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Post by djm16 on May 23, 2021 4:29:26 GMT
Needed because on renewing the pinion oil seal, I noticed that the pinion bearings were graunchy.
The first things I noticed after cleaning an horrendous concatenation of hardened oil and grease off the diff was the liberal coating of black paint over everything including the drive flange. Next, the very old leather oil seal. Could this be an original untouched diff from 1963, or a slightly tacky rebuild from later? When did leather seals go out?
When I pulled out the pinion and its bearings I found part of the problem. A skinny outer pinion shim had disintegrated. Fortunately it had not jammed up the pinion bearings, but it had damaged one of the diff carrier / cage bearings which had been rotating in its seat.
I believe I can source most parts from Ashcrofts Transmission in the UK. Anyone know of a similar supplier in Australia?
What about the thrust washers though? The ones I took out are Paxolin / Tufnol and are 40thou. To take up the slack now would require a 60thou thrush washer, and standard Rover ones only went up to 50thou. I have looked at all kinds of alternatives including cutting my own from Paxolin sheet, having someone machine up some bronze washers, and trying some almost but not quite right washers from SKF or Spicer.
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Post by djm16 on May 26, 2021 2:11:21 GMT
In order to pick the correct Rover part number for my diffential, I need to know if the axle is "A" or "B".
I have found a number on the differential (3.9 11905 6411) but I have not so far found anything on the axle casing. Any clues where to look? I cannot see anything in the places suggested on Series Land Rovers.
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Post by enigmas on May 26, 2021 8:59:07 GMT
Why not just look for a good usable 2nd hand 3.9 differential centre (pumpkin) from another Rover 3 litre (or fit a 3.5:1 ratio from a MK3 or P5B as an alternative?)
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Post by djm16 on May 26, 2021 12:06:49 GMT
Why not just look for a good usable 2nd hand 3.9 differential centre (pumpkin) from another Rover 3 litre (or fit a 3.5:1 ratio from a MK3 or P5B as an alternative?) Hi Enigmas, Yes that would be the sensible thing. However, my OCD compulsion is to fix things rather than replace them. Also I do not have a suitable diff to hand. I know where there are several in axles, but of unknown provenance, and sitting around for 10-20years. Same guy has about 100 original headlight bezels in reasonable condition.
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Post by djm16 on Jun 15, 2021 13:32:29 GMT
In working on this diff I figured out a few things, firstly that the axle was probably rebuilt at some point (judging from the liberal use of black paint, and given the leather pinion oil seal, probably early 70s at latest?), secondly that the work was done by the lowest form of human life.
Remember, the bearings were damaged by circulating swarf, most likely from a disintegrated smaller pinion bearing shim. The only way the shim can be free is if there is no force pinning it between the pinion shaft and the inner race. So instead of setting the pinion bearing pre-load by adding or taking away shims, the *&^% unmentionable just torqued up the securing nut until it felt right, making the shims redundant. As I had to add two 1mm homemade shims to get some purchase between the pinion shaft and inner bearing race, it sounds like he just lost one of the fatter shims and didn't bother to replace it.
The other exposition of supreme criminal incompetence was the failure to drive home the collar on the axle securing the wheel bearing. Realistically the wheel was unlikely to fall off any time soon. But how can any self respecting mechanic ignore the 5-6mm of axial play on the rear wheel?
Fortunately I have a friend who has a friend with a 30T press, so the old collar is now off, a new bearing is ready, and I have 2 spare collars I bought years ago.
Back to the diff. I have set perfectly the pinion bearing preload, and have now measured the large shim thickness required to set up the pinion to crownwheel as per Rover. That thickness is 0.85mm give or take. Since I have 1mm mild steel to work with, and cutting annulus-shaped shims is a major PITA, is anyone going to give a rats-arse if I raise the pinion by 1.00mm instead of 0.85mm?
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Post by enigmas on Jun 16, 2021 14:32:56 GMT
It seems like you're beginning to enjoy all the detailed fettling encompassed in a differential rebuild David. Personally I try to avoid anything that relates to setting up a crown wheel and pinion...especially a very tired unit. Not that I don't give you full credit for going there and wanting to experience the joys of rebuilding a differential.
Hopefully it wasn't noisy before disassembly and if so you made note with bearing blue or similar marking paste (artists titanium white) of the engagement of the pinion with the crown wheel both on the drive and coast sides. As they are now a matched well worn set, it's critical that the gears engage precisely as they did prior to any disassembly.
To my view assembling differential gears successfully seems to be a mix of both mechanical aptitude and innate feel. And there's nothing worse than a howler after putting in a lot of work.
Good luck with setting up the gears...I sincerely mean it. 👍
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Post by djm16 on Jun 17, 2021 4:18:50 GMT
Hi enigmas, thanks for your encouragement. I did my P4 diff about 10 years ago and it came out OK. This time round seems to be more troublesome. The latest snafoo is that the pair of carrier bearings that a friend ordered for me turned out to be Britpart "made in China" despite being assured that they were SKF. Mightily pissed! You would not think this could be so much trouble. And if it turns out to be a howler, then I will just turn up the music and sing along.
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Post by Jens Munk on Jun 17, 2021 7:22:45 GMT
Don't be surprised if SKF have their bearings made in China too.... Hi enigmas, thanks for your encouragement. I did my P4 diff about 10 years ago and it came out OK. This time round seems to be more troublesome. The latest snafoo is that the pair of carrier bearings that a friend ordered for me turned out to be Britpart "made in China" despite being assured that they were SKF. Mightily pissed! You would not think this could be so much trouble. And if it turns out to be a howler, then I will just turn up the music and sing along.
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Post by djm16 on Jul 24, 2021 3:56:13 GMT
An update on the differential saga.
Shimming the diff
The satellite and sun pinions: the original tufnol shims / thrust washers were approximately 40 thou from memory, with little wear, but the additional wear on the gear teeth and the bedding in of the satellite gears meant that there was a huge amount of play. I therefore resolved to take out the extra play by fitting oversized shims. In retrospect I could have saved myself a lot of trouble simply by sourcing a pair or shims in the maximum available size: 50 thou, but being me, it had to be perfect and nothing less than 60 thou would do. After an age searching the internet, I came across some IGNUS composite thrust washers at a nominal 1.5mm. Apart from the long wait to get them mailed from Germany to Australia, value approx 10C, total cost to me approx $60, they were not what I expected. They were not remotely flat. As I do not have anything resembling a milling machine, I resorted to various grades of sandpaper and the bed of my pedestal drill to even out both sides. That took several hours, and multiple trial fits before I had a diff that would even turn. When I was done, I discovered that I now had a pair of relatively flat shims of approximately 1.4mm thickness (or 55 thou), hence the statement that I would have been better off just getting 50 thou Rover shims.
Wheel bearing replacement
Although I have done this before with my P4 and not encountered significant problems, this was not the case here. A friend pressed the bearing and sleeve off the axle, but in so doing bent not only the brake back plate (expected) but also the bearing carrier. I managed to get these both straight again with the aid of a press, but the next problem was that the new Roverpart wheel bearing would not slide onto the axle. With my P4 the new bearing slid down relatively easy with a piece of steel pipe as a drift and a few moderately energetic taps with a sled hammer. Not so this bearing. I had to drift the d#$%m thing off again. When I checked its internal diameter, I found that it was approximately 1 thou smaller than the original bearing that cae out, and 1 thou smaller than the new SKF bearing from Statewide Bearings. The general finish on this Roverpart bearing also seemed a little coarser than the new one.
Sliding the axles home
Again, this had previously been easy. It is a little tricky getting the toothed end of the axle to engage with its female counterpart in the diff, but this L axle just refused to slide home. It was at least half an hour before it dawned on me that I was trying to put the R axle into the L side. At least I did not resort to the clubmans' screwdriver (hammer).\
I will let you know whether it whines or not after the first outing on Monday, when it goes for a pre-inspection inspection.
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Post by enigmas on Jul 25, 2021 9:17:24 GMT
Hi David, I was never aware that there were left and right hand side axles produced by the Factory for P5 differentials. They're not offset in the casing. I am aware that axle splines on a particular side do take on a torque loading (which can be visibly identified on the half shaft splines.) Once fitted, marking an axle L or R or PS or DS makes sense. Flipping them side to side without noting the torque loading on the splines can lead to the inevitable fracture/break. Housings may vary slightly, so it may be worthwhile carefully removing any ridges that exist along the splines where they slide into the side gears. If not marked, try and note the direction of the major torque loading on the splines before fitting an axle to a side.
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Post by lagain on Jul 25, 2021 14:46:13 GMT
I might be wrong but if I remember correctly my axles were slightly different lengths
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Post by Sam Bee on Jul 25, 2021 15:21:20 GMT
They ARE different lengths.
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Post by harvey on Jul 25, 2021 17:00:08 GMT
They ARE different lengths. That's why the special tool comes with a spacer so you can press the shorter shaft out.
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Post by djm16 on Jul 26, 2021 5:44:14 GMT
The R axle is about 1" longer than the L.
So far, so good and no whining! I have only driven to a petrol station and back. I have a temporary permit to move to drive to my friends hoist before inspection in August.
Does anyone have a picture of the "special tool" in case (God forbid) I ever have to do a rear wheel bearing again?
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Post by harvey on Jul 26, 2021 12:43:42 GMT
Does anyone have a picture of the "special tool" in case (God forbid) I ever have to do a rear wheel bearing again? There's probably an illustration of the tool in the factory workshop manual, there is in the P6 WM. It's also used for the same job on Series land rovers.
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Post by enigmas on Jul 27, 2021 3:49:12 GMT
Yes...the rear half shafts (axles) are different lengths.
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percy
Rover Rookie
Posts: 71
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Post by percy on Jul 27, 2021 10:48:49 GMT
I made a note in my WM some time ago. The O/S is 780 mm's and the N/S is 750 mm's. Probably end to end and approx just to remind me when I was refitting but I can't say the measurements are exact.
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sandhurst
Rover Rookie
I am in Victoria Australia, and chasing a full rear axle and diff for a P5b , any available?
Posts: 9
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Post by sandhurst on Sept 8, 2021 11:08:21 GMT
Are those P5 axles? If so do you recall how many splines on the axles and what diameter the axles are ?
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Post by djm16 on Sept 11, 2021 10:50:41 GMT
Those look like 9 (10?) splines.
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Post by enigmas on Sept 11, 2021 11:12:23 GMT
Are those P5 axles? If so do you recall how many splines on the axles and what diameter the axles are ? If your referring to the image above of the 2 axles side by side...then yes they're P5 axles.
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Post by Sam Bee on Sept 14, 2021 11:55:45 GMT
The technical name is 'half shafts'. On the P5 it is a bit more than that as it includes the hub bearing mountings.
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Post by enigmas on Sept 15, 2021 0:25:42 GMT
Yes...the rear half shafts (axles) are different lengths.
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