Hey man, use the quote feature so we know who you're replying to.

I'm assuming you meant to upload an image with this post?

 

Tube seals also have rubber fins on the outside and fit snug into tubes. Very secure.

 

i know i should expect small vibrations and rattling from a jeep, but recently I started noticing a sort of vibration or pulsation when pressing the brake pedal at a red light / long stop. Is that something to be expected or maybe sign of some pulley going bad? motor mount? it doesn't seem to be the brake themselves. when I brake, everything is fine and nothing unusual. but once I'm stopped completely, it just seems like there's something shaking under there. With my right foot on the brake, I also feel it on the floor mat with my left foot that is resting.

While searching I found a post on a bmw forum where a guy explains a lot better than me, and it seems to be the same symptoms.

turned out it was his water heater valve that, upon replacement, fixed the problem.

 

Try shifting into neutral and see if it still does it.

 

Just for general knowledge, what do you think would be the cause if it continued or stopped?

 

i'll give that a try once I leave work, didn't cross my mind this morning.

I was thinking the same thing, since at a stop nothing is moving, other than all the belt driven stuff at the front. I'm wondering if there's something near the footwell on the outside that could cause it. recently it was the front driveshaft, but that was when driving since it obviously doesn't move when stopped.

 

It's possible you have a motor mount going bad. Mine did this when it started going bad and, though it doesn't bother me, it still kinda does it now with my brown dogs... but only because it's a firmer mount.

When your Jeep is in gear with your foot on the break, there's load on the motor. With a bad motor mount, the motor wants to "torque over" to the spot that the rubber is falling out of and it can come in contact with the metal surrounding it. Once you remove your foot from the break, the load is decreased, and once you accelerate, you quickly move past the harmonic point that the jeep vibrates at, so you don't notice it.

Try shifting into neutral and seeing if it stops. If it does, check your motor mounts.


Sorry... little wordy, I know.

 

Makes total sense. Thanks for the explanation.

 

Hope it helps

 

cheers, makes perfect sense. I suggested motor mounts in my first post, but I didn't think about it that way.

while we're on the subject, what's the best replacement? I'm not hardcore wheeler, so I'm not interested in brown dog's, since like you said they're stiffer and noisy. I'd rather get an oem replacement but don't trust the crown ones I found online (unless someone says otherwise and has experience with them. Anything else that has standard rubber or that won't make squeaking/annoying noises?

 

They're not noisy by any means. They're just firmer so they don't take out as much vibration as the factory mounts. Pretty much any mount made with this style will do that though.... which is pretty much anything but OEM mounts.

Crown is good, so is Omix-ADA as far as OEM style mounts go.

OEM-style mounts...



There is more rubber below the bolt sleeve. Keeps vibrations at bay when engine is at idle with no load on it because motor is "resting" vertically straight down on the mounts.

Once load is applied, the driver's side of the motor torques upward where there isn't as much rubber.


Aftermarket-style mounts (i.e. brown dog, daystar, ironmanfab)



Same amount of rubber all the way around the bolt sleeve. Doesn't dampen as much vibrations, but much more durable and holds the motor in place better.

 

i have a jeep cherokee 2000 about a 150k miles. was running fine all day, went to start it started really weird starting shaking and just got worse. tryed to turn on and off, but would only stay on for a few seconds.

 

Is the check engine light on? If so, what codes is it showing?

 

came on about a week ago. it was a cylinder missfire on 3 and 4. i replaced the spark plugs everythings been fine but the let hasnt been off

 

have your head checked yet?