Fitting 4W disc brakes? Other wheels?

[Bulley]

Has anyone attempted to fit newer-designed, larger discs to a 412? how about on the rear? I'm thinking specifically about the A2 Jetta/Golf GTI set up, but I'm interested in ideas/experieinces.

------------------
Matthew
[email protected]

Towns can't pave thier way to beauty, or drive their way to prosperity.

[func412]

Here´s my idea getting ready to 1973 / 412->

[ubercrap]

Are those Porsche 944 turbo hubs and calipers? Give us the details if you're gonna tease us with pics.!

Anyway, these guys specialize in fitting custom brakes to VW's, etc...

http://www.vdubcustoms.com/

Oh, and the late A2 GTI/GLI maximum brake size I believe was 10.1" vented rotors, which might actually be smaller diameter than late type 4 brakes, not sure about early, though the GTI brakes would be vented. Still, I'm not sure it would be worth the hassle if you didn't go bigger and vented. Many earlier A2 GTIs and GLIs I believe came with just 9.4" vented rotors. All the A2 9.4" brakes, used the same caliper I believe, but the vented rotors used thinner pads. Corrado G60's came with 11" vented rotors, as did VR6 Corrados I believe, which are A2 based. Early A3 VR6 GTIs also have 11" rotors, while later cars got the 11.3" rotors. The 11.3" A3 calipers are the same as the early Audi TT 12"? brakes, just with just different carriers.

CB performance has a rear disc brake kit which I believe we concluded would fit with very minor modifications. Also, Mid America Motor Works sells a kit that is similar, if not the same. MMAW also sells the caliper brackets seperately, but I don't know which calipers they use, nor what rotor you could use. Possibly Porsche 914?

[func412]

Those are Volvo 240 front calipers (4x38 mm) and audi 100 (C4) rear hubs. The disc will be BMW e34 (302mm) vented disc.

Only some small machining must be done to fit the disc (bolt pattern 5x112mm in audi (bmw 5x120mm)

[ubercrap]

Those are Volvo 240 front calipers (4x38 mm) and audi 100 (C4) rear hubs. The disc will be BMW e34 (302mm) vented disc.

Only some small machining must be done to fit the disc (bolt pattern 5x112mm in audi (bmw 5x120mm)

Cool! Did the Volvo calipers bolt straight on? Oh well, I don't know of any 240's that came to the U.S. with 4 piston calipers.

[func412]

Cool! Did the Volvo calipers bolt straight on? Oh well, I don't know of any 240's that came to the U.S. with 4 piston calipers.

Yes, they bolt on straight. And the bonus is that they reguire bigger brake discs. All volvo 200 series in Finland has 4 piston calipers in front. Some are vented, some are not.

I´m just planning vented discs to rear with subaru Leone front brakes. They have 54mm piston and a handbrake.

We´ll see if the original master cylinder (20,64mm) will still be enough for those calipers? Maybe not.

Edit: those calipers still fits in most 15" wheels.
BTW The Audi hubs have the inner bearings the same as type 4, but outer bearings needs to be replaced and fitted to original stub axle.

This conversion might be done also with the BMW front axle bearing package by replacing the original stub axle.

This is guite a heavy set of brakes so I hope that my car is still able to run fast.

[farmer]

Func412. You seem to have thought a little into this. I was thinking about replacing the entire strut and trailing arm with one from say a 944. But have never gotten around to actually get my hands on a 944 strut and comparing the two. The reason was that if that was possible, you got an approx. 40 mm lowering job for free, better brakes, space for wider wheels if needed, and a lot more adjusting possibilities on the front end.

What do you think about that.
T.

[ubercrap]

Hmm...I would be skeptical of the 944 strut swap, but other people have suggested the possibility before. There would be so many areas for problems, it would be a miracle if it just bolted on...

Anyway, func412, I found that Volvo 240s did indeed come with 4 piston calipers for the U.S. market in versions with vented or solid rotors! Seems like it would make sense to go vented if one is going to the trouble to custom fit brakes! If you would be so kind to share your further brake secrets, I have some questions. I'm not sure I understand exactly what you did to make the outer Audi hub section/bearing mate to the Type 4 spindle? Also, does the center of the BMW disc fit the Audi hubs, or is there some machining needed? Does the BMW disc line up properly with respect to the caliper, or is it that critical with the 4 piston calipers?

[func412]

I was thinking about replacing the entire strut and trailing arm with one from say a 944

I havent thought of porsche brake system because of two reasons. First they're usually guite expensive and second I dont like 5x130 bolt pattern because the wheels are more expensive and harder to find. They would be cool though. When I started to think better brakes, I had first in mind to replace the 412 front end with BMW E30 325, beacause it has been good on racetrack. I haven't buried that idea yet, but I try this "easy" way first. I´m planning "budget" system, because this is just a hobby for me.

I found that Volvo 240s did indeed come with 4 piston calipers for the U.S. market in versions with vented or solid rotors!

Good!

If you would be so kind to share your further brake secrets, I have some questions.

Well Í´m happy if this planning will help you too. There´s no reason to tease you. I must say this system has not been tested yet, but it will be within few months.

I'm not sure I understand exactly what you did to make the outer Audi hub section/bearing mate to the Type 4 spindle?

The outer bearings cup diameter is 45,237mm in audi hub. In VW it is 39,878 mm. The stub axle diameter in VW is 17,462 mm. I didn't find proper bearing to this so there is two ways to solve this problem; to machine hub or stub axle. I decited to machine stub axle.

I bought bearing "12749/710" which has 21,986 hole in the center and fits into audi hub directly. So I need to machine a bushing into a VW spindle.

Also, does the center of the BMW disc fit the Audi hubs, or is there some machining needed? Does the BMW disc line up properly with respect to the caliper, or is it that critical with the 4 piston calipers?

Bmw disc needs also a centering ring machined into audi hub. Also the disc must be machined into 5x112mm bolt pattern (from 5x120mm)

Bmw disc does line up very near when thinking of offset to caliper. There is 2-4 mm need to be adjusted. I could machine the stub axle when the hub would be adjusted closer to caliper and by that you could get an original wheel gauge. I decited to machine calipers, so i get few mm more space for new 5x112 wheels from inside. That is also easier way. I´m goimg to replace also the rear drum brakes with discs and as a result the original wheel gauge is going to ingrease few mm also at the rear.

The bmw e34 525-535 front disc (302 mm) seems to be perfect as we think how good it fits to brake pads by discs diameter. The newer BWM disc was 296 mm by diameter and it was 2 mm "short".

There seems to be third way to implement volvo brakes. I havent measured yet, but the BMW E39 bearing (includes stub axle) would be one solution also if the original stub axle could be removed an replaced by the bmw bearing system. That would maybe reguire smaller machining and result a bolt pattern 5x120mm. Unfortunately the 412 spindle has so little material, it might make mouting of the bmw E39 bearing a little bit difficult.

Here are pictures of bmw bearings ->

[ubercrap]

Great information, thanks! You've really got me thinking now. The main advantage of your brake setup is the direct bolt on of the nice 4 piston Volvo caliper. I really like this, as a caliper adapter for, say, Porsche calipers looks complicated and potentially fragile, and having somebody like vdubcustoms make one-off components might prove quite expensive, not to mention the expense of the calipers. One of the standard things that vdubcustoms does is adapt the variety of Porsche 944 hubs to VW spindles, so the cost seems reasonable for this. Porsche 944 turbo vented discs are 298mm and are designed to work with very similar looking 4 piston calipers, as well as looking quite similar to the BMW discs you are using; I wonder if they could work?

[func412]

Porsche disc is not very good choise with the audi hub, beacause porsche disc has so big center hole (103mm). It wouldn't leave much connecting area for disc, because the bolt pattern in audi hub is 112 mm and the hub diameter is about 130 mm.

But the porche disc diameter would be just about enough, but I don´t know how good porsche hub would be assembled into 412 spindle. I mean disc offset, wheel gauge and bearings. It could be good combination for 5x130 bolt pattern, if those things match.

the website www.brembo.com - > after market -> catalogues -> cars -has made my life easier when planning this setup. Unfortunately there was no porsche 944 turbo disc available. Because of that I cannot say how potential choise the Porsche disc and hub setup would be.

Maybe somebody has more information of Porsche944 turbo hub and disc, anyone ?

[Wally]

Good thread.
Very interesting, as I have looked for the 'usual' way (for me that is) to mount the rear 944 disk set-up to the 412 rear axle, but the 412 axle is way different than the bug's or type 3's rear backing plate mount....

So, for me, finding a way to properly mount a caliper bracket to the rear would be the most difficult part.

Tnx,
Walter

[farmer]

Walter.
I´ve been thinking bus parts in the rear, but have not checked it out yet. I have also been thinking discs, but could´nt find anything which was an easy conversion.
T.

[raygreenwood]

I just held in my hands this weekend...a very nice rear caliper bracket that is made for type 1 and 3. It is cast steel...and very nice machine work. It will bolt right up under the rear bearing cover on the type 4. Hands down nicer than the type 1 and 3 aluminum unit CB makes. It fits front caliper bolt spacing from a super beetle. The guys said they can order brackets only. It looks like it can easily be made to fit...if it does not already...either 914 rear calipers or type 4 front calipers. I have a scheme for the e-brake that should be easy.

I know where to get them...but the guy said that he is notsure of the manufacturer. It was marked AC industries. It should use either a 914 rear disc....or a Saab 900 rear disc with few mods to the center hole.
The disc unit that came with it was very nice but heavy. It was a single complete casting that incorporated the disc, the "hat" and the outer flange to bolt thewheel to. It had bolt hole spacing for all cars...and had holes in it complete for 4 or 5 lug. It has a splined center for types 1 and 2...but also there is a version for type 3 available. Ray

[func412]

Walter.
I´ve been thinking bus parts in the rear, but have not checked it out yet. I have also been thinking discs, but could´nt find anything which was an easy conversion.
T.

Farmer, if you figure something out fitting bus or vanagon rear parts into 412, I´m very interested. I have a spare part vanagon (-87 TD, burying under the snow) and I was thinking to examine if I could get 5x112 bolt pattern from that. And of course to built mountings for Subaru leone calipers.