Diagnosed "Suspension" Rattle

[c5 rv]

After a year and multiple tries by my mechanic, my son-in-law (a mechanic) and I diagnosed an ongoing suspension rattle as coming from the rear brakes. When going across small bumps at low to medium speed, I hear a rattle from under the car. It seems to happen when the rear tires hit the bump. My SIL and I went for a ride tonight and he confirmed hearing it. We both felt around under the car and couldn't find anything loose. I had him stand at the side of the road near a bump and he confirmed that it occurred when the rear wheels it the bump, the sound came from the rear, and it came from both sides. He then felt the brakes and said it could be the brake pads rattling. I suggested repeating the pass-by bump test but with my foot lightly on the brake. Sure enough, the car wouldn't rattle when the brakes were lightly applied.

Maybe the wrong pads were used or the retainers are missing.

[carnut]

This is a single piston, floating caliper design. If the pads dont have the anti rattle paste applied especially to the outboard pad, the pads simply lay loose inside the caliper till a little pressure is applied. On both Allante's I've owned, I've never had to replace the rears, so I would research vendors for a 'hardware" kit to see if it included shims, but I always use a sicon based pad paste that, in a fashion, glue the pad to the caliper and provide a cushion to lessen rattles and squeaks. I would also make sure the parking brake cables are adjusted to spec to lessen inboard pad movement.

[babylac89]

Originally Posted by carnut

This is a single piston, floating caliper design. If the pads dont have the anti rattle paste applied especially to the outboard pad, the pads simply lay loose inside the caliper till a little pressure is applied. On both Allante's I've owned, I've never had to replace the rears, so I would research vendors for a 'hardware" kit to see if it included shims, but I always use a sicon based pad paste that, in a fashion, glue the pad to the caliper and provide a cushion to lessen rattles and squeaks. I would also make sure the parking brake cables are adjusted to spec to lessen inboard pad movement.

Absolutely great tip!!! Where are you located in California?

Chief

[c5 rv]

Thanks for the suggestions. I'm debating whether to ask my SIL if he'll do the job or take it back to my mechanic that changed them.

[carnut]

Stockton!! the home foreclosure capitol of the world!! Oh, and I meant silicon based paste not sicon. My stuff is made by BENDIX brakes, is bright pink in color and when dry has a rubber type consistancy. The bottle is about 8 ounces? Have had it probably 8 years. I only use enough to apply a THIN coat to the back side of each pad prior to install.

[babylac89]

Originally Posted by carnut

Stockton!! the home foreclosure capitol of the world!! Oh, and I meant silicon based paste not sicon. My stuff is made by BENDIX brakes, is bright pink in color and when dry has a rubber type consistancy. The bottle is about 8 ounces? Have had it probably 8 years. I only use enough to apply a THIN coat to the back side of each pad prior to install.

Stockton is in the mix, but Detroit is definitely #1 in forclosures and repo's!!!

I'm definitely going to buy some of that silicon based paste and try it.

Chief

[carnut]

The brand is CRC

[babylac89]

"Thanks!!!"

Chief