300tdi rear crank oil seal how to

I did my rear crank oil seal last week since the body is off and access was easy.

I've noticed over the years that no one has ever posted any proper pictures of the seal and fitting process so thought I would take some pictures.

Attached are a selection of images which will hopefully help for those of you looking at doing the rear crank oil seal on a 300.

I might as well put a few words down about the process so it's all in one place.
Assuming gearbox is off or engine is out...

Remove clutch cover/torque converter then remove the flywheel or flexplate. To undo these bolts you can put two bolts into the flywheel/flexplate and then put a bar or spanner or something across some of the gearbox mounting studs to lock the engine in place. Undo the 8 bolts and remove (I used the two clutch cover bolts to rock the flywheel back and forth until it came off).

You can now undo the seal housing bolts, slide it off and discard.

Clean up the back of the block, the crank shaft everything so it is oil free and generally just squeaky clean.

Fit two M8 studs into the block to act as guides when your pushing the new seal on. These stop the seal from being put on at a bad angle and possibly damaging it.

There is a plastic protector/expander on the oil seal, this stops the oil seal from being damaged and also expands oil seal over the end of the crankshaft as you fit it - DO NOT REMOVE IT.

Once you are ready to fit the seal put some RTV silicone round the seal housing, be careful not to get too much near the oil seal itself in case it squeezes onto the seal and contaminates it.

Unlike other seals DO NOT oil or grease the crankshaft or the seal, there is a Teflon coating on the oil seal (well the OEM ones anyway) this in itself will help the seal slide over the crankshaft, it won’t be as easy as an oiled or greased seal certainly but it won’t be terrible, the hardest part is getting the seal to open up enough and push the expander through. Oiling or greasing the seal or shaft will put a thin film between the crank shaft and the oil seal, the seal is designed to come into direct contact with the crank via the Teflon coating. Creating a film between the two will almost certainly cause it to leak.

Put the seal housing onto the two studs and as squarely as possible push it up against the crankshaft, the expander will make contact first, keep pushing it will be quite hard and require a fair shove, if you maintain good pressure the oil seal will slowly glide over the expander and it will slide onto the crank, when it gives it may slip quite quickly (testament to the fact the Teflon is doing its job), but the studs will help to keep it straight and true.

Put in all the bolts and do them all up finger tight progressively and in opposites, then use a small ratchet and keep working progressively until the bolts are all reasonably tight, then use a torque wrench and tighten to 25nm. If you do not have a torque wrench, a small wrench (4 inches) done up pretty tightly will be about 25nm.

I then refit the flywheel and test ran the engine for a while to check for leaks.

ADDEUNDUM:

The gasket you can get (pictured) I did not fit, I didn’t fit this for two reasons, the seal had not been fitted with it previously so fitting the new one with a gasket would push the seal out slightly further therefore the seal would be running on part of the crank that previously it did not before, the crank was clean and the surfaces were good but there was some marking/discoloration on the crank further out which would have been, although not detectable with my finger, slightly rougher and or with raised edges. Having the seal running on this surface may lead to premature seal failure.

Had it been fitted with the seal previously I may have considered it dependant on the crank surface.

It is also commonplace that the housing is put on with RTV rather than the gasket.

never fitted one with out gasket ,gasket is an improved version ,it helps seal around main bearing cap as crucifix seals have often leaked on lrs ,(so if not using it ensure you silicone all the joints )and cater for movement during heating/cooling cycles its common in engineering to fit seal on used surface if possible ,polishing crank first

Fair enough, each to their own. Most don't use the gasket including leading LR engine rebuilders.

As you correctly say standard engineering practise is to use surface previous seal had ran on, so again why I didn't use the gasket in this instance.

My T seals are fine or I would have changed them, no gasket or RTV on the outside is going to stop oil weeping down the join and leaking out anyway.

Hello everyone, this is my first post on here and stumbled on this forum through searching oil leaks on google. I have a 300tdi defender which has an oil leak (no suprises there), i was convinced it was from the sump pan and have recently taken it off and resealed with RTV. However my drips have returned . Im not talking massive amounts, just enough to annoy. Im starting to wonder if its from where the gearbox bell housing meets the engine block, would this be likely? Its not dripping from the bellhousing drain which would suggest the rear crankshaft seal, its more from the outerside of the bellhousing where the block meets it, i get drips from the sump pan bolts closest to this. I have checked above, so far ive renewed exhaust manifold gasket, brake servo vacuum pump gasket (and replaced the riveted cover with bolts and sealed with RTV), renewed split diesel runoff loops, oil cooler pipes, so im absolutely sure the oil is not from anywhere above (ive jetwashed the engine too)

What do you think? i am tempted to retro fit a sump gasket rather than the RTV as im not overly happy with it.

PS discomania, i see you took gearbox out rather than engine out, was that easy enough to do? ive done a clutch in a 90 2.5TD CSW and took the gearbox off, but in my 300tdi defender the bellhousing seems a bit further forward

silicone is more than adquate if surfaces are oil free (cleaned with solvent etc )leak could be above running down but also could be rear main bearing cap seal sits in a aluminum housing which with a gasket seals this plus sealing crank with the seal,housings can warp over time

Looks good thanks I think my mates one needs doing

Naylz said:

What do you think? i am tempted to retro fit a sump gasket rather than the RTV as im not overly happy with it.

PS discomania, i see you took gearbox out rather than engine out, was that easy enough to do? ive done a clutch in a 90 2.5TD CSW and took the gearbox off, but in my 300tdi defender the bellhousing seems a bit further forward

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I would stick with the RTV, cleanliness and some time spent on it will give a good seal.

My 300tdi is in the 2.5NA position and I have a shortshaft R380 gearbox coupled to that so that's why my engine looks to be in a different position.

I have the whole body off my 90 at the moment so it was a doddle to pull the boxes off and do it this way. Had I not had the body stripped down I think I would have gone for engine out - but to be honest - gearbox out isn't that bad really, you can always strip the seatbox off and do it that way.

I had to do a clutch fork replacement on my Td1 300 diesel. As I also had a small oil leak from the rear crankshaft oil I just replaced it with a Britpart seal.

Took all the necessary precautions during fitting and unfortunately, I have a an oil leak much worse than before.

Any idea" as to what I should do? Is Birtpart for such oil seals not good quality?

depends if britpart supplied an oe or pattern , the seal and gasket do need to be oe , and care taken when fitting seal dont touch the seal itself ,

Hi, For what its worth here is my story.

Bought an Ex MOD 90 that had a 2.5 NA in the front,

Stripped out the old lump and bolted and welded in a 300 TdI from a 95 discovery to the LT77 2 years ago

Did not upgrade the exhaust!

Had to replace the gear box as when i was taking up drive you more of a bang that you normally get on Bonfire night.

Started it about 5 weeks ago doing a bit hear and there, Andy from AW transitions sorted me with a LT77s and carried out some repaiers to the transfer box " A Dam Decent Man" in my book.

Replaced the rear crank case oil seal with new one OEM Britpart one from Stevie Parker's, fitted it all as per the book taking care to clean down the faces with thinners and not touching the seal it self.

Put the whole thing back together over a day or so, treating it as a proper job,

Took the 90 for its first run and the gear box was running as smooth as a very smooth thing, stopped out side the work and about an hour later had a wee look under my new pimped up 90

And there it was, right under the wee breather hole and on the gear box cross member then to the works car park , the black oil from the rear crank case seal.

To say that i have had better days would be an understatement, need to strip it all back out and start from scratch, Next set of seals will be from Landrover and depending on what is after stripping i might use the silicon gasket seal.

Sympathy and Comments all welcome

did you fit new gasket ,seal needs to be tightened diagonally and care taken to ensure seal is central,

Removed the seat box and floor and lifted the lot out from the top and replace the Exhaust with one from Stevie Parker.

The Hardest bit was watching my son crawling underneath to reach all those awkward bolts

Jim

Did that and tightened it as you said,

Think ill get the engine running for a few hours at revs prior to fitting the gear box

when you remove it check ali housing is flat ive had a few new ones warp in the past

jim,

Ok will do, ill have some photos of it posted up here so we can see whats went wrong

sparkie said:

Hi, For what its worth here is my story.

Bought an Ex MOD 90 that had a 2.5 NA in the fr...

...the silicon gasket seal.

Sympathy and Comments all welcome

Click to expand...

We should start a support group.

Just finished replacing the seal for a second time, Was on the phone to Turners Engineering , Who say the original pattern seals are 4 mm out where the rubber should be more on the crank shaft, Sealed it with the sealant they recommended and all seams to UK now