariler...I guess if you REALLY want to enjoy the scenery you can hook this line to vac but I think it would be better off passing some boosty

Pete Burton · #12 04-08-2005, 08:36 AM

Quote:

Originally Posted by willrev

I removed the banjo bolt from back of intake manifold and cleaned and reinstalled. When I tried to remove vac line from it, so brittle it broke off. Cut off piece still on nipple and tried to push back on. Would not go far down on nipple and keeps coming off going down highway. Hose is hard and brittle.

Suggestions? Is this hose supposed to be that brittle? Thought of heating up and softening it and pushing it on nipple.

That plastic line is nylon or acetal I think. It isn't really supposed to get brittle but they all do as they are exposed to the natural environment under the hood. If you can buy the line with the banjos installed, that's certainly the easiest. You can also get some plastic tubing (try a small engine or marine repair shop) and install yourself. Heating the tube helps but what really does it is to make a little 2 piece clamp that allows you to hold the tubing and press it onto the barb. I've done this several times with Saab fuel systems, which use plastic lines for fuel system.

lrg · #13 04-08-2005, 12:15 PM

You guys are right about the vacuum. At most you'll get a small amount of transitory vacuum but its noexistant compared to a gasser when the throttle plates close. For the most part this line has pressure as it eventually makes its way to the Alda to trigger fueling increases as boost builds. That being the case a short rubber hose patch that fits snugly should work just fine.

#14 04-08-2005, 03:12 PM

Also truck air brake line would probably work decently for this application. I am just not sure how soft it gets when hot. Anyone have ideas?

Johnhef · #15 04-08-2005, 08:06 PM

Quote:

Originally Posted by lrg

You guys are right about the vacuum. At most you'll get a small amount of transitory vacuum but its noexistant compared to a gasser when the throttle plates close. For the most part this line has pressure as it eventually makes its way to the Alda to trigger fueling increases as boost builds. That being the case a short rubber hose patch that fits snugly should work just fine.

exactly right. I have an el cheapo sunpro boost gauge. it doesnt generate enough vacuum to even move the needle.

another thing while we're on vacuum, no more mityvacs! I went and bought a craftsman vacuum pump (well, a brake bleeder kit) and it works GREAT! The main point is, it WORKS! I went through 4 mityvacs, and will have no more!

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