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

[DrWong]

so that forced me to turn my attention to the sill again... this time I took @DrWong s and @Althulas advice and went right back to bright steel.....I'm actually thinking/hoping ? I might actually save the jacking point and get a patch butt welded in ?... it's the lighting but that definitely shiny (where it's not pitted !)

That's more like it mate - much better! All the black stuff that's left is what the Deox will now attack.

It's worth pulling out the prestal cages that the screws for the outer sills go into, as likely to be rust behind them. They come out dead easy if you can get a hook behind it. It's one of the things that always gets me about the Redish videos, cos they always leave them in.

I didn't take them out the first time I did the sills and rust started spreading from some of them. Did some remedial work a year later and they've been fine since.

Subframe looks amazing!

 

[Matt Barnes]

That's more like it mate - much better! All the black stuff that's left is what the Deox will now attack.

It's worth pulling out the prestal cages that the screws for the outer sills go into, as likely to be rust behind them. They come out dead easy if you can get a hook behind it. It's one of the things that always gets me about the Redish videos, cos they always leave them in.

I didn't take them out the first time I did the sills and rust started spreading from some of them. Did some remedial work a year later and they've been fine since.

Subframe looks amazing!

good tips mate thank you...yeah I was shocked how well the subframe came out...apart from the seams and the inside where the diff sits there was only surface rust..those poly scuff discs are a game changer..I'll try and get the prestal cages out when I'm next under there...cheers !!

 

[Matt Barnes]

Bit of Segway.. DREMEL TIME !.... we all know how important a good dremelling is!... After mine packed up causing me a near heart attack as I've come to rely on it so much.. I decided to pull it apart...

did a continuity test on both coils... one was fine, the other side of the stator was dead....

managed to unhook the connector and saw one end of the wire to the connector had come off....

managed to unwind one loop of the stator coil to make a new connection

connected the pin connector back on, trimmed off the excess... tested it and got good continuity again !...put it all back together, Dremel now working again !! phew !!

 

[Mint]

Bit of Segway.. DREMEL TIME !.... we all know how important a good dremelling is!... After mine packed up causing me a near heart attack as I've come to rely on it so much.. I decided to pull it apart...

did a continuity test on both coils... one was fine, the other side of the stator was dead....

View attachment 274997
managed to unhook the connector and saw one end of the wire to the connector had come off....

View attachment 274999

managed to unwind one loop of the stator coil to make a new connection

View attachment 275001

connected the pin connector back on, trimmed off the excess... tested it and got good continuity again !...put it all back together, Dremel now working again !! phew !!

View attachment 275003

Always a good feeling to mend something
I take the view that if it is already broken I can't make it any worse but could save a few bob attempting to repair it.

 

[Matt Barnes]

Always a good feeling to mend something
I take the view that if it is already broken I can't make it any worse but could save a few bob attemting to repair it.

exactly.... you can buy replacement Stators for about 14 quid....but where's the fun in that !?...new Dremel is about 50 quid... I'd rather spend that on Z3 parts or materials !!

 

[DrWong]

Very impressive. Also prefer to attempt repairs on anything myself (cos I'm a tight northerner), but am generally baffled by anything to do with electrickery. Did recently manage to replace the PCB in my boiler myself though, which saved me a few squids.

The DIY mentality certainly helps if you drive a Z3, unless you have deep pockets.!

 

[Matt Barnes]

Very impressive. Also prefer to attempt repairs on anything myself (cos I'm a tight northerner), but am generally baffled by anything to do with electrickery. Did recently manage to replace the PCB in my boiler myself though, which saved me a few squids.

The DIY mentality certainly helps if you drive a Z3, unless you have deep pockets.!

I have a degree in electronic engineering but it was all theory and formulas...I'm relatively handy with electrics (home electrics etc)..but as we're among friends...I confess I saw this fix on a youtube video..and just went.."of course!..you idiot!"..and just did the same thing...

 

[Matt Barnes]

Afternoon.... well after deciding to jet wash the patio, while it was all out, I decided to jet wash under the car.. get rid of all the grime....

and then jet wash the tank.....I still have the vent pipe connected as I'm not sure yet how the black plastic connector comes off

now it's at this point I really need your help... because I have no arse end.. I want to get the back end higher, so I can get the jack stands on the chassis rails and jack up the front... this is the method I've thought of to jack up the back when there's no Diff.... do you reckon this is okay? as long as I'm not under it when I'm lifting... I think it should be ok ?... and then put jack stands on the chassis rails behind the wood ?

 

[Matt Barnes]

another day in the garage..... think I might have gotten a little carried away removing the surface rust from the subframe

after I got it lovely and shiny... I decided to give POR15 a go.... I'd had already bought it so it was a bit of a trial....

it is a bit of a faff as you have to keep it wet for 20 minutes.... I've not kept anything wet that long since my 30s !

after 20 minutes you're then supposed to wash it off thoroughly... I did made the mistake of letting it dry... and I got yellow discolouration...actually it looks worse now!.. but hopefully now have a zinc coating.

while that was doing it's thing.. I washed off the De-OX Gel from the Sill that had been on there for two weeks and started grinding that down with polycarbide discs....I actually got it so it looked like chrome in places !!.... I'm hesitant to grind it all smooth as that's taking out a lot of material ?

I used POR15 again on here... but this time didn't let it dry.... seemed a bit better than the subframe....looks a lot more dull now... but hopefully that's now a protective layer of zinc phosphate...

 

[DrWong]

You're right, insofar as if you want to grind the dark pitted areas away, you'll also have to grind the surrounding good metal to the same depth as well. That's what the Deox is for, but I think you need quite a few more cycles of applications. Mine weren't as bad as yours and took six weeks to get to the stage in the photo below, with each gel application staying on for about two-three days, before wire-brushing, cleaning off with water, and then applying/taping up fresh gel.

 

[Matt Barnes]

You're right, insofar as if you want to grind the dark pitted areas away, you'll also have to grind the surrounding good metal to the same depth as well. That's what the Deox is for, but I think you need quite a few more cycles of applications. Mine weren't as bad as yours and took six weeks to get to the stage in the photo below, with each gel application staying on for about two-three days, before wire-brushing, cleaning off with water, and then applying/taping up fresh gel.

View attachment 275263

thanks mate..... yeah I'll have another crack this weekend..... I was thinking of my holes and that my holes may be small enough to plug weld?... evidently you can do it in layers and work your way down the hole. I saw a youtube video of a guy plug welding a hole bigger than mine by slowly over time closing the edges of the hole until it was completely filled...dunno

 

[IainP]

You can plug weld, or spiral weld, holes like that. But, it’s not easy and it puts loads of heat in, though that shouldn’t really matter being the inner sill. A copper block, or a 2p coin makes it easier.
Those pits though, that steel should be 2mm thick, where the pits are will be below 1mm, if ‘twer mine i would cut it and insert a piece of new metal. Would be quicker.
Stick a finger in the jack point and see how rusty it is on the inside.
This was mine

 

[DrWong]

Can't advise on welding I'm afraid, as have no experience of it. Have seen similar on Youtube though, with fabricators closing holes up with weld.

Can you weld? Are you gonna have a go yourself??

 

[IainP]

Plug, or spiral, welding is not something to start on. It’s a fantastic way to make small holes bigger if you get the initial amperage or time wrong. Also it will spark, Lots, it’s a wonderful way of starting off a weld burn collection.
I’ve never attempted it with flux core, but I can turn my Portamig down to 15amps, turn up the gas and pulse weld just outside the hole, then pulse weld, at higher amps, in a spiral into the middle. A series of very short tack welds really, chilling periodically with an airline. Though a wet cloth would work.

 

[Matt Barnes]

You can plug weld, or spiral weld, holes like that. But, it’s not easy and it puts loads of heat in, though that shouldn’t really matter being the inner sill. A copper block, or a 2p coin makes it easier.
Those pits though, that steel should be 2mm thick, where the pits are will be below 1mm, if ‘twer mine i would cut it and insert a piece of new metal. Would be quicker.
Stick a finger in the jack point and see how rusty it is on the inside.
This was mine


View attachment 275987

thanks @IainP .. The jacking point is rock solid..it's just those two areas which must be where water's settled..thanks for the advice I'll have a think

 

[Matt Barnes]

Can't advise on welding I'm afraid, as have no experience of it. Have seen similar on Youtube though, with fabricators closing holes up with weld.

Can you weld? Are you gonna have a go yourself??

I've never welded but thinking of getting a flux core welder as they don't need gas..thought this would be a good test case

 

[Matt Barnes]

thanks @IainP .. The jacking point is rock solid..it's just those two areas which must be where water's settled..thanks for the advice I'll have a think

I really want to do everything on this myself so I learn new skills..I've never done any of this stuff before and I've learnt so much doing the Z3... if it means chopping out something the size of a credit card and welding in a new piece then I'm happy to give it a go

 

[DrWong]

If it was me, I'd be leaning towards giving it a go myself tbh. Always wanted to learn welding but never had a reason to - but you do! If you fk it up, just get a professional in, i.e. you'd just be back to where you started, no drama etc.

Doooo ittttt! Happy to be your enabler here hahaha

 

[IainP]

This is nearly the way I do it, my mig is modified to go super low so I can do a series of small tacks, then tack inwards in a spiral depending on how bit the holes is

View: https://youtu.be/bdnm1fG2Dao?si=DQPw5WrVONO2_DGw


Dont wear anything melty or flammable, or a flammable lining, ‘cos this happens.


A baseball cap reversed stops zapping the top of your head, back of the neck.

 

[Matt Barnes]

so it was back on the sills today.... hot one as well... hadn't spent a lot of time on the passenger side for a while... so stripped off the plastic... looks worse than it is.. they aren't holes

so set about grinding with the knotted wheel and polycarbide discs and got to this ...

Then decided to attack the rear ends of the sills... and channelled my inner @DrWong

on the driver's side..really got in there and picked out the seam sealer as much as I could.. .noticed a small rectangular hole... it looked so uniform it looks almost factory !!

then hit the rear of the Driver's side sill

then it was time for more Deox Gel and taping up..

things to do going forward.. I REALLY need to get the front wheels off the floor.....I'm nervous about lifting the front when the rear's on axles as I can't get to the sump or anything central... and I don't want to jack from the side in case it tips..... open to suggestions on how I can move the jacks to the chassis rails ....