What Master Cylinder To Use With 944 Brakes On A Beetle

[GUTTERS]

I HAVE GOT A LITTLE PROBLEM, WHICH MASTER CYLINDER DO I USE A BRAND NEW STANDARD BEETLE ONE OR THE PORSCHE 944 ONE I REMOVED FROM THE DONNER CAR. ME AND MY MATE HAVE HAD HOT WORDS WITH EACH OTHER OVER THIS HE IS SAYING VW ONE AS IT MIGHT OVER BRAKE ON THE FRONTS, BUT I THINK THE PORKER ONE WILL BEST AS THATS WHAT WAS WITH SET UP WHEN IT WAS NEW. PLEASE SOMEONE HELP ME. :confused:

[Jim Andritsakos]

You can use a late beetle M/C, also Kerscher (www.kerscher.de) sells a M/C for 4 wheel disk brakes.Also late VW buses w/o servo are using quite big M/C.If you decide to go for a bus M/C you might have to drill two new mounting holes in the pan.Toss the 944 M/C.

[Pillow]

As Jim said the 944 one would not be a good choice.

I like the early 911 dual circuit unit. It seems many people run the VW unit with good success though.

[paul_f]

Adrian,

What about on a split bus with 944 disks all round? Are you still thinking of putting the 944 one in your bus or are you going to try the early 911 one?

Paul

[Pillow]

Hi Paul,

Yes, for the bus I will use the 944 unit as it seems matched very well to the bus's balance. It has a built in pressure balance plunger that is great!

For a Beetle I would stick with a 911 unit though.

[paul_f]

Thanks Adrian,

What does the pressure balance plunger do?

Would you also fit a valve to allow the rear brakes to be balanced or do you think that it would be okay without?

Have you got any further with putting the discs on the back of your bus?

Thanks
Paul

[Pillow]

I am on pause for a while with the rear setup... More like thinking hard.

For the money spent I can easily just go Beetle IRS in the rear and have all the luxuries of a IRS rear end so I can mount 944 parts all over it.

Plus I would not have to get a different ring and pinion for the tranny either as a stock IRS would be fine.

Also the bus is driving so well now I hate to tear her apart again... But it will happen. I need to clear a few projects out of the garage which will make my wallet happy and enable me to start aquiring again. I still need to get hopping on the 2007 T1 motor and CIS FI system for her and mount the RX-7 oil cooler. Once done this split will be one hard running bitch.

Later,

[paul_f]

IRS IRS IRS!!!! I need to finish the front end so I can spin her round to work on the IRS for the back end. The only problem for you is that you like the stock ride height don't you?

I am lowering my bus so it doesn't bother me, but the rear disks onto redux boxes sounds painfully hard!

Paul

[typ4boy]

i have built 4 cars now with 944 brakes both early slide type calipers and brembos. i would not use anything other than the 944 master cylinder, using a beetle master cylinder is barmy in my book puny drum , drum disc , drum , master cylinder(VW) with porsche brakes not from my workshop, regards Lee www.laperformance.co.uk

[Pillow]

I agree Lee. Personally I cannot imagine not running a Porsche MC with Porsche brake system. Note the word system ;)

On the bus with the Beetle IRS kit is seems I can drop the rear only 1" which is acceptable to me... I will get 2.5" drop spindles for the front to keep it level.

I will run 16"x6" Disc Porsche wheels from an early 924 Turbo (931). 52.3mm offset and all that and forged.

When I get the Beetle I will get another set of the same Discs as well. Different look than what most people run which is cool to me. Plus I can put Kumho 712s on the 16s

:D

I love those tires.

I have a lot of research still on this bus setup as it is not something I have explored before. Seems straight forward though.

Take Care,

[hot66]

I'm using a 944 turbo m/c & servo in my type1 cabrio with brembo' all round. I'm also fitting a brake balancer to fine tune things. My car isn't finshed yet so can't report on performance :(

[Wally]

I like to hear everybody's experience with which m/c to use with the various tyoe of breaks.

I have had a 1303 with which I used original front discs and 944 discs (old slider type, appr. 1983/84) at the rear with original VW m/c. This works great! IMO because the rear 944 piston caliper is larger than the original rear drum cylinder of the 1303 and thus giving more brake pressure. Since the weight of the bug engine is behind the rear axle, it braked even better without locking up the rear first.

I now have 944 turbo Cup brakes front and rear and still use the bug m/c. This works not well at all. Front locks up very quickly and the rear hardly gives any brake result.

IMO everything has to do with the combination of the caliper piston sizes, brake pad sizes in relation to the piston diameters (front/rear) of the master cylinder used.

Could anybody inform me about the piston diameters of the brake master cylinders of the bug/1303 and 944 (turbo)/911 ?

I think from a weigth distibution point of view, the 911 m/c should be closest to a bug with discs front and rear. And it has no servo (pre 3,0 ltr?)to find room for. Can you bold it right on?

I' am interested in the opinions from you all on this.

Walter

[GUTTERS]

I AM GOING TO GO WITH THE 944 MASTER CYLINDER, BUT THE RESOVOIR IS MOUNTED ON TOP OF THE CYLINDER, CAN I CHANGE THE RESOVIOR TO THE ORIGINAL BEETLE DUAL CIRCUIT, BY USING THE PUSH IN STALKS WHICH CAN BE REMOVED FROM THE ORIGINAL M/C AND THEN RUN THE FEED PIPES DOWN LIKE A STANDARD SETUP.:confused:

[typ4boy]

can i kick it yes you can

[Pillow]

Gutters, also look into the 911 MC. For a Beetle I am not sure what would be better as I have not research the differences between the 944 and 911 MCs.

[GUTTERS]

CHEERS PILLOW, I WILL HAVE TO LOOK IN TO THE 911 UNIT AS I STILL IS NOT TO SURE WHICH UNIT TO USE.:confused:

[kdanie]

Gutters, the resivour swap is easy, just like you discribed. Be careful, the platic nipples can get brittle over time, I broke one of mine (lucky to have a spare).
ken

[Richie]

I used the 944 Turbo M/C with the stepped pistons 19/21mm in my racecar with the 944 slidercalipers all around. The only thing I had to do was to shorten the pushrod for about 10 mm.
The pedal was always rockhard and kept on performing even after 30 minutes of competition.
Good brakes can win a race!

Take care,

Richie

[Wally]

Richie,
Is the 944 turbo m/c 19 mm front and 21 mm rear for piston diameter?
Can you just srew the brake assist of then ?
Does it bolt right on or did you make an adapter? Since the mounting flange for a 1303 is different than for a 12/1300 model, for which application did you use it?
Thanks,
Walter

[Richie]

Wally,

It's a straight bolt-in for the 12-1300, for the 1302-03 you'll have to make an adapter or make new mountings.
The turbo m/c is 19mm for the rear and 22mm for the front brakes.
Just take it off the brake-assist. Al you have to do is to fabricate a mounting for the brakelight-switch. I've done that with a Tee in one of the pipes.
Hope to have helped you.

Cheers,

Richard