I have a chrysler 300m 2004 I resently had the wheel bearings done now I have a grinding ,pulsation feeling in the brakes can you tell me what this might be

Have it rebalanced to check for bent rim or wheel imbalance, but check bolts and shimmy by grabbing the wheel on two sides and shake it to make sure a tierod,wheel bearing or other problem as well.

It could be a warped rotor or an out-of-round drum but it might also be loose wheel bearings, a bent axle shaft or loose brake parts. Or you might just be feeling you ABS kicking in. If it is one of those parts and you need to replace it, consider looking online for used auto parts.

The front calipers are not the problem...did a shop replace the pads and rotors? Or did a friend replace these parts. The Chrysler front pads and rotors are an excellent design...easy to service and replace parts...only 2 bolts hold on each caliper, and the rotor is held in place with the caliper, and wheel. My first thought was a front wheel bearing is grinding, but you should have noticed this before the brake parts change. The pads could be installed backwards also...my second thought was you may have a loose wheel or two...retighten all 5 lug nuts by using the "star" tightening method, you may be surprised that the loose lug nuts are the only problem. Hope this helps.

I would check the front brake pads. Also, check the front wheel bearings.

The most common cause of brake pulse is wheel bearings, because the rotor wobbles.
The way to tell is that you will also feel it through the steering wheel, when not applying brakes.
If the rotor wobbles, it will also make the brakes spongey, because the wobble will cause some piston retraction, causing a longer throw when applying.
It is usually the fronts that go bad before the back. And one side before the other, often because a bad seal allowed water in. But you can tell by jacking up and feeling for play.

If not a wheel bearing, then I would consider ABS problem, or the rotor was installed wrong.

If they are not worn beyond tollerance they can be machined on the vehicle.
Also make sure its not tyres or wheel bearings.

remove wheel
remove brake caliper( leave the hose connected)
remove centre cap
remove split pin and lock
unscrew bearing hub nut
rotor should come off
fit new bearing races in new rotor
grease new bearings
fit inside bearing and seal
refit rotor, outer bearing,washer,nut,lock, splitpin and centre cap
(tighten nut until no play in bearing plus 1\8 of a turn)
refit caliper and wheel
bleed and test brakes before driving

when your bearings start going bad two things happen first the ring gear that the abs reads the wheel speed moves to where it doesnt get a reading so that would probly be the abs light and second the flexing in the rotor will tend to colapse the brake piston leaving extra gap between the piston and the brake pad you might be able to confirm this by doing small short pumps and see if the pedal improves and it stops better i suggest replacing the bearings in pairs if you continue to drive the vehicle you run the chance of ruining the calipers hope this helps

Wheel hub bearing. Take it to a reliable auto repair business.

when turning left vehicle distributes weight to right front wheel bearing causing load. since u describe a noise in right front while driving straight i would suspect failed right front wheel bearing. see if your noise changes/goes away while turning right that should tell u 4 sure

Check tyres for bad wear or flat spots.