Poor braking, 2x the distance to stop

[evansaero]

It seems that my cars anti-lock system kicks in early and now take longer to come to full stop.

The car takes way to long to stop. The car has braking its just that the antilock system is causing it to increase the stoping distance 2x.

I tried the same stop in a different car at the same speed and the p-car took 2x the distance.

Also when parking in a stall with the wheel turned and apply some brake, say 30% braking power the anti lock system kicks in.

I know there is something wrong, but not sure what.

Edited October 23, 2006 by evansaero

[Loren]

Last time your brake fluid was changed and bled?

Anything new like pads and/or rotors?

Have you had the ABS system read for faults by the Durametric Software or a PST2 or PIWIS tester?

[D_Man]

I would go with the simple things first. Flush the brake fluid with new DOT4. I always bleed from the most furtherest wheel RR, LR, RF , LF. I have seen dramatic performance in stopping power with just a Bleed job.

If the problem persists check those things Loren has outlined.

D_Man

[evansaero]

Last time your brake fluid was changed and bled?

Anything new like pads and/or rotors?

Have you had the ABS system read for faults by the Durametric Software or a PST2 or PIWIS tester?

Drained fluid about 1 month ago. Don't have power bleeder so I did not flush.

Pads and rotors haven't been changed, Pads and rotors look good but have not measured them.

No ABS faults on dash, had the PST2 hooked up last month and it ran its full system test and found no faults.

Is there a way to bleed brakes without buying the power bleeder?

Thanks Guys

I guess I'll start with flush then pads then rotors. Hope one of these will fix it

Edited October 24, 2006 by evansaero

[D_Man]

Its very odd since Porsche brakes are some of the best.

What brand of Pad was used? Did they get properly bedded in. You might try a few hard drives in the country to get the system heated up. When I first put on new Pagid pads they didnt seem to stop all that great untill I got them very heated up to the point of smelling them and making them fade. Surprizing ly the car started stopping better.

The only other tip is to make shure you have a firm pedal, a spongy one is never good.

Good Luck

D Man

[D_Man]

As far as bleeding your brakes I have always used the traditional method of using a helper (your wife or Girl friend) inside the car pressing the pedal as You (outside the car) open the bleeder valve on each caliper, remember there are two bleeder ports on each caliper that have to be bled. The order is important since you want to work your way around the car from the fartherest point to the next furtherest point from the Master cylinder. (Order: RR, LR, RF, LF)

A Power bleeder is well worth the money, since you only need yourself to do this job now. Power bleeders work so well the Mfgs do recommend the traditional discribed above any longer, ether way works just fine.

I bought this bleeder from Pelican parts. Black Label European Power Bleeder Kit works on most all euro cars.

http://www.pelicanparts.com/catalog/shopca..._BLEEDR_pg8.htm

$68.00 and some change.

D Man

[evansaero]

D man,

Thanks for the info. :cheers:

Pads are porsche oem. They might need to be replaced being thta I'm not sure when or if they have been replaced. Just looking at the pads (eye-balling)I would say I have about 1/4 inch left maybe a little more

I went out the day before I wrote this thread and really worked the brakes hard. I thought the same thing, but brakes just don't have the stoping power they should have.

I'll update this after I bleed.

[viper501]

Bleed the brakes man! If you just drained the fluid and refilled, that is definitely your problem. I'm hoping that I misread that. The traditional technique outlined by Dman should work great in place of the pressure bleeder.

[evansaero]

Update: Bleed findings

1) Found that old brake fluid was light green in color, not the DOT 4 color that I put in

2) Yes there was some air in each line.

3) In some of the line there was a milky white fluid coming from rear brakes (what is that?)

4) Stoping distance was decreased, just need new brakes now.

Didn't have the wife around so I used a 2x4 to hold brake in while bleeding each line.

[viper501]

Your car is lactating. :D Seriously, not sure what it would be unless it was a sign of water contamination in the fluid. Again, that is just a guess. Congrats on getting the job done with some 2x4 engineering.

[lrapoport]

First, buy a power bleeder if you are going to bleed your brakes yourself. I got one of the generic European ones for about $48 online. If you read the Porsche service manual, you are not to bleed these brakes through the traditional push/pedal method. They are to only be bled at high pressure (around 1.5 bar or 22 psi) with a remote fluid reservoir. Go by Porsche's numbers, not the ones in the power bleeder instructions.

When you read the instructions for the power bleeder, they say not to use over 20 psi. Porsche uses a much higher pressure braking system due to the amount of fluid flow required to actuate 4-braking pistons at each corner. The reason for this is that the brake systems uses independant braking circuits with electromagentic valves. When you actuate the pedal, the valves close and the additional fluid returns through the return flow for pressure reduction rather than flow back through the valves. This is the reason why you are not recommended to use the push/pedal method since you can introduce air into the lines through the return path and damage the brake system bleeding it through this method.

The good thing is even despite have 8 bleeders (2 per caliper), using the power bleeder makes this one person bleeding job the easiest you will ever do. There is no need for a second person to bleed the brakes. Just monitor the power bleeder to keep the pressure over 20 psi. I usually start at 25 psi and check it after each caliper. When it goes down to 20 psi, I pump it back up to 25 psi. The result is a perfect bleed job everytime.

Edited November 11, 2006 by 02 Carrera