Winter Project - Titan LSD project

[CtrMint]

@James, I believe I installed the clamp correctly but something is clear amiss.    Also I don't believe the travel accounts for the offset in the wheel.

@Mrp, not sure it would be acceptable to send parcels to where we are, or whether we'd be able to gain access to them once delivered.  `I limped the car back from South Wales, I'm sure I can make it to Heysham without issue. 

[CtrMint]

A quick update.

The UJ didn't move at all, all the rotation is in the wheel is at the clamp joint.  It travels from say 12hr to 1hr maximum and only under significant torque such as the dry steering I've described and of course heavy load through a bumpy mountain pass .   I've just been and put fuel in for tomorrow's homeward journey and found the steering dead center again because I've positioned the clamp in the correct position by forcing it back.  

So annoyed with myself, I'm not sure how I've cocked up and ruined the our trip, will certainly have to chalk this one up to experience.  Oddly demonstrates why I have a desire for knowledge and the strategy with the diff as per what the thread is about.

[ChrisC]

For me a Titan owner, the strategy is simple, monitor the pre load and rebuild when the clutches wear out.  If you monitor it regularly you should be able to predict your diffs life and which winter to rebuild it.

I expect that to be about 4 year time for my car.

Apart from that regular spanner checks, that's about it.

[Shortshift]

"For me a Titan owner, the strategy is simple, monitor the pre load and rebuild when the clutches wear out.  If you monitor it regularly you should be able to predict your diffs life and which winter to rebuild it."

 

Unless it's the Belleville's or thrust washers that fail (as they do), in which case there's no gradual loss of preload to monitor and every chance of having shrapnel doing the rounds...

 

James

 

[ChrisC]

Well in that case, I can't believe I managed 2 seasons already without a problem. Thankfully I have had my plates and bellevilles in my own hands, less than a week ago.

Poor Mark, no strategy for you, until you pander to the haters on the internet.

[Shortshift]

"Poor Mark, no strategy for you, until you pander to the haters on the internet."

What a strange and uncalled for comment.

Good luck Chris (and Mark) with your Titan units.  Your experience so far, Chris, is certainly different from mine - but no hate involved.

James

 

[David_Long]

I've run Titans for nine years now with no spring failures. I don't want repeat the posts about springs I made in the previous thread, but put simply, if you read up on Belleville's website you'll find they operate well within design limits. The argument put forward about 100% deflection being bad is based on miss-reading / misinterpretation of the parameters  (and there's some evidence that the spring never reaches a 100% as it sits in a dome). The spring life relates solely to the ratio of total deflection to preload deflection. Excessive deflection after the preload deflection is lost is the main reason for failure. So if you keep the preload within limits there is no problem.

Edit to add:

''As a result of manufacturing processes, residual tensile stresses occur at d , the upper inside diameter edge, which will revert to normal compressive stresses when the disc spring is deflected by up to approximately 15% of its total deflection.The fatigue life in applications involving large numbers of cyclic deflections, will be drastically reduced by these stress reversals. For this reason alone, it is important that disc springs used in dynamic applications are pre-loaded to a minimum of 15% of their total available deflection.''

[Billy.Whizz]

#52. Mark at least you didn't cock up on thinking of safety first and carrying on thinking it'll probably be ok, so well done for that and I hope you get it sorted soon.

Bill.

[ScottR400D]

Yes, it's a shame it ruined your trip but a lesson learned. 

 

[7 wonders of the world]

David 

I suggest you fully read the information of the Belleville website as your post is wholly out of context, it appears to be you who is misresding / misinterpreting.

It clearly differentiates between 'Static' and 'Dynamic' applications, stating Dynamic applications should use springs conforming to DIN 2093 - as stated in paragraph 1.

https://www.bellevillesprings.com/disc-spring-selection-and-installation/

Helpful Tips For Selecting Disc Springs

1-If the application involves large numbers of deflection cycles, i.e. ‘dynamic’ application, or if the required forces or deflections are of a critical nature, we strongly recommend that you select from the range of disc springs that conform to the DIN 2093 specification.

 

The link to DIN 2093 is below

https://www.bellevillesprings.com/estimating-fatigue-life/

For clarity the last paragraph is copied below:

Rules of Thumb

1-The pre-load should be a minimum of 15% of available deflection
2-The maximum deflection must not exceed 75% of the available deflection
3-To improve the fatigue life, we can reduce the upper stress or increase the preload or both

Flattening of springs is acceptable in static springs used for instance in a self locking applications.

[CtrMint]

Just moving the conversation back to my level 

So far I've purchased;

• New diff including cradle.
• Top bolt & nyloc
• Spacers for the top bolt

besides the oil, is there anything else I should consider sourcing before starting?

Also any advice dismantling?

• Removing the prop-shaft bolts?
• A frame, and dedion, I'm assuming that all needs to come out.   Can I keep certain parts together?

Thanks

[David_Long]

Isn't that exactly what I'm saying. 'Available' deflection of a spring is 0-100%. 'Maximum' deflection is the maximum designed deflection in the system. "Maximum deflection must not exceed 75% of available deflection". It does not state were that deflection has to occur. It could be 25% to 100%. It says that the stress reversal of the first 15% are undesirable so it is likely to be in the range 15% to 100%. Nowhere does it state 0-75% is the only useable range, in fact they advise the first 15% as a fatigue risk. They state deflection to flat is safe. The 75% figure is mentioned to advise compression forces are less predictable above 75% avaliable deflection.

[ScottR400D]

If you don't mind DCL, I'll take my advice from someone with a proven track record. 
 

 

[7 wonders of the world]

Available deflection = cone height

Calcs are based on this.

[ChrisC]

Mark, as I said, did this week before fish & chip run, without a scratch to any component.

1. Loosen prop bolts
2. Drain and disconnect the rear calipers
3. Disconnect handbrake from the calipers 
4. Disconnect speed sensor and rear ARB
5. Remove the Ear / hub assembly as one unit each side. 
6. Remove Shocks, radius arms, A frame 
7. Remove rear ARB
8. Disconnect the dedion tube brake hose
9. Remove the dedion tube
10. Remove the tunnel cover (may need to remove a seat)
11. Discount handbrake cable from the handbrake.
12. Remove handbrake cable from the diff carrier
13. Remove the diff bolts and remove the diff. 

Don't be tempted to remove the wheel bearings from the driveshafts, you might end up needing to replace both, due to bearing fretting.  Leave what isn't broken alone.

New diff driveshaft seals will be included in any rebuild, so no need to worry about the seals, and if you kept the bungs that the diff came with you can also leave the oil in place.  (Maybe not if your posting it)

Remember you still have to refit it after, which from your blog looks like it wasn't the most pleasant of experiences, so worth consider when you determine your approach.

Still think this is pointless until you actually have a problem, but that's just me.  Would have loved to have been driving my car instead of tearing it apart, and putting it back together again under time pressure.

[aerobod - near CYYC]

There is enough space on my R400D to just remove the diff without removing the deDion tube, if you can keep it in place the rear calipers can also be kept on the lines, just need unbolting from the caliper slides and hanging off the spring. All suspension components other than the ARB and A-frame can be kept in place if the deDion tube stays in place. With the calipers, upgrading to the braided flexible brake lines also makes this procedure easier.

Depending on how the handbrake cable is routed through the diff carrier bracket, it may be kept in place, too. mine has a small notch in the bracket that I enlarged slightly so it is large enough for the cable sheathing to pass through, but not the adjuster, so I just have to slacken the adjuster for the cable to be free of the bracket. With the calipers, using the braided flexible brake lines also makes this procedure easier.

If you don't want to remove both deDion ears, you can remove the driveshaft on one side, lower the diff, then move it sideways to keep the other shaft in place. If you remove the left driveshaft, you don't even have to remove the speed sensor.

You do need enough space below the car to maneouvre the diff clear, though, about 500mm minimum, as the diff needs to be tilted almost vertically to clear the deDion before the input flange can be "unhooked" from the tube behind the driveshaft, so the new diff needs filling once in place. This is what it looks like just before diff removal in terms of components removed, I have always removed the diff with the carrier:

[Shortshift]

Mark - exactly as James (Aerobod) just above has outlined.  There is no need to remove the DeDion and several of the other components as suggested in one of the other threads.  There is no need to remove any interior trim!  Don't make it more complicated than it needs to be.

You seem to be missing the most important new/replacement parts on the list that you have provided; you will need new Schnorr locking washers.  And plenty of medium grade thread lock as well.

Whilst you're at it, you might as well add a magnetic filler plug to the diff.  Depending on the type of rear cover this may or may not need a bit of attention with a flat-face file to taper the outer surface to ensure adequate clearance to the DeDion and the brake pipes that are attached to it.

All of this, and more, is contained in the long-running thread on Titan LSD's that was started by Geoff Brown last winter.  I'd suggest you read through that and cherry-pick the content that is relevant.

James (Shortshift, not Aerobod)

 

[CtrMint]

Thanks, I did read Geoff's thread but to be honest forgot about it, I'll go back and reread.  His thread and guide also pointed out the magnetic plug, I've already sourced two from DemonT, the gold AP-22 ones.   

I'll get the Schnorr washers on order also, I might order all the hardware around the diff and prop just to be sure.  I did consider the flexi brake hoses sometime ago, I guess I might as well now.

For what its worth I've also reached out to Simon Rogers, since I'm stripping her down, I'm going to uprate the suspension.  The suspension doesn't feel anywhere near as good as the 620R suspension.  Might as well do that lot.

 

[Geoff Brown]

Any parts you remove always clean & inspect thoroughly. Check bolt shanks for any in service fretting especially the forward A Frame attachment bolts. Even with the low mileage best to inspect & replace if necessary.

Don't forget new Schnorr washers though you can reuse only once more.

New spring washers a priority.

Nylocs can be reused if they pass the turn down test. Using fingers wind down on to a bolt. If the nut tightens & stops before the bolt is through then reusable. Flush with top of nut is the extreme but no more.

You can remove the diff without dropping it complete with support frame. The DD tube can stay in though it is a tad tight to clear. If your car was longer in the tooth (8 -10 years) I would suggest removing the DD tube to closely inspect every aspect. So don't bother.

Everything else is in 'THE' thread ! 

[7 wonders of the world]

Forget replacing the spring washers - they serve no locking purpose at all, bin them.

Schnorr, Nordlock or suitable threadlock on applications where no self locking nut is used.

[CtrMint]

what about aerotight nuts?

https://accu.group/fr/46_aerotight

[ScottR400D]

Not really necessary. As said above don't make it more complicated than it needs to be.  It's really not rocket science!

 

[7 wonders of the world]

Nylocs are perfectly fine for all your suspension, 

Philidas are great if there's heat involved as theres no nylon to melt.

 

[L66TEY]

Hi Mark,

I look forward to following this thread on this and reading the blog - especially as I expect I'll need to give my Diff some TLC very soon in light of it getting a bit clunky during Monday's track day - albeit only at low speed and usually upon returning to the pits after some so called hot/fast laps. 

At this stage I remain to establish what Diff is fitted to my 2010 R300D

Could any of you far wiser Caterham owners on here please help me with this Diff identification?

With thanks

Chris

[CtrMint]

there's a bit of scope creep going off at the moment 

I'm now doing the diff, braided rear lines, and a suspension upgrade, also need to fit the CC rear LEDs.  Undecided whether I need to fit the gearbox spacer at the moment. 

Following the recommendations provided, I've source every single piece of hardware, nut bolt and washer that's associated with the diff, A frame, dedion and suspension, basically rearward of the passenger area.  Plan is to replace every one, any that can be reused will be stored for emergencies etc, 

All will be covered here in detailed and on the blog.