odd vibrations

[beaver]

cheers guys, will def get onto sorting it out. the swing arm is only mounted to the car by the two 'shackles' at the front correct?

[Charles H]

Correct, but you will also need to undo the bottom of the damper.

[beaver]

where damper = shock absorber?

we call things different over here haha.

helicoil kits are rather expensive here, so might see what I can pick up a 2nd hand arm for (I know a few guys etc)

[Alec]

Hello Beaver,

they are called shock absorbers here also, however that is an inaccurate description of their function and damper is correct as that is what they do, damp out the spring oscillations.
Lecture over

I use a product called Recoil to repair damaged threads and I understand that they are of Australian manufacture and relatively inexspensive? http://www.afsrecoil.net/threadrepair/en

Alec

[beaver]

haha cheers for clarifying.

ive managed to track down some decent arms for $50 a side (which is about 20 pounds), so will likely end up replacing the arm rather then fluffing about fixing the threads

[Alec]

Hello Beaver,

the problem with second hand is that they may well have the same problem and you find the replacement also has stripped or weak studs.

Your choice but personally I would repair the ones you have?

Alec

[beaver]

Hi Alec,

Yeh I see where you are coming from. I will look into both options.

The guy who is selling them is a triumph nut and knew exactly what I was talking about when I talked to him about my problem. I have dealt with him before and he is genuine, but yes, they could also be weaker than normal.

[beaver]

well I found the time today to pull out both outer axles. the UJs looked in good condition (one was newer then the other), so I greased them and stuck them back in. havnt done a road test but I dont think this was the cause of the vibrations.

Im starting to think its not the back end now, as everything appeared in good nick. I have a theory that it may be the gearbox or engine mounts, so that is next on the list of things to check.

[beaver]

Right, digging this thread up out of the depths.

Since last time I have greased up all the UJs in the back end as well as on the prop shaft (Only one UJ on the prop shaft had a grease nipple), and I replaced two of the missing studs in one of the rear trailing arms.

So, the vibration still exists, BUT, it becomes a lot more apparent when the car sits lower due to having more weight/people in it. When im driving by myself its hardly noticeable, but as soon as I get a passenger or two in the back then it becomes more noticeable.

So obviusly in is being caused byt he non ideal operating angles of the rear driveshafts (caused by the car being a lot lower than standard to begin with, and then making it worse by having extra weight).

Am I correct in saying the only things that change when the car gets lower are then angles of the rear axles (which leads to changes in the angles at the UJs on each side). obviously the trailing arm will be moving as well, but this wouldst be a cause for a vibration in itself.

So im convinced that it is the 4 rear axle UJs. Come next pay check I will be ordering all nerw ons and fingers crossed it sorts itself out.

Cheers

[Jonathan Lewis]

Am I correct in saying the only things that change when the car gets lower are then angles of the rear axles (which leads to changes in the angles at the UJs on each side). obviously the trailing arm will be moving as well, but this wouldst be a cause for a vibration in itself.

Yes, and I think that you might be correct with regard to a worn driveshaft UJ not liking being articulated through an increased angle, having previously experienced this myself on another car (non-Triumph) with independent rear suspension.

One other point that might be worth checking (if you've not already done so) is for any signs of excess play or roughness in the rear wheel bearings - as the car sits lower, then the greater the camber will be on the rear wheels, which may possibly highlight any shortcomings in this regard.

Good luck!