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Vented disc brake upgrade for 4 stud from Beetle / BMW parts

Posted: Sun Aug 02, 2020 12:36 pm
by Jonny Hart
Hi, I have been thinking about this but I don’t have enough knowledge of VW and BMW parts to know the answer. I don’t want to fit 911 5 lug parts.

Firstly, solid disc BMW E30 brake callipers are an upgrade for the 914 working with the 914 solid front disc. They bolt straight on early 914s and need a slight facing for later cars.

Secondly, there are vented disc kits available for Beetle, KG etc. From pictures, the Beetle disc looks to be the same as the 914 in that the disc and hub are ‘combined’ into one part.

Q1: Is the Beetle /KG hub spindle profile/taper/length the same as a 914? This would allow the above kit to bolt straight on and retain the same PCD.

Q2: The sportier E30s has vented discs so presumably their callipers are wider but still fit the same suspension leg and thus would also still fit the 914 leg. Can anyone confirm?

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 2:28 pm
by KS
914 front disc is shared with VW Type 4, not Beetle.

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 2:59 pm
by Jonny Hart
KS wrote:914 front disc is shared with VW Type 4, not Beetle.
Ok, thx. I guess what I’m asking is whether the spindle is the same. If the beetle disc/bearing/nut fits on, then potentially offset issues might be solvable with a calliper spacer.

Have you got any bits you lying around Keith you might eyeball for me? Thx.

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 3:05 pm
by KS
Type 4 discs aren’t interchangeable with Type 1, I’m afraid. Spindles are different.

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 4:43 pm
by Jonny Hart
Maybe you can’t tell from pictures but this:

https://www.heritagepartscentre.com/uk/ ... qjEALw_wcB

Looks pretty much exactly like this:

https://www.thesamba.com/vw/classifieds ... id=2246205

I am just referring to the tapered spindle part.

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 7:23 pm
by RichardJ
The shaft part of the spindle is the same as a Beetle , as are the wheel bearings. The difference with a 914 / type 4 disc is the positioning ('offset') and the size of the disc part relative to the bearing housings. I've machined the disc part away from a pair of the new aftermarket Beetle 5 x 130 discs, with a nice very thick section for the stud threads, to make 5 x 130 hubs to suit the vented discs from a modern model.
I didn't compare the position and size of the disc on the old 914 discs and the new Beetle ones before turning them down, but as the disc part I machined off the new Beetle discs are still under my bench, I just measured them. They're 278 x 9.4mm. I believe a new type 4 / 914 disc is 281 x 11mm (the ones I removed were worn down to about 7mm!).

Vented disc brake upgrade for 4 stud from Beetle / BMW parts

Posted: Sun Aug 02, 2020 8:10 pm
by Bruce M
Fairly sure the depth of the bell is different, although there are two 914 front discs. 411 and 411B

If it helps, this is the technical drawing for a stock beetle disc. The vented version will obviously be thicker but the depth will be very close to avoid hitting the spindle.

Maybe worth a chat to Sebro? They claim to offer advice and will do low volume production for clubs etc.

Image

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 9:49 pm
by stevenery
Hello Jonny,

With regards to using the vented Kerscher or Sebro Beetle discs this thread might be of interest: http://www.914world.com/bbs2/index.php? ... &p=2112755

Also, are you aware of the Alfa GTV6/75 Brembo callipers that can be fitted to a 914? http://www.914world.com/bbs2/index.php? ... &p=1279971

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 10:50 pm
by Jonny Hart
Thanks all. Looks like I have some reading to do.

Re: Vented disc brake upgrade for 4 stud from Beetle / BMW p

Posted: Sun Aug 02, 2020 11:14 pm
by Jonny Hart
The Kersher discs are exactly what I’m looking for. They even do 100/4 which is the PCD I’m after.

Brilliant!