Ital axle question

[Dirty Den]

Apologies for the long post -

 

I recently (a couple of months ago) had my 7 serviced at a 'reputable' place that I do not wish to name online.

 

At the end of last week I noticed a squealing noise coming from the back of my car for the first time. Phil Waters looked over the car for me and after checking the brakes, suggested that it may be the axle, it might need topping up with oil.

 

Over the weekend I topped it up and when I drove the car last night, the squealing noise had disappeared. I assume that topping up the axle with oil did the job. Anyway, when I topped it up, I guesstimate that I put half a litre of EP90 in. The build guide says the axle takes 0.7 of a litre, so my axle could have had very little oil in it.

 

I can't see that I have leaked half a litre of oil from the diff in a couple of months, so I can only guess that at the last service, the diff oil level was not checked. That would be very bad news as I have already done an airfield day and trackday since. I thought it reasonable that the service would have been done properly and I even told them of my intention to take it out on a trackday when they serviced it.

 

If I was running the car with little oil in the axle, what sort of damage could be done? How would the damage manifest itself? The car seems to drive fine at present.

 

Den

 

😬 - Self portrait - still unable to remove the smile!

[Graham Sewell]

I guess this is the modern variation of Chapman's gear change tweak. BAck in the bad old days, in order to get the correct ratios, Lotus took a mixed bag of cogs that did not quite fit so they put a bottle of brasso in the oil and ran the car for a few months before draining it out. At this point, the gears meshed properly!!!

 

Low tech luddite - xflow and proud!

[JonP]

Hi ,

 

In my prior experience of the Ital axle, running one dry first makes itself known by the crownwheel and pinion getting very noisy, so if its still quiet then all is OK. It was recommended that the axle was over filled for racing/trackdays (1L total) etc...not sure if this is still valid advice, as high oil level makes leaks from the halfshafts more likely and the brakes may get contaminated, but it stops the CWP running dry during cornering. There is (should be!)a small baffle inside the diff casing which helps too.

 

Was the car absolutely level when you filled the diff?..if it was nose down you will overfill.

 

Suggest squeaking could be rear springs touching the dampers and not the diff!

 

BR's

 

JonP

 

 

 

Back Se7ening again! (with apologies to Andy Webber....

[Stuart Faulds]

From dry to a sensible level for track use, the axle should take around 1.5 litres - I wouldn't run one with much less than that.

 

Stuart

[philwaters]

ok, but what damage will have been done by running it with very little (0.2L) in it 🤔

The underside of the car around the axle was bone dry so if it has been leaking it has been doing so for a long time ❗

Den, still that slight end play to consider though.

 

Phil Waters

Zetec is in and running

[Stuart Faulds]

It's hard to say. For a start I don't think you only had 0.2 of a litre in it - I reckon closer to 1 litre which should be enough for the crownwheel to pick up when the car's in a straight line. If you're really concerned, it's not too big a job (just bl00dy messy) to pull it out and have look, but if it's not making much noise and still working, then it's probably as good as you're going to get. I did a precautionary change of one a couple of months back, and the 'new' one was just as bad as the one I took out.

 

I would just leave it be and not worry about it.

 

Stuart

[Graham Sewell]

I can see where the 0.2l came from. The book says 0.7l to fill to the normal level. It took an additional 0.5l to reach this level => only 0.2l in at start. The fact that the general concensus is to overfill does not mean that the filler plug has been moved. ❗

 

Low tech luddite - xflow and proud!

[edmandsd]

Is checking the diff oil level part of a normal Caterham service then ?

[Jimbo]

I too remember the 0.7 litre figure from somewhere when I refilled by axle. Other than the car being on ramps at the back I just filled mine through the overflow and got well over a litre in (1.5?).

Is this 0.7 figure true?

Jimbo.

[Dirty Den]

The 0.7 figure is quoted in the back of the build manual for my car, towards the back of the manual.

 

I can't remember where I downloaded the service schedule from but someone did an Excel spreadsheet with the service schedule details in it. The 3k service is shown as including a diff oil level check in that spreadsheet.

 

Den

 

😬 - Self portrait - still unable to remove the smile!

[Graham Sewell]

I can well believe the 1.5l can fit as the filler plu is well below the centre line of the axle. From what I understand, the reason to overfill is to give some level of protection (mainly on circuits) for long fast corners where the oil ends up in one of the half shaft tubes. This is not very likely for road driving as the amount of time pulling that level of lateral G is very low.

 

Low tech luddite - xflow and proud!