Braking Not Smooth (Not Vibrations)

[liquidzyklon]

Car information first. My car model year is in my signature. Only my passenger mount has been replaced at 50k (now at 70k) and brake caliper pins have been lubed every spring. Pads and rotors are from the factory mileage.

Problem: So most people when trying to stop would apply brakes to slow down the car. Once the car's speed has slowed down to about 5km/h (i.e. just prior to complete stop), we tend to ease off the brake pedal slightly to minimize the abrupt kick-back when the car comes to a complete stop. The problem is also present if I just apply the brakes fully without easing off at the end. Now the problem is just before the car comes to a complete stop (i.e. ~5 km/h), I notice that the car has an slight abrupt jerk prior to a complete stop. Other than that the car runs fine. So my questions are:

Is this a brakes / rotors problem? I do not experience vibration when applying the brakes.
Is this a sign that another engine mount is going? Or is this a sign of engine movement?


Thanks for your help.

[Astig02]

Car information first. My car model year is in my signature. Only my passenger mount has been replaced at 50k (now at 70k) and brake caliper pins have been lubed every spring. Pads and rotors are from the factory mileage.

Problem: So most people when trying to stop would apply brakes to slow down the car. Once the car's speed has slowed down to about 5km/h (i.e. just prior to complete stop), we tend to ease off the brake pedal slightly to minimize the abrupt kick-back when the car comes to a complete stop. The problem is also present if I just apply the brakes fully without easing off at the end. Now the problem is just before the car comes to a complete stop (i.e. ~5 km/h), I notice that the car has an slight abrupt jerk prior to a complete stop. Other than that the car runs fine. So my questions are:

Is this a brakes / rotors problem? I do not experience vibration when applying the brakes.
Is this a sign that another engine mount is going? Or is this a sign of engine movement?


Thanks for your help.

Info on Sig. too. Mine is not quite in the same situation. Whenever i try to slow down, releasing gas pedal, (initial press on the break), i feel like the car accelerates for a bit, then slows down as i press the brakes. I`m not referring to abrupt push on the breaks that may cause you to move forward due to momentum and inertia. I try to really press the brakes slowly and i feel there is that little instance that i feel the car accelerates prior to slowing down, then actually start slowing down. The acceleration was instantaneous ( quick).

Anyone had experience this?

[bluemazda3]

could be motor mount or suspension..

[stock3]

Is the car in question an automatic or manual? If it's automatic, try putting the transmission in neutral before coming to a complete stop. To me it sounds like one of the mounts is gone, possibly the transmission mount.

[liquidzyklon]

Is the car in question an automatic or manual? If it's automatic, try putting the transmission in neutral before coming to a complete stop. To me it sounds like one of the mounts is gone, possibly the transmission mount.The car is Auto. I will keep that in mind and shift to Neutral when braking for the next little while to try and pinpoint if it's the Transmission mount.

[liquidzyklon]

Update: stock3 pointed me to the culprit for this little abrupt jerk. By shifting the car from D to N definitely eliminates this problem. But at a complete stop and shifting back into D from N also cause a little jerk too since the transmission needs to engage.

Now after paying more attention to the Auto Transmission, the abrupt jerk happens just right after the transmission shifts from 3rd gear to 1st gear when slowing down (behaviour of a 4-speed auto, similar for 5 speed?). This means it's gear change that causes the jerk and I don't think it's the transmission mount. Anyone else who has an Auto transmission notice similar behaviour?

Thanks for you input.

[stock3]

Good to hear you have some results.
I think it is one of the mounts for sure, any of the drive train mounts can cause this as the engine and transmission work as one unit. Don't worry, your transmission is fine, and the behavior is absolutely normal. Basically, when you engage the transmission in D, the torque from the engine is transferred to the wheels, but since the wheels are not moving, all that torque causes the whole drive train to twist a bit. Normally all this movement is absorbed by the mounts, hence no jerk, but if the mounts cannot absorb this little jerk, it transfers to the car. Similar thing happens when you come to a complete stop, except that opposite torque is applied when the transmission shifts to 1st gear because of the change in RPMs.

Get the car up in the air, preferably on the lift, and inspect all mounts. Also, you can have someone engage the car in D while you watch the engine bay, you should see how much the drive train moves and if the passenger mount has extra movement during the engagement.