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Rear noises when driving over bumps


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Happy New Year everyone!

In anticipation of my road trip to the Laon Historique Festival this May, I’ve decided that it’s time to sort out the strange noises coming from the rear of my ’63 TR4. I wonder if you could help me to diagnose where the problem is likely to be?

It’s a series of loud knocks, bangs and squeaks which I can only hear when I drive over bumps and into potholes (not deliberately, I might add!). The noise isn’t there when I’m driving on a level road although I’ve sensed some slight ‘movement’ when I drive into bends, like something is slipping at the rear. I’ve already checked that my wire wheels are bolted on securely and that the castellated nut holding the bearings in is set to the correct tightness.

I suspect it could either be the rear suspension bushes, the lever shocks, or the links (or all of the above), but I’m not sure how I would go about testing each component. I’m no mechanic but I’m quite happy to wield the spanners when needs must. I just need to know what to look for as I’m loathe (i.e. too tight fisted) to replace everything just for the sake of it!

Or... could it be something else?

Any advice would be greatly appreciated.

Regards

Glenn

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Hi Glenn,

 

I suspect you will get a wide range of possibilities. On my TR4 it was loose bolts that hold on the lever dampers to the chassis. Nothing obvious to move or see but the bolts needed tightening and it sorted out the banging.

 

Mark

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Hi Glen, we had similar issues exposed by the rural lanes of Knockholt! Often a large knock or clunk when turning out of a corner / junction under ower.

 

The causes included those that you have highlighted:

  • dampers failing
  • springs not great (leaves sticking)
  • absence of the larger spring washer
  • bushes worn out
  • body mounts needing repair

(and that was only the back end !!)

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"Something is moving at the rear"

 

Start off by tightening the u bolts holding the rear axle onto the springs. Tighten to the appropriate torque, the progress onto checking and tightening the front spring bush nut and the nuts on the rear of springs drop links. After that go for the shock absorbers links and chassis mountings for the s/a bodies.

 

Then give it a road test before attacking anything else.

 

Mick Richards

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"Something is moving at the rear"

 

Start off by tightening the u bolts holding the rear axle onto the springs. Tighten to the appropriate torque, the progress onto checking and tightening the front spring bush nut and the nuts on the rear of springs drop links. After that go for the shock absorbers links and chassis mountings for the s/a bodies.

 

Then give it a road test before attacking anything else.

 

Mick Richards

Reminds me the horror story....

https://www.facebook.com/profile.php?id=1089104818&sk=photos&collection_token=1089104818%3A2305272732%3A69&set=a.10202264632032415.1073741850.1089104818&type=1&l=7ac031b447

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Concur on loose shocker bolts. Got the noises and looked underneath. Shockers seemed tight so looked everywhere else first, then tightened them. Problem solved. But..... A few hundred miles later the problem was back. Really really tightened new bolts etc. plus Loctite. that seemed to work.

Later converted to poly bushes new springs and shockers etc as part of planned winter restoration job.

This was one of the best things I have ever done to my car. Till then it had been slightly disappointing compared to youthful memories, after it was as good/better.

 

Mike

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Good call chaps!

 

The nuts holding the lever arms on were loose (one was very loose indeed). I replaced them all with new locknuts and oiled the springs while I was there.

 

The result? I found some pot holes to drive into (not hard in north Kent) and there's no more worrying knocks, squeaks or bangs. That was the cheapest fix ever!

 

Thank you all for your advice.

Glenn

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Glenn,

 

You might want to think about replacing the hex head bolts/screws holding on the dampers with socket cap screws - much easier to hold with an allen key when tightening, as there is very little room beside the damper for a socket.

 

Mike

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Glenn,

 

Loose shocker mounting bolts must be the favourites

to check those first. Difficult to get good purchase on

the front bolt to hold it, but the bolts must be really tight.

 

IF the noise goes away briefly, then returns, suspect

the hole in the chassis mounting to be elongated.

 

Then move onto the other causes mentioned above.

Starting with cheapest first - shocker links - then work

through the rest of the possibilities.

 

AlanR

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Why didn't we think of that !!! (see above posts)

 

Try to keep up Alan :P:P

 

Seriously though, the holes in the mounting plate probably do elongate, & it's asking a lot for the tightened up bolts to hold the shocker still using compression only. I am wondering about the benefits of welding the bolt heads (or conversely the nuts) to the mounting plate rear, thus eliminating movement there. One may have to use socket head bolts if spanner access is not possible on the shocker side ?

 

 

Bob.

Edited by Lebro
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I had the same problem with rear knock on bumps and it was the rear damper nuts being loose. I replaced the bolts with Allen head bolts for proper purchase and all seems good now and haven't come loose since.

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