What brake upgrades to do?

[mkinne]

I was just about ready to order parts for a brake upgrade (19mm MC, SS lines, etc...) when last weeks thread got me all confused. Seems to be good arguements on both sides.

So, are there any more recommendations for a '73 1.7L daily driver? All parts concerned are currently in good condition except for a few piston dust seals. New pads and fluid will be required. Which ones?

Thanx in advance.

BTW, isn't today one of the best days of the year!

[John Rogers]

If your car stops well and parts are okay, I wouldn't worry. If parts are worn out or if you autocross or time trial occasionally I would recommend the following: New 19mm master cylinder($90), new OEM rubber lines($25), BMW 320i front calipers(see PP article)($100), Tee to replace the prop vave($13), DOT 4 fluid such as NAPA($10) and Metal Master pads(semi metalic)($75 for all wheels). This setup keeps the 4 bolt hubs which is a big cost factor. Both our 914s have all the above, one is my daughter's daily driver and autocross car the other is a dedicated track car. Both stop like they have had an anchor thrown out the back with no rear wheel lockup. Unless it is a dedicated track car with lots of maint to be performed, I would stay with the factory flex lines. Metal Master pads are a good compromise with little dust, easy rotor wear and no squeal when cold and they handle repeated stops very well with no hi temo degredation. Others will probably recommend other items, so I would find a shop close to where you live and can trust and let them provide some guidance too.

[This message has been edited by john rogers (edited 09-14-1999).]

[This message has been edited by john rogers (edited 09-14-1999).]

[mkinne]

Thanks for the feedback, John

This car is strictly a daily driver, no time yet for autocrossing

I've heard little about replacing the prop valve with a T. Is there any danger of locking up the rear too early? Weather and road conditions here in S. Cal are generally good but a brief rain can make things very scary (mostly due to other drivers).

[John Rogers]

The Tee issue can be debated a lot it seems. Some people swear by them and others feel they are unnecessary. I went on the recomendation of Chuck, the owner of CNC (makes racing brakes) in San Diego, who makes brakes and he said it was not necessary. So far neither car has had a problem with lockup.

[paulhagedorn]

Not trying to say anyone is wrong, just saying what is on my mind.
Wouldn't the prop valve have been put there for a purpose. If you take it out, wouldn't that mean that the rear brakes would be getting more brake fluid. Given that it wouldn't be as much as the front, but it would still be getting more than normal. Also, being that the rear brakes are smaller, they would need less fluid to push the pistons out farther. Thus, wouldn't the rear brakes lock up a lot faster? Meaning, if you aren't careful, or you need to brake quickly in the rain, lock up...CRASH?

Just my 2 cents worth.

If it actually does not pose a safety problem, I might consider doing it, but not before I got in a 914 with that setup.

Paul

[Joe Bob]

The rear brakes would get more pressure w/o the proportioning valve. Since the stock rear brakes are smaller than the front, lock up SHOULD not be a concern. But if the front brakes are worn the rears COULD lock up first and that would be a problem.

I have removed the valve but use big vented rotors and calipers up front. The rears are stock, because I like having an emergency brake.

PS-Hint, don't use E-Brake after doing real hard braking... the pads and heat can combine to weld them together as they cool off. Ask me how I know.....better yet don't...

[This message has been edited by mikez (edited 09-16-1999).]

[John Rogers]

All of our Porsches are without a prop valve. If I stomp the pedal hard enough, generally all the wheels lock about the same time, but over the years I have gotten to the point where this doesn't happen very often. Out 1987 Turbo came this way and is much heavier with much bigger brakes(all are same size) and usually the fronts will break loose first. On the 914s, we haven't had any problems with rear wheel lockup and from what I was told the prop valve was a safety factor since this was supposed to be an "entry level Porsche" drivers would not know how to drive it correctly, meaning locking up the wheels, etc. The San Deigo Reigon of PCA is having an autocross on 9/25 and I'll gladly let anyone take a ride in the race car as long as they are entered in the auto-x and you can see what it is like.

[BeeJay]

My daily driver has the T. Best improvement to my brake system yet. The rears have never locked on me, even in the rain. I also put the 911 master cylinder and braided lines. The brakes always felt mushy before the t.

[Dave at Pelican Parts]

Actually, if you re-read the original response, it mentioned BOTH the BMW brake upgrade *and* the Tee. This appears (at least so far!) to balance out pretty well, since the BMW calipers seem to give you more front braking force.

I'm with Brian. I wouldn't remove the proportioning valve on a street car, unless I had upgraded the fronts only. Or upgraded them much more than the rear brakes. Actually, I might be tempted to install an aftermarket adjustable proportioning valve, but only if I felt confident I could match the stock specs with it.

And I don't.

--DD