I changed all disk brakes on my car. Now i got vibration,when i push brake. I can‘t even tell if its front or back.
These are only suggestions to consider: After you changes the discs, did you also change the brake pads? If ya didn't, you should have. There may be a bent wheel or an improperly balanced tire. Check into that. And finally, my personnal beef with mechanics; I hate the fact you spend a ton of $ on work and the first thing they do is take an impact wrench to your lug nuts when the reinstall the wheels. I have always, for many years, retightened the lug nuts to the proper torque with a high quality torque wrench. This prevents disc warpage. By having each lug nut tightened evenly, this would prevent the warping and in theory, you should never have to replace the discs unless you let the pads grind into the discs. I had a 2001 Dodge truck I put almost 100K miles on it and never did a brake job on it. And the brakes still had 50% of life on them. Each lug nut was to be torqued to 120 foot pounds. Anyway, I hope this helps a little. G'luck!
[not air in the system, not your master cyl and not anti-lock brake problems] and the prize goes to! . . . replace the rotors, and lube the calliper floating pins or mounts (depends on the make). If the rotors are old they can warp, or the surface can wear unevenly. Most places don't even have the re-surfacing equipment or the knowledge to do it right and rotors cost as little as $20/each, about the cost of turning the old ones down!! If the calliper floating mechanism is not free to allow the callipers to slide when the brakes (not breaks!) are applied, only the piston side pad will contact the rotor which causes a side load on the rotor and bearings and causing pulsations in the brake pedal If it is working properly and the calliper is sliding in its mounting pins, the calliper will pinch the rotor applying equal force to both sides of the rotor.
It could be a few different things most likely would be that you need to bleed your brake system -- if there's air in your system, or too much volume (since the calipers don't need to depress as far), then it might be causeing that. Another possibility could have to do with antilock, if you have it on your vehicle. If one of your speed sensors got disconnected or damaged, it could be activating the antilock system while braking. Another could be that your discs have heavy grooving, and the last pads were conforming to the discs? Hard to tell just by hearing of the vibration, but perhaps you just need to put brake grease on the backs of your pads (NOT on the friction material).