MGB Rattle under front end?

[Joe Reed]

I've got a fairly loud rattle under the front end of my '78 that is driving me nuts. It sounds as if it's coming from the right side of the suspension, but I can't find the cause.

It only occurs when hitting a pretty sharp bump at speed - like a pothole or a speed bump. It sounds like pretty solid metal-on-metal...not like something thin like sheet metal. It does not affect the handling at all, and I can't feel it through the steering wheel.....no symptoms other than the sound.

I've got the car on stands with the wheels off. Crossmember pads are in place and the crossmember is tight. Suspension bushings are in good shape (Superflex blue bushings) and everything is tight. Sway bar bushings are in excellent shape. Calipers are not loose. Bumper is solidly attached.

Any ideas other than just turning off my hearing aids??

 

[Mickey Richaud]

Joe -

Shock mounting bolts? I had a similar issue and found a couple weren't tight.

Mickey

 

[Joe Reed]

I'll check those again. I think I may drop the spring and see if I can find anything loose. Maybe the tension of the spring is masking something....

 

[Brinkerhoff]

check the inner a arm rubber bushings too.

 

[Joe Reed]

All the bushings are Superflex blue poly installed about 8000 miles ago...

 

[JPSmit]

asking the obvious I know but have you tried bouncing it on the ground?

 

[Mickey Richaud]

One more thought: Check lube on upper and lower points on the kingpin.

 

[Joe Reed]

Mickey nailed it in post #2....shock mounting bolts were just slightly loose. The thunk is gone

One lesson learned here is to make notes of what you've done or checked if several days pass between the times you get to work on the car. I could have sworn I checked them last week, but I didn't take notes...and I obviously can't remember everything from one week to another. Funny how "I need to check those bolts" one week becomes "I checked those bolts" in your memory by the next week.

 

[Mickey Richaud]

Glad you found it! Can't tell you how many times I've gone over tasks I'd gone over before and found I'd actually missed something.