Rear disc brakes

Michael--so a search on here about the CB rear disc brakes.  As you will read, mine as well as other SOC members' came apart because the rotor is made with two parts , a larger aluminum part ---the outer part-- fused to a smaller steel part that fits onto the axle . I was warned about this and was told that if they are are torqued right when installing, this wouldn't happen.  They were and it did. So I had the inner steel part firmly onto the axle while the outer aluminum part could spin around the steel part.  It was a pretty good jolt when the slack was taken up! This happened in Richmond VA and it was an unpleasant long drive back home to Arkansas.  I was worried that the slack wouldn't take up and the outer part would freely spin around the inner part.

For me the cure was to get two new rotors to replace the faulty ones and I found solid steel rotors from SoCal Imports, p/n 113615601DNS at $ 84.95 each.

This was three years and the replacements have worked perfectly---and why not, they are solid steel!   The new steel rotors were plug and play and fit good onto the rear of the CB Performance disc brake kit.   You might look into the whole kit that So Cal Imports offers because the whole affair is designed to work together.  Call 'em and see what measurements you should provide to swap with the drums on your CMC. The number is 562/633-4979.

I read here that we don't "need" rear discs but a panic stop once out on I-40 with rear drums told me the truth---and we need all the safety we can get with these cars.

Good luck with it!  You are damned sure doing the right thing.

ps--My C.B. Ones were called "race strength" too. Disclamer--this was my experience and maybe CB Perf. has changed the way the two part rotors are made.  Call and find out.

Well, there's racing......   

And then, there's "Jack Crosby Racing"!    

The current "race strength" rear disc brakes use 914 rotors. They use studs pressed into a steel (I think) hub under the big nut and the studs pass through the rotors. The brackets for the calipers are aluminum. 

I would like to be sure they will fit before ordering them.

Thanks for your replies.

I was speaking with one of my customers who owns a high tech machine shop. He and his adult son race formula bee at Watkins Glenand he has quite a collection of VW performance goodies around his shop. I mentioned that I was considering a rear brake upgrade to discs

 He showed me his rear drum pads. They are made for the form v cars and have carbon steel as part of the pad material. He is not cheap but he loves these as they are tested and proven to stop better than the disc conversions! I trust him. He is an aerospace engineer.  Just one of my odd experiences.

Formula Vee!

Michael McKelvey posted:

The current "race strength" rear disc brakes use 914 rotors. They use studs pressed into a steel (I think) hub under the big nut and the studs pass through the rotors. The brackets for the calipers are aluminum. 

I would like to be sure they will fit before ordering them.

Thanks for your replies.

Yes, "pressed".  That's the problem.  Pressed doesn't hold together.

"He is an aerospace engineer.  Just one of my odd experiences."

Yes.....    In my experience, Aerospace guys are always kinda weird......  

Jack Crosby posted:

Michael McKelvey posted:

The current "race strength" rear disc brakes use 914 rotors. They use studs pressed into a steel (I think) hub under the big nut and the studs pass through the rotors. The brackets for the calipers are aluminum. 

I would like to be sure they will fit before ordering them.

Thanks for your replies.

Yes, "pressed".  That's the problem.  Pressed doesn't hold together.

 

Jack,

You had a problem with the CB wide 5 kit, Michael is talking about the 4-lug kit. Totally different animal. The "pressed" part he was talking about is the lugs, which are a world better than the screwed in studs. Regardless, I believe the steel hub centers on the wide-5 kit are friction welded, not pressed into the AL hub body. The hub separation you got with your wide-5 kit can't happen on the 4-lug kit because the entire hub on those is steel.

Michael,

I'm pretty sure they aren't truly "zero-offset", although I could be wrong. I just checked-- there are no competition 4-lug kits with E-brakes, only the heavier iron rot-hub kits are available that way.

Michael McKelvey posted:

The current "race strength" rear disc brakes use 914 rotors. They use studs pressed into a steel (I think) hub under the big nut and the studs pass through the rotors. The brackets for the calipers are aluminum. 

I would like to be sure they will fit before ordering them.

Thanks for your replies.

The most common way of adding 914 rear rotors is with type 3 hubs which add about 5/8" track per side, so I would double check with CB (or whoever you end up buying from) to see how they do it. I forget, Michael- is your car swingaxle (long or short axles and tubes) or irs?

Michael McKelvey posted:

I am considering installing CB's Race Strength Rear Disc Brake Kit, 4 Lug, IRS, With Emergency Brake.

 

@ALB, IRS

@ALB  are there any pictures of this type of install on an IRS rear end with the parking brake cables?

Terry Nuckels posted:

Michael McKelvey posted:

I am considering installing CB's Race Strength Rear Disc Brake Kit, 4 Lug, IRS, With Emergency Brake.

 

@ALB, IRS

Of course! Thanks Terry.

IaM-Ray posted:

@ALB  are there any pictures of this type of install on an IRS rear end with the parking brake cables?

I'm sure if you checked the Samba, Ray, you could find pics (I'm going to bed). Hot VW's magazine (Dec. '94) did an article titled "Adapting 914 Rear Disc Brakes To An IRS VW" and give plans for home fabricated caliper and emergency brake cable brackets. I could scan and send it to you if you like (it'll give me a reason to learn how to use the scanner function on the printer).

Sure that would be nice..

Here is something I just found ... 914 rear brakes and Mk IV VW and brackets & have emerg brake too ... Carrier brackets are billet alloy available from Sharpbuilt

sharpbuilt.com

Here is a good look at the kit and its installation:

http://www.huelsmann.us/bugman/Rear_Disc_Tech.html 

Thanks for posting

Yep, I see now that the kit you're talking about does have an ebrake.

That's a nicely detailed writeup you linked, Michael. I have the Airkewld rear kit for short axle swing, and it doesn't add any width at all. Not that that matters to you. But it does use the same caliper as the CB kit. Pretty much every single rear VW kit uses the Varga caliper.

The install went exactly as your link, the only exception in the Airkewld case is aluminum hub and powdercoat steel caliper bracket. It's not that big a deal to do the install.

Loosening and tightening axle nuts are always best done on the ground. If you don't have anyone to help, make a wheel chock with a 45 degree cut on a 2x4. 

I don't understand the whole Varga VW thing. There's got to be better, more common, lighter rear calipers available.