Diff mount

[Dave Keeper]

Hi all not had my z3 for long and noticed the diff was clunking one thing I used for a bargaining point! Now it's time to get it sorted so had a look underneath and just wanted to see what everybody thinks! Do I need just the pollybush or the bush housing and polly bush as a whole? Any info on best way to tackle it etc will be brilliant
Many thanks

 

[Dave Keeper]

Here's she is

 

[Dave Keeper]

And another

 

[stevie_a]

I will be doing this in the spring, you can get the diff back plate with the bush already installed from BMW for £80

All you would need extra would be a gasket and oil.

On the same subject can someone tell me the best oil to use that could quieten the diff whine down a bit, it is not loud but i can hear it.

 

[Brian4]

Lee will be along soon with some more hands on advice but if the diff bush is worn as it looks to be the rear subframe bushes will be worn as well so may as well do all 3 together.

 

[stevie_a]

I have just replaced my

rear sub frame bushes
rear shock top mounts
rear shocks
rear drop links

and if that doesn't fix the bl**dy clicking noise from the back, i dont know what to replace next

 

[GazHyde]

Dave, this is pretty much the job @Lee and myself (mostly Lee) carried out on my 2.2 Z3. My rear diff bush was completely shot, as were the main beam bushes. Also the main prop shaft bush (guibo) was badly cracked. The gear change and drive train bump in mine was horrendous.

We replaced the diff bush with a Powerflex purple one, as they are so easy to push in to place. I know as I pushed it in to place without much effort myself.

If you want to see what we ended up doing to mine, then read my progress thread on the link below. Lots of pictures and descriptions of what we did. There are a couple of videos in there as well showing the condition of the bushes before we changed them.

https://zroadster.org/threads/gazhy...pasblau-metallic-rosie.3229/page-2#post-74983

 

[Dave Keeper]

Thanks that's a great help! Do you have to take the diff plate off to get the bush on? Saying that if I take the diff plate off I'll need to change the oil and gasket !

 

[GazHyde]

The diff bush can be changed without dropping the differential. Extracts from the thread from when we discussed it.

The worst bit is getting the old worn bush out. I think @Lee can give better advice, but if I recall his dad said it could be done while the car is on the floor. Fitting the Powerflex bush is pretty easy with gentle pressure from a g-clamp.

like gaz said you can actually change the rear diff bush without having to drop it all out. Pair of 19mm spanners/hacksaw

 

[stevie_a]

Is this the ones you got Gaz?

http://www.ebay.co.uk/itm/BMW-E30-3...its=Car+Make:BMW|Model:Z3&hash=item19d0570f25

 

[GazHyde]

Is this the ones you got Gaz?

http://www.ebay.co.uk/itm/BMW-E30-3-Series-82-91-Powerflex-Rear-Diff-Mounting-Bush-PFR5-300-/110869548837?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car Make:BMW|Model:Z3&hash=item19d0570f25

Yes, that's the one I fitted. A good price too considering I was quoted at least double for OEM from BMW.

 

[stevie_a]

So to remove this did you just saw the steel ring in two places and hit it out ?


.

 

[GazHyde]

Initially simpler than that, in that I stuck the biggest screwdriver we had in the centre and levered it out. Unfortunately it left the metal outer ring still in the hole, so had to hacksaw through this ring and tap it out.

 

[t-tony]

With that type of bush "shell" you will only need to split it at one point, then lever one edge over the other and it will fall out of the housing.

Tony.

ps. Unless you want to get rough with an air chisel.

 

[Dave Keeper]

Thanks for the advice guys sounds like a nice fix for me to start with!
I'm going to have a good study on your fix now lol

 

[Stormy_be]

As people as talking about changing the diff plate, anyone ever thought about changing the backing plate to one with 2 mounting points?
Is it even possible?

 

[Stormy_be]

So nobody even thought about this?
Maybe I'm the only nuttcase that was thinking about it then.

 

[GazHyde]

changing the backing plate to one with 2 mounting points

I've not personally heard of anyone doing this, but seen various cars where they have switched to a twin ear diff. Can't see why it would be needed on your average car personally, unless you are putting extra power through the back end over stock. That's why @PeterJ switched his as part of his power upgrades (along with a Forbes kit). Well, and that fact the torque he is running almost ripped the thing off completely

 

[Stormy_be]

I've not personally heard of anyone doing this, but seen various cars where they have switched to a twin ear diff. Can't see why it would be needed on your average car personally, unless you are putting extra power through the back end over stock. That's why @PeterJ switched his as part of his power upgrades (along with a Forbes kit). Well, and that fact the torque he is running almost ripped the thing off completely

I've heard (on this site if my memory is any good) about the mounting cracking...mainly with Z3M's.
Having the double mountings would also solve that issue.

 

[GazHyde]

Stormy, it is a possibility that the diff mount can crack or tear off on the ///M's and bigger engined Z3's. BMW used to repair these faults under warranty when they started happening, but that good will has long run dry. It's certainly something that should be inspected from time to time, or if you are buying a Z3. Also if you are planning on boosting power, or driving hard for track use.

The more common issue is the welds popping in the boot area, which generally just needs them rewelding.

That said, there are plenty of Z3's & Z3M's running around without showing either of these problems!