PPF bolt "sleeves"??

Black_Penguin · Postby **Black_Penguin** » Wed Jun 04, 2014 1:48 am

When I swapped my torsen in the spacers didn't want to come out so much I unbolted it from the gearbox and took the diff and ppf out as one.

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ralt · Postby **ralt** » Wed Jun 04, 2014 2:04 am

Hi.
The job with the ppf is made simple after removing the bolts going to the top spacer in the ppf do not knock the top nuts up there is no need as the diff casing is flat the spacer is flat and the nuts are on the top of the spacer and in no way interfere with removing the diff unit. Get your scissor jack after removing the two long bolts put the base against the rear suspension and wind by hand the ppf just clear of the bottom diff spacer remove the two rear bolts on the diff housing ears and you can remove the diff unit.No the jack it will not bend the ppf. Once the new unit is in position remove the jack and put the bolts through the ppf and you have done the job without hammering or levering.

revhead · Postby **revhead** » Wed Jun 04, 2014 2:15 am

Is it advised to get replacement ppf bolts/sleeves/spacer just in case I damge them? If so, where from?

Should I be replacing the diff bushings? Require a press?

I think the only way I am going to be able to wrap my head around this is to actually get under the car and observe how it is held together. I can just tell this is going to be a huge mind f@#k.

I have already had one generous forum member offer a hand if I decide to go forward with the install this Saturday. The more the hands and minds, the better!

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JBT · Postby **JBT** » Wed Jun 04, 2014 6:11 am

Diff removal/replacement for the NA8 is straightforward. There are no issues with sleeves, bolts etc. and the PPF.
A friend and myself did a torsen swap on my NA8 (when I had it) but we had access to a hoist which made it more comfortable.
We put new seals on the torsen before fitting - easy to do while it is out of the car.

zossy1 · Postby **zossy1** » Wed Jun 04, 2014 8:28 am

Yep Phil, that's the PPF assembly. But what that doesn't show is the tube spacer that lives with the Diff housing. It is not part of the PPF and is probably shown on the diff schematic.

manga_blue wrote:
zossy1 wrote:Phil, check your diff - the sleeves are *supposed* to wedge into the PPF in order to hold it in place and align it properly. The sleeves can be removed with the diff out and they may have been with your diff which is why you don't have this problem.

However, having said that, I have seen at least two different designs for this mounting... there may be another I haven't seen!
Now you've got me thinking, Chris. I've got everything that's in the parts catalogue in there, basically 721, 722, 723, 724 and the floating spacer thingy at the top at the back.

Then again there's been this mystery knock in the back for the last 9 years... If I find it and fix it how much improvement will I get in lap times? I think I need another 2 secs to help me look like I can drive.

manga_blue · Postby **manga_blue** » Wed Jun 04, 2014 8:39 am

Black_Penguin wrote:When I swapped my torsen in the spacers didn't want to come out so much I unbolted it from the gearbox and took the diff and ppf out as one.

I'd forgotten about that method, Pete. I've done it that way once and I think it was an easier way to go. Granted a bit of extra weight but the whole unit was a bit more stable that way. Then if you need to you can sort out the PPF/diff join on the bench. I was just changing mounting bushes so I didn't even touch them that time.

Revhead, as JBT said you won't break any bolts but check the seals.

manga_blue · Postby **manga_blue** » Wed Jun 04, 2014 8:44 am

zossy1 wrote:Yep Phil, that's the PPF assembly. But what that doesn't show is the tube spacer that lives with the Diff housing. It is not part of the PPF and is probably shown on the diff schematic.

OK, got it now thanks Chris.

You're right. No worries. That stuff has always been seized onto the diff housing on mine and I've never had to remove it.

BTW, revhead, here's the best bit of write-up that I've seen for the job. It's official Mazda and it's from their NA8 series.

differential.pdf

zossy1 · Postby **zossy1** » Wed Jun 04, 2014 1:18 pm

greenMachine wrote:Dynabolt is your friend.

Seriously.

Props for a great idea! I will remember this

green_comet · Postby **green_comet** » Wed Jun 04, 2014 3:11 pm

I didn't have any issues with sleeves when installing SE diff/axles into my SP a few weeks back. I followed Keith Tanner's instructions in his MX-5 performance projects books, his alternate method worked fine.

revhead · Postby **revhead** » Wed Jun 04, 2014 9:11 pm

So sleeve is an interference fit to the top portion of the ppf? It slides into the top of the diff to loacte it in space. The ppf bolts tie the ppf, ppf sleeve, diff, ppf spacer together as one?

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greenMachine · Postby **greenMachine** » Wed Jun 04, 2014 9:28 pm

It sits on the 39-722 bolt in the schematic above, the one with the shoulder.

Interesting, Keith implies that the sleeve is threaded internally - which would make sense.

Can someone please check this next time they have it out ... that would make life a lot easier!

:mrgreen:

ralt · Postby **ralt** » Thu Jun 05, 2014 12:10 am

Hi.
Yes the front long bolt which has the locking collar goes through the spacer which has a threaded insert and the thread is at the bottom of the insert.

revhead · Postby **revhead** » Thu Jun 05, 2014 12:53 am

Ok, so I pull the long bolts out. Pry off the little spacer at the bottom. Reinsert the long bolt and thread it enough to grab the bottom of the sleave. Somehow pull the bolt back down to shimmy the sleeve all the way out of the diff. Remove old diff, place new diff in. Now I need to somehow slide the sleeve back Into the new diff with the bolt attached. Remove threaded bolt, place lower spacer thing back in.Then thread bolt the rest of the way to tighten it to the ppf.

Sounds so confusing haha.

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greenMachine · Postby **greenMachine** » Thu Jun 05, 2014 7:55 am

revhead wrote:Ok, so I pull the long bolts out. Pry off the little spacer at the bottom. Reinsert the long bolt and thread it enough to grab the bottom of the sleave. Somehow pull the bolt back down to shimmy the sleeve all the way out of the diff. Remove old diff, place new diff in. Now I need to somehow slide the sleeve back Into the new diff with the bolt attached. Remove threaded bolt, place lower spacer thing back in.Then thread bolt the rest of the way to tighten it to the ppf.

Sounds so confusing haha.

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No, you will need, according to the post above, another bolt. re-read the Tanner quote.

:mrgreen:

zossy1 · Postby **zossy1** » Thu Jun 05, 2014 9:26 am

Hmm... I don't recall that upper sleeve being threaded. In fact I'm pretty sure it isn't on earlier NA8 diffs as that would make two separate threaded receivers on the same shaft which wouldn't work.

I have to pull another diff (this time out of a NB8A) this weekend. I believe they had the removable upper spacer that was a 1 piece item so I'll check and report back.