Swapping 1.4 TDi rear axle for 1.6 FSi rear axle with disks

Fed up of my rear drums and was wondering about a rear disk upgrade, I know it's not a performance upgrade, it's more cosmetic and pleasing.

I have an axle from a 1.6 FSi available with disk brakes, looking at ETKA/Elsa they seem identical and the rear axle doesn't seem too hard to swap. Would the hand brake cable need to be changed?

Any help, deterrents, don't do it's not worth it etc....

I'm pretty sure our Teutonic friends on the German A2 forum will have done something like this. Maybe Brett can advise?

I guess you will get a little bit more braking power which given you have a decent remap could well be worth it, although rear brakes on the A2 get so little use due to the weight bias (and general low weight of the car) that rear discs do have a tendency to seize up.

They do definitely look nicer.

That's not helping is it?!

It's not a performance issue, it's just the drum seizure and aesthetics. I think it's a fairly easy job and having an axle with the disks already on makes it easier.

I definitely agree they do just look nicer!

The handbrake cables are different but only about £12 each.

Iirc the axle itself is the same, so you could leave that place and swap the brake assemblies over (I think there are four main bolts into the axle itself) because the mounts allow some adjustment, though swapping the complete axle may be easier/quicker and the bushes could be replaced at the same time. Either way it's probably worth a quick geo check afterwards.
Personally I'd love to have rear discs just so I don't have to tweak the adjustment on the shoes every couple of months.

Are the rear axles the same? looking at Elsawin the disk brake axle seems to have the brackets and holes required to mount the calipers, whereas the drum brake axle doesn't have this. Would that be correct?

Having said that, there are only two parts for the axle in ETKA and one has superceded the other.

8Z0 500 051 A and 8Z0 500 051 AB as the supercede. So I'm guessing the Elsawin diag could be wrong.

It seems that if I can remove everything from the axle stub, I can refit the disks with a new handbrake cable

I haven't had a look for a long time, and don't have Etka here, I thought the two versions were 1.2 and everything else, and then different stub axles for the different brakes.
I don't trust my memory at the moment though, I'd definitely advise no one else to (unless I forget)

There seems to be two axle stubs, light weight and normal, but no differences for brake types.

Hi Craig im also looking at doing this as i hate the drum brakes from aesthetics and i'm also aware that discs don't offer any more stopping power. When i looked at a donor axle it certainly looked to me that the "ends" can be swapped over along with the cables and possibly brake lines? i 'm hoping to get a complete axle and have it stripped and powder coated before refit. My fsi has discs and in the 5 or so years i have had it i have only changed the discs once(nearly 100k miles i have driven in it)
so good luck and i'm keen to know how you get on cheers mike

Hi Mike

From what I can gather, it's a fairly simple job, you need the splash guards, caliper adaptors, calipers, rotors & pads, new hand brake cables L&R, possibly new brake hoses for good measure. But everything should fit onto the existing axle stubs, unless I'm missing something obvious here?

I don't see the point of going to the trouble of swapping rear axle members now. Anyone got a link to the german forums from anyone that has done this mod and has piccys.

I have a vague memory that Mike Hill (Skipton) may have done this before. Although my memory is notoriously bad so I am making no guarantees!

There is a full picture guide from our friends in Germany (you wouldn't have guessed!). It doesn't look too bad of a job. The swing arm is the same, just get the brake components and handbrake cable. I'll post a link once I can actually find it again! I know I have the pdf saved on my home computer.

update: link found, as with other stuff, google.de and type your search terms in German after a translation

http://www.leibbrands.de/Scheibenbremsen.pdf

Nice find Humps. I've added your link to the 'How To - Mechanical' section of the Forum

Cheers Spike

Thanks for that, I can see some caliper brackets that don't seem to be mentioned anywhere on ETKA and elsawin.

They seem to have come from a lupo, so are available for around £12 each

He has also changed the handbrake lever, seems there is a difference between the two.

Good one Humps, I knew it had been done on the German forum
There you go Craig, go for it!

I'm not mechanically minded, I need to convince one of my mates at Audi to "help" me with it.

Plus the amount keeps building required to do the conversion.

Unless I can find a donor 1.6FSI or TDI90 then it's too expensive and cold to be messing about with brakes.

As you may have noted, there is a new rear beam P/n from chassis No 8Z3............ but it does not appear to be specific to 90 TDis and FSIs.
I wonder if that was the start of rear discs and the beam end plates now incorporate the extra lugs to cater for both discs and drums.

Cheers Spike

Ah, I wonder if that also ties in with the G22 suspension being brought in? It was tweaked to improve comfort; I think the front springs/bump stops etc are the same as earlier with G22 specific dampers, the rear springs are different and the bump stops longer, again with G22 specific dampers. I wonder if the torsional stiffness of the back axle was altered as well?

I think Spike's reason is more likely though... I guess it could be simple to check, have a look at an FSI or 90 rear axle and see if they're built in.

9N Polos 55kW> had rear discs so could provide the calipers and carriers, as an aside the 9N rear axle came in different stiffnesses and I wonder if it's fit an A2.

For those with 312s on the front, Golf/Bora V5s had 256 vented rear discs

Craig

I have removed my rear axle twice, once to clean the corrosion, powdercoat, and refit when I upgraded the suspension and again when I upgraded to the bigger fuel tank. At the 1st attempt, I investigated the option to upgrade to the disc brakes. The axle fitted to my (51) TDi is different to the FSi unit in that it does not have the rearward protruding "ears/tabs" where the caliper carrier would attatch to. I have confirmed this visually too when Petra had the FSi ColourStorm. This is something that Mike -A2Sumo can confirm - he has both TDi's and an FSi and can also visually inspect by looking at the reat axle from under the rear bumper. At the time, I did not want to spend the money to get a new beam but nor was I aware that there is a bolt-on bracket available to accomodate the caliper carriers. It is my understanding that Audi have now standardised on the newer axle beam that accomodated both brake arrangements.

As far as asthetics go, the disc is by far the better option but I think I have mentioned before on the forum - under normal operating condition, a drum brake is far more efficient than a disc brake. A drum with leading/trailing shoes, as fitted to an A2, also has a better handbrake as well as having superior stopping ability when reversing.

If anyone intends to remove the rear beam for repair/upgrade, I suggest it is removed from the main bush - avoid removing the styrup mounting as this will upset the rear wheel alignment. A good idea would be to replace the main bush too - not too difficult but does require a special tool to fit.

Hope that helps.

blue skies
tony