TVR Techncians (Tuscan)...............Help

[Jim Green]

Ok......... I'm no TVR Technician but I think of myself as a damned good amateur mechanic and started what should be a simple job which has turned into a nightmare due to the design and placement of the Propshaft Bolts on a Tuscan.

I've had a rear end vibration that comes in at 100mph + which I've been trying to diagnose for quite some time (Replaced both drive shaft assemblies, including CV Joints, Two new rear wheels, Front Wheels fully checked to make sure they're running true, All four tyres (which needed replacing anyway), a full balance & Alignment Check)and I still had the vibration. A few days ago I decided to have a concerted effort to find the problem. On close inspection I saw that one of the propshaft bolts (Propshaft to Diff) was loose, and on removing it I noticed that the shank on the bolt was not long enough to go through both the propshaft flange and into the diff flange. The shank part of the bolt was only as long as the thickness of the propshaft flange. This could allow movement between the two flanges, as the threaded part of the bolt given time, and the torque that its fighting would become worn in the diff flange, causing movement between the two. Which over time would dead to movement between the two and becomin un-centered, causing possible rear end vibration and a clunking on taking up and letting off power.

Cross referencing pictures of my old bolts and those offered by Clever Trevor, the difference can be clearly seen. The shank on my bolts is about half the length of those sold by Clever Trever. The car has always been serviced since new by the TVR Center, and there is no record of the need for the propshaft to have been removed since the car was new, so I can only guess that these have been in since it left the factory ......... Hmmmmm. So I decided to order a replacement set of bolts and replace all four. The loose bolt came out easily........................


My Old Bolt.........Notice the length of the shank.



New Bolts...........With what appears to be the correct lenght shank, which will go through both propshaft and diff flange to locate the two securely.


The other three bolts however............Don't want to come out ! ! !

Problem is that one of the chassis cross members is right in the way, just where you need to get a spanner to remove the propshaft bolts which connect the propshaft to the diff flange. "REALLY" Bad placement of either the cross member or the diff flange position, and the nuts don't allow a ring spanner to go over them, as they are almost touching the diff nose. Don't want to muller the nuts using an open end spanner on the nuts, and the bolt heads are exactly the same (Not sufficient space to get a ring spanner over them as they're tight up against the UJ Joint.
How the hell do you get around this................... ????

Edited by Jim Green on Saturday 7th February 04:37

[rev-erend]

I'm not familiar with the Tuscan but I'll ask the not so obvious question..

Have / Are the diff mounting bushes still OK and in place.

They have been known to fail and this could explain the access issue and also the vibration issue...

[Noisy]

I've had the prop off mine a number of times, I use a socket on bolt side and a open ended spanner on the nut, loosen or tighten the bolts you have access too, then turn the wheels rotating the prop so you can then access the next ones. Having a extension bar with the wobble head helps as well.

Paul

[Jim Green]

Thanks Paul.............. Out to the garage I go again ! ! !


30 minutes later = 2 bolts out. God what a pain though, even using snap-on tools (Which are compact and not overly bulky in design, and it's still a pain).

Edited by Jim Green on Wednesday 4th February 16:16

[rev-erend]

Noisy said:

I've had the prop off mine a number of times, I use a socket on bolt side and a open ended spanner on the nut, loosen or tighten the bolts you have access too, then turn the wheels rotating the prop so you can then access the next ones. Having a extension bar with the wobble head helps as well.

Paul

Yes - I have to use the same technique on my 450 SEAC..

Dont forget to mark the prop and axle locations.. it may only go back together in 2 of the 4 positions possible.

[Jim Green]

rev-erend said:

I'm not familiar with the Tuscan but I'll ask the not so obvious question..

Have / Are the diff mounting bushes still OK and in place.

They have been known to fail and this could explain the access issue and also the vibration issue...

I'll try and check these once I've done the Propshaft bolts.

If these do need doing then it'll be a job for the specialists. Car has only done 19k, but obviously don't know how it was driven prior to me getting it.

Previous owner said he'd never had it over 100mph, so wasn't aware of the problem or he'd have had it sorted, which I tend to believe as he spent a fortune with TVR Center keeping it in really mint condition. (A genuine money no object car).

Thanks for the advice.

Edited by Jim Green on Saturday 7th February 04:49

[rev-erend]

Another frequest failure item on the Tuscan is the engine mounting rubbers.. being so close to the manifolds..

The SC power replacements look very good - I've fitted a set to mine (£75 for a pair).

[Jim Green]

Engine mounts replaced for uprated item last year, so i've discounted that one.

OK........Thats a coffee and cigarette, so now I'll get back in the garage and try for the last two bolts. I can see now it's just a matter of persisting, and getting a few skinned knuckles and bruises. Also left some WD40 on them to give me the best chance possible.

Oh for my old M5....... She was so easy to work on......LOL

Thanks for the advice and encouragement...........Really Appreciated.

Edited by Jim Green on Saturday 7th February 04:46

[Noisy]

30 minutes for 2 bolts? What are you doing under there? Only took me 50 minutes to get the complete gearbox out I have always had the exhaust off mine though when doing them as was removing the gearbox too.

[Jim Green]

45 Minutes and 1 left............Arghh,

Taking the exhausts off would certainly have helped, and worth doing in the future for any similar work. But bear in mind the car is only a foot off the ground on axle stands so not doing too bad, bearing in mind the design.

Why the hell they didn't put the right bolts in at the factory amazes me.

Edited by Jim Green on Wednesday 4th February 19:15

[Jim Green]

All Bolts Out.........

Checked the bolts and there's a definate area of wear on the threads which would have been in contact with the diff flange, which would also indicate some movement between the two flanges. Looks like I've caught it before it started to enlarge the holes in the Diff Flange. The torque that they would have been fighing against is huge, so it's quite understandable that they would start to shift.

Hopefully the new bolts will be here tomorrow and she'll be back together. Weather that's the reason for the rear end vibration or not, it's certainly a job worth doing to prevent any failure in this area.

Using the correct bolts with the right length shank, it is the shank which prevents the two mating surfaces from moving and prevents any movement between the two flanges, not the torque of the nut and bolt. All the nut and bold really do is hold the two flanges tighly together and prevent any slackness between the two.

If you plan on doing this job.............. Just allow your self more time than you think, due to the awkward position of the bolts, due to the small cross member which prevent easy access.

Ideal Tools for the job :

3/8 Ratchet
6" Extension Bar (With Wobbly End
14mm socket (The less bulky the better...... I used a Snap On Short/stumpy Socket)
14mm Open Ended Spanner
Can of WD40, soak the nuts/bolts for a couple of hours before you start the job.

Put the open ended spanner on the nut which is at the diff end of the bolt, and use the Ratchet, extension bar & 14mm socket on the bolt head. Turn the prop shaft until you can get the socket on the bold head in the best position.

It is possible to do the job without removing the exhaust, but it would be alot easier with the exhaust off.

When you've done all of this, it's worth pulling the propshaft and checking the UJ Joints.

GOOD LUCK

Edited by Jim Green on Saturday 7th February 04:51

[rev-erend]

Jim - something else worth checking is the wheels ..

Have all 4 balances and while it's on the machine check that non have gone egg shaped .. you normally have to talk nicely to the fitter though (not easy I know )

I've found quite a few TVR alloys to have a slight oval to them.

[Funky Jo]

Yes these original bolts are worth checking. My 2004 4.0l S had the bolts replaced last year at 20k miles as well, after she had cracked appart one of the original (too short !) bolts when strongly accelerating in first gear (wow this is torque!).
It took a professional 3 hours to get the original bolts out, having to weld a nut onto the broken bolt etc....
Now everything is perfectly fix and stable.

[Jim Green]

rev-erend said:

Jim - something else worth checking is the wheels ..

Have all 4 balances and while it's on the machine check that non have gone egg shaped .. you normally have to talk nicely to the fitter though (not easy I know )

I've found quite a few TVR alloys to have a slight oval to them.

Not wheels..... I purchased two brand new rear wheels, for no other reason than I thought they were advertised at a good price, as they've now stopped making them without putting in a special order. Fronts are perfect as I had them both checked professionally (Put on a lathe and ran against a dti gauge. No Distortion all all.

Edited by Jim Green on Thursday 5th February 20:18

[Jim Green]

Funky Jo said:

Yes these original bolts are worth checking. My 2004 4.0l S had the bolts replaced last year at 20k miles as well, after she had cracked appart one of the original (too short !) bolts when strongly accelerating in first gear (wow this is torque!).
It took a professional 3 hours to get the original bolts out, having to weld a nut onto the broken bolt etc....
Now everything is perfectly fix and stable.

So my four hours to remove four bolts wasn't as bad as I though...........LOL. They're a total pain to get out due to their location, and that rear cross member put exactly below where you need to put your spanners totally kills any normal way of spannering them off.

[rev-erend]

Jim Green said:

rev-erend said:

Jim - something else worth checking is the wheels ..

Have all 4 balances and while it's on the machine check that non have gone egg shaped .. you normally have to talk nicely to the fitter though (not easy I know )

I've found quite a few TVR alloys to have a slight oval to them.

Not wheels..... I purchased two brand new rear wheels, for no other reason than I thought they were advertised at a good price, as they've now stopped making them without putting in a special order. Fronts are perfect as I had them both checked professionally (Put on a lathe and ran against a dti gauge. No Distortion all all.

Edited by Jim Green on Thursday 5th February 20:18

Excellent !

That really only leaves the driveshafts and prop as major sources of vibration ... unless it was a tyre ..

[Jim Green]

Both drive shafts replaced (200 miles ago) complete with new CV Joints, courtesy of Dom at TVR Power (Ultrafast Delivery)........ I think I've replaced everything now, so just need to refit the prop (Probably early next week now as I work weekends) and I'll update with the results.

I'm embarrased to admit I've spent a bomb trying to resolve the rear end vibration issue, but at least for my own peace of mind I know that everythings new at the back end. The added bonus of spending hours underneath it, is that now I know every inch of the chassis and I've cleaned and polished most of it. Guess thats why we have winters..........so TVR Owners can spend time getting ready for the good weather.

Edited by Jim Green on Saturday 7th February 05:05

[Jim Green]

Sorted.......... It seems like the reason for the rear end vibration was the prop shaft bolts not fitting correctly. I can only guess that over the 19,000 miles from new, the diff flange had started to wear on the threads on the bolts and the propshaft flange had started to move against the diff flange. Plus the fact that one of the bolts wasn't tight.

Had the MOT at Fernhursts yesterday, and she passed with flying colours, and the opportunity to stretch her legs on the way back (Private Road of course.........) I took her up to 130mph with no vibrations at all.

Sorted at last After replacing : both drive shaft assemblies including cv joints, 1 new rear wheel, two new rear tyres, prop shaft bolts.............. At least I have a new rear end now.