GermanLook Forums  

Go Back   GermanLook Forums > Technical Section > Brakes

Reply
 
Thread Tools Display Modes
  #1  
Old February 1st 2019, 05:20
H2OSB H2OSB is offline
Registered User
 
Join Date: Jan 2003
Location: Modesto, CA
Posts: 147
964 C2 rear calipers up front

There was a thread SOMEWHAT about this in 2009, but it's been too quiet around here, and many years of experience has been added to all the heavy hitters on here who fiddle with these things.

First off, I have successfully gotten 42mm 914 front calipers over 944 rotors by installing REAR M caliper spacers in the 914 calipers making them clear. However, I could only do this by turning down the rotors (and the hubs, slightly). After the machine work, the calipers are bolt-ons for my 944 spindles (on a '74 1303). I'm certain these will be all the brakes I'll need for my modest 125hp T4 2056. However, it doesn't sit well with me to modify consumable parts of the brake set up, so as an academic endeavor, I would like to see what could be done to fit C2 2-pot rear calipers to the front.

One thing I discovered while playing with this idea, the 924 spindle has the correct caliper mount spacing of 94mm to bolt the caliper directly on. I thought this would be a boon for 1303 owners because it shares the 15mm ball joint, unlike the 944 spindles, which use a 17mm ball joint (requiring Kerscher ball joints.....perhaps). The major flaw with this idea is the 924s stock rotor size of 257mm is FAR smaller than all of the 299mm rotors that have the correct 24mm width to use the C2 caliper. That's a difference of 42mm. I don't know how far the body of the C2 caliper places the clamping surface out from the center axis relative to a 924 caliper, but I think the rotors would need to be modified to clear, which defeats the purpose of this exercise, OR an adapter would be needed to space the calipers further out. This would be the preferred choice. Additionally, the 924 uses the same bearings as the T1s, so a hub would need to be made, perhaps from a redrilled T1 brake drum...or some of Lanner's wizardry.

How about using a 944 spindle? Can anyone throw some ideas out? Lotta ready made hubs for this, and the rotors go right on. Caliper bolt spacing is off, but an adapter could fix that.

I like the C2 calipers because they're very light and ridged. I like that they have 44mm pistons. They might be ever so slightly too large to go along with my 944 rear brakes, but I doubt it. And I could always try a more aggressive pad on the rear, or perhaps, switch the brakes to the Mk3 Golf caliper/914 rotor set up which has slightly larger pistons (and is probably a lighter set up over all).

Thoughts?
H2OSB
__________________
johnL (aka H2OSB)
'74 1303, Outlaw sedan (with a GL flavor)
'73 1303, Sports Bug look
Reply With Quote
  #2  
Old February 10th 2019, 15:08
H2OSB H2OSB is offline
Registered User
 
Join Date: Jan 2003
Location: Modesto, CA
Posts: 147
Follow up.

NA 944 hubs with late 80s 911 Carrara rotors would cover those two parts of this set up, and still allow the use of 15 inch wheels(I have fixation with using 15s).

After talking to Lanner about this, he thinks he can make and adapter for the C2 calipers on 944 hubs, however, he thinks the factory caliper ears would need to be removed for lack of space. The alternative would be using 1303 spindles and a custom hubs. I think the 944 spindles would require less work/$$. Plus you get larger bearings with the 944 parts(and potentially longer life). Another advantage of the 944 set up is retaining the backing plate(with slight mods).

Thoughts?

H2OSB
__________________
johnL (aka H2OSB)
'74 1303, Outlaw sedan (with a GL flavor)
'73 1303, Sports Bug look
Reply With Quote
  #3  
Old March 15th 2019, 14:26
Wally's Avatar
Wally Wally is offline
Registered User
 
Join Date: Nov 2002
Location: The Netherlands
Posts: 2,445
Hi John,

I've also always loved the C2 calipers! Great lightweight caliper and with 44mm cup just that bit bigger then the 40/42mm steel Girling units from beetles or type 3's.

Now I agree with Lanner in that the ears of the 944 spindle are annoyingly just not right enough to make an easy adapter, but I would still try to go that way (using the 944 hub and rotor.
The advantage of the 944 rotor is also that you can use the 3,2 Carrera 24mm thick rotors as they attach the same as the original 944 front rotors, but you already knew that huh? ;-)

There is no easy fix however..
__________________
'75 Super.
...because race car!
Reply With Quote
  #4  
Old March 15th 2019, 16:32
H2OSB H2OSB is offline
Registered User
 
Join Date: Jan 2003
Location: Modesto, CA
Posts: 147
G'day Wally,

Yeah, I knew about the Carrera rotors. I bounce ideas off Lanner's brain constantly, so he always reigns me back in when I get some idea I'm SURE will work, like 924 spindles...which don't. I even sent up a set to him to play with, but he couldn't make them work. I think he's come up with the most likely way to get the C2 2-pots to work for the least effort and money. 944 spindles with ear removed, 944 hubs, 3.2 Carrera rotors, C2 2-pots (obviously), and an adapter similar to what's used on a US spec 1303 to adapt Ghia brakes, bolted to the backing plate holes. The holes for the backing plates need to be opened up a bit and retapped (M10, I should think), but with slight mods, the backing plates should still be usable as well.

All that said, I was just telling Lanner yesterday I need to cut the crap and quite playing with this. I need to devote my time to getting my T4 built so I can get the car on the road. I'm certain I'll be quite happy with my 914/944 hybrid brakes. The Ghia brakes on my other 1303 stop the car on a dime...but then, that's not an autocross car like the one getting the T4(i.e. stock 1600 T1).

H2OSB

P.S. For the record, most of my brake questions on here are aimed at you, due to the high standard to which you've prepared your car. Others as well, for sure, like SteveC, but he's gone over to the dark side with some Japanese engine...Toyota or something (JK JK, I thought about using a Subi mill for a long time). Both you, Wally, and Steve were the first to tell me, independently about the nice balance of T3/914 front, na 944 rear brake set up which put me on the path for the set up I currently have.
__________________
johnL (aka H2OSB)
'74 1303, Outlaw sedan (with a GL flavor)
'73 1303, Sports Bug look

Last edited by H2OSB; March 15th 2019 at 16:42.
Reply With Quote
  #5  
Old March 15th 2019, 18:52
flat flat is offline
Moderator
 
Join Date: Dec 2002
Posts: 664
Whenever you're ready John..
Lanner
__________________
www.vdubengineering.com
Toronto (Mississauga), Canada
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 16:14.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
© www.GermanLook.net 2002-2017. All Rights Reserved