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Les Henson

Replacing the diff pinion oil seal.

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Not much of an intro to this one. The diff pinion oil seal wears out from all the trips to Tesco's, and replacing one is not too bad - with the exception of the flange centre nut, which 99% of the time requires explosives to get undone. Method of replacing the seal is the same as any other L/R - the nut and it's tightness varies though, and you should make sure that the method/torque wrench setting is correct for you axle.

Signs of the oil seal failing is what you would expect - yet another pool of oil on the drive, a quick check underneath will confirm -

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Raise the drivers side wheel and put an axle stand under the axle. There's plenty of room around the rear prop/axle to get at all the bolts, so apply hand brake. The prop is held to the flange by 4 x 14mm head nuts/bolts, so propshaft tool and 14mm spanner.

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Once all 4 are removed - cable tie the prop out of the way. The flange centre nut can now be seen. This is the early castellated nut and split pin type - later models have a nyloc nut.

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The axle case has to be drained, and there's a square key bolt almost at the bottom - a 1/2 drive extension bar with no socket fits just nicely. Clean around the drain plug and then remove it.

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The flange centre nut is very tight, a breaker bar was neede to undo it. Retrieve the washer, and the flange will then just slide off the pinion shaft.

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The reason this seal failed was because it had been renewed incorrectly. This type of seal has to be fitted with the raised centre level, or slightly below the axle casting. Whoever fitted it just put it so that the edge was level with the casting - the result was that the drive flange wrecked the seal.

The diff pinion oil seal has an inner and outer lip - each with it's own retainer/tensioner. This was all that was left of the outer one.

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Raised outer lip on the new seal - this has to be level or slightly lower than the axle casting.

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The inner lip - again with it's own retainer ring.

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Clean the axle case and then tap/press the new seal in the correct amount.

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Re-assemble the flange according to your axle/nut type, and re-attach the prop. Replace the drain plug and then fill the axle case with the correct amount of fresh EP80/90 oil.

Les. :)

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Dont forget to check the seal track on the diff flange for wear , This is usually the most common cause of seal failure along with blocked axle breathers .

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These are really handy HOWTOs Les. The relatively simple LR jobs that come up again and again.

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Les, correct me if I am wrong, but if you remove the flange nut is there not likelihood of needing to re set pinion height/backlash/mesh?

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Indeed, depending on your L/R. Rebuilding the diff assembly would have to be a different thread, as it's a lot more work, and quite complex. If you had excessive play in the pinion/crownwheel mesh before replacing the seal, then you will still have it after doing this.

Les. :)

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Les, correct me if I am wrong, but if you remove the flange nut is there not likelihood of needing to re set pinion height/backlash/mesh?

Hi Landmannnn,

This excellent post by Les is for the 'rover' type diff fitted to the front and rear axles of all SWB series landrovers, 90s, Discos and Rangerovers. It also applies to the front 'rover' axles on all LWB series landrovers and 110s. It differs slightly in relation to the Salisbury rear axle fitted to LWB series from late series 11a or to the rear salisbury fitted to 110s(and any very rare salisbury front axles).

The difference between the two types is that the 'rover' type diff has the pinion bearing preload set by shims, whereas the salisbury axle has the pinion bearings preload set by a crushable spacer.

What this means is that providing you have no play, you can change the rover pinion seal without worrying about upsetting the pinion bearing preload. With the salisbury axle, providing you have no play in the bearings, you can still change the seal, but you should very carefully mark the pinion shaft and nut before undoing them to make sure that when you reassemble them, the same amount of preload is applied to the bearings. If you tighten the pinion nut too far, you could put too much preload on the bearings by crushing the spacer between the bearings too much.

Hope this helps,

Regards,

Diff

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Les, do you have the Rover part number for that pinion seal? I have never seen the double lip/spring pinion seal in Australia and I am looking for a more effective seal because my upside down rear diff really floods the normal pinion seal.

Bill.

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Bill :-

Rover Number is FRC4586 - 'Oil seal for pinion'

If you have Bearmach over there, then their number is BR0668

Les. :)

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Bill :-

Rover Number is FRC4586 - 'Oil seal for pinion'

If you have Bearmach over there, then their number is BR0668

Les. :)

Thanks Les. Their is a BM agent over here.

regards Bill.

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Paddocks website shows that part number for Series and RR upto 1985, wish I'd known this before I changed mine yesterday as it looks better than the FRC8220.

Richard

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nice tutorial, only thing missing is how to remove the old seal. Guessing you just pop it out with a screw driver or something?

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Screw a small self tapping screw into the old seal, and prize it out with a pair of pliers or a claw hammer.

Prizing the seal out with a screw driver could scrape the surface deep enough to cause another leak. You can buy a seal puller from such as Machine Mart but the above has worked for me every time.

Mick.

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Paddocks website shows that part number for Series and RR upto 1985, wish I'd known this before I changed mine yesterday as it looks better than the FRC8220.

Richard

I was told by my local LR garage that the FRC 8220 R seal was a heavy duty seal & better than the FRC 4586 or BEARMACH BR0668 if off roading.

Any truth in it????

Cheers,

Terry.

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I've never heard of a 'heavy duty seal'. As far as I know - you can't get better than the twin-lip seal.

Les.

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There are two seals for differing Pinions

I have both seals in the spares box

the rear was replaced when I put the latest pinion on the Defender

I'll get both part numbers later.

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Part numbers for the front & rear diff pinion seal

upto chassis KA930455

FRC4586 noted as heavy duty

FRC8220

from chassis LA930456

FTC5258

FRC8220

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It depends on the type of mudshield you have. For the one pictured in the post either FRC4586 or the later FRC8220 will do. Note FRC8220 is a "thicker" seal than '4586.

If however you have the circular mudshield which actually partly sits inside the nose of the diff (rather than external) you need to use FRC4586. You can't get the thicker FRC8220 to sit far enough inside the diff nose to clear the mudshield. Been there, done that the hardway. :rolleyes:

FRC8820 is a triple seal but with no outer external lip. FRC4586 is a double seal but with a 3rd external lip which as Les stated has to be seated deep enough to clear the mudshield. The circular recessed musdshield actually has a ridge which this outer lip runs inside.

I "borrowed" this from the Defender forum and it shows the type of mudshield that runs inside the diff nose and uses the same seal as Les fitted.

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On the subject of differentials, while waiting for delivery of a new cylinder head for my 300 TDi I've been giving the old girl a complete service. total exchange of suspension rubbers, new timing belt and gears, I've replaced the radiator core with larger water-ways from 4 x 1/4" to 4 x 1/2" and then I checked the two diffs. I've put new universals in both propshafts and rubber cussion, the rear differential was replaced some 12000 k's ago with a brand new unit and only needed new bearings, (well actually only one of the carrier bearings was shot so I replaced them all) but the front diff needs a new crown wheel & pinion set. Can anyone advise me on where I can obtain a set, the local LR guy only has a listing for a complete new differential and I dont want to go to this level of expense as I fully intent installing ARB "Air-Lockers" to both axels later this year.

Second question; How easy is it to upgrade the front and read disc brake calipers to the larger pad size units found on the TD5 ?

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Les, whats your way of making sure the seal is fitted straight? I normally use the flange and the old seal as a tool, and use the nut to wind it in, but the last time that backfired badly on me. Obviously, I dont have the special tool (true cheapskate!).

Daan

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On the subject of differentials, while waiting for delivery of a new cylinder head for my 300 TDi I've been giving the old girl a complete service. total exchange of suspension rubbers, new timing belt and gears, I've replaced the radiator core with larger water-ways from 4 x 1/4" to 4 x 1/2" and then I checked the two diffs. I've put new universals in both propshafts and rubber cussion, the rear differential was replaced some 12000 k's ago with a brand new unit and only needed new bearings, (well actually only one of the carrier bearings was shot so I replaced them all) but the front diff needs a new crown wheel & pinion set. Can anyone advise me on where I can obtain a set, the local LR guy only has a listing for a complete new differential and I dont want to go to this level of expense as I fully intent installing ARB "Air-Lockers" to both axels later this year.

Second question; How easy is it to upgrade the front and read disc brake calipers to the larger pad size units found on the TD5 ?

In the UK, Ashcrofts or KAM for ring and pinion sets. Not sure about Aus though....

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Help!:/

I decided to have a go at this job myself after reading this helpful post! Long story short......I took off the propshaft expecting to see a castellated nut or nyloc nut and I am greeted with a 15mm bolt! I take all the necessary measurements etc and undo the bolt! The flange comes out and the seal looks nothing like frc8220 or frc4586! Can anyone shed any light in this?! Do I have a completely different diff assembly?!

Thanks!

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