Center rear clunk/thud on hard accel in 2004 E320
 

Car has 57,000 miles on it. Rear suspension replaced last year w after market standard suspension w conversion kit. Hard acceleration causes a loud clunk/thud that comes from the center rear of the car (literally sounds/feels like the spare tire is lunging--but it's not.) Any ideas of what's causing this problem?

Hello and welcome to the forum! Have you put the car on a lift and checked the aftermarket suspension to make sure nothing is loose? What is the conversion kit that you used?

HIya! The car has yet to be on a lift--will be next week w the same mechanic who did the suspension. I don't know what suspension kit was used, however, I can find out next week. BTW, the sound comes primarily from rear center/rear right

Confused now
 

I've been driving the car like an old lady since the clunking/thud sounds started--so I've not heard the sound since. Yesterday, I brought the car to a mechanic, and told him the problem. He couldn't get it to make that sound while driving (which I found odd). However, when he got it on the lift, he said the rear body to sub frame bushings are bad, and that my left brake line severed while on the lift. I pick up the car today to see if I can get the sound/thud to happen again, and I can't....I now have 2 questions:
1: what gives?
2: is it imperative I have the rear body to sub frame bushings done?

Thanks:confused:

The bushings are important so you don't have metal on metal contact, which is likely happening if there is an issue with the bushings. I don't know if it will cause a safety issue, the mechanic can assess this.