Torsion bar ears spline wear?

[chrisallen01]

Hi All,

I'm getting a "clonk" from the near side front (left) when the suspension loads up going round a bend and another clonk when the suspension unloads after the bend and settles back, now having checked/replaced the ball joints and suspension bushes I'm wondering if it is wear on the splines of the torsion bar ear on the left side of the reaction plate as this seems to be where the noise is coming from. Has anyone any experience or seen spline wear in these ears? any and all suggestions as to the potential cause of the clonk will be most gratefully received and welcomed.

[Mich7920]

Hi Chris,
Difficult to think of wear on the splines of the torsion bar ear, it doesn't move so no friction.
I also had a "clonk" in front when I arrive into a bend and for me the solution had been to change the bushs of the anti-roll bar.
Simple to find if it's this. dismount a link between anti-roll bar and wishbone and unscrew a little the nuts of the anti-roll bar brackets.
Drive the car as normaly and listen.
Mich

[Tom W]

Wear in the torsion bar causing a clunk is unlikely. The torsion bar is always somewhat twisted, even at maximum suspension droop. So you never actually see a reversal of load on the splines, just a change in magnitude.

[Moeregaard]

As Tom mentions, the torsion bars will always have a pre-load on them, even if the car leaves the ground. I suspect your clonk is coming from the bolt that serves as the lower damper mount. The bolt and its nut capture the two pieces of the lower A-arm, as well as the steel shock bushing, which often seizes to the bolt. Through some mysterious force of nature, the bolt loses its tension and you'll begin to hear clunking coming from the front end of the car when passing over minor bumps. Simply replace the bolt, nut and bushing, and lather everything with copper grease during reassembly. You clunk will most likely be a thing of the past. When I restored my '65 FHC, the bushes were in short supply, so I turned a pair from #302 stainless steel, but I believe they are available now.

Other sources of clunking in the front end can be worn steering-rack mounts, worn tie-rod ends, or loose ball joints where the tie rods join the steering rack. Any of these require immediate attention. A final possibility is that your rubber bonnet buffers are worn or missing, leading to yet another mystery clunk at the front of the car, but I'll lay odds that the noise is coming from one of your lower damper mounts.

[Mich7920]

As usual, a "clonk" can come from a lot of places.
This car is a box of resonance !
Proceed by elimination to find the proper solution.

[abowie]

As above, the splines shouldn't be able to wear. The teardrop they attach with, however, can certainly move if the bolts are loose, missing or have worn. Worth checking them.

My money's on the clonk coming from your front suspension somewhere.

[chrisallen01]

Clonk sorted !

My thanks to Mich, Tom, Moe, Mich and Andrew for suggestions. Front Anti roll bar disconnected made no difference but well worth the trip around the block to try. Then I remembered that last time I had the engine/gearbox out I replaced the 1/2" bolts/nuts holding the reaction plate to the chassis rails and hey presto the nyloc nut on the nearside was not tight, so much for self locking nuts! now replaced with a split washer and ordinary nut and I'll be replacing the 2 bolts/nuts holding the ears to the frame soonest as well.

Thanks again Guys.

[Mich7920]

Great!
The most important is that you find the solution.
Finding a " clonk" can becoming a nightmare.
Mich

[Series1 Stu]

Chris,

For info, Nyloc nuts, or prevailing torque nuts as they are more accurately known, are most definitely NOT self locking! That is a dangerous assumption, as you potentially discovered.

Nyloc nuts simply provide an interference on the thread that helps prevent them rattling off under vibration. You still must tighten them to the correct torque value, which is usually the standard figure plus the prevailing torque figure.

Regards