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View Full Version : TR4/4A TR4A-Chasing Down the Rattles and Knocks



KVH
05-07-2012, 03:06 AM
On my IRS I fixed a loose shock mounting, and that was an improvement, but it still sounds as if something is thumping the underside of my interior/tub whenever I hit a significant bump, particularly if both wheels and springs react to the bump at once. It's annoying 'cause it literally sounds like everything in the trunk is flying--but on my test drive my trunk is empty.

My question is whether those emergency brake cables jolt around much on stiff bumps. I'm able to replicate the sound by jiggling those cables, and the cables seem to be located where that sound is coming from. Any hints or ideas? Can those cables be a source?

tdskip
05-07-2012, 08:42 AM
Are the body to frame bolts all tight?

Exhaust?

DanB
05-07-2012, 09:28 AM
It could be the differential mounts, they are prone to breaking loose. If that is the case, the frame will need to be repaired. What type of exhaust do you have? That's what I would hope for...

Dan B

Geo Hahn
05-07-2012, 10:14 AM
As for the handbrake cable -- on mine I finally slipped a short length of foam pipe insulation over the offending spot and zipped tied it in place (cheesy but effective). I also fitted short lengths of hose (usually fuel line) over the several spots where the hard lines were near the frame.

That said -- neither of those areas would seem noisy enough to produce the sound you're getting.

donbmw
05-07-2012, 10:54 AM
I have to check the bolts to my rear shocks every know and then. They will get loose and the shocks will move on the bolts and make a loud rattle whe hitting some bumps.

Don

DanB
05-07-2012, 02:15 PM
Good point, Don. I had a lot of trouble with those lever shocks too. You would think they were tight, but the holes would be oblong. Eventually one of the ears broke off. At that point I installed shocks through the coil springs, similar to Ratco's kit.

Dan B.
S. Charleston, WV
66 TR4AIRS EFI
80 TR7 DHC

donbmw
05-07-2012, 04:07 PM
I would change if a kit was aviable for the TR3

TR3driver
05-07-2012, 04:39 PM
Good point, Don. I had a lot of trouble with those lever shocks too. You would think they were tight, but the holes would be oblong.
Me too. But I seem to have discovered a formula that works, at least it did for quite a few years on my TR3A.

First, note that the SPC calls for a "Washer, plain, under nut" for the shock mount bolts. Likely that is an error, there isn't room there for the WP0036 washer that is called for. But I ground down some steel flat washers so they would fit in the space (only where needed, so they cover the full flange).

Second, I used metal-to-metal locknuts, instead of the nylon insert nuts ("Nyloc") specified. I discovered many years ago that the Nylocs would not stay tight if substantial vibration was involved (my driveshaft bolts kept working loose, even with new nuts & bolts), so I picked up a box of what MMC calls "Distorted Thread, Oval Lock with Conical top" locknuts. They haven't come loose yet!
https://www.mcmaster.com/#catalog/118/3199

Third, I ground down a 6-point thin-wall socket just a bit, so it would fit onto the nuts securely.

Forth, get those suckers tight! The book torque is 27 ftlb (+/- 1), but I use closer to 40. Haven't stripped any threads yet, nor have they come loose.

Alec
05-08-2012, 09:57 PM
+1 for tdskip suggestion on exhaust - if not enough clearance it will hit the chassis on the odd bump if there is sideways motion.