Rear crank seal. Renew?

[John Roberts]

I'm doing some work on my '82 R100RS, including overhauling the gearbox. It's done 65,000 miles, my natural inclination is to change the rear crank seal even though it seems ok, but I think I heard somewhere that it is better to leave it if it isn't leaking.

So, change it, or not?

A couple of quickies before I go,
Should I use sealing compound on:

Pushrod tube rubbers
Cylinder base face
Cylinder head gaskets​

and if so, what should I use?

Please.

 

[Steptoe]

If you decide to replace the rear crank seal, chock the front of the crank so the crank can't move forwards.

Otherwise there is the high posibility of the crankshaft thrust washers/spacers falling off their locating pin. Which means a crank out job to re-install them.

And did you find any sealants when you dismantled the parts ? No. So put it together as you found it.

 

[John Roberts]

If you decide to replace the rear crank seal, ...

Are you saying there's no definite answer as to change/don't change? What would you do on yours?

And thanks for the warning re thrust washers.

 

[mavis cruet]

if you leave it its bound to leak within 100 miles of the rebuild! then again if you replace it its bound to leak anyway. i wish id replaced mine when the box was out..... ho hum.

 

[Kenny]

I personally wouldn't change it...where do you stop? Not a big job to do if it fails in the future !!
No sealants required although some smear a (very) fine silicone gasket compound on the crankcase face..and I mean very fine

 

[(RIP) pastyman]

personally I would never use silicon where it could get into the lubrication system. I would use something like Wellseal. An oil based jointing compound . It is excellent and if you do happen to overdo it ,it dos'nt forn blobs that can find their way into your oilways.

 

[Kenny]

Pastyman, just the merest of applications is applied more to seal any scrape marks etc from previous over enthusiastic rebuilds etc( for the life of me I can't remember the name of it ) but it is for engine work Mr Farmer will know the name of it.
As Mr St. Eptoe states, if non was on there then no need to use any.