17z vs 18z

[bengone1]

I am looking to go with one or the other and both will be more than adequate in the stopping dept. I am running 19s so room is not an issue but bigger is not always better, especially with the stock master cylinder. My question is if there is an increase in brake travel on the 18z vs 17z, anyone compare both?

Thanks,
Ben

[v8a6]

18z piston size are 30/34/38mm
17z piston size are 34/36/38mm

So, the 17z have a larger overall piston area and will take more brake travel to push (although in reality you probably wouldnt notice a difference between the two)

I planned to swap the master cylinder on my car for an RS6 one when I installed my 18z. However, the used MC was bad, so I had to use stock. It seems to work fine, and 99% of people who installed the 17z or 18z are all using the stock MC with no complaints.

BTW, I have a set of 18z for sale on eBay right now.

http://www.ebay.com/itm/130936359178...84.m1555.l2649

[Castor Troy]

How hard was it to swap the MC? I've got an RS6 MC for my S6, but not sure that I wanna tackle it myself. It took me 20 minutes to do the master on my dad's corvette, but I've read it's kind of a bitch on a6/s6

[Vinchenzo51]

Hardest part is disconnecting it from the brake pedal inside. Mostly just a decent amount of swearing and beer will do the trick.

[v8a6]

Sorry, I can't comment because it was the garage that actually did it, not I.

[Widebody4.2]

For me it will be 17z as well as a set of rotors from Adams rotors its the best budget bbk IMHO

jhm rotors are way to expensive

[bengone1]

Thanks for the piston info. I will look into Adam's rotors.

[lucio_liu]

do I need to replace stock brake line when updating to 18z?

[v8a6]

do I need to replace stock brake line when updating to 18z?

Yes, custom length lines are needed on the fronts. I left my rears stock.

[bengone1]

Yes, custom length lines are needed on the fronts. I left my rears stock.

Does anyone sell a compatible set? How much did the RS6 master firm things up?

[v8a6]

Does anyone sell a compatible set? How much did the RS6 master firm things up?

It didnt work when I had it installed. I bought it used and it was apparently seized up. So, I am back to running stock, which seems fine.

[julex]

you can buy the lines from centric, essentially stock part they have "Centric Front Brake Hydraulic Line 950.33006":

http://www.carpartkings.com/centric-...950-33006.html

at $40 you can't beat that.

Also, 18z work with my stock 17" wheel too

[2001A6]

As I understand 18Z require 18" wheels..

I'm going with 17Z's up front and B6 S4 300mm rears. Planning on keeping the stock MC.

Widebody4.2, does Adams make a set of rotors for these calipers. I thought the only direct fit option was JHM's 2 pieces. I know Mercedes ML350 rotors and C230 sport rotors (both 330mm) work with the 17Z's but they require modification.

[Castor Troy]

As I understand 18Z require 18" wheels..

I'm going with 17Z's up front and B6 S4 300mm rears. Planning on keeping the stock MC.

Widebody4.2, does Adams make a set of rotors for these calipers. I thought the only direct fit option was JHM's 2 pieces. I know Mercedes ML350 rotors and C230 sport rotors (both 330mm) work with the 17Z's but they require modification.

18z's will fit under some 17" wheels

Adams rotors does not make a rotor for this application, and they won't modify Merc rotors to fit(I asked). If you have a V8(A6 4.2/S6), the 17z's will go on without any modification.

[bengone1]

you can buy the lines from centric, essentially stock part they have "Centric Front Brake Hydraulic Line 950.33006":

http://www.carpartkings.com/centric-...950-33006.html

at $40 you can't beat that.

Also, 18z work with my stock 17" wheel too

Is that for a pair of lines? If so, Super cheap. Have you tried these at full air suspension travel?

Does anyone have the bolt specs. I have a friend that may be able to machine me a set with the shoulders built in. I also did not see any rotors for this app listed on Adam's site.

It looks like the RS6 MC is a 27mm vs the allroad's stock 25.4mm. Rock auto has Centric or A1 Cardone brand rebuilds for about $130. I may look into it down the road if the pedal has too much travel.

[julex]

Is that for a pair of lines? If so, Super cheap. Have you tried these at full air suspension travel?

Does anyone have the bolt specs. I have a friend that may be able to machine me a set with the shoulders built in. I also did not see any rotors for this app listed on Adam's site.

It looks like the RS6 MC is a 27mm vs the allroad's stock 25.4mm. Rock auto has Centric or A1 Cardone brand rebuilds for about $130. I may look into it down the road if the pedal has too much travel.

Well, they're still here working after 6 months of driving allroad so I would say they are tested on all levels . It is for a pair.

The bolt. I went different route. I don't feel safe with just nut holding the bolt so I bought big 16mm tap and instead tapped the uprights, you know, so that the calipers mount to upright the way they do from factory. This way I am treading the bolt into the upright which has a lot of meat. This also allows me to use run of the mill 16mm bolt instead of some funky special order contraptions with weaker 14mm treading.

[2001A6]

18z's will fit under some 17" wheels

Adams rotors does not make a rotor for this application, and they won't modify Merc rotors to fit(I asked). If you have a V8(A6 4.2/S6), the 17z's will go on without any modification.

:/ I have a V6 car. Dumb question, could I use a set of V8 rotors? Or are the dimensions between the rotor and spindle totally different? They are only 10mm smaller.

It looks like there are 2 different offsets for V8 rotors, 16.7 and 22.7.

[v8a6]

:/ I have a V6 car. Dumb question, could I use a set of V8 rotors? Or are the dimensions between the rotor and spindle totally different? They are only 10mm smaller.

It looks like there are 2 different offsets for V8 rotors, 16.7 and 22.7.

no, v8 rotors are different

[Tech/Sales@JHM]

bengone1-

If you don't feel like piecing together your own kit, we have both 18z(350mm) and 17z(330mm) Big Brake Kits available!



Click HERE to check them out!

Jake

[v8a6]

I bought my rotors, bolts, pads, and stainless lines from JHM, and purchased the calipers used from a wreckers. By the time I put it all together, I would have been better off just purchasing the entire kit from JHM. Their pricing on the complete kit is hard to beat.



BTW, the rotors look HUGE in person. For some reason they don't look as big in the pics.

[Tech/Sales@JHM]

V8a6,

The kit looks sweet behind those peelers!

Jake

[v8a6]

Thanks!

Another pic from the side

[bengone1]

Well, they're still here working after 6 months of driving allroad so I would say they are tested on all levels . It is for a pair.

The bolt. I went different route. I don't feel safe with just nut holding the bolt so I bought big 16mm tap and instead tapped the uprights, you know, so that the calipers mount to upright the way they do from factory. This way I am treading the bolt into the upright which has a lot of meat. This also allows me to use run of the mill 16mm bolt instead of some funky special order contraptions with weaker 14mm treading.

Thanks, I was kicking around the idea of tapping it like that. I didn't like the nut either. At the least it would have to be welded on. You go with a 16mm x 1.5 12.9?

bengone1-

If you don't feel like piecing together your own kit, we have both 18z(350mm) and 17z(330mm) Big Brake Kits available!



Click HERE to check them out!

Jake

Thanks Jake, I have time on my side to source the parts so I will try to save a couple bucks. JHM has plenty of nice bits I will spend money on for sure.

[Widebody4.2]

As I understand 18Z require 18" wheels..

I'm going with 17Z's up front and B6 S4 300mm rears. Planning on keeping the stock MC.

Widebody4.2, does Adams make a set of rotors for these calipers. I thought the only direct fit option was JHM's 2 pieces. I know Mercedes ML350 rotors and C230 sport rotors (both 330mm) work with the 17Z's but they require modification.

I'm sorry I've only owned widebodies and I kinda got your hopes up one track mind style.

[disrepos]

Thanks, I was kicking around the idea of tapping it like that. I didn't like the nut either. At the least it would have to be welded on. You go with a 16mm x 1.5 12.9?

Another inexpensive bolt option in lieu of 16mm is to go SAE - 5/8"-18 such as Mcmaster.com:

• 91251A404 Black-Oxide Alloy Steel Socket Head Cap Screw, 5/8"-18 Thread, 2-1/2" Length, Packs of 5 1 Pack 1 0 11.35 Per Pack
• 90949A112 Black-Phosphate Grade G Steel Flange Locknut, 5/8"-18 Thread Size, 15/16" W, 21/32" H Overall, Packs of 10 1 0 4.59 Per Pack
• 26035A217 Carbon Steel Hand Tap, 5/8"-18, 4 Flute, Taper

I tapped the uprights and used locking flanged nuts on the outboard side for added insurance. Also went with longer bolts with partial threads (so that the threads wouldn't dig into the calipers) and ground to correct length.

[bengone1]

Good idea, but I can't bring myself to put SAE bolts in a metric car. I live in a good place for car geeks. Plenty of fastener stores, welders, and machinists.

You can pick up a pair of reman calipers by a1-Cardone off eBay/Rockauto for about $450 shipped. They appear to come without the cross over pipe and the last pair I got from them had the banjo bolt sealing surface bead blasted away then the internal e-brake cable snapped. Hard to mess up these calipers though.

[julex]

Thanks, I was kicking around the idea of tapping it like that. I didn't like the nut either. At the least it would have to be welded on. You go with a 16mm x 1.5 12.9?

I believe so, whatever pitch is standard for that tread size.

[bengone1]

Looks a bit short.