rutz964C4

Hi

I am upgrading the brakes of my 1990 964 C4, the car right now has 58.000Km but when braking at high speeds you donīt feel that the car is braking as it should, so I have bought some front drilled brakes and before performing the change I am thinking of making some other modifications like better brake fluid and steel brake lines, also the brake pads, maybe someone can recomend me some (maybe mintex, pagid...). I am looking for some that I can use also daily (traffic, city, Highway)without needing them to warm them up before

Thanks

ALEX

Christer

Alex

If you feel your brakes are not functioning as well as you expect I would recommend getting them checked over (or serviced) by a Porsche specialist. An upgrade should not be necessary unless you do heavy track driving, it is probably a case of something not functioning quite right as opposed to the system not being effective enough in standard form.

Bill Gregory

Alex,

Be careful of drilled rotors. Porsche rotors have the holes cast in, while truly drilled rotors create stress risers in the metal, causing cracks to form between the holes, which means you throw the rotor away. Porsche rotors with cast holes will eventually form the cracks too, but nowhere near as quickly.

I agree with Christer that something isn't working right, and you should sort that out first.

Replacing your brake fluid should be the very first thing you should do - it may totally fix the feel, for much less than possibly un-needed brake upgrades.

Next, I would replace your rubber brake hoses with new Porsche rubber brake hoses. After around 8-10 years, the rubber brake hoses can swell internally, inhibiting the hydraulic pressure in the system. I'm not a fan of the braided stainless teflon/kevlar brake hoses for street usage, unless you're willing to inspect them religiously and possibly replace them every year or two. For street usage, and some would say for track too, it's hard to beat the stock hoses. Front lines are Porsche part # 993.355.139.00 and rear lines are part # 911.355.087.00.

It's possible, not likely though, that your pistons might be binding, thus your calipers might need rebuilding, and that should be looked at.

Unless you are tracking your C4, and need extra heat sink capacity, fix what you have. Our 964 brakes are really pretty good for street usage and even non-racing track usage.

rutz964C4

Thanks for the replies Christer and Bill, I will make some Porsche specialist to check the brakes, I donīt know if in this 10 years anyone has change the Brake fluid, so Iīll do that first at the same time I change the Brake Hoses, iīll also check if I need to replace the Brake pads, do you have any special recommendation (mintex, pagid...).

The drilled brake disk are from Sebro I think, do you know how its quality is?.

Thanks for your help

ALEX

Spanish 90 964 C4

AK

Does Porsche make cross drilled rotors for the 964?

I had cross drilled rotors on my last car, E36 bmw, and had no cracking problems at all. They were on the car for 50k miles. They were brembo rotors with stock pads and I never took the car to the track. I felt that there intial bite was a bit better than before. They also seemed to work better when wet. The biggest improvement by far was going from the stock 195/15 tires to 215/17 with some good rubber. I suspect it is the same with the 964.

Bill Gregory

[quote]<strong>Does Porsche make cross drilled rotors for the 964? </strong><hr></blockquote>
Not without changing the calipers although there might be something from the 968 line that would work. I should add that my comments are rotor cracking are born from track usage versus street usage, so YMMV.

GeoffD

I drove my C4 year round and found that an annual removal and cleaning of the calipers was required in order to keep the pads from getting fouled with dirt, corruption etc and getting "hung up" as a result. There is very little clearance between the pads and the caliper and a very small amount of dirt will cause them to bind within the caliper so that they do not slide with the piston. As a result, the only force that you exert on the disc is through bending of the pad against the disc. Also, the pad will not retract as it should and the brakes will drag. This is not how the system was intended to work and does not deliver good braking performance.

Try a little test. When you stop your car on any road, driveway, etc which is not totally level does it want to roll forward or back or does it stay put? If it doesn't want to roll, your calipers probably need cleaning.

Good Luck1