Which 944 M/c

[steven erwin]

undefinedI'M RUNNING 83 944 CALIPERS ON MY 74 BEETLE. I WENT TO THE LOCAL AUTO STORE TO GET A 944 M/C. THERE WERE 2 PART #S, ONE FOR $50 AND THE OTHER FOR $150. SHOULD THERE BE 2 PART #S FOR THE M/C AND DOES IT MATTER WHICH ONE IS USED?
THANKS FOR YOUR TIME

[boygenius]

Maybe non ABS and ABS equipped.

[steven erwin]

Originally Posted by boygenius

Maybe non ABS and ABS equipped.

THANKS BOYGENIUS, I'LL ASK THEM!!!!!!!!

[super vw]

So i have another question.... Is the 944 MC the one to use with a early 944 brake upgrade (single/slide piston calipers all around) without having a spongy pedal or having one to hard AND having the correct brake bias?

So far i have heard, 944, 911 and stock 1303 super beetle MC???? whats the best one to use?

Thanks
Jonathan

[boygenius]

I'm no brake expert but I would think that the piston size in the 911 master cylinder would better complement a rear engined car than the 94 unit. Then again using the 944 brakes could change the characteristics of the 911 master cylinder.

[Maynard]

I converted to 944 NA (single pot) brakes on my 1303. I originally tried the 1303 MC since it was already hooked up and would not require any extra work to try. I did not like how far I had to press the pedal to get the brakes to engage. Then after researching this more on this forum, I saw that others had the same issue with the 1303 MC and that the 944 MC was recommended with the 944 NA brakes. Thinking about it, using the same MC that was made for the brakes made sense to me. I installed it and couldn't be happier with the results.

[super vw]

Nice, do you have a part number of the 944 MC you are using?

Thanks!
Jonathan

[Maynard]

I pulled the brakes and the M/C from a 1985.5 Porsche 944 that I found in the junkyard. There are 2 types of M/C's that should work with all the NA Porsche 944s from 1983-86 depending upon the brake booster. One is for use with a Girling booster (944 355 011 00) and the other with an ATE booster (944 355 011 01). Someone on this forum indicated at one time that it did not matter which you used. Since you would not be using the booster, I suspect they are correct although I cannot say that I have tried both types.

[Angelo Amato]

www.customspeedparts.com

[TOW74]

What's up Maynard?

Maynard how did you run your brake lines? If you have pics please post them for me, if not please explain. Thanks, TOW74

[LLVWGL]

how do you make this M/C work with a stock brake pushrod?

(pre-86 944 MC)

[Jeza]

Fortunately it bolts up using the same bolt pitch. The alloy tube pokes inside the floor pan. Fit the stock Beetle brake pedal push rod inside the tube and adjust appropriately, so that there is a small amount of free play in the pedal before the push rod starts to push on the MC. This is very important! Have a read of a manual- Haynes or Bentley.

You will lose the rubber dust cover, although I'm sure you could find something from another car (have a hunt around a wrecking yard) that might serve the purpose.

Cheers
Jeremy

[What-r-u-doing]

I guess the issue you are having or don’t want to have, is a piss poor pedal and spongy brakes.

The question is why do I have spongy brakes.
1- You have air in the system
2- You haven’t done the job correctly
3- You have missed matched the components of your conversion


I won’t even go into answering question 1 and I will only touch on question 2.

Question 2 - You haven’t done the job correctly
E.g. if you have used second hand rotors and they have heaps of radial run out in them, you will never get a sharp pedal why because each time the rotor turns one full rotation the pads and hence the calliper piston will get knocked back too much and you have to reset the calliper and piston back to the disc rotor face before affective braking takes place, the first pump or two are crap then the pedal firms up.

Question 3 - You have missed matched the components of your conversion
IT doesn’t really mater what type of brakes you want to run on your car, 944s, 944Ts, Big reds, Brembos, Willwoods or even AP racing callipers, what maters is that the all the components in your system work together.

So as we are trying to improve the braking of a rear engined car we can carry more brake on the rear wheels that say some one with a Nissan 180sx turbo –why because we have more weight over the rear wheels.

If you compare a drum brake VW beetle to a the above Nissan with 4 wheel disc brakes you would find that the beetle has roughly the same sized drums and shoes front to rear compared to the Nissans and you would also find that the beetle would be placing more brake effort on the rear wheels % wise than the Nissan.
Lets assume that you modified the Nissans brakes to give you the same % front to back as a Beetle how would the Nissan behave under braking well if I was a betting man I would be putting my $$$ on the fact it would lock up its rear brakes first and you would lose control.

Now you think I don’t know what I’m taking about cause you Daddy’s got a old Chevy pick up with drums all round and the rears are as big as the fronts and lets assume that the master cylinder has the same bore size on the front and rear circuit so that means roughly 50% of the total braking effort goes to both the front and back, with me so far.
And as you know at least ohh 65% if not 70% of the vehicle weights on the front wheels and it doesn’t lock up its rear brakes all the time.
How ever your Daddy’s pickup truck has a think called a load sensing proportioning valve in the rear brake line, so when you have 3 tons of sugar and copper line in the back you get all the braking effort available to the rear wheels at the rear wheels when you only have that old hound dog on the back you may only be getting 13% of the braking effort on the rear wheels. Still with me?

So if we were trying to buy parts for our killer conversion would we want to use the complete system off a Honda CRX, Nissan 180sx, Porsche 911, Porsche 944T or Porsche 944.
Well it would be better to use the components off a vehicle with approximately the same weight distribution as your car –still with me.
I’m going to make some big assumptions here, cause I’m to lazy to look it up so lets say a 911 has a weight distribution of 55R/45F and a 944T and a 944 has 45R/55F and a CRX as 28R/72F and a Beetle is 55R/45F, what vehicle’s braking system would be the best to use, the answer is a clear as mud, the 911 followed by the 944 and to be on the safe side its better to have more braking on the front than the back. By the way the above is an assumption and is only there to prove a point, I don’t care if a 911 is 49R/51F or a CRX is something else.

So why is it when you use early 911 rotors and callipers and a Beetle master cylinder the brakes are awesome, or 944T 4 pot callipers and rotors and a stock Beetle master cylinders the brakes are good??? Yet when we use 944 single piston sliding callipers and rotors and a stock beetle master cylinder the brake pedal sucks, and you can’t even get a hard pedal???

Here are some quotes I found when looking at this site and these are made me put pen to paper, well fingers to keyboard.

As quoted by Boygenius
“I'm no brake expert but I would think that the piston size in the 911 master cylinder would better complement a rear engined car than the 944 unit. Then again using the 944 brakes could change the characteristics of the 911 master cylinder.”

As quoted by Wally
“Because of the rear engine and 'reverse' weight distribution of the bug compared to a front engined/watercooled car, mounting the same m/c seems pointless to me. Fitting a m/c with 21/19 cups rear/front would make more sense to me...”

As quoted by Jezza
“I think I will fit the 944 master cylinder, its front to rear ratio (having actually done the calculation now) isn't as bad as I suspected it would be.”

What Boygenius and Wally have said is so far from the truth it scares me that they are allowed to modify their cars and drive on the same roads as me.
At least Jezza is close to the truth but by looking at his other comments it must be by share luck or he was able to seek some professional help.

The answer is if you use a beetle master cylinder the hydraulic volume and pressure is incorrect for the single pot front callipers, if you only fitted the rear 944 brakes and checked it you would have a good pedal, fit the front and it goes out the window, the Beetle master cylinder bore size is 19mm front and back, and the 944 master cylinder is 23mm front and 19 rear, so do you see why the 944 rear callipers would work on the stock beetle master cylinder.

But in fairness to the above guys yes when swapping from the beetle m/cylinder and 944 callipers to the 944 m/cylinder and 944 callipers it will affect the front rear brake bias, but only cause the front callipers were not MATCHED correctly with the beetle master cylinder.
But god only knows how you came to that conclusion.



And again its true that changing your master cylinder size will affect your front rear brake bias, look at any real race car and you will find they have a thing called a balance bar, with two master cylinders, this is do they can change the pedal effort between the cylinders and if its not enough they can change cylinders with out too much drama to alter the front rear brake bias..


If you are going to modify your vehicles braking system or mix and match brake or suspension components please seek professional help, they know what they are doing.
Yes it may cost more in the first place but it could save your life, or at least stop you from crashing your car.

That’s my 20 cents worth….

[Jeza]

Welcome to the forum....

I take it from your post that you have spent a lot of time on brakes either as a career or a hobbie.

I appreciate your comments but you have been quite bold, you have forgotten that we are all here to learn and perhaps we don't get it correct first time, so we ask a few questions and realise our mistakes then do it better.

I assume you have done your reading of this site, as you have mentioned that it was perhaps by luck that I matched my components better, judging by some of my other comments. I realised I had a problem with miss matched components very soon after assembling things, so went about to correct it.

You don't have to worry about poorly selected parts ending up on cars where I come from, the Land Transport Safety Authority has a very strict set of rules, and all modified cars have to be given an engineers approval before they can be sent through the standard set of safety tests that is required for every car on the road, MOT in the UK, Warrant of Fitness here in NZ, and it is tougher than the MOT. There are large fines for those that choose not to comply.

I do appreciate your concern though. Brakes and suspensions are components that cannot be worked on lightly. If they fail the results can be life threatening, as opposed to an engine that gives up.

I hope you are able to stick around and share some more of your knowledge, and tell us a little about your own projects.

Thanks
Jeremy

[What-r-u-doing]

OH MY GOD, well large fines will slow those down with unsafe vehicles.

I asume that you have worked in the UK and in NZ on vehciles and there for know that it is harder to get a WOF than a MOT?

I have to say that the standard of vehicles in New Zealand is pretty low, but then hell its not much better in the UK

As Quoted by Jeza "You don't have to worry about poorly selected parts ending up on cars where I come from, the Land Transport Safety Authority has a very strict set of rules, and all modified cars have to be given an engineers approval before they can be sent through the standard set of safety tests that is required for every car on the road"

On the roads in New Zealand I saw a 1302s with a rover v8 engine in the back (hmm whats that done to the weight distubution) with a rought as guts roof chop, Upon asking the owner of this vehicle how come the law didn't stop him from driving this beast he told me that he had a modifed vehclie cert (and showedit to me- it was stuck to the firewall and it had the LTSA logo on it) he then said he didn't have a WOF because he had to fix abit of rust in the floor, when i asked him what had he done to the shocks and springs to deal with the incressed weight, and what he had done to the brakes to cope with the extra horsepower and weight he said that they were the stock parts and as far as the LTSA was concerned that was legal, he did say the man who did the checking of the vehcile wanted him to put a bag of sand in the front to counter the extra weight of the engine.... hmm so if this meets the rules in NZ how could you say the rules are thougher in NZ than in the UK???????

Reminds me of a great saying "she'll be right mate"