Help: Turbo master cylinder mounted in early car

Shaun @ Tru6 · 05-10-2004, 01:52 AM

I am running Turbo brakes on the 73 track car project and need help in locating/mounting the master cylinder/servo unit.

Does anyone have info on mounting the unit? Clearly some sheet metal needs to be cut. Does it need to be reinforced?

Pics? Dimensions? Do's and Don'ts?

Thanks

Shaun

Shuie · 05-10-2004, 02:56 AM

Ive never done it myself, but when I was researching this I found more than one suggestion to cut the complete section from a turbo car. Good luck!

dean · 05-10-2004, 05:14 AM

Do a search. Someone did a nice job with pics a couple years ago.

ChrisBennet · ChrisBennet's Garage

Steve Timmins has a nice writeup. See http://instant-g.com/Projects/BM/Brakes/index.html

john walker's workshop · 05-10-2004, 08:24 AM

best to graft in a donor section from any power brake car. there's also a outward hump behind the fuel tank that is part of the power brake sheetmetal, that has to be installed to allow clearance for the later pedal assembly. the donor section is trimmed down as small as possible to include the top section with the dip, and the reinforced front hump, as a unit, and carefully fitted, and butt welded. one of the metal tank vent lines thru the tunnel can be used for vacuum.

Bill Verburg · Bill Verburg's Garage

The easist path is to use a 23.8mm non boosted ATE m/c. Its an easy bolt in.

Shaun @ Tru6 · 05-11-2004, 06:04 AM

Thanks everyone for the responses. 3 unique solutions. The Al plate looks like a good compromise, but simply plugging the unboosted ATE into the stock spot seems like the easiest way to get this car on the road by mid-June.

Bill, do you know where I can get one of these?

Thanks guys.

Shaun

ChrisBennet · ChrisBennet's Garage

I think the non-boosted 23mm is sometimes referred to as "the Mercedes M/C" if that helps.
-Chris

Shuie · 05-11-2004, 06:37 AM

part number for the the nonboosted 23.8mm master cylinder, aka the 23mm mercedes truck m/c (got it from an old post):

ATE # 3.2123-1003.3

Shaun @ Tru6 · 05-11-2004, 06:44 AM

Thanks guys, this board is truly the best!

john walker's workshop · 05-11-2004, 08:16 AM

pretty damn hard pedal with the 23mm and turbo calipers. just doesn't have the "feel".

Kahuna · 05-11-2004, 08:47 AM

Quote:

just doesn't have the "feel".

I disagree I have 993 calipers(even bigger pistons than turbo) and the non boosted 23mm. Feel is the best part, it does require more leg than stock but modulation is superb!

Bill Verburg · Bill Verburg's Garage

The non boosted m/c w/ 23.8 mm & w/ 930 calipers has a master/slave ratio of 16.539

If you have ever driven a turbo w/ the power assist disabled you know what this feels like, it' not that bad. For most of the past 6yrs I used setup w/ a 16.171 ratio, modulation is outstanding and most racers that have driven it seem to desire the same for their own cars.

stock non boosted 911 is 20.656

The lower the # the more effort is needed but better control is provided in compensation.

If you go for the non boosted m/c buy a kit from someone like Steve Weiner at Rennsport Systems . There are 2 versions of the m/c one has the operating ports on the wrong side, Steve wil also supply the correct operating rod and a couple of plastic bits that make installation easier.

Shaun @ Tru6 · 05-11-2004, 04:07 PM

Thanks Bill. I ended up with the kit from VCI (Vehicle Craft) today. Complete kit: $195 + shipping.

http://www.vehiclecraft.com/Brakes/930_upgrade.htm

Thanks again for all your help.

Week 7 pics of the project ought to be up next Sunday. The big job will be cutting/grinding the rear control arms to accept the rear turbo calipers.

Looking forward to that.

Shaun

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by Shaun 84 Targa
The big job will be cutting/grinding the rear control arms to accept the rear turbo calipers.

Looking forward to that.

Shaun

When I " Van Gohged" * my aluminum control arms for 930 brakes it was a piece of cake. What are you using for control arms?
-Chris

* Vincent Van Gohg: french impressionist who cut off his ear

Shaun @ Tru6 · 05-11-2004, 07:44 PM

Chris, I've got 84 rear trailing arms.

What did you use for your artwork? grinder? Sawzall?

Hald · 05-11-2004, 08:12 PM

Shaun -

A grinding wheel [stone] will quickly fill up with aluminum. I've used both a cut-off wheel and a rotary rasp with good success.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by Shaun 84 Targa
Chris, I've got 84 rear trailing arms.

What did you use for your artwork? grinder? Sawzall?

Like Mark said, a cutoff wheel takes them right off. I can't remember what I smoothed them up with. I have rotary rasps/burr and files so I probably did it with one of those.
-Chris