Wobble??

Steve68

Active member
My 67 Custom 240 drives so well, it's smooth as silk and a real pleasure to drive. But......it has a very strange rear end wobble at 60mph. It's the same with standard wheels and my new set, so unbalanced wheels / damaged tyres are out. I knew my rear shocks were a little tired so I've replaced both rear shocks, all rubbers, and bottom mounts, but still, the wobble is there. I'm not sure if it's actually a wobble or a hop but if I'm driving alone the passenger seat back shimmies back and forth really quickly. There are no strange noises or anything else untoward, only the wobble. If I get to 65 the whole car seems to shimmy. It's not a massive shake like I'm sitting on a washing machine, it's just a small but quick wiggle. (If that makes sense.)

Is there any reason why the propshaft would go out of balance? (It's a 3 speed manual.) I have noticed that clutch take up isn't as smooth as it was (slight judder), could this be the prop UJ's? And could they possibly be part of the issue?

It's such an annoying little problem that I can avoid easily, just cruise at 55 :) But sometimes it's good to get past those never-ending lines of lorries in the slow lane and I worry I may be damaging something with the wobble/shimmy.

I'm about to put her away for winter but I'd like to get this issue sorted if I can so I don't have to worry about it next season.

Thanks all,
Steve.
 

B RON CO

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Hi, most u joint failure seems to show itself when the trunnions clunk against the caps. It is possible for a u joint to feel OK during a quick check but if you remove the driveshaft you may find that there is binding during part of the travel. If the u joints prove to be good, I would safely set the rear axle on jack stands and run it in gear. Then you can watch the driveshaft spinning and may see something wrong. Another possibility is the rear bushing in the tranny, but if that is worn you would probably be leaking tranny fluid. Good luck
 

bubba22349

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X2 on the U Joints and the Trans tail housing bushing is a good place to start. Driveshafts don't go out of balance in normal use however if the shaft got bent even just a little from being hit or driving over something that would cause this kind of issue. Good idea to test it on some good jack stands as BRonCo suggested or you can use a dial indicator on a magnetic stand to check the runout at the front, the back, and the middle of the driveshaft for compareision. Another thing to check is the rear axles control arm bushings and the panard bar bushings. Also check the body to tire clearance on each side and the angle of the panard bar to the ground with the car setting on some level ground. Good luck
 

InlineDave87

Well-known member
Have you looked at the drive shaft? It could have lost a balancing weight at some point… or have you even checked to see if your axle is straight? Maybe if one of the axles is slightly bent i could cause a wheel to wobble at higher speeds
 

Steve68

Active member
I've not had a chance to get under the car due to work commitments but I took the car for an oil change Saturday morning. On the way home I took the car up to "wobble speeds" while going downhill, then lifted off the throttle but stayed in top gear. The wobble turned into what felt more like a vibration and definitely felt as though it was making its way through the middle of the car. So hopefully this week I will have time to check the UJ's and update you with my findings.
 
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