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Gearbox Oil Leaks
I have a 4 speed crash box that leaks at both ends,has anyone fitted lip seals and was it successful.
The Cornwall A7 site shows the output,but the crash box has a step in the casting a small seal would be needed.A thrower could be fitted between the speedo gear and output flange with a little machining to the inside does anyone have any thoughts.
On the input end it is fairly straight forward but i would use a larger diameter than the CA7c advises to suit the casting.On this end a V ring thrower could be used inside and a sealed LJ35 bearing with the internal seal removed again any thoughts or ideas appreciated.
As per my answer in the post on GB removal are you sure the oil level is correct?
Black Art Enthusiast 
I only put in 1/2 pint so i think thats ok,just turning the output flange and oil appears.
Seal size for front g/box cover187x112x25 this is the same dia: as the the nose bearing, not had a problem with rear drive flange leaking check scroll is not blocked
 or damaged. Use 1/2ltr/1pint of 75/90 semi syn gear oil a heavy oil does not help stop leaks.


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Looking at the picture I presume this is a synchro box as there are two drainage grooves ,my crash box only has one so perhaps it makes it more prone to leaking?.
Another check to make, if you are intending to remove the first motion shaft, is to check the integrity of the core plug inside the shaft. This prevents oil leaking from inside the box through to the splines. Whilst holding the shaft pour some paraffin or petrol into the inner bearing hole and see if it passes through.
From purchase in 1940 my synchro car was maintained as book and always gave trouble with oil on the clutch. A seal as illustrated was the single most useful mod ever undertaken.
Personally I have run several cars for many years and many thousands of miles with unmodified Synchro boxes and NEVER had issues with oil getting onto the clutch. I believe over filling the gearbox and over zealous lubrication of the release bearing to be the prime culprit of oil on the clutch. I should say that I have completely rebuilt all my gearboxes at the outset so they have been in extremely good condition rather than clapped out which of course may have some bearing on the outcome, if the input shaft flaps around due to worn races it may well leak.
Black Art Enthusiast 

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