Lblackman

Folks ...

I need some quick advice here.

Last week I was changing brake pads and ended up crimping a connector line on the right front caliper. I had a serious brake fluid leak, as a result.

I limped the car over to our local shop and asked them to fix my mess, and they were great -- they rushed the car in, ordered the part in, and got the car back to me today with a full brake fluid flush.

I picked the car up this afternoon and all looked fine, but I did not look under the front hood when I picked it up. Driving the car, the brake pedal felt a bit softer than I was accustomed to, but not seriously and it stopped very nicely. When I got home, I did pop open the trunk and saw that the cap had not been put back on the brake fluid reservoir. I put that on, fired up the car, and the rock solid, hard brake pedal feel was back.

My question ... is there any risk that air got into the brake fluid system? There was no spillage of fluid around the container, no apparent blow back of fluid onto the inside of the hood of the car. Everything was clean and good.

But ... I am tracking the car on Thursday this week and don't want to take a chance. Should I have the system flushed again?

Thanks for your perspectives / advice.

Lorne

Edgy01

If you never ran the reservoir dry than you couldn't introduce air into the system. Since you recently replaced your brake pads the pad travel distance is substantially less than on a car which has highly worn pads. As a result, less fluid moves on a car such as yours, today.

The softness you might be feeling is from the new pads. Did they brief you on the burn in procedures for the new pads? (Or did they do that for you already?)

The chance of air getting into the system? Slim to none.

Lblackman

Dan --- thanks for the quick response. But to clarify ... I was swapping my street pads out for track pads ... both sets are well used and well bedded in.

I presume that the softness on the pedal was because the cap wasn't on the fluid reservoir, so there was more expansion capacity than the norm in the hydraulic system.

My only worry is that any air in the system would be a problem on the track on Thursday.

Lorne

JW911

With a full resevoir you couldn't get air down into system regardless of whether the cap is on or off. The air would need to get to the bottom of the resevoir which just couldn't happen when full.

TD in DC

The cap cannot be the cause of the problem, but you have probably taken more time worrying about it than it would take you to just bleed the brakes again. Now, it probably isn't necessary BUT the peace of mind will be worth it. Do you have a motive?

Lblackman

nah ... that's part of the problem ... I would have to take it into the shop to do it. But I'm going to quit worrying about it.

Thanks for all your info ... need to get a Motive!

Lorne

TD in DC

Why yes, yes you do. If you can change brake pads you can bleed your brakes. Motive is a great tool to have.

dD/dt

The bigger risk would be moisture contamination, which might only manifest itself when the brakes get hot enough for the water to boil out -- like when you're on the track.

I'd get the system re-flushed right away. Brakes are important enough I wouldn't take the 1% (or whatever) chance that any water got in there.

TD in DC

It is seriously doubtful that you would get significant moisture contamination from simple exposure to air due to a cap being removed for such a short period of time.

That said, I would reflush due to the spongy pedal and to get peace of mind.

dD/dt

You're absolutely right. The chance is small.

My point is that I'm not going to drive a car on the road -- let alone the track -- if it's 'seriously doubtful' that the brakes will fail. I want more certainty with brakes. And given his circumstance, getting moisture in the brake fluid is more likely than air in the lines.

TD in DC

A friend of mine who used to be the chief tech for the local PCA region has an instrument that measures the amount of moisture in brake fluid. He has kept an opened can up on his shelf now for years, and you would be shocked at how little moisture contamination there is. Also, the systems on our cars are not perfectly sealed, so they are exposed to air/moisture all the time anyway.

A soggy pedal would make me think that the pads are not bedded properly or, more likely, the tech somehow put an airbubble in the system. Difficult to imagine how, but stranger things have happened.

Nonetheless, like you, I like feeling really confident about the whoa pedal because I really, really like to use the fun pedal without reservation.

cello

+1 - Moisture, not air, is your enemy here.

brendo

lorne - are you going down to portland on thursday by chance? i'll be down there with the guys from proformance

Lblackman

Yup ... i'll be there. A couple of us from Vancouver are going down. Robert M in his 996 turbo was at Seattle yesterday (Weissach day) ... sounds like they got washed out with the rain.

Look me up .... black C2S with a BC decal front license plate and Volk track wheels.

Lorne