Introduction
Information about adapters for Brembo 17Z calipers from Porsche Cayenne / Audi Q7 / VW Touareg. I’ll briefly describe the problems I encountered before installing the calipers on my Polo and how I solved them.
First adapters from OLX
Since I initially bought Brembo 17Z calipers with my older Polo in mind, I didn’t do much research about the adapters. I wasn’t in a hurry with this upgrade, so I simply bought the calipers to put them on the shelf to wait for their turn quietly. I bought the calipers in a set with adapters for Golf 4/Leon. Theoretically, Polo has the same calipers as Golf IV, the hole spacing is the same, so I incorrectly assumed that the adapters should fit as well.
Unfortunately, several months later it turned out that the adapters didn’t fit my Polo 6C wheel knuckles. Currently, the only normal new wheel bearing housings from the dealer have 6C0 numbers, which is why I use them even in my Polo 9n3. 🫢
With used wheel knuckles, there’s a high risk of problems with proper toe alignment, as they tend to bend – especially in cars with higher mileage, or from people who hit a pothole at higher speed – that’s why for Polo, regardless of its year, I always prefer new OE wheel knuckles.
Besides the fact that the adapters didn’t fit, it turned out they were quite crudely manufactured, you could see laser cutting marks on them, which theoretically minimally weakens the steel properties, but a bigger drawback is lower dimensional tolerance precision…
This is how the first (wrong) adapters looked:
And here I’ve marked the spot on the wheel bearing housing that interfered with proper adapter fitment:
I’ll mention right away that this wasn’t due to the powder coating – the same issue occurred with the old 6C0 wheel bearing housings… While the adapter could technically be bolted on, it wouldn’t sit flush against the wheel bearing housing, instead sitting at an angle:
Tobiasz, who bought the same set, tried grinding down the adapter/wheel bearing housing to make it fit, but without success. Besides that, their thickness was too great across the entire surface – they were 17mm thick…
Unfortunately, most sellers in Poland only offer complete sets, the YouTube influencer selling DZB calipers only sells them with calipers and not for 5×100 fitment, similarly WRK – also only with calipers and currently prefers to focus on high-end cars…
German Epytec-403 adapters
The only ready-made product that can be bought normally are the German-made adapters from Epytec. There seem to be no problems with selling just the adapters there, I don’t know why this is so problematic in Poland.
The original Epytec adapters look like this (photos from manufacturer’s website)
Polish Copy of Epytec-403 adapters
Quite by chance, I managed to find someone on OLX who had copied the Epytec adapter, so I ordered adapters theoretically for Polo 6R/9N/Audi TT/Audi A3/VW Golf IV/Skoda Fabia/Seat Ibiza etc.
The guy from OLX made these for someone with a Skoda, because their original Epytec adapter cracked near the thin wall where the bolt mounts. The OLX seller modified the Epytec design and makes smaller holes, which allows for thicker walls, but this makes it a bit harder to find fitting bolts – something I found out a bit later…
These adapters for 17Z in Polo are 15.5mm thick, so they’re thinner than the first ones (should work without spacers etc.).
Fitting bolts to Polish adapters
Originally, Epytec uses regular hex head bolts with 10.9 hardness rating, but because of the hexagonal heads, the adapter is very thin at the mounting point, which led to cases where it would crack at exactly this spot:
PS. When you’re using original Epytec-403 adapters, be careful when tightening bolts in areas with thin walls! According to VW, factory caliper bolts should be torqued to 124 Nm.
The Polish copy of Epytec-403 with thicker walls doesn’t allow the use of such bolts, so you need to use ones with smaller heads – like Allen head, Torx type, etc.
My Allen head bolts from the previous adapters, besides being too long, protruded slightly beyond the adapter profile – and this prevented proper seating of the Brembo 17Z caliper.
As a test, I decided to try several ready-made brake bolts from Allegro – I bought bolts from PSA/BMW etc.:
The BMW bolts almost okay, however the protruding TORX head was too large, it wouldn’t fit:
However, none of these worked out, all were even worse in terms of fitment.
So I bought shorter hex socket head cap bolts with 12.9 hardness rating and planned to shorten their heads so they wouldn’t protrude.
This is how it looked when inserted as far as possible – according to my measurements, the heads needed to be shortened by 3.5mm:
Theoretically, material could be removed just from the adapter, but this would weaken the adapter itself. Standard hand work with a Dremel was out of the question.
I gave the bolts along with the adapters to my cousin who works in the tool room at a local aluminum components company. There they determined that removing material from the bolt head might make it impossible to tighten the bolt with a wrench and decided to remove 2mm from the bottom of the bolt head and 2mm from the adapter – this way the bolts fit perfectly:
When I finally test-fitted the new adapters, despite them fitting perfectly to the caliper, it turned out things weren’t so rosy and they still didn’t fit well to the 6C0 wheel bearing housings (6C0407255A + 6C0407256A). The problem was a thickening at the edge instead of a regular 90-degree angle in the marked area:
which meant it wouldn’t be possible to properly mount the caliper because it created too large of an angle.
Besides that, the hole spacing was correct, there’s no strange teardrop shape for adjustment, everything was made to exact dimensions:
Problem with Epytec-403 adapter fitment
I wasn’t the only one with this issue, because in Polo groups, with used adapters I found photos confirming that others had the same problem. That’s why with used Epytec adapters, they are simply ground down on the wheel bearing housing side, as shown here:
According to info from Michel, Epytec-403 adapters fit plug & play to older 6Q0 wheel bearing housings (6Q0407255S + 6Q0407256S previously manufactured for Polo 9n3 GTI Cup Edition etc.). Later, apparently Volkswagen changed factories and the mold they use for casting iron changed slightly. I’m not sure about wheel bearing housings with 6R0 numbers, but 6C0 wheel bearing housings, meaning 2014+, have slightly thicker cast iron. Interestingly, the German adapter manufacturer didn’t notice this. Probably not many people use them specifically in Polo, and with older Golfs, or Audi A3 and TT this problem doesn’t exist.
When using budget aftermarket wheel bearing housings, the fitment depends on the casting.
Milling the adapters
To mount them properly, some material needed to be removed. I doubted my manual abilities with Dremel carving, so I gave the adapters to someone who specializes in milling. Thanks to this, they look almost perfect (they’ll be perfect after painting the outer sides blue):
Of course, I wouldn’t be myself if I hadn’t sprayed the front surfaces with a thin layer of zinc, and the visible sides with several layers of blue paint 🙂
Now we can finally move on to installation 🙂
Test fitting the Brembo 17Z calipers
Once we managed to fit the adapters, it was time to test fit the calipers. It doesn’t look bad:
If anyone has a better method for fitting 334mm rotors or other sizes that will work with 17″ wheels, please let us know in the comments below.
