Subframe refurb on my 06 Z4 M Roadster

camtwister · Post by **camtwister** » Fri Oct 22, 2021 2:33 pm

Will you get the propshaft balanced before fitting?
This was an essential process during restoration of older cars that I've undertaken.

Joycey · Post by **Joycey** » Fri Oct 22, 2021 3:01 pm

camtwister wrote: ↑Fri Oct 22, 2021 2:33 pm Will you get the propshaft balanced before fitting?
This was an essential process during restoration of older cars that I've undertaken.

We don't need to as we've not actually touched it, only removed it and will be refitting.

Gazhyde · Post by **Gazhyde** » Sat Oct 23, 2021 7:00 pm

Day three was a day of general fettling, more parts arrived and dumped in the boot. Hammerite and paintbrushes were the main order of the day, some things we planned to paint, others missed by the powder coaters after blasting.

Today was mainly about painting brackets, brakes and sundries with Hammerite and also looking in to an oil leak up front. @Rally was down as well who helped identify the likely cause of the oil leak (and also tell me part numbers).

Most of the parts, everything will be black except for the upper wishbones that get a coat of silver which is closest to their normal aluminium colour. Befores:

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The drying rack, mid painting and afters...

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Gazhyde · Post by **Gazhyde** » Sat Oct 23, 2021 7:02 pm

Continued from above post...

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Didn't get pics of the oil leak, but it appears to be the timing chain tensioner which is common on the S54 engine. Thanks again to Rally, my favourite Insta Influencer

Another part to add to the list, but this is a simple unscrew/screw back in again and it's not horrendous to access either. Part 5 on this diagram referred to as "chain tensioner" pn 11317838675

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More parts delivered this week including an OEM set of rear discs, EBC Yellowstuff pads, HEL braided brake lines, Bigg Red caliper rebuild kits, Febi gearbox oil. More parts arriving this week, also forgot to order new bleed nipples for the calipers. The boots getting full!

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grannyknot · Post by **grannyknot** » Mon Oct 25, 2021 12:29 pm

Gazhyde wrote: ↑Thu Oct 21, 2021 6:00 pm My parts spreadsheet has 25 lines,

Love the work you're doing! I'm right at the beginning of the same process, going to strip the car down to the shell and build it back up all new and fresh. Any chance that you could post your spreadsheet of bushings? That would be a big help to me and I'm sure many others.
I notice you are replacing some bushings with original rubber and others with poly, how did you come to that decision of which is which?
Thanks

Smartbear · Post by **Smartbear** » Mon Oct 25, 2021 12:42 pm

Was wondering if one of those motorbike fuel tanks was from a Yamaha virago?

Rob

Joycey · Post by **Joycey** » Mon Oct 25, 2021 3:58 pm

Smartbear wrote: ↑Mon Oct 25, 2021 12:42 pm Was wondering if one of those motorbike fuel tanks was from a Yamaha virago?
Rob

Very good spot, its from a sister bike very similar, Yamaha Maxim X.

Gazhyde · Post by **Gazhyde** » Mon Oct 25, 2021 4:07 pm

grannyknot wrote: ↑Mon Oct 25, 2021 12:29 pm Any chance that you could post your spreadsheet of bushings?

Happy to, but of course the parts I'm listing are for a UK RHD model. Unsure if any differences for Canada. If circled in RED the obvious bits you are looking for. I've only included the PNs for the core subframe stuff, my spreadsheet is now growing with other bits and pieces that are mainly aftermarket like braided brake lines, caliper rebuild kits, oils and other sundries.

For reference I started with realoem.com and found the relevant sections to identify what's needed. You end up going down a bit of a rabbit warren locating the PNs to order because some of those shown on realoem have been superseded by later PNs - you find this by clicking on each PN in turn for the latest.

Subframe: Z4 E85 Z4 M3.2 Rear axle carrier
https://www.realoem.com/bmw/enUS/showparts?id=BT92-EUR-05-2006-E85-BMW-Z4_M32&diagId=33_1333

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Trailing arms and lower/upper wishbones: Z4 E85 Z4 M3.2 Rear axle support/wheel suspension
https://www.realoem.com/bmw/enUS/showparts?id=BT92-EUR-05-2006-E85-BMW-Z4_M32&diagId=33_1139

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Description BMW PN Amount
RUBBER MOUNTING front left 33312283573 x1 (Subframe bush)
RUBBER MOUNTING front right 33312283574 x1 (Subframe bush)
RUBBER MOUNTING rear 33312283419 x2 (Subframe bush)
ARB bushes 31352229711 x2 (Anti rollbar bush)
Rubber mounting 33326770824 x2 (Lower Wishbone bush)
Rubber mounting 33321092247 x2 (Upper Wishbone bush)
Handbrake bowden cables 34416785397 x2 (Handbrake)
Drop links 33552283743 x2 (Drop links)
Rear trailing arm bushes 33326770817 x2 (RTAB)
Upper/Lower Ball joints 33306852895 x4 (Ball joints)
Diff front/back PowerFlex PFR5-4620/PFR5-4621

Sorry for the lack of formatting, forum doesn't seem to like tables...

Gazhyde · Post by **Gazhyde** » Mon Oct 25, 2021 4:16 pm

grannyknot wrote: ↑Mon Oct 25, 2021 12:29 pm I notice you are replacing some bushings with original rubber and others with poly, how did you come to that decision of which is which?

Our philosophy is to replace everything with rubber bushes - either better than OEM, or OEM bushes.

The reason for poly on the diff was that the twin ear bushes don't look to have separate part numbers, so you need to change the whole rear cover. PowerFlex make a kit which does all 3 bushes (2 rear and the front), so that decision was convenience really. I'm sure if I did more digging I may have found the part numbers, but time was pressing!

grannyknot · Post by **grannyknot** » Mon Oct 25, 2021 9:09 pm

Gazhyde wrote: ↑Mon Oct 25, 2021 4:07 pm Sorry for the lack of formatting, forum doesn't seem to like tables...

Excellent, thank you.

camtwister · Post by **camtwister** » Tue Oct 26, 2021 2:32 pm

This is a helpful and informative thread.

Gazhyde · Post by **Gazhyde** » Tue Oct 26, 2021 3:38 pm

camtwister wrote: ↑Tue Oct 26, 2021 2:32 pm This is a helpful and informative thread.

Appreciate the feedback

Gazhyde · Post by **Gazhyde** » Fri Oct 29, 2021 7:37 pm

Day 4 update: Most of the day it was Trev and myself but we made great progress until Joycey turned up mid afternoon

It's another "bitsa" day, just trying to make progress in to the huge collection of bits and parts. We still have some more bits to paint so we got Trev setup on the bench, first thing to paint was the diff.

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Before we started on prepping it for paint we removed the 2 ear bushes, which pretty much fell out will minimal effort. If you look carefully you'll see the OEM bush cores are oval, so must allow for some lateral movement of the diff (remember that for later).

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Definitely the correct call to replace these, they are mush.

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Fitted the new PowerFlex Black bushes which are 3 piece, 2 poly sections pushed in from either side and a central aluminium core. The central core on these are circular, not oval. I'm keeping an open mind about these now they are fitted, will see how they go...

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While I left Trev painting I quickly change the gearbox oil and then got on with the 4 x subframe bushes. The 2 rear are the same part number, but the fronts are two different part numbers. The reason for this is that one of the fronts has an oval core and the other circular. Not 100% on the reason for this other than to make lining up the subframe easier when removing/reinstalling at a vague guess.

For this procedure it really pays off taking photos as you take stuff apart, lots of photos. The bushes are all directional in one orientation and have triangles in the rubber. However the diagrams don't tell you what direction they need to face, so referring back to my iPhone library I could zoom in on a previous picture and see that the triangles point to the front and rear of the car. Always take photos.

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Then it's a simple assembly of threaded rod and a large socket for the bush to pull through in to. The socket is essential as the bush protrudes through the subframe, and this allows full insertion! A nice coating of grease on the bush helps. Rinse and repeat 4 times.

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Back to Trev, who quite frankly has outdone himself this time. It looks almost new, not bad for a 15 year old diff!

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Gazhyde · Post by **Gazhyde** » Fri Oct 29, 2021 7:39 pm

Cont. from previous post...

aaaand, back to the bushes... This time the rear trailing arm bushes. We actually have a Z4 trailing arm bush removal tool, which includes a metal insert for pulling bushes in again. Again a thick coating of grease and simple threaded rod setup and ease them in.

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Each trailing arm has a top and bottom ball joint, again pretty similar puller setup but using 2 large sockets on either end. No specific pics of that, just and after shot showing them at the top and bottom. You'll also notice that we pushed the new Meyle HD wheel bearings in as well.

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This is a complete trailing arm, next stage will be to fit the hub and build the brakes on to it.

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There are still more bushes to go, but the supervisor arrived home and got stuck in as well.

Lower camber arm bushes.

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Upper wishbone bushes:

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Final job for the day is to remove the wheel bearing race from the hub face. This happens on every rebuild, Z3 or Z4 when you pull the hubs. There are a couple of ways to do this, and we found it easier to cut the race this time around. Think this is how we will do Z4's in the future, it's just quicker than heating and beating on it with a chisel.

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Lynchy · Post by **Lynchy** » Fri Oct 29, 2021 7:45 pm

Great work Gary and Lee

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