Winter Project - Titan LSD project

[ScottR400D]

2015 420 Titan, about 10k miles. Bought from CC at 8k. 

[L66TEY]

#99

Hi Dan,

The odometer says 18k (albeit due to the speed sensor not being reliable at times eg above certain speeds) - I suggest it's higher, say 20k.

However, I have paperwork from previous ownership that refers to a labour charge for "Diff removal/refit" in 2014, but no details of whether this was a rebuild or potentially a Diff replacement.

I've not got the car jacked up and have commenced with the dis-assembly.
Looking forward to removing a drive shaft and using the guide below to identify the Diff.
Credit to Angus Davidson for his fantastic website;
"Building a Limited Slip Differential" https://www.mycaterham.com/66828/117416.html

Chris

[CtrMint]

Hi

Out of interest why did you take it?  What was the general noise like before discovering this?

Thanks

[ScottR400D]

Who's the question for, Mark? 

[CtrMint]

yourself sir.

[ScottR400D]

Fair enough! The car was bought with a noisy diff. CC said it was OK but I'm told it was unacceptable.  Then the car was exhibiting unsettling behaviour on the road so it was taken out and replaced with a Tracsport after finding it like this. 

It's owned by someone who posts on here and who's taken the process further than most of us making comparisons with open diffs and gathering info from other owners. A pretty competent owner who is determined to understand exactly what's going on.  I'm sure he'll contribute if he wishes to. Unfortunately he has told me of friends with similar issues too. 

There is a chance of some duplication here, there are so many diff threads and 'tales of the unexpected' it's easy to lose track but I'm pretty sure these images are new here. 

[CtrMint]

it's all a bit unsettling, a complete failure could lock the rear axle and cause serious harm.  I'm glad I'm sucking up the cost and dropping mine out after 5k.  It will be interesting see what sort of state it's in.

I've got everything now, diff, plus complete bolt packs for the rear suspension and axle, along with the braided brake hoses kit.  I'm also trying to sort new suspension through Meteor also, figured I might as well upgrade that too.

If I can use up the half tank of fuel tomorrow I might get cracking on my tear down too.  Sadly the fuel in the car is a mix of E10 and E5.  Following CC's recommendation i don't want to leave it with E10 for any length of time.

 

[ScottR400D]

I don't think the risk of a full lock up is too great, though I wouldn't really know. This one is the worst I've seen to be honest and still the bits were well contained. It was beyond repair of course. 

Have another. 
 

[ScottR400D]

I think the worst that would happen is that the LSD would lock up solid so corners might present a challenge! 
 

[L66TEY]

#108

Peter,

Is that from a sintered or carbon Diff ?

Chris 

[Nigel B]

It's a carbon plate diff, by the looks of things. It's a good effort, I though mine looked bad when it was pulled apart! 

[ScottR400D]

Yes, carbon. 
 

Well it was........ 

[aerobod - near CYYC]

Re #108, Peter, a couple of possible differences compared with my Titan.

1. The surface that the inside of the Belleville washers rests against seems to be flat as opposed to domed on mine, allowing 100% deflection, compared with 80% or so on the domed ends of mine.

2. The thrust washer for the side gear that is exhibiting heat marks doesn't have oil grooves in it, compared with mine (unless it was fitted backwards).

 

[David_Long]

What is interesting from the photo is that the BMW crown wheel is smaller compared to the Sierra. There appear to be 8 bolts on the BMW and  there are 10 on the Ford, The BMW crown wheel is also recessed further back (I guess to get the crown wheel in the correct position), but the net result is a smaller diameter LSD casing in the BMW version. Although torque delivered to the wheel will be the same, it does suggest that the BMW is a higher stressed CW&P than in the Ford Sierra (ie the CW&P gears are smaller).

[ScottR400D]

#113 James, that's interesting though I couldn't begin to explain why there would be differences. This is a 2015 car and those, as far as is known, are the remains of the diff as it came from the factory. 
 
IIRC your car is older than this one? So, assuming that the parts you received for your rebuild were similar to those you replaced does this imply that there were more design changes made than just the plates, at some point, which may or may not have been reversed now?

 

[ScottR400D]

#114 David, certainly with the Tracsport LSD the BMW version is slightly smaller than the Ford version. 
I understood that the Titan was the same size in both, and that the rebuild kits are identical but that may not be the case?

Can anyone confirm that? 

 

[David_Long]

The clutch and plates are billed as being the same in both BMW and Ford, but when I ordered parts, I was asked which diff I had, read into that what you like.  The Sierra version also has no holes in the top bearing carrier. 

And the there are some differences to the bushing at each end.  Whether this one has domed thrust surface for the Belleville spring is difficult to tell (I didn't check at the time) but the photo does not exclude that possibility.

[ScottR400D]

Just to throw another thing into the pot this is what I've been told, I have no first hand knowledge, though it makes some sense:

The back plates of the original BMW housings were shaped to direct oil, flung from the CW, towards the front of the housing and onto the pinion and it's bearing. The CC backplate is not so shaped and there's a risk of the pinion and bearing being starved of oil under acceleration so the higher, 1.2L of oil, recommendation that was in place until a few years ago might well be the better option. 

I'd have thought that the CW would throw oil off at every point so the pinion and bearing would get it's fair share but I'm not particularly familiar with the internal arrangement in this respect. 

I'm not aware of pinion or pinion bearing wear being an issue so this may be a red herring but I found it interesting. I've never suffered from driveshaft seal oil leaks (famous last words?) so may revert to the higher level of oil. 
 

[David_Long]

This is pretty good at explaining all that 

 And yes, pinion bearings can get starved of oil and it's a very real problem. As said in another post, Ford spent a great deal of their resources to get this right and the Sierra diff has a profiled back and an oil gallery at the pinion end to  help allow oil to flow forward against the pumping action of the crown wheel. 

[ScottR400D]

Thanks for that, very interesting. 

[Dan R]

As with all these things there is a lot of careful thought and research that goes in to the simplest items.  Once you start to delve into the finer details it opens into a huge topic!!  Fascinating.  

[CtrMint]

I finally made a start this evening,......

Successfully removed the ARB and A-frame, all going well if a little basic. 

I figured the next step would be slacken drive shaft nuts, release the handbrake cable and then release the brake lines.  Does anyone have any clever tricks for temporary sealing the brake lines so I don't get fluid every where.  I'm thinking the fingers from a rubber glove slipped over the brake line and cable tied.  Any recommendations appreciated.   

thanks

[OldAndrewE]

The best thing is a matching brake union with a short length of pipe crimped over.  You obviously need a brake pipe flaring tool or some old pipes to make this.  Also some cling film under the master cylinder cap will help reduce leakage 

[CtrMint]

Actually you've given me an idea, liberally wrap the pipe ends in cling film, that should do the trick.  Thanks.

[CtrMint]

Does anyone know the part code on CC's parts site for the "White nylon anti-squeak washers" that sit between the A Frame and DeDion mounting.  Struggling to find the part.

thanks