Death or Glory! Nick attempts to work under the car
 

The suspension has gone clunky over bumps and ruts with nasty feedback through the steering wheel. This, combined with the MOT man mentioning some under body corrosion has persuaded me to stick the car on axle stands and do some work.

I will try to do fairly regular updates on progress, even if it is only slight progress, just so you know I haven't been crushed beneath the car.

There will be lots of pictures as people like pictures.

First get the kit you need
https://farm5.staticflickr.com/4654/...bd1706d0_c.jpg20180118_121402 by WCA!, on Flickr

Look how much space I have to work in
https://farm5.staticflickr.com/4608/...05c955b8_c.jpg20180119_114934 by WCA!, on Flickr

Look at all the crap piled up to make that space
https://farm5.staticflickr.com/4664/...84f1d981_c.jpg20180119_114947 by WCA!, on Flickr

Get the car in the garage
https://farm5.staticflickr.com/4674/...69d998a1_c.jpg20180119_115133 by WCA!, on Flickr

Realise I can't get the jack under the front of the car
https://farm5.staticflickr.com/4672/...cf8f9b6e_c.jpg20180119_115926 by WCA!, on Flickr

Drive up the ramp to raise the front a bit
https://farm5.staticflickr.com/4765/...5db025f9_c.jpg20180119_121702 by WCA!, on Flickr

Now the jack fits (and I have also spotted a leak)
https://farm5.staticflickr.com/4722/...2024dffe_c.jpg20180119_121848 by WCA!, on Flickr

Use the wooden block to get a bit more height
https://farm5.staticflickr.com/4722/...db9da82b_c.jpg20180119_122528 by WCA!, on Flickr

Round to the back and jack positioned just in front of the rear diff
https://farm5.staticflickr.com/4621/...a3d3a115_c.jpg20180119_124159 by WCA!, on Flickr

Once I had both ends raised I had to jack the front of the car up a bit more and re-position the axle stands as they had started leaning backwards when I raised the rear of the car. All raised and level now.
https://farm5.staticflickr.com/4751/...d629aea3_c.jpg20180119_125947 by WCA!, on Flickr

And the garage door shuts with millimetres to spare
https://farm5.staticflickr.com/4652/...b8015d86_c.jpg20180119_130122 by WCA!, on Flickr

Now I guess I ought to start doing something as you can see the corrosion.

Corrosion
 

Great to see someone do a thread on treating a Z3. We will all have to deal with this sooner or later. Take plenty of pics,

The first task went a lot easier than I was expecting so a quick update already.

iu am planning on replacing both lower control arms as mine are pretty cruddy and I suspect the clucks are coming from worn ball joints.
https://farm5.staticflickr.com/4757/...77aa33af_c.jpg20180119_132411 by WCA!, on Flickr

Before that though I decided to removed the front anti roll bar (ARB) so that I can clean it up and treat with POR15 to hopefully slow the return of the rust.

As I will be replacing the ARB links as well it seemed easier to just undo the 16mm bolt that held that to the control arm.
https://farm5.staticflickr.com/4724/...81f3fa09_c.jpg20180119_132924 by WCA!, on Flickr

Amazingly it unbolted with little or no swearing so I move onto the 14mm bolts holding the ARB bushes in place and again, they simply undid. What do these crazy Germans use to stop their nuts from sticking?
https://farm5.staticflickr.com/4655/...2964e23f_c.jpg20180119_132507 by WCA!, on Flickr

Within 5 minutes of starting the ARB was free from the car and I was feeling happy.
https://farm5.staticflickr.com/4631/...078de7d2_c.jpg20180119_133714 by WCA!, on Flickr

The bushes would need rteplacing and the holding brackets cleaning
https://farm5.staticflickr.com/4631/...965fc30c_c.jpg20180119_135014 by WCA!, on Flickr

There are lots of different sizes for the front ARB apparently so measure carefully before ordering the replacement bushes.
https://farm5.staticflickr.com/4631/...965fc30c_c.jpg20180119_135014 by WCA!, on Flickr

Now I need to work out how the get the ARB Drop link off the ARB as when I turn the nut, the whole thing just turns within the ball joint. As it is being replaced I suspect some violence may be used.

Next I try to remove the old lower control arms. I shall be using this YouTube video as my guide* : https://www.youtube.com/watch?v=4iSrW61Zbz4


* mainly for the music and cool hair style

Now I need to work out how the get the ARB Drop link off the ARB as when I turn the nut, the whole thing just turns within the ball joint. As it is being replaced I suspect some violence may be used.


No violence was needed. Just a 16mm spanner to hold the flat spots on the side of the link.

https://farm5.staticflickr.com/4757/...96ae6627_c.jpg20180119_143109 by WCA!, on Flickr

Easier to see when it is removed of course.
https://farm5.staticflickr.com/4602/...43b1d055_c.jpg20180119_143347 by WCA!, on Flickr

Removing the control arm looked easy in the video and for me, one of them was (relatively) easy, the other is currently still in place after being strongly sworn at but still removing to budge.

First, locate the nut above the ball joint at the wheel end.
https://farm5.staticflickr.com/4673/...ac4d7f4f_c.jpg20180119_143546 by WCA!, on Flickr

Loosen this as much as you can but it will soon hit a bit of the suspension. The best way I found to loosen this was drown in WD40 and leave for 20 minutes. Put a spanner on it and then hit the spanned repeatedly to gradually shock it loose. It is a really tight space and you can only locate the spanner against one pair of faces on the nut. The first one I tried by just pushing the spanner has slightly rounded those two faces on the nut so that control arm is currently still in place.
https://farm5.staticflickr.com/4703/...c89a2cf9_c.jpg20180119_154039 by WCA!, on Flickr

Once the nut is as undone as you can make it you need a ball joint splitter. If you don't have one then buy one for about £10 at Halfords or similar. Smack it repeatedly with a hammer until suddenly it pops loose and the control arm drops and you can undo the nut from the rest of the thread. This also has a 16mm flat spot to stop it from just spinning. It is worth remembering this rather than just spinning the nut pointlessly for about 10 minute (yes, I did).
https://farm5.staticflickr.com/4723/...8c152e45_c.jpg20180119_153954 by WCA!, on Flickr

Next find the 22m nut above the central ball joint. This is easier to point at than to actually reach with a spanner
https://farm5.staticflickr.com/4752/...0190c703_c.jpg20180119_144411 by WCA!, on Flickr

When I did get a spanner on it I couldn't swing the hammer enough to use the shock wrench technique so was reduced to just adding extra leverage. A small socket on the end of a socket extension bar gave just enough extra leverage to loosen the nut. Once the stick was unstuck I could just the spanner on its own to turn the nut but at no point was it finger tight like on some YouTube videos.
https://farm5.staticflickr.com/4707/...152431ec_c.jpg20180119_160107 by WCA!, on Flickr

Beforer trying to break the middle ball joint, locate the rear bush mounting bracket. These bolts are easy to get at and I loosened them both a few turns but left them in place while I tried to break the ball joint. When the ball joint gave up the control arm dropped suddenly but the two loose bolts help it in place just a few centimetres from my face. I was releived I though to leave the bolts in place
https://farm5.staticflickr.com/4616/...3836ec3a_c.jpg20180119_161535 by WCA!, on Flickr

Having moved my face I undid the bolts fully and the control arm fell smoothly to the ground.

Now to compare the old and new swing arms. Well the new one was black and clean instead of silver and dirty which was a start but the surprise came when I wiggled the bolts stick up out of the ball joints. On the old one they wobbled freely whereas with the new one they were absolutely stiff. The old ones were definitely knackered.

I will try to post a link to a video showing the difference. Please can someone click on the picture and see if they get taken to the video and let me know if it has worked.

https://farm5.staticflickr.com/4770/...51ee7857_c.jpgControlArms by WCA!, on Flickr

Summary of lessons learned following contemplation in the sauna with a bottle of wine:

1) You know that crap piled up around the garage to make room for the car? Stack it well. I have a VERY sore head after being hit by a falling chromed cocktail stool.

2) Wear safety goggles. All that rust, dirt and crap on the bits you remove falls straight into your eyes until you have it removed.

3) Find some magic gloves that don't tear, don't get in the way of what you are doing and stop all the little cuts and scratches on you fingers.

4) Don't fully unbolt the easy last two bolts at the back of the control arm before breaking the ball joints.

5) Speaking of ball joints, once you have used the ball breaker on them you need a 16mm spanner to undo them.

Of these wise words I only used number 4 today. Number 5 occurred after 10 minutes.

Anyway, Still alive and more tomorrow

Video works thanks. I am sure this thread will be of use to many.

Great thread, very useful guide that I'm sure a lot of people will find useful (and entertaining)

Your build up of 'things' in your garage looks surprising similar to mine (except my garage is a single :violin: )

The plan for today it to get the other control arm off and then as many hours as I can stand with a wire brush cleaning stuff up.

Probably less exciting photos but I will try to capture the Before and After as I go along.

I have hit a small snag so I thought I would post a quick update while I google the solution.

First, some useful bits when doing this. A nice warm wool carpet on the cold concrete garage floor and a couple of LED lamps. The lamps were a couple of quid from B&Q or similar and can be positioned around the engine bay so they cast light on what you are working on instead of a torch with a norrow beam simply casting shadows everywhere.
https://farm5.staticflickr.com/4605/...a92259ee_c.jpg20180120_103138 by WCA!, on Flickr

This morning the 22mm nut holding the middle ball joint on came loose fairly easy. Watch out for the two studs that held the ARB bush in place as the can give a nasty scratch. Also note that with the ARB in place it would be much more difficult to get at the bolt so it looks like removing it first was the right thing to do.
https://farm5.staticflickr.com/4715/...60c9cc97_c.jpg20180120_101903 by WCA!, on Flickr

Feeling confident and after slightly loosening the two bolts holding the rear bushing I had another look at the 18mm nut by the wheel. Why do all the guys on YouTube have so much more space to work? I was totally blocked by that bracket and was in serious danger of totally rounding what remained of the bolt so I stopped and assessed the situation.
https://farm5.staticflickr.com/4651/...65f3224f_c.jpg20180120_101231 by WCA!, on Flickr

I had a piece of metal bracket in my car that the other guys didn't. Why?

I had fitted after market adjustable coil overs and they were blocking proper access to the nut. Now I am going back to the garage to disconnect the coil overs and hopefully get proper access. I might we do this on the other side as well as it will made the wire brushing around tghe brake a whole heap easier.
https://farm5.staticflickr.com/4627/...0902fe48_c.jpg20180120_101258 by WCA!, on Flickr

I tried just removing the lower bolts and loosening the top bolt so I could move the hub a bit
https://farm5.staticflickr.com/4715/...e43f40b4_c.jpg20180120_112139 by WCA!, on Flickr

This gave me a better view of the nut that I was gradually rounding off but still not enough room to work
https://farm5.staticflickr.com/4630/...27de7be2_c.jpg20180120_112223 by WCA!, on Flickr

Releasing the top bolt let the whole hub drop supported just by the ABS wire and the brake hose. A quick grab for a spare axle stand saved the day! I now had lots of room to work. It still wasn't easy but at least it was not possible.
https://farm5.staticflickr.com/4616/...cffd7e51_c.jpg20180120_113912 by WCA!, on Flickr

I have now taken a break before continuing with the ball joint breaker to soak my thumb joint in iced water. Yes, I hit just smack my thumb joint with a lump hammer. Ow!

When working on rusty suspension nuts and bolts I would suggest that you only use 6 sided sockets, they won't slip like 12 sided sockets, once you have rounded a couple of nuts off you will realise why.
A bit of WD40 and a quick wire brush on the visible threads makes the job much easier.

The position of the nut before I dropped the whole hub meant an open spanner was the only option unfortunately. I agree with the 6 sided principle though.

I am thinking of sticking copper slip on the contact points and bolts when I put it back together. Any thoughts on that?

Copperslip is a very good idea for suspension and brakes.
I did put it on bonnet releases but found it dried out so not so good.
With suspension parts, if you can get a six sided socket on, use a breaker bar rather than a ratchet as you can damage a ratchet. A decent extension bar is always very useful, not much you can't undo with a 6' scaffold pipe on the end.

1. Has to be a contender for quote of the year already.
3. Marigolds

I can confirm that cleaning the rust and crap off the bottom of a car is not something you want to do. you want to pay someone else to do it. There is no fun, pleasure or joy in doing this. Anyway, I went through this to show you why you don't want to.

First, get a selection of wire wheels that will fit in your hand drill. I started using a battery drill but even using an 18v Panasonic drill, the corded version was so much better and the cord didn't really get in the way when working. The ones on the right were good for most surfaces. The bright copper wheels were best for cleaning narrow pipes as you could get them to clean all around the pipes and tubes. The skinny round on on the left was okay for small spaces.
https://farm5.staticflickr.com/4631/...ecdbc296_c.jpg20180120_131436 by WCA!, on Flickr

Here is a 'before' of the hub
https://farm5.staticflickr.com/4743/...051c0e24_c.jpg20180120_131656 by WCA!, on Flickr

A close up of my finger tip and the cracking rusty surface of the metal.
https://farm5.staticflickr.com/4749/...6033cbfd_c.jpg20180120_131702 by WCA!, on Flickr

Breathing mask and goggles before starting. Believe me, you really, really want to be wearing these or preferably one of those fully enclosed white space suits.
https://farm5.staticflickr.com/4660/...c88334e2_c.jpg20180120_131847 by WCA!, on Flickr

The wire brush in action. Be careful not to brush the rubber bits as they disappear quicker than the rust.
https://farm5.staticflickr.com/4708/...51855106_c.jpg20180120_132027 by WCA!, on Flickr

I am not sure of the benefits of removing rust from the brake discs but they were easy to get at so I gave them a quick once over.
https://farm5.staticflickr.com/4697/...1915bbc2_c.jpg20180120_132415 by WCA!, on Flickr

A bit less scabby now.
https://farm5.staticflickr.com/4632/...34d52dfb_c.jpg20180120_132619 by WCA!, on Flickr

The crusty flaky surface is now smoother. Still some rust but I plan to paint it all with POR15 which is fine only small amounts of rust as long as you remove the flaky bits.
https://farm5.staticflickr.com/4649/...08d049ec_c.jpg20180120_133316 by WCA!, on Flickr

Having cleaned up the drivers side hub I decided to start at the front of the car and work my way back underneath it. Lots of pictures, mainly for my own record but basically you are stuck in a cramped space in a cloud of rusty dust with a drill whirring in front of your face. No pleasure at all.
https://farm5.staticflickr.com/4670/...9e127cf3_c.jpg20180120_140601 by WCA!, on Flickr
https://farm5.staticflickr.com/4664/...7573d53c_c.jpg20180120_141151 by WCA!, on Flickr

https://farm5.staticflickr.com/4696/...4c005908_c.jpg20180120_141223 by WCA!, on Flickr

https://farm5.staticflickr.com/4740/...3f310859_c.jpg20180120_141611 by WCA!, on Flickr

https://farm5.staticflickr.com/4746/...dfc8eaa6_c.jpg20180120_141642 by WCA!, on Flickr

https://farm5.staticflickr.com/4626/...b294e272_c.jpg20180120_142339 by WCA!, on Flickr

https://farm5.staticflickr.com/4613/...4a374fa8_c.jpg20180120_142955 by WCA!, on Flickr

https://farm5.staticflickr.com/4696/...8d2a5aee_c.jpg20180120_143846 by WCA!, on Flickr

This got me about half way along the car and I decided to call it a day. I know it is an early finish but I am not being paid so there is no rush.

And this is what my nice woollen carpet looked like after all that cleaning
https://farm5.staticflickr.com/4605/...8ce5bdcb_c.jpg20180120_151118 by WCA!, on Flickr

I shook the carpet out but needed to clear out all the dust. Google suggests compressed air so I opened the garage door and generated some compressed air in my own special way.
https://farm5.staticflickr.com/4657/...cb7822da_c.jpg20180120_151306 by WCA!, on Flickr

When using the wire brushes, use the brass cup type in an angle grinder, far more effective than a drill. You must wear goggles as some of the strands come loose.
The brass type doesn't damage the metal and can also be used as a rapid way of removing paint as well as rust.
Before painting the parts I would suggest brushing on rust converter, this kills the rust, then wash it off and paint. Loads on eBay including some in aerosols so you can convert rust that you can't get too, not ideal but better than nothing.
Last picture, is that one of those Black & Decker anal probes?

I thought the angle grinder would be too fierce and hard to control in the limited space.

I plan on using POR15 Metal Prep, wash it down and then silver POR15 before top coating it in gloss black.

POR15 will degrade in UV so the top coat is important.

The washing off of the metal prep is worrying me as I am stuck inside a garage. Perhaps wash off and leave an air heater on overnight.

I still need to get the back of the car prepped before that which is probably tomorrow taken care of. I will try the angle grinder and wire wheel on the ARB and use that for the first test of Metal prep, POR15 and top coat as that is free standing and easy to work on. That might help me plan the car underbody painting.

Thanks for this useful thread, Nick.

I have all of those parts in my round tuit box.

I'll be doing mine al fresco on the gravel drive once the weather improves.

My tips:

Penetrating fluid- 50% acetone + 50% ATF sounds like the best.
Gloves- "rigger" gloves from Poundland
Axle stands- cut from railway sleepers - they don't collapse.
Undercar work- I'd really like one of those tipping rigs.
Rust killer- Bilthamber Hydrate. Can be painted over when dry.

Weather isn't great and it looks like it is raining for the rest of the day (maybe forever)
https://farm5.staticflickr.com/4614/...151534d1_c.jpgWeather by WCA!, on Flickr

I know I have the luxury of a garage but today I was planning on de-rusting the back end of the car which would be easier with the garage door to be open. I will spend some time walking around the garage, sucking my teeth and planning before I decide if I will fre up the wire wheel again. I must admit I am not looking forward to another session under the car after yesterdays.

Updates may follow

And I thought the cold weather was part of your plan........ Any bashes to the knuckles or similar have little effect because the hand is so cold :roll:

It's currently snowing here.

My plan is to complete this before the surgeon takes my foot of to try and fix it back on again straight this time. Roll on Feb 1st. Left is how it looked two years ago, right is what it looks like now. the plan is to put a couple more bolts and possible a plate across the joints marked in blue
https://farm5.staticflickr.com/4558/...01b0bbb0_c.jpgAnkle by WCA!, on Flickr

So with that thought driving me on I bought a fan heater to take the edge off the chill. Might also help the drying process when applying the degreaser, metal prep, POR15 etc
https://farm5.staticflickr.com/4671/...65610320_c.jpg20180121_111534 by WCA!, on Flickr

Crawling under the car showed very little corrosion or damage on the middle section immediately behind where I finished yeasterday. I was glad.
https://farm5.staticflickr.com/4695/...229fbb9b_c.jpg20180121_113957 by WCA!, on Flickr

There was this rusty bracket just in front of the driver side rear wheel. I also realised I still had the rear wheel on and very little room to try and remove in. A problem for later in the day.
https://farm5.staticflickr.com/4631/...9b25788e_c.jpg20180121_114010 by WCA!, on Flickr

A little possible bubbling on the rear suspension but nothing like as much as the front end. I wonder what the wire wheel will reveal.
https://farm5.staticflickr.com/4670/...48357cfc_c.jpg20180121_114020 by WCA!, on Flickr

There was just one bit of the old under seal that was lifting around this bracket. I am hoping not to disturb the rest which still looks good. Possibly just degrease and paint over with top coat for a nice consistent finish.
https://farm5.staticflickr.com/4700/...9fa74675_c.jpg20180121_114102 by WCA!, on Flickr

Looking at the earlier pictures there was surface rust on the bits behind the rear diff and possibly in the brake pipes. I will check this out when I get back under the car with the garage door open.

Nick the photo series is excellent, stay with it.

A day of some success, some challenges, some dirt in my eyes and finally a problem.

Rusty Clamp
https://farm5.staticflickr.com/4666/...facd81e5_c.jpg20180121_121300 by WCA!, on Flickr

Less rusty clamp
https://farm5.staticflickr.com/4650/...4dacf762_c.jpg20180121_121952 by WCA!, on Flickr

Just a little bubble of rust...
https://farm5.staticflickr.com/4757/...4d9f2843_c.jpg20180121_123417 by WCA!, on Flickr

Grew as I ran the wire wheel over it
https://farm5.staticflickr.com/4656/...6d84f876_c.jpg20180121_125010 by WCA!, on Flickr

The rear diff didn't show much rust but had a bumpy silver surface. I prodded it with a screw driver and a big lump fell off (top of picture, side of diff)
https://farm5.staticflickr.com/4746/...fc5a1d9b_c.jpg20180121_125249 by WCA!, on Flickr

A bit more prodding got most of the silver stuff off.
https://farm5.staticflickr.com/4660/...c36dcf81_c.jpg20180121_130145 by WCA!, on Flickr

This was properly thick like a tarts make-up
https://farm5.staticflickr.com/4658/...67d98683_c.jpg20180121_130306 by WCA!, on Flickr

A final buzz over with the wire wheel got down to metal eventually
https://farm5.staticflickr.com/4619/...6ea4c3e4_c.jpg20180121_131443 by WCA!, on Flickr

Rear ARB looked rusty
https://farm5.staticflickr.com/4707/...2401247a_c.jpg20180121_153704 by WCA!, on Flickr

and the drop link rubber was clearly knackered so they would need replacing which would make it easier to clean the rear ARB once removed.
https://farm5.staticflickr.com/4654/...b7a905b9_c.jpg20180121_153734 by WCA!, on Flickr

No more photos at this point.

There is one nut holding each of the drop link brackets on. The passenger side one undid, the drivers side didn't and is currently soaking in WD40 until I get another chance to attach it but it is so far gone I am not sure how I will get it off.

There is one nut holding each of the ARB bush brackets in place. Neither of these move even a little bit and the 12 point socket just spins. I will see if I can get a 6 sided one but again I fear the worse.

Any suggestions less drastic than the angle grinder are welcome.

If you can get in there to cut through the bolt that is often the quickest and easiest way. You can struggle for hours trying to get rounded nuts off a seized bolt. First rule with badly rusted bits, "If in doubt, cut it out"

As well as 6 sided sockets being better than 12, the sockets which use the flats are much better than both 12 or 6 sided! I've got some seriously rounded nuts off with wall-bearing sockets.:thumb:

Jeff you absolute bastard. Every photo I show now will look crap. I aspire to your level and ability.

YOU INSPIRE ME, THANKS MATE

��

As I said, thanks. I will be trying my best but I start from a point of no experience and learning as I go along. I listen and look at those that know and attempt to copy.

I post my threads so that other first timers don't need to make the same mistakes as me.

I don't mind being honest about my mistakes and learnings but sometimes just watching people who are experts can become daunting.

Having said that, can the experts keep on posting the right way to do things so I can continue to learn.

My thoughts entirely, utter, utter bastard. I'm going to inspect those pictures very carefully in the hope that I can spot a paint run.

Jeff is not OCD!
Simply focused. We can all take a lesson here. Well done.
We just need to keep on keeping on.

Jeff is what we aim for.

I am my best efforts

And that is how we should all should be!

Bloody typical - Sunday is pisses down the whole day and then Monday when I am back at work the sky is blue and not even a breeze. Fortunately I am working from home today so managed to nip out for a few minutes. I didn't have time to go under the car, getting dirty and trying to remove the remaining three nuts but I did manage to use the dry weather to take the front ARB I removed earlier outside to clean it.

https://farm5.staticflickr.com/4609/...98822d31_c.jpg20180122_104220 by WCA!, on Flickr

As the ARB is just a solid lump of metal and I was standing outside wather than tucked under the car I felt happy using the angle grinder with a big wire wheel on it. So I started with this:
https://farm5.staticflickr.com/4709/...71e4b485_c.jpg20180122_104257 by WCA!, on Flickr

And less that 2 minutes later I had this:
https://farm5.staticflickr.com/4672/...0bd41897_c.jpg20180122_104504 by WCA!, on Flickr

The whole thing done and dusted within 10 minutes, including getting the tools and stuff out of the garage and putting them back.
https://farm5.staticflickr.com/4697/...0eb9a7ea_c.jpg20180122_110218 by WCA!, on Flickr

I wish I was brave enough to use the angle grinder under the car, it would have been so much quicker. Having said that when using it standing I was getting hit in the legs with the occasional loose wire, if I was lying under the car then they would have been bouncing off my face and head.

looks good. If you need to really make sure all the rust is gone, then I recommend Hammerite Rust Remover, which does exactly that - I used it on the rear brake hubs for my Quantum over 10 years ago -(ok only 9 if those have been outside), but after painting they have stayed good (liquid or for this, the jelly version). I add that it's the only Hammerite product I'd use - I think Hammerite paint is the Devil's product!

The angle grinder is not as aggressive as you may think, try it on an old panel with paint on and you will see that it removes the paint but does not damage the metal at all. Just make sure you are using a metal brush with the gold/brass coloured wires, you can get heavy duty thick wire cups but they are very aggressive.
If working under the car I would suggest a balaclava (the one you go stalking in) and a good tight set of goggles and decent gloves.
I find the wires spin off into my jumper, real pain to pick out.

Mitchelkitman - I plan to treat the whole underside with this little lot.

https://farm5.staticflickr.com/4655/...b745c428_c.jpg20180121_104718 by WCA!, on Flickr

TFR350 - Metal degreaser dilute 1 :25 cleaner to water so 5L should last me the rest of my life.
POR15 Metal Prep - Creates the perferct surface for the rust treatment
POR15 Sliver - I whole silver so I would get good contrast to the black top coat rather than painting black over black
Gloss Black Top Coat - Covers the POR15 which degrades in UV apparently
Cheapest brushes I could find as POR15 does not clean out of brushed.
Gloves because POR15 does not was off skin, you literally have to wait for the skin to flake off. I got some on my forehead 2 weeks before a friends wedding and despite repeated scrubbing for 12 days I ended up using a razor to shave my forehead and remove it.

Hopefully I will never need to touch the underside again.

Wow - Certainly a thorough job! I like the idea of silver followed by an 'overcoat' of black - If any chips off you'll easily spot it. Re the brushes - have you tried cleaning them with acetone? The benefit of good brushes is being able to get a good even/brush mark - free finish very quickly, but I'd certainly not want to throw away a brush costing £8 :nono:

That is a pack of ten brushes for £8. Cheaper than cleaning them.

Bit pricey those brushes, I buy the 2", 24 brushes for £9.35 inc P+P Ideal for fibreglassing and slapping on some paint underneath. Postage is a bit slow.

https://www.ebay.co.uk/itm/RREM-I-24...kAAOSwubRXDkPu

Hmm...

I am now wondering about getting a slightly softer wire brush for the angle grinder and doing the whole underneath of the car.

Do I want the hassle and disturb what looks okay on the surface?
Do I want to do this all again in a years time when I realise there was rust under the original paint?

Decisions, decisions...