Brake Upgrade

Porsche_monkey · 07-30-2003, 04:31 AM

I am not really thrilled with the brakes on my 74 911. They are original (cast iron) calipers without power brakes. I guess you could say I can only improve from here.

What is the next step from here, I know there are aluminum calipers, which I think only reduce weight, power brakes and bigger calipers.

Without going to the big $ big reds, what can gives me the most bang for the buck?

masraum · 07-30-2003, 04:57 AM

Carrera brakes which offers more rotor mass, then there are 964 brakes and turbo brakes.

Bill Verburg · Bill Verburg's Garage

These Carrera fronts will be a nice bolt on upgrade fpr a '74 that already has either A or S calipers. If you only have Ms then you will need to update the struts as well. But for any decent brake upgrade you need to start with 3.5" ear struts.

You only want the front calipers and rotors but there is someone that only wants the rears, Make a deal.

Porsche_monkey · 07-30-2003, 06:06 AM

And forget about power brakes?

Bill Verburg · Bill Verburg's Garage

Yes, p/b are a fairly involved project.

Zeke · 07-30-2003, 07:13 AM

With enough pad, you shouldn't need power brakes. I have S calipers on the front of my 914 with M fronts on the rear. I don't need much pedal pressure at all. I stepped up to a 19mm MC as well, reducing the mechanical advantage. If your system is fresh, all the pistons are working freely and the pads/rotors are in good shape, it should stop very well with moderate pedal pressure.

I would check for the 3.5" spacing, in which case, you already have S or A calipers. I know there were some option years in there somewhere, but I don't know too much about which strut, which caliper went with whcih model.

The brakes can't have ANY leaking fluid on the pads/rotors. Check that out first.

widebody911 · widebody911's Garage

What makes you think your brakes are inadequate? Are you getting brake fade? Are you consistently plowing into the back of school buses Is somoene else beating you by .01s/lap?

If not, then they're probably potentially perfectly fine.

When was the last time you changed the fluid and bled the system ($20)? Rebuilt the calipers ($50)? What pads are you using ($100)?

From what I've seen, 95% of 911 'brake problems' are 'catalog envy'.

Porsche_monkey · 07-30-2003, 07:32 AM

I have just rebuilt everything on my car changed the fluid and pressure bled the system. It just seems to me I have to push awfully hard to stop.

This is my first 911 and I have not driven it a lot. Maybe I'm just too used to North American power brakes, but I expected a lot more. I might be confusing force and stopping distance, ie I stop fine but I'm just not used to pushing that hard.

I will have to put a few more miles on my car, you might be right Thom.

(What's wrong with catalogue envy? How can a guy with a 3.6 say that with a straight face?

)

masraum · 07-30-2003, 07:42 AM

Your brakes are fine. They will feel worlds apart from American cars. If you are used to the American power brakes then get a '65 Impala with manual brakes and steering and drive that around for a while. You'll think the Porsche brakes are the world class brakes that they are.

The key to good brakes is not how much pedal pressure you have to exert, but how well they stop the car. It sounds like you just need to get used to them.

Porsche_monkey · 07-30-2003, 07:44 AM

Time to pull the stairmaster out of the closet...

89911 · 07-30-2003, 08:32 AM

Yes your brakes are adequate, but to think that no improvements can be made on a system that is 30 (thirty) years old is stone age thinking. I was once a naysayer until I upgraded my "adequate" carrera brakes with turbo's. I took a full 2 seconds of my best track time that I had been running for 4 years the first outing. Yes, you can improve on original equipment if it is done wisely. This board would'nt exist if we didn't!

Bill Verburg · Bill Verburg's Garage

The poor guy just asked how? not Should I? Why is everyone jumping on his back?

Porsche_monkey · 07-30-2003, 09:08 AM

More guys on back = stronger legs

masraum · 07-30-2003, 09:16 AM

No piggy back rides for me thanks. After this statement

Quote:

This is my first 911 and I have not driven it a lot. Maybe I'm just too used to North American power brakes, but I expected a lot more. I might be confusing force and stopping distance, ie I stop fine but I'm just not used to pushing that hard.

I was just validating/reassuring him that he was correct on all counts.

Bill Verburg · Bill Verburg's Garage

I guess that I better not let him try mine w/ the 23.8mm m/c an no boost. Good thing I'm doing 50mi/day on my bike.

masraum · 07-30-2003, 09:29 AM

Jeez Bill, that must feel like you are standing on a dead pedal.

Bill Verburg · Bill Verburg's Garage

No biggie, about like a 930 when the p/b aren't working, Makes modulation at the edge easier.

Excessive pedal pressure in a non boosted 911 can be caused by glazed or contaminated pads and/or high temp pads in street use.

A very cheap item would be Axis Metal Master pads, a nice low dust street pad

Pelicans brake pad selection

I have also heard good things about the Mintex pads but have not used them myself.

By the way, Zeke be careful about brake recomendations, that caliper combination may work on a 914(I do not see how

) but it is totally wrong for a 911. You end up w/ a 1:1 bias.

A 911 wants 1.6:1 or better bias, the lowest the factory ever went was 1.3:1 and that wasn't a perticularly successful performance setup.

You don't need much pedal pressure because you have a very high master/slave ratio @ 21.6:1. This high a ratio makes modulation ergonomically more difficult than necessary

Cali · 07-30-2003, 03:31 PM

I have the same problem and I have been looking at upgrade options beyond the standard pads, lines, fluid... If you have Boge struts you can either buy the front suspension off of a later car (like a carrera) and use those brakes, or go for BMW brakes. A race shop I worked at for a while said they used BMW 320 brake calipers on those struts because they were almost the same as the S calipers. There is a 914 tech article that talks about this upgrade and I think it applies to our 911s as well. Cheap new calipers, check it out.

dd74 · 07-30-2003, 05:08 PM

Quote:

Originally posted by Cali
If you have Boge struts you can either buy the front suspension off of a later car (like a carrera) and use those brakes, or go for BMW brakes. A race shop I worked at for a while said they used BMW 320 brake calipers on those struts because they were almost the same as the S calipers. There is a 914 tech article that talks about this upgrade and I think it applies to our 911s as well. Cheap new calipers, check it out.

Is the later suspension specific to cars equipped with Boge struts? What about Bilstein and/or Koni strut cars?

Are the 320 brakes that much better than non S brakes? Is it a straight bolt on proceedure?

Tyson told me just some better pads - Porterman, Porterhouse (wait, that's a steak)...something like that - and a good flushing out with some ATE fluid replaced, and the brakes would be fine.

But I'm always open to other suggestions/thoughts.

Thanks.

Cali · 07-30-2003, 05:37 PM

He is right that you could improve braking that way, and you might want to try that first. As far as the suspension goes, if you have Boge struts then you have M calipers with the 3" spacing, the others had the 3.5" spacing of the A and S calipers. We got screwed out of that easy upgrade, but the BMW brakes should bolt up no problem, or with the minor machining.

Oh, and yes they are that much better, MUCH larger pad area/thickness. You use S pads with them and shave a little off the corners.