Rear crankshaft seal.

30csl

30csl

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I'm sure this has been asked before but I searched and couldn't find it.

How easy is it to change the rear crankshaft seal? I have a suspected leak from it and guess its a bit of a pain to do.

Thanks,

Rohan
 
I'm sure this has been asked before but I searched and couldn't find it.

How easy is it to change the rear crankshaft seal? I have a suspected leak from it and guess its a bit of a pain to do.

Thanks,

Rohan
 
There are certainly more exciting jobs to do. You have to remove the oil pan, and you have to remove the exhaust and transmission (and driveshaft obviously). The rear main seal is pressed in to an aluminum carrier which is held to the block with about 6 m6 bolts. I think there's a gasket in between it and the block as well. You'll also need to make a "press" in order to get the new seal back in to the carrier. I've only done this job when I was doing an engine rebuild. In fact, just two days ago I was staring at the rear main seal on The Silk Shark thinking "should I replace it"? It wasn't leaking, so I left it as it was. Don't fix it if it ain't broke.

-tj in Los Gatos
 
There are certainly more exciting jobs to do. You have to remove the oil pan, and you have to remove the exhaust and transmission (and driveshaft obviously). The rear main seal is pressed in to an aluminum carrier which is held to the block with about 6 m6 bolts. I think there's a gasket in between it and the block as well. You'll also need to make a "press" in order to get the new seal back in to the carrier. I've only done this job when I was doing an engine rebuild. In fact, just two days ago I was staring at the rear main seal on The Silk Shark thinking "should I replace it"? It wasn't leaking, so I left it as it was. Don't fix it if it ain't broke.

-tj in Los Gatos
 
30csl said:
I'm sure this has been asked before but I searched and couldn't find it. How easy is it to change the rear crankshaft seal? I have a suspected leak from it and guess its a bit of a pain to do.
Thanks, Rohan
Click to expand...

Talk about loaded questions! Replacing the seal is quite easy when you have the seal exposed with the engine on a stand in front of you. The real difficulty is in accessing the seal with transmission and clutch removal being most of the heavy lifting.
 
TJ,

I'm not sure which seal you are talking about with the aluminum carrier, but isn't the rear crankshaft seal the one you usually replace when you do a clutch job? You remove the transmission, the clutch, then the flywheel and there it is. No need to drop the oil pan. You pry it out with a simple seal puller. Replacing the pilot bearing is recommended at the same time.

Charlie P
 
TJ,

I'm not sure which seal you are talking about with the aluminum carrier, but isn't the rear crankshaft seal the one you usually replace when you do a clutch job? You remove the transmission, the clutch, then the flywheel and there it is. No need to drop the oil pan. You pry it out with a simple seal puller. Replacing the pilot bearing is recommended at the same time.

Charlie P
 
Thanks for the replies guys.

I am surprised the oil pan needs to come off.

Seems an involved enough job - not looking forward to it one bit!
 
Thanks for the replies guys.

I am surprised the oil pan needs to come off.

Seems an involved enough job - not looking forward to it one bit!
 
Press the seal into the carrier using a bench vise with wood blocks to spread the force evenly.

Don't damage the sump gasket taking the carrier out, and use gasket seal between the carrier and sump gasket when replacing the carrier.

Do use a torque wrench on the two bolts (vertical as you work) which hold the carrier against the sump flange. You need to be sure it's done up, but excess force is guaranteed to strip a thread- don't ask how I know. I've seen other postings warning about this.
 
Press the seal into the carrier using a bench vise with wood blocks to spread the force evenly.

Don't damage the sump gasket taking the carrier out, and use gasket seal between the carrier and sump gasket when replacing the carrier.

Do use a torque wrench on the two bolts (vertical as you work) which hold the carrier against the sump flange. You need to be sure it's done up, but excess force is guaranteed to strip a thread- don't ask how I know. I've seen other postings warning about this.
 
Fair enough, you could do it without removing the oil pan gasket, assuming your oil pan gasket is in good condition. But if I were going to all that trouble, I'd do the oil pan gasket as a matter of preventative maintenance. But you're right, you could replace the main seal without if you wanted.

-tj in Los Gatos
 
Fair enough, you could do it without removing the oil pan gasket, assuming your oil pan gasket is in good condition. But if I were going to all that trouble, I'd do the oil pan gasket as a matter of preventative maintenance. But you're right, you could replace the main seal without if you wanted.

-tj in Los Gatos
 
Oh, and by the way, talk to me about pilot bearings. My life has been all about pilot bearings and clutch kits for Euro M6s these days. I found a rather rare variant of pilot bearing used on some BMWs. It's much smaller than the one typically found in our E9s and uses needle bearings rather than the caged rollers.

-tj in Los Gatos
 
Oh, and by the way, talk to me about pilot bearings. My life has been all about pilot bearings and clutch kits for Euro M6s these days. I found a rather rare variant of pilot bearing used on some BMWs. It's much smaller than the one typically found in our E9s and uses needle bearings rather than the caged rollers.

-tj in Los Gatos
 
Thanks for all the helpful posts guys.

I guess while I'm there TJ i should replace it. I havent had a look at it yet and just thought i the pan wasn't something to worry about. I will probably attack this after the summer as the oil leak isnt too bad and gives the underneath added rust protection!
 
Thanks for all the helpful posts guys.

I guess while I'm there TJ i should replace it. I havent had a look at it yet and just thought i the pan wasn't something to worry about. I will probably attack this after the summer as the oil leak isnt too bad and gives the underneath added rust protection!
 
My '74 3.0CS has one of those needle-bearing type pilot bearings. When I had it opened up to do my 5-speed upgrade last year I tried to replace it with the more durable ball-bearing style. There is a kind of adapter sleeve that accompanies the smaller bearing that I had to pull out in order to install the other type. But even with a pilot bearing puller borrowed from Autozone, I couldn't get that sleeve out, so I had to just put another of the needle-style back in.

Charlie
 
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