• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR6 Twitchy rear end

Share this page

John_Mc

John_Mc

Jedi Knight
Country flag
Offline
(Not itchy! That would be a different problem that I'd talk to my doctor about). As much as I love driving my '71 TR6, I feel like the rear end wants to jump around a bit too much. If I hit bumps in the road it really seems to be twitchy, and at times a little scary. Is this a lever shock issue, worn springs (I replaced them about 12 years ago), lack of anti-sway bar, or something else?
 
Could be bad trailing arm bushings as well...

Cheers
Tush
 
Not familiar with the configuration of this suspension, but I would not be surprised at bushings, a broken part or broken weld.
Bob
 
Rear springs and bushings were replaced probably 11-12 years ago (seems like yesterday) with standard BPNW springs and urethane bushings. Visually the bushings look okay. I can't see any broken points in the frame or elsewhere. What would I be looking for on the rear axle hubs? And how would I determine spline lock?
 
You can check the rear hubs by jacking up the rear of the car and grabbing a hold of the tire at the 12/6 and 3/9 to see if there is any movement. Spin and check for bearing noise as well..

Cheers
Tush
 
If everything else seems fine and you still don't like how your rear end feels in certain situations I would try a rear sway bar, I drove my car a little before I fit the rear bar, it went from squirrelly to planted, big difference.
 
"Twitchy" might be subject to interpretation but the rear wheels and tires are on the hub...
 
In my case the "twitch" occurs when accelerating and then lifting off the throttle which causes the rear end to move or yaw off center. The hubs have excess play (0.038) which I will be addressing by replacing the beairngs and adjusting the shim packs.
 
According to the mechanic who helped me with my front brake issue, he thinks it's my shocks. I have the stock lever shocks on. I disconnected them from the trailing arms and felt their movement and there seemed to be plenty of resistance (versus gurgling or sucking sounds that i've heard/felt in the past) but I suppose they could still be providing less resistance than is needed. I should replace/refurbish them, or consider a tube shock upgrade. What is everyone's experience with shock conversions? Pros/cons? I've heard the warnings about the simple tube shock conversion that bolts directly where the lever shock bolts in, that the force can bend or break a weak crossmember. I'm wondering if anyone has considered fabricating a cross-brace that connects the two tube shock mounts. If a metal brace was welded to both brackets and arced up over the differential, wouldn't that reinforce the shocks considerably, thereby eliminating the risk of them tearing loose?
 
I have removed the heavy duty tube shock set up on the rear of my TR6, and replaced with the upgraded lever shocks because i was worried about the weakness of the crossember, but didn't realize these were not the cheaper type that are sold, and didn't really need to do the swap out. I am selling the set up since i already spent the money for the better lever shocks. If you haven't bought the set up for your TR6, i would sell them to you for $80.00, plus shipping. The tube shock set up sells for $259.00, at Moss, you can check that out. Thanks.
 
I wonder if your problem could be the known issue with the differential mounts breaking? I believe it is the right front that usually breaks first.
 
There are lots of wear and potential break items in the TR IRS. You also want to make sure the mounts for the rear trailing arms aren't loose and/or the frame to which they mount is not collapsing internally.
 
Twitchy : I am not sure what your car is doing. but some of the bugs in the IRS to 250 were fixed. thing like squat on take off from standing. Noise would be a good start with wheels off the ground and a good tug also. And as one said the dif. rods mounts can pull out also rubber mount could be bad. A quick check on alignment can be done with with a long stick checking between the stick forward and back against the tire there may be a slight toe in with car empty. I have seen the pivot to the frame pull out due to rust I added a extra plate to the frame for that reason the thin frame has tubes so the pivots can be tighten. The added sway bar can make the car run like a plate on turns. As for shocks pressings on the rear of the car it should go down and up once and what one of the three spring you have how far you can push the rear down. I put the heavy spring in and took them out poor ride. the book says 8 1/2 coils the size of you small finger. There is a lighter spring I think from the early cars. For me to soft. Empty car rear tires will be NEG and loaded maybe plus 1DEG positive for good road contact and turns. keep us up on what you find. And if you see Twitchy tell her I said HI HA HA Madflyer
 
Back
Top