Reimu

I miss my 944's brakes back when they would actually stop the car. Its really taking away from the experience and it seems like everyone on the internet who has the same problem just learns to live with it. I don't find this acceptable for a Porsche.

I have bled, bled again, bled a dozen more times, and bled a little more after that. Classic pump method, speed bleeders, pressure bleeder, gravity bleeding, you name it. A bathtub's worth of fluid has been through my system (well I am using the same bottle over and over now).

The car sat for a couple of years and wasn't driven. When I took it out for the first time the pedal was really hard and it wouldn't stop for anything, on top of a vacuum leak and "woosh" sound when the brake was pressed. Replaced the brake booster which gave me a super soft pedal with the same braking performance. I went ahead and replaced the MC at this point just in case. Also got my rotors resurfaced as another "well might as well give it a shot" thing.

They haven't improved at all. Is there anything that could be wrong with any other point in the braking system? Maybe a caliper has some sort of seal that can fail and pass fluid through without compressing it as much? I pumped the brakes and held them down with a broomstick for over 24 hours and the fluid level never went down a mm.

This whole thing is really getting old. I can bleed until I'm blue in the face but not so much as a microbubble will pass through the tube.

Mikes-951

sorry to hear about that! I just did all my brakes and my car stops on a dime! especially after I bled them. I've heard of air pockets building up in calipers in areas that they will not flow out of the bleeder nipple. Perhaps pulling the caliper and rotating it around, up side down? and I assume you have checked for leaks through out the system?

Reimu

Yeah I'll probably try removing them and juggling them or something. I bled my brakes twice on the 944 in the past with no problems.

Yarf

It is recommended to bleed a new Master cylinder first before bleeding each caliper.
Brake bleeding information: http://www.clarks-garage.com/pdf-manual/brake-07.pdf
Also the rubber flex lines at each caliper could be at fault if they have deteriorated and are spongy under pressure.

Reimu

Yeah I bench bled for a long time. I inspected the lines the best I could but is it possible for there to be some sort of internal collapse?

F40LM

While I have never bothered doing it myself, we have probably all heard the old saying about swapping your pads and rotors at the same time. The guys on "Under the hood" were talking about it on a recent show. Could it be when you first tried driving the car again the pads and rotors both 'glazed'? Is it possible the pads are bad even if they look good?

HICKS

Could it be that the fluid you're reusing is getting air mixed in it? You're also flushing the system, and trying to reuse the flush fluid. I wouldn't do that, I would buy some über cheap fluid from your flaps. How old are the brake lines? Have you tried tapping on the calipers to dislodge bubbles? Are your calipers on upside down?

HICKS

Also try driving on a bumpy *** road, or a dirt road to see if it dislodges and bubbles.

turbodave

Is this an ABS car? Model and year please?

Reimu

I've driven on them plenty hard to see if they would eventually start to settle or wiggle some bubbles loose. Lot of daily driving, lot of hard stops from 60 (not that I can lock them up anyway). Lines are stock as far as I know.

Ah, forgot to mention. '87 n/a; no ABS

turbodave

Hi, What compound brake pad are you running? Have you replaced them or did a PO. If they are a racing compound you will never generate enough heat in them, in even heavy street driving, for them to be effective. I run the Hawk HPS, which is a great performance street pad, but they don't work as good as OEM until they get some heat in them. Another thought is that since the car sat for some time, is that rust may have accumulated in the piston cylinders in the calipers and caused the pistons/o-rings to bind or not reach full travel. Brake fluid, condensation and cast iron calipers are conductive to this. Also I would recommend replacing your brake lines. After a quarter of a century of faithful service on a sports car they have earned their retirement! I know you will get this sorted out. Be careful...Dave

pr951

Slight sponge with current car. Bugs me though and I may try replacing the rubber brake lines, maybe try braided.

Considering everything you have already replaced the lines might be worth trying.

OntarioTurbo

Just replaced both front flex lines on my Volvo last night. Pedal is noticably firmer and less spongy. Perhas some new lines would help you as well.

morghen

Thats strange that it does not go away when driven...everytime i did work on the braking system and had to bleed it, i could never get a solid brake pedal only by bleeding the system.
Its always after a few drives that the pedals feels like it should.
If you took out the calipers/pads...its normal to get a moushy feel for quite a few miles before the pads re-seat on the disks...this even if its the same pad on the same disk.

PorscheDoc

If you pump the pedal a few times, does it ever get hard?

You might look into picking up a reverse bleeder, they usually work the best on a stubborn system, but I think it is likely you have a component issue somewhere. It is definitely possible to get a bad master cylinder out of the box.