MORRIS MARINA DIFF OIL LEAK
QI
have a 1973 Morris Marina 1.3 coupé which has been dropping a small amount of oil at the rear. Looking up under the car I have found this to be coming from the diff seal at the propshaft flange. I have kept the diff topped up and the leak is not terrible, but I would of course like to address the problem before it gets much worse. Is there a complicated procedure for this job, or is it simply a case of removing the propshaft and flange and fitting a new seal? I would like to avoid the possibility of making matters worse by carrying out the job incorrectly. Jim Finch A The job is quite straightforward, but before starting you should mark the propshaft and flange to ensure that they are fitted back in the same positions – this is not strictly required, but may avoid the problem of any imbalance afterwards. I would also mark the pinion flange in relation to the axle to ensure
that this is also fitted back in the same position. Once the propshaft has been removed, also mark the position of the flange securing nut to ensure that this is replaced in the same position, because if this is over-tightened, then the load on the diff pinion will be altered.
The nut can then be removed and the pinion flange tapped off. With the flange off, the old seal can be removed and the new seal fitted in place. When the flange and seal are removed, oil may drip from the diff and so you should ensure that you have a tray in place to catch this. After fitting the new seal, a light film of oil should be spread over the contact surface before then refitting the flange and replacing the nut, securing it in the same position as when it was removed. The propshaft can then be refitted and the diff topped up.