That was a year that was..

[Mk2 Chopper]

Great write up (and pictures) of how these fit, they do look good, I'm sure they'll perform well too, awaiting your first test drive. 

Gareth

[MilesA]

On 11/21/2022 at 4:34 PM, Mk2 Chopper said:

Hey some progress and at least you have the ultimate drive shafts to go on next. 

Did you have new rear hubs to go on too I can't remember? I would certainly get the wheels balanced again and also change the front bearings as that's a fairly easy thing to do after you've switched the drive shafts. 

Fun these old cars eh. Bet you'd find mine quite a rattly,  noisy drive trained car, I'm just used to it. 

Gareth

The other pictures from my trip:

Denbies Gareth?

Miles

[Mk2 Chopper]

20 hours ago, MilesA said:

Denbies Gareth?

Miles

Yes Miles, in for two cups of luke warm coffee. 

Gareth

[Bfg]

On 11/23/2022 at 7:30 PM, Bfg said:

I had hoped to fit the other side today, but a neighbour had issues with his car's headlamps, so I've postponed fitting the RH side until tomorrow. 

^^ this didn't happen because a friend who lives on his boat down at Fox's marina called up to go for lunch.  At first I declined the invitation but then thought that he sounded as if he needed to have someone to talk to.  We had a good roast-turkey lunch at the Swan, in Westerfield, and good conversation. 11 hours later and one too many coffees, it was late night and so no second half-shaft on Katie .  Missed my local (East Saxons) TR group meeting in the evening, but that's just the way it goes sometimes.

Today, was cool but sunny here on the east coast, and natural light makes working on, and even under, the car much easier. . .

^ Fitting this was very much the same process as on the left side ; with wheel and brake drum off, old shaft removed, new half-shaft's hub removed, and the ferrous metal parts coated with clear lacquer, the spline and thread protected - it was ready to fit.

The only difference to fitting the half-shaft into this side of this car was the exhaust pipe. . .

    

^ Fortunately Katie  is fitted with a nice n' quiet exhaust system - a single pipe running back to the cross-box-silencer under the spare wheel well. But still, the hole to feed the half shaft through was not quite big enough. Happily with the silencer's RH exhaust clamp removed, and supporting strap released, I could prise the pipe down enough just enough to squeeze the half-shaft through.  It did lightly scratch the shaft's new clear lacquer, across the black adapter piece - which is about 4mm larger in diameter than the flange, but thankfully the shaft went through without further dismantling of any other component. 

   

^ the mating face of the brake's back-plate was a bit cruddy (..perhaps that reddish layer was hand painted red-oxide primer).  I scraped that off so the hub's flange would mate onto a flat surface.  Then it was just a matter of my wiping moly-lithium into the spline (carefully not onto the thread) and dropping the hub back onto the end of its shaft.  As said before the six 5/16" UNF nylocs (1/2" AF socket) are tightened to just 16ft.lb.   I didn't use Loctite on these threads, but I did on the diff flange nylocs. . . 

^ with the exhaust clamp back in place and the exhaust shoved around to make sure it cannot reverberate against the chassis (particularly where it goes through the tunnel and I have additional T-shirt plates), and the job was almost done. 

Brake drum and wheel back on, and the car lowered to the ground, I tightened the outside hub nuts to 212 ft.lb.

Inclusive of scrabbling around on the floor, stopping to take photos, removing the car off the four car-ramps, and putting the tools away - this side to took me about 2 hours to exchange.

- - -

Test drive - down the A14 wasn't at all comprehensive because of its traffic on a Friday afternoon, however from what I might ascertain . . . 

• Town speed driving, getting to n' from the dual-carriageway through housing estate and a slow stretch of major trunk route, revealed the drive-train to be discernibly quieter and smoother than before, most notable through roundabouts and tighter turnings.
• On the dual-carriageway itself though - I'm just a little disappointed to report that Katie's  resonant-type vibration persists between 60 and 70mph ..peaking around the mid 60's.  At all speeds she's now smoother than I've yet known the car, but only below 60mph and at 70mph and above is she smooth.

I still have a few more thing to do, not least to rebuild the front suspension, adjust the front's height, and to replace those wheel bearings. I noted today that the front-right wheel bearing is a little too loosely adjusted, and that in itself may contribute to some vibration. I also want to swap the old rear-brake-drums for the lighter-weight Alfin ones. 

So more tasks, and therefore more reports , yet to come !

- - -

My primary concern, in spending the money on these shafts, was not one of vibration, but of a hub failure - after so many have been reported. Eradicating spline lock-up was a big bonus, and then smoothness is ..well a dollop of fresh cream on the top.  In respect of the hubs, I'm pleased to say that I'm very-much-more confident (without the disconcerting clunks of the splines) to power-accelerate around roundabouts and tighter corners. 

Happily I'm getting close to being able to drive  the car as she was designed to be used on the road. 

The half-shafts I've just taken off ?  There's little or no discernible amount of play in those UJ's or splines, nor indeed in their wheel bearings. The UJ's are floppy though, and I suspect that with new UJ's and the splines freshly greased with moly-lithium - they would have been much smoother and quieter too.  New hubs could have been bought separately. 

CV joints or UJ's .?   By design, a pair of CV joints ought to offer smoother telescopic-articulation than a spline & UJ's  ..of comparable quality.  The CV joints used on these half-shafts are physically very small though, (by necessity ..to fit within the confines of a TR).. compared to the few front-wheel-drive ones I've had prior experience of.  They are mass production items and I've put my money on trusting that they'll be fine for the power I might ever put through them, even when driven hard and with the car loaded.

Although the original UJ half-shafts have already lasted a handful of decades of reliable use, I decided against buying a pair of uprated UJ half-shafts with coated spline. I guess I was enticed by the prospect of smoothness.   You pay's your money . . . etc

Pete

 

 

Edited November 25, 2022 by Bfg

[PodOne]

Evening Pete

Great write up as ever and glad the CV shafts have met your expectations other than the continued vibration at around 60mph. You seem to have covered the most likely suspects. Just a thought and given its a large rotating mass I wonder if the flywheel/clutch cover has been unbalanced or haven't been balanced and one or the other isn't quite seated flush to the crank or flywheel ? When it occurs have you tried dipping the clutch to see if it remains unchanged.

I grant you its a real pain to check and I hoe a simpler cause is found. 

Another thought is the engine mounts and the mounting points any cracks?

Andy  

[peejay4A]

Re possible concerns over the size of the CDD CV joints, the ones on my XJR were smaller and they handled around 400 hp without difficulty. 

[stillp]

When I first put my 4A back on the road it had a similar vibration - fine below 60 or at 70. It disappeared when I found that I'd forgotten to tighten one of the 4 bolts on the rear of the propshaft. I was surprised a loose bolt could cause a vibration, after all it's the same weight whether tight or not, but when it was tightened the vibration disappeared.

Pete

[Bfg]

Thanks Peejay,  that's reassuring to know. 

As I said my own experience with CV joints is very limited to those on my Chrysler Voyager and on the A-series Citroen .

For those who have never seen the guts of one, below are some photos of my refurbishing those on the Citroen (602cc - 1200 cc / 24 to 60 bhp) which were quite a bit bigger than those I now have on the TR . . .

Pete

 

 

Edited November 26, 2022 by Bfg

[Mk2 Chopper]

So why are they better than a UJ and sliding drive shaft? 

Gareth

[Lebro]

Main difference is that a CV joint does what it says on the tin - even at an angle the output shaft rotates at the same velocity as the input shaft all the way round, whereas with a UJ the output shaft will speed up, & slow down as it rotates. As long as you have two UJ's in the drive train, & they are assembled in the right orientation, the the net result is "constant velocity" but the bit inbetween them (the propshaft for instance) is performing as said above.

Bob

[Trumpy]

Great ‘tutorial’ on drive shaft fitting. Thanks Pete . 
Thought I would fit mine today , on my shiny extended ramp . ( Que smugness) 

 

All went exceedingly well , even a last minute dash to Rimmer’s for some new 5/16 nylocks. 
One side completed and just torquing the very last bloody nylock when it kept going and sure enough the stud pulled out of the alloy housing ! 
I’ll have to get an upgraded stud from CDD next week I guess 

 

[Bfg]

 

21 hours ago, Mk2 Chopper said:

So why are they better than a UJ and sliding drive shaft? 

Gareth

As Bob says, a universal joint's output shaft will speed up & slow down as it rotates.  Two UJ's correctly orientated and with their input and output shafts parallel to each other will balance this phenomenon out. Then the rotation of the output shaft will be constant to the input shaft (in this scenario - only the intermediate shaft's velociy varies as it rotates).  There are youtube animations which help illustrate this ..much better than most of us can hope to explain in writing, but it's because the loci swept by the angled intermediate shaft's bearings is an ellipse ..relative to the axis of the input shaft.

The problem arises when the orientation between UJ joints is not so good.  It's pretty easy to sort out for a prop / driveshaft where the gearbox and the diff are pretty close to being fixed locations and at set angles to each other (aside from slight distortion in their mounts), but when one UJ is fixed in position and the other articulates at constantly different angles as it swings through an arc ..whose pivot axis is set at a peculiar angle (such as is the scenario with a trailing arms of our TR ) then the speeding up & slowing down "balancing-out" is far from perfect. 

In practice, inherent slack in the drive-train and flex in the tyres usually make it indiscernible - but it is still there ..and it can trigger harmonic amplification at certain speeds, especially when the hub end is bolted directly to a hollow-box trailing arm, and that has a coil spring on it which reverberates back to the chassis.

 

You also mention the 'sliding drive' or spline of the UJ half-shaft. . .

Splines are parallel deep ribs ..with a good amount of surface area along their length to take the full torque of the transmission to the wheel.  But when the spline is under this huge amount of torque - it's also expected to quietly & smoothly (telescopically) slide in and out.  Most obviously its failing to be quiet or smooth happens on tighter corners &/or when a lot of power is applied.  The torsional force being transmitted through those splines is enough to squat the rear suspension (compress the suspension springs more than two heavy people, an overloaded boot, back seat space, and a full tank of fuel !) ..and at the same time ( in tighter corners ) the car rolls ..which extends or compresses the suspension even further.  As the suspension extends or is compressed - the distance from the hub to the diff flange changes, and that spline has to slip in or out.  Coated splines work, as of course does high-shear lubrication (on the bare metal splines) - but old worn splines, and those where the coating or lubrication is passed its best ..well their telescopic motion locks up, and then is suddenly released with a disconcerting clunk and a change in suspension height &/or momentary loss of tyre grip.

The problem with many splined joints is that they are generally not been designed & made with adequate lubrication points (..and where they have - few owners use them ! ).  A positive attribute is that they are so crude and generally robust that it takes 50 years to wear them out. They will clonk for thousands of miles yet.! 

The CV jointed half-shaft doesn't have this telescopic splined joint (the sliding / length differences are accommodated in the CV joint itself). . .

The problem with CV joints is that the telescopic action happens as the needle-rollered balls slide up & down in their grooves. The balls offer a tiny contact area, which is really great for minimal friction, but not so good for longevity.  Like any joint they will wear through use.  CV joint grease (high pressure & high shear) and it being enclosed in a sealed gaiter really helps, but at some point they will begin to clonk, and in time will likewise have to be replaced.  And that replacement is usually as a driveshaft-assembly rather than just (as in the case of a UJ joint) the cruciform and four bearings. 

In my own case - I'm too old to worry about when the CV joints might next need replacing.  

Pete

 

 

 

Edited November 27, 2022 by Bfg
added for clarity ; (in this scenario - only the intermediate shaft's velociy varies as it rotates).

[Bfg]

39 minutes ago, Trumpy said:

All went exceedingly well , even a last minute dash to Rimmer’s for some new 5/16 nylocs. 
One side completed and just torquing the very last bloody nylock when it kept going and sure enough the stud pulled out of the alloy housing ! 
I’ll have to get an upgraded stud from CDD next week I guess 

Allow yourself a little smugness - you've earnt it

I look forward to very soon  seeing your planned improvements to the crossbeam under-chassis supports you used to use ..in place of the only-just-on axle-stand and trolley jack.

...  It clearly works as a great bench to lay your tools out on too !

Undeniably.. I have green ramp envy !! 

 

Sorry to hear that a stud's thread pulled out of the trailing-arm.  Personally I'm likely to say that they're a **** design with too fine a thread into the aluminium, but as they've lasted this long - I guess they got it just right !    Only 16 ft.lb of torque, which I easily exceed even with my little (just 4" handle) ratchet.

I presume you don't have a helicoil kit to hand.?  

Pete

p.s.  please don't forget to cover the spline to prevent grit ingress as you repair that thread. 

 

[Trumpy]

Haha , yes the axle stand does look a little precarious in that pic although the Jack is fully on the ramp . A decent jacking beam is next on the plan . 
I have a helicoil set but metric of course. It would helicoil to 8 mm but it’s a shame to mix threads . 
I have got a Unf tap/ die set though . 
I see CDD only advertise the upgraded studs in sets of 16 which is a bit excessive if I only need one . 

[Mk2 Chopper]

Thanks for all the explanations regarding uj's and sliding shaft verses cv joints. Makes a little more sense and particularly how suspension travel affects it. 

Gareth

[RogerH]

19 minutes ago, Trumpy said:

Haha , yes the axle stand does look a little precarious in that pic although the Jack is fully on the ramp . A decent jacking beam is next on the plan . 
I have a helicoil set but metric of course. It would helicoil to 8 mm but it’s a shame to mix threads . 
I have got a Unf tap/ die set though . 
I see CDD only advertise the upgraded studs in sets of 16 which is a bit excessive if I only need one . 

Hi Trumpy

I have the 5/16th UNF helicoil kit if you want to borrow it.  PM me your address. It'll be there by Tuesday

I have used the original axle system and never had a problem.   Indeed you need to maintain it, but it is an old car.

 

Roger

[RogerH]

Hmmmm.   Having read the above explanations I am now perplexed, confused.

The term Constant Velocity also applies to a UJ - if the input does 1000 RPM so will the out.   Otherwise the propshaft will get rather twisted

What can happen is that the UJ angular loading may apply forces to the UJ and possibly slow that RPM. The force depending on the angle.

So at what angle does any force become a concern !!!!

The CV joint does not allow these forces to take place so and RPM fluctuation caused by these forces does not happen.

But!!!   is it noticeable, is it a concern.

It is to the supplier as there is plenty of profit going round. Cynical me.

Perhaps the correct term for a CV joint should be Constant Force

Roger

 

[ed_h]

2 hours ago, RogerH said:

The term Constant Velocity also applies to a UJ - if the input does 1000 RPM so will the out.  

 

I think you know this, Roger, but for completeness--

UJs only exhibit constant velocity in pairs, and only under certain conditions of orientation.

Ed

[RobH]

2 minutes ago, ed_h said:

UJs only exhibit constant velocity in pairs, and only under certain conditions of orientation.

...and Constant Velocity refers only to the input and output shafts. The intermediate shaft linking the joints is subject to cyclic velocity variation and the amplitude of that variation is proportional to the shaft angle. (i.e. it is zero only when the assembly is in an exact straight line).

[Trumpy]

12 hours ago, RogerH said:

Hi Trumpy

I have the 5/16th UNF helicoil kit if you want to borrow it.  PM me your address. It'll be there by Tuesday

I have used the original axle system and never had a problem.   Indeed you need to maintain it, but it is an old car.

 

Roger

Thanks for your generous offer Roger , I’m going to test try an 8mm helicoil with a unf tap and stud as they are probably the same ,  if this fails I’ll report back and a 5/16 coil would be great thanks . 
Dave 
 

[RogerH]

Hi Dave,

do not cut/tap the hole until you are sure. There is room for second chances.

My kit could be with you by Tuesday(ish)

 

Roger

[Bfg]

1 hour ago, Trumpy said:

Thanks for your generous offer Roger , I’m going to test try an 8mm helicoil with a unf tap and stud as they are probably the same ,  if this fails I’ll report back and a 5/16 coil would be great thanks . 
Dave 
 

The studs tapped holes into the thin walled rim of the trailing arm are very close to the edge.  Even though you imply that you'll do a test try (..not into the trailing arm itself) - Roger's offer is very generous, and expedient - I urge you to take it Dave.

Try a 5/16" bolt in a 8mm nut and you'll see that they are not  probably the same.  Then you'll be obliged (by the size of the 8mm threaded helicoil's hole you've made) to go up to the next size ..by buying a set of 16. 

Pete

[harrytr5]

Listen to Uncle Roger he knows best!

Regards Harry

[PodOne]

 

5 minutes ago, harrytr5 said:

Listen to Uncle Roger he knows best!

Regards Harry

+1 Was in the same situation and benefitted from Rogers tooling to resolve the issue. 

[RogerH]

Not Necessarily. 

I am searching for the bottom line.

 

Roger