TR2/3/3A Mystery clunking and banging from rear of car when driving over rough road or bumps?

[karls59tr]

I'm trying to track down the source of the annoying sounds coming from the rear end of the car. Here's what I have done so far. I have secured the spare tire so it does not move. I limited the amount of spare parts in the trunk and put foam underneath my toolkit.The rear springs have been replaced and all mountings seem secure. The rubber stops on the axles are in place. I can rock the back of the car up and down and it rebounds as it should with some slight squeaking only. That leads me to believe that the shocks are functioning and do not seem loose.
How is the body actually fastened to the frame at the rear of the car? Is it possible that the body is lifting off the frame when I hit a pothole or bump? I know that some have compared the ride of a TR3 to that of a buckboard but I still think something is not right. Any thoughts?

 

[bobhustead]

Muffler, resonator, tail pipe, gas tank, rubber shock pad between frame and axle, loose anything in the suspension.
Bob

 

[GilsTR]

Shock arm.
gil. NoCal

 

[charleyf]

Shock arm.
gil. NoCal

There are two body mounting bolts at the rear. They are on each side of the spare tire compartment.
I would say take a closer look at the shock mountings. Sounds like you have a loose one.
Charley

 

[Geo Hahn]

Shocks can appear secure when you try to move them but the forces that occur with a bump in the road can cause them to move if not very tight.

I secure them with socket head cap screws and Stover nuts.

 

[chlem]

Agreed, re-check torque on mounting bolts for rear dampers. Mine loosen after a couple of thousand miles of driving. The rear dampers then clunk (move in the mount) over bumps, but not when pressing down/releasing body at a standstill. I use Stover nuts, too.

 

[Marksg11dna]

Clunking maybe similar to yours. Mine turned out to be a bad u-joint so I swapped all 6. Also check the differential mounts.

 

[karls59tr]

Well it turns out that it was the mounting bolts for the rear dampers that caused the clunking as many of you had mentioned. The passenger side damper had one bolt missing completely and the one beside was just about ready to go. I replaced them with Grade 8 bolts, nuts and lock washers. Could not find the Stover nuts locally. Are they similar to Nyloc nuts? I might go with them if the present set up does not work out. Cant believe I lived with that irritating clunk for so long! Always something new to discover about these cars. Thanks to all who responded.

 

[charleyf]

Well it turns out that it was the mounting bolts for the rear dampers that caused the clunking as many of you had mentioned. The passenger side damper had one bolt missing completely and the one beside was just about ready to go. I replaced them with Grade 8 bolts, nuts and lock washers. Could not find the Stover nuts locally. Are they similar to Nyloc nuts? I might go with them if the present set up does not work out. Cant believe I lived with that irritating clunk for so long! Always something new to discover about these cars. Thanks to all who responded.

You should consider Loc-tite if you have to go back in.
Charley

 

[Gundog61]

Agreed, re-check torque on mounting bolts for rear dampers. Mine loosen after a couple of thousand miles of driving. The rear dampers then clunk (move in the mount) over bumps, but not when pressing down/releasing body at a standstill. I use Stover nuts, too.

Stumbed across this thread looking for a mystery banging in the rear end of our Healey as the OP described. Spent months looking for this, I am working on brakes so with it on jacks I went and check the shock. Sure enough the shock is loose and causing the banging. Thanks all

 

[Geo Hahn]

Repeating prior recommendations... Stover nuts are great for this fitting.

My use of socket head cap screws is just to enable getting everything tight in locations where wrench access is limited.

 

[mt10flyer]

The mounting holes on the my brackets became enlarged due to the wear caused by the bolt movement. So the bolts don't seat correctly and can move around. I used the grade 8 bolts and nuts with extreme torque idea, but eventually will have to replace the mounting brackets.

 

[charleyf]

The mounting holes on the my brackets became enlarged due to the wear caused by the bolt movement. So the bolts don't seat correctly and can move around. I used the grade 8 bolts and nuts with extreme torque idea, but eventually will have to replace the mounting brackets.

I would suggest that you try filling the oversized holes by welding them closed and then drilling new holes.
Two cautions-- first you are welding directly below the fuel tank, so use some protective shield under the fuel tank also make sure the area under the tank is clean to start with.
Second --make a template of where those new holes need to be before you start.
Charley

 

[karls59tr]

I would suggest that you try filling the oversized holes by welding them closed and then drilling new holes.
Two cautions-- first you are welding directly below the fuel tank, so use some protective shield under the fuel tank also make sure the area under the tank is clean to start with.
Second --make a template of where those new holes need to be before you start.
Charley

.....and plug the tank vent tube temporarily.

 

[KVH]

I had this happen once--the bolt holes were ruined. On someone's advice here, I bored out the holes ultra-carefully, using a power drill held by hand, of course. I forget the size--either 3/8 or 7/16. I then tapped the holes for fine thread, IIRC. I then had to bore my new shocks as well. It really didn't take much time. Most of the time was spent with me worrying about how to drill straight into that threaded hole. Anyway, it worked great. Never had a clunk since. I used longer bolts that protruded beyond the backside of the mounting plate and put nyloc nuts there, too. Again, because someone here recommended that brilliant step. No welding. No down time. Good luck.