TR4/4A TR4a [solid axle] rear twitch-iness question

[tdskip]

is twitch-iness a word? Anyway, I just pulled the rear dampers from the TR4A solid axle because my rebuilt ones from Apple arrived. I was convinced that the power on/off side step from the rear was because the rear dampers were bad.

While there shocks did appear to be leaking a bit, they still offer steady resistance.

So two question (three if you count twitch-iness - LOL);

1) How firm should they be
2) If it isn't the dampers, what should I be looking at? Leaf spring bushes?

Thanks!

 

[Don Elliott]

I had this feeling with my TR3A. On little dips in the road, the car would sashay up and down at the rear. I later found out that the 2 inner leaves on the rear spring on the RHS were broken. I found this out when I accelerated hard leaving a traffic light when the 2 outer leaves snapped. Luckily, I was only 7 miles from home and made it home slowly but safely. The irony is that I had driven to VTR in Portland Oregon and back and had driven 7200 miiles in 3 weeks. Luckily it happened only 7 miles from the end of my trip.

Check your rear springs.

Don Elliott, Original Owner, 1958 TR3A

https://mysite.wanadoo-members.co.uk/trebor/don3a_big.JPG
Photo - VTR 2001 5225 miles

 

[Geo Hahn]

is twitch-iness a word? ...I was convinced that the power on/off side step from the rear was because the rear dampers were bad.

Back in the 60's we used to call this "The Triumph Trot".

Can be reduced if the springs & shocks are in good order but I still get it a bit. You can actually get used to it and factor it into tight cornering, expecting the rear to dance around behind you.

 

[tdskip]

Can you guys take a look at the attached picture. This is the driver side rear shock link mounting point.

It looks like it has been worn to a larger size than it should be - it is certainly larger than the passenger side.

 

[Bob Claffie]

Two things to check are the springs shackles/bushings and the spring center bolts. Either could cause the random shifting. Bob

 

[tdskip]

So the driver side shock link hole being larger than the passenger side isn't likely the problem? I guess that is good since bushes etc are easier to fix than that!

I checked the leaf springs Don, but didn't see any breaks in the leafs.

Let me check the spring shackles again.

Thanks guys!

 

[TRMark]

That spacer block is aluminum so I am not sure how to repair it. If it were steel I would weld it shut and redrill the hole. Can the same thing be done with aluminum casting?

 

[trrdster2000]

tdskip, do you have wire wheels???? Check to make sure you have all short studs and thin bolts. This will cause your wheel not to seat completely to the hub. I don' think you can get all of the wiggley wobbley out, we had lots of fun autocrossing the 4A solid axle. The whole set up is a one of a kind and hard to find the parts. A good tig welder should be able to weld that hole up and redrill to the right size.

Wayne

 

[Twosheds]

Does it dart one way when you accelerate and dart the other way when you lift?

If so, it's possible that the rear axle is bent. Have the rear toe checked.

Here at The Soggy Bottom Facility, we have experimented with the effect of bent rear axles on The Dreaded TR Twichiness.

 

[Banjo]

My 66 solid axle would change direction when I got on the throttle. it was awful. I checked everything underneath, and diden't find much, but that car had so many problems I never got around to fixing the "throttle steer".
check the classifieds. I have a complete rear suspension off of another 66 solid axle for sale. make an offer.

 

[Don Elliott]

Maybe the rear axle is mounted crooked. Measure the distance from - say the rear shackle to the axle on each side to see if both are the same.

 

[NickMorgan]

I know of two TR4s where the rear axle was able to move slightly along the spring. The hole in the shock absorer plate below the spring had worn allowing the axle to move backwards and forwards. They both had to weld up and re-drill the hole in the plate to make it a tight fit on the locating pin.

 

[jessebogan]

I recently had a chance to diagnose this on a customers newly purchased TR4A. After checking all the usual suspects (spring bushes, u bolts, shockers etc.) I found that one of the axle tubes was loose in the diff. Upon close inspection, the pin that secured the tube to the center section was the culprit. Well, not the pin exactly, but the hole in the center section had worn oblong. This allowed the tube to move around. This car had pretty pronounced torque steer, and was leaking a little 90wt from the joint. The car showed no signs of ever being wrecked, it was just worn from enthusiastic driving. We replaced the rear with a known good unit, and all was well.

 

[tdskip]

Thanks for the info guys, and sorry for being slow in responding (vacation).

She does lurch hard when I get hard on/off the gas.

I have some checking and measurements to take based on every-one's feedback.

Thank you
Thank you
Thank you

(And I may well need to track down that axle for sale Banjo!)

 

[Banjo]

Good luck Skip. I'l be glad to do what I can if it comes down to it, but getting this beast from N.Y. to So Cal may be a trick (rather expensive at the least) I haden't seen your location before.
Lemme know if I can help.
Mine is an unrestored unit.I really should check it out this spring and see what it looks like inside.

 

[sp53]

The shocks should have enough resistance so that you cannot push them back and forth by overpowering them. They are pretty tough and they will pump up. I have never push on a brand new, but I have push on plenty. I just went through an interesting discovery with the help off Apple. What happened is that the Austin Healey shock and the tr2-3-4 are identical except the very tip on the Healey is bent out about 25%. The trail arm on the TR is exactly parallel to the mounting without the bend. Anyways, I just pulled the Healey arms off and put the TR arms on. I think the Healey arms might be harder to find because the guy at Apple wanted by mine. I guess I am not sure what you mean by a twitch. Perhaps the spider gears are freezing on the turn? The spider gears compensate for the different amount of turns the wheels make as the wheels turn, the outside wheel turns more in a tight turn. I do not think that whole being a little big is going to hurt anything. You could put some kind a washer set up on that and if that will not work I have got one of those somewhere.
Sp53