Differential repair and rebuild

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Differential repair and rebuild

Post by PaulAV »

This is the start of a DIY rebuild and a repair for the 231 super LSD, as I progress this will contain parts used, with suppliers and prices if I have them.
Firstly I sourced a low mileage differential, on opening it up there were 2 tabs stuck to the magnetic drain plug,
These tabs are what make the super LSD an LSD, without them it is just an open differential, they are securing tabs for the pressed steel insert that sit between the tapered bore and the taper on the spider gear.
I have received the carrier assembly back from the company I found who have carried out successful repairs on similar Mazda differentials, both mx5 and rx7s.
I have ordered a new crushable sleave from Nengun in Japan and am awaiting delivery.
Bearings and seals for the differential have been given to an engineer at work to identify for me(the bearings do have product numbers on them and they do tend to be a generic product number that translates across multiple manufacturers, however some are a bit obscure so prefer to get the correct bearing, the seals aren't identifiable from product codes but are fairly standard sizes)
I hope to update sooner rather than later with build details and part numbers.
Thank you for reading so far.
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Re: Differential repair and rebuild

Post by warpc0il »

For those that haven't seen our diff apart, this is from the Mazda EPC.
Differential.jpg
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Putting the cost of refurbishment into perspective, a new complete unit is £4,354 dealer retail :shock:

The "differential" component (shown as 27-200 in the diagram) is £1,388

While the gear set (27-110) is £1,228
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Re: Differential repair and rebuild

Post by njkmr »

Holy Moly....!
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Re: Differential repair and rebuild

Post by New Duke »

That's nearly new engine money. Mazda are weird.

Best of luck Paul.
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Re: Differential repair and rebuild

Post by PaulAV »

Screenshot_20220126-194259~2.png
First item purchased from Nengun, they do sell oil seals if anyone is interested, but I'm looking to source locally
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by SeriousSam »

New Duke wrote:
Wed Jan 26, 2022 7:04 pm
That's nearly new engine money. Mazda are weird.

Best of luck Paul.
In fairness it's not just Mazda, plenty of other firms are similar. If you fancy having a laugh, call up your local gearbox specialists and ask how much they'd charge to strip and rebuild your box with new synchro rings. Same thing's true when you crash your car - the insurers will specify new parts throughout, which is what tends to drive the cost up so high and cause them to write the car off. There's a reason breakers are so popular.
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Re: Differential repair and rebuild

Post by PaulAV »

First part on the shopping list, crushable sleeve/spacer purchased from nengung in Japan the part was about £6 and postage was around £16 so it would be worth while getting other items at the same time, I believe they stock the OEM differential seals if you require them but I'm still waiting to see if they can be sourced in the UK(or at least a similar replacement, the OEM seal has a dust shield that protrudes outwards and is compressed against the have of the item that is seals) a standard seal should work fine
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warpc0il (Wed Feb 02, 2022 7:52 pm)
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Re: Differential repair and rebuild

Post by rotatopotato »

Do you mean the driveshaft seals? I purchased a pair from https://www.ebay.co.uk/itm/160697002132 (says MX-5 but its the same part number for the 8s).
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Re: Differential repair and rebuild

Post by PaulAV »

Those are the ones, although they are cheaper here, I'm just seeing if I can get a supply through work.
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Re: Differential repair and rebuild

Post by warpc0il »

That Distance Piece is only £9.36 plus VAT (less any discount) over the counter at your local dealer, so you'd have to be buying a lot of other stuff from Japan to cover the £16 postage.
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Re: Differential repair and rebuild

Post by PaulAV »

My local dealer wasn't supplying the general public last time I called them, also this took about 10 days to arrive where as Mazda would probably have it on back order for 6 weeks
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

Update to the build project, Hayley seals in Halesowen came through as a UK supplier for the pinion bearing and the drive shaft seals, the bearings are FAG manufactured the numbers are 32308 for the large bearing and 30306 for the smaller pinion bearing and the seals are 38x58x15 TC9Y dual lip seal, they are neoprene as opposed to vitron and do not have the dust skirt of the originals.
Mazda do have the carrier bearings and pinion seal in their system but are not available.
Nengun in Japan have the carrier bearings and pinion seal, for all 3 items including standard delivery is £100.44
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Re: Differential repair and rebuild

Post by PaulAV »

New pinion seal purchased from auto doc(only supplier this side of the equator I think)
Differential housing had been wire wheeled back to sound metal, given a coat of zinc primer and then satin black smoothrite, looks like new almost.
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

DSC_0120~2.JPG
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Re: Differential repair and rebuild

Post by PaulAV »

So the opinion gear is now in place with new collapsible spacer (took about 190 Newton meters to get the bearing to move and collapse the spacer) measured 13 inch pounds of drag, which is right in the limits, new input seal and more awaiting installation of the carrier assembly
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

Pinion installed
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Pinion installed
Pinion installed
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

Carrier installed, I have a big of backlash in the diff, will need to confirm how much, if the worse comes to the worse we have shims at work that should fit and I'll only need to reduce one of the OEM shims to allow the carrier to move axially so reducing the backlash.
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Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

Internal failed components of the support lsd
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Re: Differential repair and rebuild

Post by Clive »

Maybe worth knowing that I have stripped many of the Mazda "Super Diffs" and every one had all or at least one tag broken, with most having all broken making them useless.

One option would be fitting a used RX-7FD torsion diff (geared LSD) which would be directly interchangeable into the RX-8 case and are bullet proof, only breaking when really big Turbo power is put through them.

The other alternative is to fit a Kazz plated Diff (Salisbury type Diff) as I do in the race car and we have also supplied many road car customers with these as well over the years.

https://www.racingbeateurope.com/mazda- ... 1216-p.asp

Hope this helps
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mazda-rx8-rx7-kaaz-1.5-limited-slip-differential-for-all-rx8-and-rx7-fd3s-1216-p.png
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Re: Differential repair and rebuild

Post by warpc0il »

@Clive as supplied, how are they setup?
Image
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Re: Differential repair and rebuild

Post by rotatopotato »

warpc0il wrote:
Wed May 11, 2022 11:28 am
@Clive as supplied, how are they setup?
Image
I'd guess 100% based on the description:
Using our years of experience of plated limited slip diffs, we recommend that before fitting that your new Kazz diff is adjusted for the intended use of your RX-8 / If your Drifting fit as it comes out the box, if you are Racing or using the car for Track Day's, adjust the plates for 65% lock up then for Road adjust the plates for 35% lock up.
I'm interested to know what the ratio is? Same as S1 RX-8 or R3 or different again? Or is that what the '1.5' is referring to?
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Re: Differential repair and rebuild

Post by warpc0il »

The ratio depends on the gears fitted, so no change if you're just replacing the unit.

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Re: Differential repair and rebuild

Post by Phil Bate »

A 1.5 way LSD biases the locking towards acceleration, so it will partially lock on deceleration but less so than under acceleration. A 1 way only applies locking under acceleration, and a 2 way will try to lock equally under acceleration and deceleration.
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Re: Differential repair and rebuild

Post by PaulAV »

My refurbished diff is currently awaiting the cover to be cleaned and fitted, back lash is 0.14mm which is in Mazda tolerance(equates to about 4 thou if memory serves me correctly) once the diff is back together it will be a case of removing rear subframe(installing refurbished subframe) replace rear wheel bearings and backing plates on the hubs, swap items to new subframe and reinstall with refurb diff
Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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Re: Differential repair and rebuild

Post by PaulAV »

The diff is finally together
The diff is finally together
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Led side lights, purple Led interior & puddle lights, pz grills, Ryan rotary performance coils, sump, engine mounts & sohn, HME engine rebuild at 50k, RRP exhaust & high flow cat, racing beat revi intake including scoop, quick shifter, alloy filler cap, pz alloys, suspension, mazdaspeed spoiler, japspeed toe arms & hardrace camber arms, RRP custom remap
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