Another Rear subframe refurb...

[scottmgibb]

That is punchy! Hopefully the polys work out okay

[scottmgibb]

Didn’t get much time on the car this weekend, but did get the subframe bushes out, and the new poly bush ones have already arrived – quick delivery (from Poland I thick), as I only ordered them last Wednesday!



Now that the subframe bushes are out, I have the option of powder coating. Is this generally considered better than just paining? I have a quote for £150 cash for blasting and powder coating, and might get them to do a few other wee bits too if I go-ahead with it.

Ronin – did you cover up any of the threads or holes when you had yours done? Looking at the pictures in your ‘Rear Subframe Refurb’ thread it looks like they have powder coated inside the subframe bush holes too. Did this all work out okay?

[MikkiJayne]

Powdercoating is faster, but better is entirely dependent on who is doing it. Powder tends to wick away from edges as it melts (the same as some paints do), so it takes some dialling in of the settings to get a decent coating on sharper edges. My local powdercoater does pay attention to this because I'm happy to pay extra for better results, whereas other places I've been to who are simply interested in throughput don't bother with this and very quickly the coating splits along all the sharp edges and simply peels off.

Another thing to bear in mind with powder is that it doesn't always get in to all the little spaces, because it is electrostatically attracted to the metal. It tends to coat around the little gaps and not go in to them, but with something as big and complicated as a subframe, the guy holding the gun is not going to be flipping it around and upside down to check all the nooks and crannies. I tend to go round stuff like this afterwards with a paintbrush and make sure there's no bare metal left in the corners etc.

Painting gives you full quality control over the job, but its messy and time consuming, especially at this time of year if you don't have a heated work space. Rustoleum for example needs more than 24hr to dry at current temperatures, and really needs a good week to cure.

I went round the inside of the bush holes with a drum sander and made sure it was nice and smooth, but the thickness of the powder wasn't a problem for the D3 bushes. I'm sure it won't be for poly since thats flexible anyway.

[Ronin]

Originally Posted by scottmgibb

Ronin – did you cover up any of the threads or holes when you had yours done? Looking at the pictures in your ‘Rear Subframe Refurb’ thread it looks like they have powder coated inside the subframe bush holes too. Did this all work out okay?

I did but they took the tape off anyway (it would probably have burned in the oven)

I did however put 2 bolts into the arb bolt threads so that the thread inside didn't get damaged.

I think if i used a proper masking tape for this like a lead tape or something it would have worked out better and they wouldn't have removed it.

[MikkiJayne]

You can use kapton tape to cover things up as that is heat resistant within the scope of a powdercoating process, although its an arse to get back off once the powder is baked on to it. I also put sacrificial bolts in to threaded holes, and either nuts or tape on to studs.

The people doing the coating may have silicone bungs and covers for threaded components as well.

[scottmgibb]

Thanks for the comment on powder coating!
I have been thinking about this quite a lot, and I think I am going to go with the painting option. Mikki’s comments about quality being dependent on who is doing it backed up my own concerns, as I really do not know what any of the local companies are like.

They are also all quite far away, requiring a min 1.5h round trip to drop of and then collect.

I had also (quite ridiculously) forgotten that the son of the farmer whose farmland we live right in the middle of restores old tractors, and will be happy to sandblast the subframe (when he has finished ploughing!). His shed is about two fields away… 😊

This mean I can make sure it has been properly cleaned up before refinishing it. He would even be able to spray paint it after, but I will have to see what paint he would be using and what cost that would be. I will be happy to coat it in rustoleum combicolor myself (on that note, is it worth using an additional undercoat when painting bare metal with this stuff?; I have been looking at Rustoleum CombiPrimer Anti-Rust Primer 3369 or the Clean Metal Primer Spray).

The Autodoc order of bushes etc arrived yesterday but I have not dived into it yet – that will be some fun for the weekend.

[Ronin]

Any progress?

[scottmgibb]

Not as much as I would like unfortunately! It was always going to be slow progress…

The subframe is now away to get blasted and painted. Meanwhile I have started removing the old bushes and cleaning up and painting the various rusty parts.

I bought a small pressurized sand blasting pot to use outside and that has been very useful for smaller parts. Don’t fancy doing the whole subframe myself though – and I don’t think my (smallish) compressor would thank me for it either!

Next is fitting the new bushes and getting everything ready to re-fit. I will be addressing the fuel tank straps and the brake pipes before refitting the subframe though. I also need to get the calipers off for refurbishing at my local-ish brake specialist too.

I did come across a problem with my lift though (http://forum.a8parts.co.uk/showthread.php?t=16565); the steel beams prevent me from getting to the screws to remove the plastic undertrays - I should have removed these first. I think the easiest solution at this point is to just cut them out and replace them later when the car is back off the lift. Luckily someone on ebay was selling both sides and I got them both for £30 delivered. I will wait until I have them before doing anything to the existing ones though. The screws are pretty rusty so getting them out is not going to be fun (I looked at these a while ago when servicing the car to change the fuel filter and decided to leave them for another day…).

Then it’s on to replacing the driver door skin (there is a big hole under the handle which leaves lovely white stains running down the door when it rains; I have a replacement in the same colour from Prestige), fixing a leak at the near-side driveshaft, and fixing the front valance which is badly split.

I replaced all the front suspension arms/bushes etc with a full Meyle kit a couple of years ago, but I would like to do the actual subframe at some point too. Plenty to keep me busy 😊

I will keep this thread updated, but it will be sporadic!

[scottmgibb]

Can’t believe it is almost a month since I last posted in this thread…

Things are moving slowly but surely. I have got the subframe back and it is looking great – it has a really good finish. I have popped the poly subframe bushes in and they fit very well 😊





I also replaced all the bushes in the arms and hub carrier over the weekend. They all went in perfectly except one of the upper control arm bushes, which collapsed ☹. A different bush went in the hole no bother, so not sure what went wrong. I have ordered another and fortunately they are not too expensive…

Reassembly beckons, but while I wait for some final bits and dwell on what to do with the shocks (I am leaning towards getting the Bilstein B6 with the standard springs) I am going to take of the front subframe and get it blasted and painted too…

[Conan_the_Librarian]

Looking good.
Very interested in ride and handling with the new bushes.