Brake Problems! - 97' Boxster

[1turb993s]

I have a 97' Boxster that just recently started having some brake issues. Sometimes when I step on the brake, it feels as though the piston/caliper sticks, and the car will not move. If I tap the brake pedal again lightly, it releases until I stop again. I repeatedly have to tap the brake pedal for the brakes to release. I recently installed 19" wheels on the car, and I read in the owner's manual that sometimes the ABS system will mis-read a different tires size. Could this be the issue, or could it be the calipers? Car does not pull to either side which usually signals a bad caliper. Pleae Help!!

[nick49]

Unsure of your braking problem, but thought you might like to know, Porsche strongly advises that on your year of car, 17" wheels are the largest diameter that should be used. This is up 1 inch from the standard 16". The chassis was not built stiff enough for the additional stresses caused from a larger and heavier wheel/tire combo.

[1turb993s]

I've heard that, but I've also heard that it's not a real issue if I don't track, or race the car. This is my basic driver, and I am not very agrressive with the way I drive it. Pretty much babied. It also seems to feel a lot better with the 19's than with the factory 17's that were replaced.

[RFM]

If its concerns a 986 Boxster MY 1997, remove the brake booster and look at the inside for water and / or rust. There is water infiltration in the booster when the water drains are clogged, it is a well known problem in rainy country's as mine. If it is the case clean the drains and replace the booster.

[pricebill]

I've got the same problem. Two days ago the brake pedal on my '98 goes just slightly mushy at the first touch. About an inch of soft play and then a quick pump will bring it back to the firm feel I've been used to. LAST night I hit the brakes at very slow speed and they locked almost immediately. I pulled the pedal back with the side of my shoe and we were off. The brake fluid reservoir is full and there's no dripping in the driveway.

As per this discussion over on pelican parts here I'm going to replace the brake lines and then replace the booster. I'll let you know how it goes.

-bill

Edited May 15, 2007 by pricebill

[1turb993s]

Sounds like we are having the same issue. I thought perhaps it was because I installed 19" wheels/tires on mine and the ABS was procesisng wrong due to the different tires sizes. I put the stock 17" wheels back on, and I'm still having the same issue. Please keep me posted as to how it goes after your repairs.

Thx

[pricebill]

I ordered a new brake booster and stainless lines from Pelican and finally got a chance to install all this weekend. Here's how things went.

After removing the battery cover and the left side piece of plastic over the steering I found a small swimming pool of brackish water. Initially I paid no attention to RFM's earlier advice about water in the brake booster because I'm in Southern California and it just doesn't rain here. Being a new owner I DID wash the car myself (also unheard of in Southern California) and the drains for this area of the car were completely blocked. So really, in washing my car I managed to destroy my brake booster. Excellent.

Installing the new one involves removing the master brake cylinder and ABS brake pump. While I was bleeding each brake I installed the new stainless lines. Three new tools now live with me; a Torx 45 driver (to remove the booster), a low profile jack (my big one just wouldn't fit under the baby porsche) and a Motive Power Bleeder. I can't believe I had never heard of this last piece of equipment. I spent a whole afternoon this summer using one of those stupid mighty-vac's on my '74 Thing and having the most miserable time bleeding the brakes. Pump up the Motive to 20 psi and open the valves at each wheel. SO easy.

The brake booster was more canteen than booster. It was slightly rusty inside and filled almost half way. If I had to do the whole thing over again I'd pull the line from the manifold and stick a long wooden matchstick in there to check for water. I'm certain that sucking it out with a tube might have gotten it working again and saved me the 5 or so hours I killed this afternoon. Maybe someone who knows how this piece of equipment actually works could let me know if it can ever be brought back to life after drowning. I know that I did the right thing in replacing it but I was sort of hoping to DRIVE somewhere this weekend.

The brake fluid that came out of each valve was particularly brown and ugly. The clear beautiful stuff that followed was nice to see. I'm going to go out and bleed the clutch in a second.

I was pretty certain when I bought this car that I would never touch it mechanically. Having owned a series of ancient vehicles (Scout II, DeVille, 230SL) that I worked on myself I just couldn't imagine taking apart anything on a Porsche. This is the second time in two weeks that I have avoided very expensive trips to the mechanic just by listening to advice given here on renntech.

Thanks. My car now stops.

-bill