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James (Jim) Lee
Experienced User
Username: graycar

Post Number: 12
Registered: 8-2005
Posted on Sunday, 11 November, 2007 - 18:03:   Edit PostDelete PostView Post/Check IP

As indicated in my previous thread,S3 auto, I have now removed and stripped the rear axle. I should mention here that the Chassis is B 604CN Eng.BCN302 and the Diff. is EG929 (13x40).
Indications are that this assembly has not been opened up since it left the factory. Initial examination shows the following,
As suggested by both Norman Geeson and Bill Coburn there was plenty of sludge and I am very pleased that I have taken their advise,even though this wont be easy and the cost will be considerable.
The good---The crown wheel and pinion are in good condition. There is no discernable backlash in the pinion gears. The trunnion shafts seem in good condition, showing less than 1 thou. difference between the running and non running parts when checked with a micrometer.The bearings supporting the inner case are a good press fit and the half shaft splines and the keys and keyways are good on the pinion shaft.
The bad--The cups for the inner case bearings can be turned and removed by hand although there is no obvious damage to the case or the thrust washers. The oilways, although not blocked, were restricted down to about 40% of their normal size and maybe enough oil got through to reduce the damage. The bearings are not pitted as in some and this may also be due to at least some oil getting through.
Clearly I need to replace all the bearings and seals, including the wheel bearings, and address the turning cup problem. Any advice on what to do about the cups moving would be appreciated and also any about where I can purchase the bearings and seals. If I can get these things sorted, I will then be able to think about how to get the backlash and preloads correct.
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Norman Geeson
Unregistered guest
Posted From:
Posted on Wednesday, 14 November, 2007 - 00:45:   Edit PostDelete PostView Post/Check IP


You have no need to worry about the bearing cups turning, unless they have been spinning around like mad. In that case it will be evident by marks on the adjacent components and a ridge in the alloy main case.

Having stripped many dozens of these units I would suggest you have no problem (at least with bearings)PROVIDING that you renew the UG 523 Belleville washers adjacent to the right hand bearing track (many $$$$$$).Fitting them the correct way round and not forgetting the 0.260 inch spacer.

Do NOT on any account mechanically scrub the main axle pinion inner verticle face or you will remove all the manufacturing data, which is etched on.

Bearings, you could obtain through a bearing agent except for the FT 3548 nose bearing.I would however point out that I do a tremendous trade in overhauling units which have been fitted with an incorrect bearing in place of the FT 3548. So be warned do not fit a substitute and the same goes for the leather side seals.

If you do obtain the bearings through a local agent also be warned the bearing suffixes are 'X'and no other, except for the righthand one.

Failing no bearing agent stock or silly prices you can contact me as a last resort, my e-mail is on KDA 132.

Although you believe the main hypoid gear set is good be prepared for some axle noise if you try to refit these gears.

You will need all new bevel / pinion thrust washers, and also new bearing and backlash spacers according to your settings.

(Message approved by david_gore)
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James (Jim) Lee
Experienced User
Username: graycar

Post Number: 13
Registered: 8-2005
Posted on Saturday, 17 November, 2007 - 08:37:   Edit PostDelete PostView Post/Check IP


Good news about the cups, I was wondering why there is no sign of damage and clearly it is because it is normal for the cups to be turned by hand. Thank you for explaining that.
I have been, and will continue , trying to locate parts.

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