Time for an overhaul of my 1.9 '98 BMW Z3 Individual

[Andyboy]

'Anti roll bar'.

 

[Matt Barnes]

'Anti roll bar'.

soz

 

[Matt Barnes]

So another weekend...... thought I'd tidy up the Diff a bit more and then park it to do the rear calipers

Calipers were obviously very grubby but obviously fully functional as they only came off the car in July

plenty of meat left on those pads !!

my method of getting the piston out..... doesn't matter as I'm replacing them, Mole grips and hit it with a hammer... that works

mindless time with the angle grinder, wire wheel attachment and Dremel

then I decided I might be going a bit too far... POR15, then Hammerite red oxide on the exhaust hanger, ready for a top coat of Smooth Black

Then thought I'd treat my Wife to some new Christmas Tree decorations !!
these will get a top coat of Smooth Black Hammerite as well....

 

[Duncodin]

My calipers are even worse than yours. I was going to clean them up but decided My time would be better spent doing something else. I replaced the disks and got new pads but just couldn't get the new pads in. My old padsz like yours, still had a lot of miles left on them so I just gave them a bit of a rub and put them back in.

In the summer I'll do new calipers. They're not that expensive. And take aniother look at those too-fat pads.

I've also done the beam bushes and hand brake cable, spring rubber shim/seats etc but I just can't bring myself to polishing up my springs, diff and arms. They'll stay au naturel rust color.

 

[Matt Barnes]

My calipers are even worse than yours. I was going to clean them up but decided My time would be better spent doing something else. I replaced the disks and got new pads but just couldn't get the new pads in. My old padsz like yours, still had a lot of miles left on them so I just gave them a bit of a rub and put them back in.

In the summer I'll do new calipers. They're not that expensive. And take aniother look at those too-fat pads.

I've also done the beam bushes and hand brake cable, spring rubber shim/seats etc but I just can't bring myself to polishing up my springs, diff and arms. They'll stay au naturel rust color.

good effort mate.....I have new calipers on the front... did that a couple of Summers ago, got them off Ebay and are still decent.... I've got an 18 inch jaw Woden vice, so I'm hoping I can do the beam bushes in that... certainly do the Diff bush...don't really want to fork out for a press if I can help it.

 

[Duncodin]

good effort mate.....I have new calipers on the front... did that a couple of Summers ago, got them off Ebay and are still decent.... I've got an 18 inch jaw Woden vice, so I'm hoping I can do the beam bushes in that... certainly do the Diff bush...don't really want to fork out for a press if I can help it.

In keeping with my 'au naturel' rust color I didn't bother taking the beam out.

I have the car on a lift. Undo the shock and anti roll bar. Big jack under one end of the beam. Undo the bolts holding the beam and lower the jack and that end of the beam to expose about an inch of the big threaded bolt above the bush. I took a couple of bits of old metal that I wedge up against that threaded bolt then raise the jack again to take the weight of the car off that corner of the lift. The weight of the car is now on the centre of the bush. Then hot air gun on the metal around the bush. After around 10 mins of hot air the rubber starts getting soft and the weight of the car pushes the bush out. Job done. New poly bushes go in easy.

 

[Mazza]

There is certainly a lot of satisfaction in overcoming these problems and working out how to do these refurbs… and luckily lots of help and advice on ZRoadster.org to enable us to be able do these jobs….

Bloody @Lee and co at Zedshed HQ have a lot to answer for spawning a generation of old cyber mechanics

 

[Matt Barnes]

just finished grinding the other caliper..... as it was there..... piston was a lot harder to get out... even the @Mazza foot pump technique didn't budge it...so it was mole grips and hammer again....

now almost factory fresh !!

 

[Matt Barnes]

In keeping with my 'au naturel' rust color I didn't bother taking the beam out.

I have the car on a lift. Undo the shock and anti roll bar. Big jack under one end of the beam. Undo the bolts holding the beam and lower the jack and that end of the beam to expose about an inch of the big threaded bolt above the bush. I took a couple of bits of old metal that I wedge up against that threaded bolt then raise the jack again to take the weight of the car off that corner of the lift. The weight of the car is now on the centre of the bush. Then hot air gun on the metal around the bush. After around 10 mins of hot air the rubber starts getting soft and the weight of the car pushes the bush out. Job done. New poly bushes go in easy.

I've seen a bloke on Youtube do that with an E30 rear beam.......mine had to come out as most of my mechanicals were like brown tree bark

 

[Duncodin]

I've seen a bloke on Youtube do that with an E30 rear beam.......mine had to come out as most of my mechanicals were like brown tree bark

I got the idea from a post on this forum. Can't remember who it was. But it works a treat. Although that person made up a nice metal ring to push out the bush. I just stacked some old nuts in there.

 

[Matt Barnes]

Early Christmas break for me, as I didn't really take much time off in the Summer so !......I'm desperately trying not to spend every day of it in the garage.... but when I do.....

Probably overkill but gotten into the habit now that if it can rust... it's getting POR15 Metal Prep !!

even coated the Anti Roll Bar in it....

once washed and dried off with a heat gun, the once shiny metal is now the tell tale zinc oxide gunmetal colour

tried different methods of preparing to paint the Hammerite Red Oxide Primer..... tried an M10 threaded bar in the Flex hose hole

which didn't really work...

then tried hanging by a wire... which again, doesn't really work especially as it's relatively thick paint and using a brush, plus trying to stop it spinning on you.

so went back to my old method of painting one side, waiting for it to dry, then painting the other side...…..

flipped over once dried and did the undersides, that will level out and dry a flat dark orange

Not decided on a top coat colour yet, but might stick to standard Hammerite Silver......or... go colour coded and go for Fiji Green !!

 

[Matt Barnes]

another day, another painting session......so I gave the calipers and anti roll bar brackets another coat of Red oxide primer..

then hit the Anti Roll bar with a first coat of primer.... I'll do the ends when the rest is dry...

I'll do the ARB and ARB brackets in black gloss, and maybe the calipers in silver.....jury's still out....

then. I'm starting to run out of stuff to do off the car (apart from all the bushes)..that means I can turn my attention to sorting the sills and tidying up underneath the body. I can't reassemble to subframe yet as I have nowhere to store it... so I'll reassemble it, when it's nearly ready to go back in.

 

[Matt Barnes]

Yesterday I thought I'd change tack and have a go at DIY zinc plating...I've tried before with various degrees of lack of success..so thought I'd try again.... caveat, this is NOT a zinc plating kit... more of a witches home brew...

The plating solution is 1 litre of distilled vinegar and 100g of Epsom salts.. the zinc plates are left in overnight to create a "pickle" solution...

the power supply is an old charger, with the positive and negative leads split and crocodile clips attached

Then I setup my plating station...

Hydrochloric Acid (HCL) which is 36% concentration, this is to strip old coatings and contamination,
De-Ionised water, acts as a neutraliser between the stages... the Zinc solution is in the bigger tub and then the passivate is to harden the zinc layer.

caliper bolt was cleaned to within an inch of it's life

It was then put into the acid until the fizzing stopped...

After dowsing with de-ionised water, it was then into the plating bath for 20 minutes

This is the bolt after 20 minutes, with a good zinc plating

After rinsing with de-ionised water and dipped in yellow passivate for 20 seconds..

And that's where the success ended.... within 15 minutes, the parts had started to flash rust....I'd clearly gotten something very wrong...

There are two schools of thought.... one is.... after the HCL bath, you're supposed dry the part completely to stop the acid stripping process, the other school of thought is, you submerge in de-ionised water straight after the acid to stop the acid process.... I went the straight into de-ionised water to halt the acid... which clearly hasn't worked.....

I'd be interested to hear from anyone that's done DIY zinc plating and whether you used a bought kit, or DIY witches brew !!

 

[hard top]

I worked in the Oil & Gas industry and our threaded components on carbon steel were treated in phosphate baths and then in dewatering-fluid baths, so that made it easy for me to take parts in to work and get them done there

I had obviously never thought about DIY at home but I can't think of a reason why it would not be possible.

Link :- https://www.sciencedirect.com/topics/engineering/phosphate-coating

Link :- https://poligrat.de/en/chemicals/dewatering-fluid/

 

[Matt Barnes]

I worked in the Oil & Gas industry and our threaded components on carbon steel were treated in phosphate baths and then in dewatering-fluid baths, so that made it easy for me to take parts in to work and get them done there

I had obviously never thought about DIY at home but I can't think of a reason why it would not be possible.

Link :- https://www.sciencedirect.com/topics/engineering/phosphate-coating

Link :- https://poligrat.de/en/chemicals/dewatering-fluid/

thanks mate...you can get "proper" home kits but they're about 250 quid...I don't like shiny bolts THAT much .. I'll get the right way through a bit of fettling I'm sure...

 

[hard top]

All you need is the dewatering fluid, it displaces the water from the metal surface and leaves a thin protective coating after drying that temporarily prevents corrosion.

 

[Matt Barnes]

All you need is the dewatering fluid, it displaces the water from the metal surface and leaves a thin protective coating after drying that temporarily prevents corrosion.

@hard top ...cheers...I'll look into that, it won't affect the zincing process?

 

[hard top]

it won't affect the zincing process?

Not as far as I am aware but obviously there is only one way to find out ....

 

[Matt Barnes]

Ok so another go at plating !...… tried a stronger power supply which was a 500mA charger... using a Centre Positive charger jack... used a rivet as a Positive connection and the connector shell as a Negative.... nothing sketchy about this at all (this is only because I'm trying various chargers, and don't want to cut the connectors off them all)

but it gave a good fizz

The difference from the other day, is that I dried the parts with a heat after each stage, so acid dip in Hydrochloric Acid (HCL), then washed in de-ionised water, then DRIED COMPLETELY with a Heat gun. Only then did I place it in the zinc tank, and let it coat for 10 minutes. After that it was rinsed again in de-ionised water and then DRIED COMPLETELY with a Heat Gun

The other major difference from my failed attempts was to NOT leave them in the garage in a potentially moist atmosphere. So they are currently "resting" next to my PC monitors... I'll leave them t harden for 24 hours, and if there's no new corrosion, I'll buff them up using a polishing pad

 

[IainP]

Back in the day we trialled tin and gold plating crowns and substructures. I wasn’t involved but I’m pretty sure they had to be dried before final plating. Checked all our archived instructions today but nothing there.
I do remember the voltage was critical to make it work effectively, and the experiments were abandoned because both kits were battery powered. Battery didn’t last. Typical NHS, would have needed a committee to order a power supply.
Even further back I did quite a bit of copper plating. Alumina blasted, or polished and steam cleaned, wiped with acetone.
Flashed for the first couple of minutes at 75%, then 20 mins at 25%. % of what I haven’t a clue, the box was that old the case was made of wood, probably WW2. Looked like something from a Hammer movie, but it played very well.

If you want those pipe brackets in stainless Matt, I’m pretty sure I have a spare pair cut, only need bent in a vice.