911pcars

Maybe Streather meant "larger master cylinder". The larger caliper pistons require more fluid volume when they move. The reservoir only provides extra fluid as the pads wear.

Sherwood
http://members.rennlist.org/911pcars

Tom W

I recall that Adrian's book specifies a larger reservior. I did not find this necessary.

I ran the black "big reds" up front and 993 rears with the stock 964 MC and reservior without significant issue. I didn't like the pedal feel and switched to the 993 MC and ran the car 2 years without issue (other than bias). I recently had the 993 MC and stock ABS removed and went to a dual MC setup with adjustable bias. As there is no power assist, it takes significantly more pedal pressure, but it does make control while heel-toe shifting easier (less change in braking while moving the foot as the control is less "touchie").

I have the old parts available if anyone wants to buy them (cheap).

911pcars

The 23mm MB master cylinder results in much higher pedal effort in some vehicles in exchange for the add'l fluid volume needed by large 4-piston calipers.

I searched for an alternative that might fulfill the volume requirements of more moderate size 4-piston calipers without the high pedal force and came up with this candidate; a 22.2mm dual MC that fits a VW Corrado. It appears shorter than the longish MB version for increased crossmember clearance in a 911. The fluid outlets (4 of them, use only 2) are angled upward - might be an issue with the existing lines.

The 2nd pic is a comparison between a Mercedes and a 911 master cylinder.

Any comments?

Sherwood

Grenouille77

Hello everybody,


I have big red on my 964 C2 and I have install the front origin calipers of the C2 to the rear !!!
But, i always have a bad feeling ...
So it advice me to install a bigger MC like the 993 one.

Then, I would like to have more information to install the MC from 993 into my 964 C2.
Indeed, the pipes of connections are not the same between 964 MC and 993 MC !
Therefore, which are the modifs to be made? parts to be changed?

Thanks for your help.
Regards
Arno

Bill Verburg

The 964 front calipers have too much piston and want too wide a rotor to be correctly used on a 964 w/ Big Red fronts. You want 993 rear calipers in the back of your 964 w/ stock or M030 951 rotors

the hydraulic lines on the 993 are 6mm compared to the 4.75mm used previous to the 993

So you need to source adaptors or run new line

Assuming that you have regular 964 vacuum assisted brakes, then, yes, you should update the m/c to the 993 23.8mm version
you need
993.355.310.00 23.8mm 993 m/c
993.355.023.10 993 vacuum canister
993.355.301.00 gasket
993.355.163.03 m/c support
the 993 m/c uses 12mm fittings(to go w/ the 6mm line) compared to the 964 10mm fittings. Easist thing to do is have new lines w/ 964 10mm fittings at the outer end and 993 12mm fittings at the m/c end

Grenouille77

Hi Bill

I will just arrived from hollidays.
And I am so happy to see your answer.

So to be sure that I have understand:

I must to find adaptator for make a new line, isn'it ? but, where can I have buy this adaptator ?
Or, as you tell me, I can make a new line ... but which part must I order ?

Even, I have already the 993 MC.
So, I need to buy the list of part that you show me below.

But, before I must to verify that I have regular 964 vacuum assisted brakes, isn'it ?
SO, how can I see it ?
In fact, I have the standard break system for a 964 carrera 2 year 1991.

Moreover, I understand that I must to find adaptator for fittings, because there are a difference between the 964 and the 993. But where find it ? I thought from Porsche with the 993 reference ?
Do you know where can I find picture for this break modification ?

I know, i know, I am a really big "boulet"
and so sorry for my very bad english.

Bill Verburg

Bill Gregory did a great write up in Pano a few years ago

this is from his article;

"There is a 12mm to 10mm adaptor made by Weatherhead, however, the 10mm side requires an inverted flare tube ending, as opposed to the bubble flare ending Europeans use. Not difficult to do with the right flaring equipment. Another option is to have your stock lines duplicated with the proper fittings. Classic Tube, (www.classictube.com), can do that for around $35/pair. You send in your existing lines, to be replicated with new 12mm/10mm fittings. Have them make the master cylinder end, with the 12mm fitting, an inch longer, to accommodate fitment into the 993 master cylinder. When you receive the lines, you’ll need to curve the end of each line to fit into the master cylinder, using one of the available brake tube bending tools.

Fitting the larger 993 vacuum canister can be a challenge. As you can see in figure 8, the 993 vacuum canister on the left is slightly larger than the 964 vacuum canister on the right. Depending on the size of your front sway bar, you may need to ensure the sway bar is mounted as far forward as possible. With RS sway bar mounts for the Porsche 24mm adjustable bar, you should be using 3/8” (9.5mm) bolts. A washer may be required between the vacuum canister aluminum mount and frame, to slightly angle the vacuum cannister off the sway bar. Ensure the plastic brake reservoir to master cylinder lines aren’t rubbing on the 993 vacuum cannister center edge. When it’s all hooked up, you may need to adjust the brake pedal so it’s even with the clutch pedal."

demonfish

Bill - sorry to drag this back up again - we are about to order a kit from FVD.de for the front of the 964...

so thats the front sorted.

Rears - will the 968 drilled rear rotors fit a stock C2 4piston setup? or do you need the 993 calipers for the back...

thanks in advance

Bill Verburg

951 352 041 91 are equivalent in all respects to stock 964 rear rotors except that they are holey. They will work w/ any stock 964 n/a rear caliper(2 or 4 pot) or the 993 rear caliper replacement.

Grenouille77

Hi Bill,

I must to change my MC this winter before begining the next season.
So, must I do to change the vacuum canister ?
or can I change just the MC 964 by the MC 993 with the 2 adaptator (10/12 mm) ?

Thanks, thanks, thanks
Regards
Arno

Bill Verburg

The vac can and m/c from a 993 are used. The adapters are for the 964 brake lines to connect to the 993 m/c.

Bill Gregory wrote a nice article on this, it's in the tech section.

Grenouille77

Hy Bill,

I had find this article ...
But, I am looking for the adaptator in France, and nobody find it ...

Then I have read on the article that :

the article :

In addition, you have to address the 12mm fittings on the 993 master cylinder versus the 10mm fittings on the 964 master cylinder. There is a 12mm to 10mm adaptor made by Weatherhead, however, the 10mm side requires an inverted flare tube ending, as opposed to the bubble flare ending Europeans use. Not difficult to do with the right flaring equipment. Another option is to have your stock lines duplicated with the proper fittings. Classic Tube, (www.classictube.com), can do that for around $35/pair. You send in your existing lines, to be replicated with new 12mm/10mm fittings. Have them make the master cylinder end, with the 12mm fitting, an inch longer, to accommodate fitment into the 993 master cylinder. When you receive the lines, you’ll need to curve the end of each line to fit into the master cylinder, using one of the available brake tube bending tools.

Classic Tube
80 Rotech Dr.
Lancaster, NY, 14086
800.882.3711
716.759.1800
716.759.1014 fax
www.ClassicTube.com

and

Eaton corporation,
Tel: 888-258-0222 Extn-4007
Fax: 952-974-7584
Email: shreenathshetty@eaton.com
www.hydraulics.eaton.com

can have this part !!!

but, I have some problem to speak with us.

Then, someone can have this information ? the price ? and the delay ?
I can send money by paypal, and if someone will be ok to send me, maybe it will more easy ...

Regards
Arno