Another Rear subframe refurb...

[Ronin]

Looking good man!

[scottmgibb]

Progress on this has continued to be slow but steady… long gone are the days when I got to spend all my evenings and weekends playing with old cars!

The front subframe is now off and away to get blasted and painted (along with the front springs). It cleaned up well with the needle gun and looks solid enough, but we will see if the blasting picks up any issues.



(Apologies for the weeds; I haven’t had time to get the roundup out yet!)

I have also now got a full set of Bilstein B6s, and the brakes are finally on their way back from Bigg Red. I also got that last bush that I wrecked replaced and pressed into the upper link, so these are all ready to go.

So I am now looking at the final(ish) items I still need to get for the rebuild. There are a few mounts/bushes and bolts which I am unsure whether or not are worth replacing, and thought I would see if anyone had any thoughts on this 😊 (for reference, the car has about 123K on it, and I assume these are all still original bits).

• Top mounts and ‘rubber buffers’ for both the front and rear shocks. These all seem in pretty good condition, but I obviously don’t have new ones to compare with. Are these typically worth replacing? Front mounts seem pretty cheap and available, but rears might be hard to get/expensive? The buffers look fairly cheap.

• Engine and gearbox mounts. How do you know if these need replaced? They look intact, but are reasonably ‘flexible’. Do they typically ‘go’? Availability seems to be questionable.

• Subframe bolts – do people typically use new ones when refitting? Are these stretch bolts? An online search suggests they are not particularly available, but I have not spoken with Audi/TPS yet.

I have also been wondering if there is anything else that I should be looking at while the subframe and front suspension is all out? I am changing both the output seals as they are both leaking (the left side badly). Is there any known issues that are worth addressing?

Thnaks, and sorry for all the questions!

[MikkiJayne]

Front top mounts are cheap and available from Febi. Rears are NLA as far as I know.

Engine and gearbox mounts are NLA. They settle slightly but rarely fail.

Subframe bolts get reused. They are technically stretch bolts (150Nm + 90) and the manual says to replace them but I never have. They're used on the D3 so should still be available if you do want to replace them. N 90711602

[Ronin]

the subframe bolts can be reused, be sure you thread them in properly when you put them in as some people have been known to cross thread or strip them

[MikkiJayne]

Originally Posted by scottmgibb

I am changing both the output seals as they are both leaking (the left side badly). Is there any known issues that are worth addressing?

The left output flange will also need a replacement bearing 6007C3 and a square-section o-ring 01V409133.

[scottmgibb]

Thanks for that – very helpful as always! I already have the o-ring on order, but I had not noted the requirement for the bearing. I now have that on order too – thanks for the link.

I have also ordered the front top mounts (as you say, they are pretty cheap), but will reuse everything else.

I am very much looking forward to putting everything back together.

[MikkiJayne]

I'll get on your bushes n stuff next week while Andrew's is getting polished

[scottmgibb]

Brilliant - thanks MJ

[scottmgibb]

And six (!) month later it is thread update time – sorry for the long post but it has been a while… it also diverts a bit from the subject of the rear subframe, but I guess that is the way working on these cars go…

The blasting of the front subframe revealed no further issues and it looked great all newly painted with the new bushes. I got the front springs blasted and painted at the same time and rebuilt the struts with the new Bilstein dampers (but forgot to take pics).



The front subframe went back on first while I waited for the final bits for the rear (thanks for these MJ!), and then it was its turn. I left most of the bits to be fitted once it was installed on the car, as I had to lift it up with a jack while balancing it and getting the bolts in, and I though the less weigh the better... MJ made some 3D printed alignment spacers to fit the polybush holes (which are smaller than the original ones) which worked a treat for aligning it.



After all the suspension bits were re-fitted I was able to lower the car off the lifts and properly remove the plastic covers in front of the rear wheels. The bolts all had to be cut away as the u-clips holding them had all disintegrated and were just spinning. There was an interesting amount of dirt on these…



This allowed me to finally replace the fuel filter which I have had for a couple of years waiting on the shelf! I also did all the fuel pipe clips as these had also disintegrated. Had to wait about a month for the clamps and plastic nuts to come from somewhere in Europe (Czech Republic, I think) but they got here in the end, and at a very reasonable cost.

Next it was onto removing all the fuel tank straps and blasting and painting them, along with the exhaust and handbrake brackets. Following MJ’s notes in one of her last WITWs, the nuts for the straps came off with no problem, so thanks for that!



Car was then back on the lift for the gearbox service. The cats had to be removed to allow me to get to the ‘hidden’ bolts as these were not for moving, which added a fun bit of extra work…
I have had a ZF kit sitting waiting for a couple of years (bought a the same time as the fuel filter), so it was good to finally get this used too. It was very pleasing to see it included everything you could need (even new magnets), though I ended up having to buy another couple of liters of oil as the box took everything it had and still wasn’t overflowing at the correct temperature… I also replaced the o-rings at the harness connector which were leaking quite badly. The sump was pretty rusty so I cleaned this up and painted it too. I spotted what seemed like more good advice from MJ on a Facebook group about refilling via the cooler pipe and that worked a treat – so thanks again!

The next big job was a weird one. The driver’s door handle has always been corroded around the handle, but it was starting to get really bad, with the handle feeling a bit loose and stains running down the door…
I got a replacement frame from Prestige in the correct colour (which thankfully matches very well) and went about stripping down the door, which as has been reported elsewhere, is a fairly major task. When it came to removing the handle, once everything was disconnected it just pushed through the frame in one piece – no need to separate the parts!



I had assumed it was just the frame that was corroded, but it turned out that the middle part of the handle was also in very bad shape, so it was back to Prestige for a handle, which fortunately they had. It was green, so I got my dad to spray the visible bits (mainly just the lock cover) to Dolphin Grey.




Then it was just a mater of (not so) quickly putting everything back together…

Then it was brake bleed time. I did a pressure brake bleed (2bar) but still had spongy brakes. It turned out that one of the (newly refurbished) rear calipers was retracting too much. I suspect the new seal was still a bit tight. I extended out the piston, left it a while and then retracted it to just the right point, re-bled just to make sure, and tested it again. Still a bit spongy. So I then bled the abs pump. This released quite a few bubbles and resulted in a much better peddle feel. Finally I fitted Mikki’s lovely looking brake block. The brakes now feel progressive and reassuring, which is something I have never been able to say before!

The last big job was fixing the front valance which got badly broken when the car was parked over a sunken wooden sleeper when the ground was frozen. When I came to move the car the ground had thawed, which caused it to sink, and as I reversed away the valance got more-or-less pulled off by the sleeper.
A bit (well a lot) of plastic welding, fiber glassing, bumper filler-ing and painting and it is looking significantly better than it used to (there were already a few cracks and splits on it). I might need to tidy the rear one now to match.
It was then off for its MOT yesterday…



…which I am happy to say it passed, though not with flying colours. It is showing as have a small oil leak for the second year running (both times the engine tray has been off) though I am not really sure where/what this is. There is certainly nothing dripping, even after sitting for a few days with the tray off. The headlamp washer pump needs replaced (I only realized this at the last minute and though it might have caused a fail; I have a replacement pump on order from Prestige). Both upper front arms have also been highlighted, but these have only done about 7000 miles… Fortunately the long bolt is still free, as I checked this when working on the front, so this should be an easy enough fix before next year.

The garage also performed a full Hunter alignment today and I should be picking it back up tomorrow.

Then it will be time to enjoy it for a while again before I do some major service work on the engine…

I will report back on any thoughts I have on the subframe polybushes and Bilstein dampers (though initial impressions are good)

Thanks for all the help on this thread, especially MJ without whom this would have been pretty much impossible.

[Ronin]

good job for the work and not giving up, not enough people do their own work on these