Noise and Shudder When Brake Applied, Not Moving

Are you saying that it makes a shudder and clicking the anytime the car is in drive with the brake applied? Like at a stop light.

Or is it that you have your foot on the brake and when you initially put it into drive or reverse it shudders and clicks?

If its the latter a CV joint is probably going bad. Most of the rubber boot on the joint cracks and the grease leaks out and dirt gets in there wearing it out. Take a look under the car at the passenger wheel and see if the boot is cracked. The inside of the wheel will look greasy too where the grease went all over.

The best way to fix that is a new CV.

Let's say I'm sitting in park, everything is fine and running smoothly. Press the brake to move shifter into drive, everything is still fine, select drive, 2 seconds later the clicking/shudder begins until I let off the brake. Hard to tell if it does it under light braking on the road, but it certainly does once at a complete stop at lights or stop signs.

There is also the possibility of a broken motor mount.

Could possibly be the automatic transmission, best get the car in for a mechanical service.

I'm trying to think of any reason that you would deduce that there was a problem with the brakes in the first place. There is none.

So, does the noise persist on drive away?

Or, how about this. Tell us why you think it is not a transmission problem.

I only think brake because it only does it when the brakes are pushed and at a complete stop. The noise seems to be intermittent and no it does not persist on driving away. I don't know that it's not a transmission problem. There is no warning lights for the A/T on the panel indicating any problems. I really do not know exactly what it is. I will be checking Motor mounts on it in a couple hours.

Could be broken motor mount. The noise could be the coolant fan hitting its shroud. Look ate the edges of the blades for marks and the shroud for marks of contact. If nothing is evident look at the engine while having someone with their foot on the brake shift it into drive. Look and see if the motor rotates and lifts up on one side.

Warn please stand to side of car while observing not in front. You never know.

Mechanic B says that your brake booster may be defective.

Here is why. When you step on the brake, engine vacuum is allowed to push the master cylinder harder than your foot was pushing it. Normally only a limited amount of vacuum is used for this purpose, because you are not standing on the brake pedal, and there is only a limited amount of space available in the booster. That way the engine will suck the available air in this area to some lower pressure than it was before you pushed the brake pedal. The engine will consume this additional air, but only a few seconds until the booster is under vacuum. And then the air fed to the engine returns to the normal amount.

But, if your booster is not sealed properly, it will have an almost limitless area to try to bring into a vacuum. This continuous air flow into the engine will lean out a carbureted engine as long as you are stepping on the brake. Some fuel injected engines may also do this if their air monitoring system is not able to sense this. This is more likely to happen with a small displacement engine, than with a big V8 engine. Why only in drive positions? Because the load of the engine being in gear, and forcing the torque converter to slip. An engine with no load on it can run at wider variances in mixtures, than an engine under load. Why does it need to warm up? Because the engines are set to run richer when cold or cool. It will get leaner once the car reaches proper temperatures.

To test this, try listening for a noticeable hissing noise when stepping on the brake. If you can not hear any noise, get someone to assist you. Open the hood, and locate the brake booster. Have the assistant apply the parking brake and hold the foot brake, then put transmission in gear. ( This technique is best done with the car backed right up against a stationary object to prevent unwanted movement.)

With the car now exhibiting the shake, squeeze the vacuum line going to the booster. Did that stop the shaking? Good luck, and let us know.

I made the car do what it does, listened for the hiss and couldn't here any discernible hissing coming from around the booster or the general area. Then I made sure to locate the vacuum line to the booster and used a pair of channel locks to squeeze the line shut and the shaking/shudder still continued. I tried it 3 more times just to be sure and also held the line closed for probably 30 seconds to try and be thorough. Nothing changed. Does that pretty much rule out a bad power booster?

Yes it certainly does seem to rule out the booster.

Can you make the car continue the shake as long as you have your foot on the brake? If so, you can try testing the cylinders for dead ones by using a pump sprayer with water in the bottle in it. Spray each exhaust port a few times. That will cool down each port of the exhaust manifold. If that cylinder is firing, it will evaporate the water off very quickly. If the water does not evaporate off as quickly as others, that cylinder is not firing.

If you have access to infrared thermometer, you can find the same thing without the water bath. Good luck, and let us know.

The symptoms described could be one of many things: uneven cylinder wear - worn, sticking or carbon fouled valves - secondary ignition components - a weak ignition coil - dirty fuel injectors - transmission fluid - electrical. The ticking noise is most likely the effect of the shaddering. If this is a high mileage vehicle, unfortunately this is normal because of the wear and tear but if not perhaps service neglect could be the cause

So I went the cheaper, easier route and replaced the passenger side engine mount. Problem of shuddering when in drive gone by about +90%. The clicking also has gone. Changed the pulse generator and inspected the driver mount and it looked in excellent shape. As did the mount to the cross member. I'd like to say thank you to everyone who gave me input on the situation, it was indeed a huge factor in fixing the car. Sorry so long since I updated. I'll be on now and then to hopefully return the favor to help someone else like myself. P.S. The Passenger side engine mount is notorious for failure in Mazda 3's of that year.