# Brake pedal extremely hard on Murano



## Rpewing (Sep 5, 2016)

Hi everyone,

I'm obviously new here, and I'm a novice at car repair as well. The most ambituous thing I've done to this point was over the weekend when I changed the spark plugs in my 2009 Murano. The accelerator had been hesitating at more regular intervals, and the plugs have never been replaced, so I figured that was a good a place to start as any. I used this guide, which made it straightforward and easy for even a noob like myself: nissanhelp.com/diy/murano/projects/nissan_murano_spark_plugs_replacement_procedure.php

When disassembling, I discovered the air duct tube was cracked in a few places, so I applied some heat resistant silicon tape to a few wide cracks. It seems to have sealed it up fairly well. I ordered a new tube, and I'll be installing it Thursday, so that's just a stopgap measure.

So I'm going to take it for a test drive tonight, and the brakes are extremely stiff and ineffective. I figured the most likely cause (after looking online) was the vacuum hose for the brake booster. I suspect this is the hose from step 7 in the above link. I had a really hard time getting that hose back on, and it's a little kinked in a couple of places and only seems to be about halfway on. 

Since I was just doing a test drive, I wasn't too worried about having it be perfect, but I'm extremely suspicious that this could be the cause of my problem. I think it's one of three things:

-- What I just mentioned
-- The faulty air duct tube...unlikely, I figure, especially since it seems like it's been that way for some time
-- I dislodged or loosened a hose related to the brake line that I can't see when I was reinstalling the air box; I initially had it outside the bottom grommet, and was having a lot of difficulty hooking it up to the front air intake until I realized the problem. Again, I think this is unlikely, but I wanted to be thorough.

So my question then is if the hose I'm referring to is what I think it is. A side question would be what type of lubricant I might use to get the hose all the way on. I know WD-40 is not a good choice, so is soap the only way to go?


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## rogoman (Dec 16, 2004)

WD-40 is OK to use for slipping hoses on; just don't use silicone sprays around the intake system; it can poison the CAT.

If you're referring to air duct tube cracks located between the MAF and intake manifold, they will create a major vacuum leak that will affect driveability.


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