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Just making sure (diff seal replacement)

9.6K views 21 replies 7 participants last post by  flahive5  
#1 ·
So I am finally getting around to replacing the rear diff seal on my 94' D90 as it has a slow leak (LT 230/R380/300tdi if it matters). I have seen posts about "pre-load" and some that sound like you don't have to do it on later models- so I am asking before I get myself in a pickle. The steps as I understand them are:
1) drop propshaft after checking UJ
2) undo center nut (Nyloc? Bolt?)
3) pull diff flange thingy (wheel puller needed...I think)
4) pry out old seal
5) seat new seal being careful that it goes in the proper way
6) bolt back on diff flange (preload?)
7) bolt back up propshaft
8) check diff fluid level and replace any lost
Am I close?

Thanks!
 
#2 ·
close

1) drop propshaft
check ujoints when prop is loose
2) undo center nut (Nyloc? Bolt?) depends on year , either will work, impact makes it easy. If nut count how many threads are exposed or mark it with a punch
3) pull diff flange thingy (wheel puller needed...I think) - will pop out with a long pry bar or a puller, or just by hand
4) pry out old seal
5) seat new seal being careful that it goes in the proper way
6) bolt back on diff flange (preload?) If it uses the bolt, tighten it all the way down with the blue threadlock on it, if the nut tighten to the mrk you made or how many threads you counted with threadlock
7) bolt back up propshaft
8) check diff fluid level and replace any lost ( none will be lost unless you did this on a hill or were WAYYYYY overfilled)


its a 15min job with the right tools. a propshaft nut tool makes it easy


dont overthink it !
 
#3 ·
... if the nut tighten to the mrk you made or how many threads you counted with threadlock
You don't tighten to a place. You torque it fully regardless to spec. All Rover diffs use shims for bearing preload. You are confusing things with a Salisbury.
 
#5 ·
You don’t need a puller. They are a loose fit.

Loctite if you have the bolt style. Not if it is a nyloc nut. You want a new nut.

Check the flange for grooves. If it is damaged, you will get a leak again.
 
#7 ·
OK, so life got in the way of me completing this until now
444553
. I was able to drop the shaft (easy) and checked all the UJ's and all are good with no wiggle (greased them while under there). Ended up buying a 1/2" impact wrench after almost killing myself trying to get the nyloc nut off. Once the nut and Shim were off the flange slid right off. I noticed there is about 1/8" of "wobble" or play in the shaft. Is this normal? And how do we mere mortals remove the old oil seal? I am attaching the pics of the inner and outer flange. Should I replace the flange since I have it off and I am already into it this far? I don't want to replace the seal if I need to do other work (i.e. address the shaft wobble)
444554
first. Hate having my girl down, so any help is much appreciated.
 
#8 ·
Splines look great .

Do you have wobble when it's snugged up or when the nut is off?

Big ass screwdriver under the seal and push towards the axle, seal will pop right out . Or put a drywall screw through the seal and use a claw hammer to pop it out


I grease the splines before assembly and also pack the new seal lips with grease
 
#9 ·
It just wobbles when the nut/flange is off....so it is normal? I had to drill a hole in the old seal to get it to take a screw and tried to pull it out with pliers, but I didn't think of the claw hammer! Trying that next!
 
#10 ·
#11 ·
If the flange requires replacing -- has grooves, can the original spacers be used?
 
owns 1994 Land Rover Defend 90 Soft top
#13 ·
no, if you are replacing the flange, tolerances vary. your differential preload is set with current flange a new flange will need a whole new preload in order to complete the job in a proper manner.
 
#14 ·
"no, if you are replacing the flange, tolerances vary....."
This is what I thought.
I was thinking if the new seal was not completely seated, the lip would ride on an undamaged (not grooved) section of the original flange. I'm trying to avoid setting the preload.
 
owns 1994 Land Rover Defend 90 Soft top
#15 ·
"no, if you are replacing the flange, tolerances vary....."
This is what I thought.
I was thinking if the new seal was not completely seated, the lip would ride on an undamaged (not grooved) section of the original flange. I'm trying to avoid setting the preload.
obviously you want to avoid all the work behind the preset, take your flange to a parts store and procure a "speedy Sleeve" this is a stainless steel sleeve which fits over the seal landing and covers your damage thus allowing better sealing. it allows you to keep original flange and presets. the last step, grease new sleeve landing, you never break in a new seal "dry."
 
#16 ·
Although it is doubtful that you would need to change the preload shims with a new flange, they are quick and easy to change. It is not something to be scared of.
 
#17 ·
Red, the shims are located in two spots on a rover diff, the first set adjusts the height or depth of the pinion against the crown wheel, this starts at 50 thou and sits behind the race of the inner pinion bearing.
proper depth dictates were the contact patch will lie between pinion and crown wheel.

the second spot, and this is very tricky, the preload. a 1 inch spacer plush a 3 washers of different thickness which will dictate how true the pinion will ride on it's axis and how well it will lubricate with out causing leak or premature fail of seal and inner and outer pinion bearings. if the height of the shoulder of a flange is changed, the measurement of preset force of pinion bearings against the races (aka pre-load) will vary, thus changing affecting every other measurement.

the last measurement, is the backlash. this is the gap between the pinion and crown wheel. too tight and your gears will grind and overheat due to lack of lube and fail prematurely, too loose the gears will clunk and humm when coasting, this clunk or slap is shock load which will result in broken gears.

any adjustment to any one of these 3 spots will affect the other 2. in order to get a proper setting, all of these must be done on a bench, with out front seal and axles to affect measurements. yes you can cheat and replace pinion seal on the vehicle, but only if reusing old flange. you need to take in consideration that a difference of plus or minus .001 in height of a new flange and worn bearings will have a negative effect on outcome.
 
#18 ·
Thanks. I know how to setup a Rover diff. The flange only affects the preload shims for the pinion bearings. They are placed between the outer pinion bearing and the pinion. With the flange off, you pull the bearing (it is loose) and then change shims as needed to get a small amount of preload. It is quick and simple to do while changing the flange.

None of the other settings are affected by the flange replacement or change to the preload shims.
 
#20 ·
I'm of the understanding this would require the removal of the tires and axles to allow for the necessary roation of the diff to check preload. Moreover, an assortment of shims would have to be onhand.
 
owns 1994 Land Rover Defend 90 Soft top
#21 ·
Popping the halfshafts out would make the feel easier. That is 5 minutes of your life. Obviously you need a set of shims.