Slow_c63

iTrader: (1)

Any tips on replacing this hose? Is there anything to it? I’m mostly concerned on how to disconnect it on the IM side.

Long story short, few months back I started having rough idle, very rough 2-1 shifts, jerky acceleration from the stop… the whole 9 yards w204 Philly Special. (No CEL or any codes by the way. But me knowing my car, I’m certain that there is a vacuum leak.

For those who have followed my thread, I’ve replaced bunch of stuff trying to pin point the issue: injectors, spark plugs, IM gaskets, IM TB Plate, Engine mounts, transmission mounts, transmission service, etc…

Fast forward to this week I decided to smoke the car again just because of how annoyed I am with the car. After some time we discovered a leak on the back of the IM. Leak was obvious and was leaking where the Brake Booster vacuum hose connects in the back.

I’m not sure if/how this leak affects the car, and if it’s related to my main problem, but it will be another thing out of the way, at least.

My concern is disconnecting the hose on the IM side. Are there tabs that need to be pressed, pulled, etc ?? I’m concerned on damaging the IM itself in the process. The dang thing has already given me enough headaches.

Thanks in advance.


Part Ordered: 204-430-08-29

Slow_c63

iTrader: (1)

I felt stupid asking this question in the first place, hence why nobody probably responded.

The locking mechanism is just two tabs that you push in, while pulling out the hose on the rear.

after MONTHS of changing parts to pin point my issues, it seems like i found my fix FINALLY!

I will make a separate thread going over my experience so that other’s don’t make the same mistake of spending thousands on replacing unnecessary parts. But this was all trial and error for me.

in short,

shifting is back to normal

2-1 shift is very smooth where it was bucking before

Coming to a stop is smooth, not jerky/neck breaking as before

coming to a stop no longer feels like I’m being rear ended

RPMs are holding up while coming to a stop, and settling very smoothly to a dead stop

Going from a dead stop was a headache. Getting on throttle from a dead stop would cause the car to bog. As if you’re learning to drive a stick shift for the first time.

Anyways, I will make a separate thread going over everything. As I see a lot of members with these same symptoms. and I dont want anyone else spending thousands like I did just for it to be a simple hose.

Keep in mind that we missed the vacuum leak on our first smoke test. Which sent me down the rabbit hole of replacing parts that had no business being replaced.

Slow_c63

iTrader: (1)

Back of the IM.


Brake Booster side plug


Part Number


All put back together.

See63Run

Hey, OP-

i know this is an old thread, but did you see or replace an o-ring on the IM side of this hose when you replaced it?

Slow_c63

iTrader: (1)

yes, I replaced the O ring and the red coupler that comes in front of it.

See63Run

thanks for the response!

for anyone that finds this thread in the future, here are the parts I ordered - all from FCP Euro

Slow_c63

iTrader: (1)

I would like to add that the 2-1 shifts become abrupt again, and getting off the lane at a light was a headache. Since I made this thread I’ve been scratching my head and kinda gave up.

Everyone I spoke to, all the shops, they all had similar feedback: “That’s how MCT vehicles are”.

I did brake flush, twice, since my brakes were sticking, especially the rears. That didn’t help. The rears at a stop would drag for 1-3 seconds before I could leave the line. And If I got on the throttle the car would over rev causing jerking forward/backwards. Breaking your neck and your passenger’s.

So I started focusing on why this was happening. LONG STORY SHORT, I finally FIXED my problem after dealing with this for some time.

Solution: It was my E-brake that was causing all of this. The E-brake would disengage, or so I thought. Until yesterday when I used my hand to check if there is any travel in the E-Brake pedal once I disengaged it with the lever by the steering wheel. To my shock the E-Brake Pedal moved almost an inch upward.


Car feels like new again. I’ve literally been all smiles since yesterday. I can’t believe it was something so simple that multiple shops missed, including me.

Car shifts 2-1 perfectly now, as I drive in Manual mode. I can’t even tell that the car shifted 2-1 at times how smooth it is now. Leaving the line no longer creates a drag which makes the car so enjoyable now.


My experience with this problem ends here.