thumping sound when breaking

[jeb]

i have been constantly working out kinks on my car since i did the swap an i think i have finally just about got them all. but now when i hit the brakes it makes an thumping sound from my rear end that kinda sounds like the diff is trying lock up but i dont see why hitting the brakes would do that. when i am driving tho its fine. any ideas what this could be?

[GSXRJJordan]

speed-dependent? brake-pressure dependent? what happens in reverse?

Could be a driveshaft issue, could be a diff issue, could be a brake issue.

Most likely it has to do with your brakes/wheels - check the torque on your wheel lugs first (cause it's easy) and if you can easily get the car up make sure the nuts on the driveshaft/diff bolts are solid. What changes the sound? Braking? Speed?

[allntrlundrgrnd]

warped rotors? can you feel it?

[jeb]

i only feel it when im brakeing or coming to a stop. its fine in reverse an taking off.i checked the tires an they seem fine.i will take a better look at things in the morning when i can see better but im trying to trouble shoot it early. how could i find out if its the diff?

[jeb]

also if it was warped rotors wouldnt i feel it all the time?

[fliprayzin240sx]

Constant thumping or just a thump or two and then goes away. If its just a thump, im thinking subframe bushing.

[SoguRacing]

perhaps worn driveshaft u-joints?

[jeb]

its constant the whole time the brake is being used

[Sileighty_85]

worn subframe bushings or loose diff mounting bolts?

[GSXRJJordan]

If it's only braking dependent, get your rotors turned (and replace the pads if you haven't already), break them in properly, and re-evaluate. Could definitely be warped rear rotors, although most of the time people warp the fronts, not the rears.

[looking4-240]

worn subframe bushings is possible. but it usually happens when you let off the gas period.....