Brake Woes

[Greenm3]

Ive just ordered a new claiper for the rear as mine is siezed, but since i noticed the rear caliper funny things have been hapening with the brakes.
When driving along after a bit of normal braking the brake pedal goes very very long, almost to the floor before anything happens! It's not a nice feeling and dont know if it's the seized caliper on the rear affecting it or not!
I'm meant to be going through France on a bit of a road trip in a couple of weeks time and really want this sorted.
I did the simple brake bomb test and it was satisfactory, got 30 pumps so not bad really.
Any ideas or shall i just throw the whole lot out and fit a massive Air brake ont op of the car!

[dan_b]

Sounds like you're losing hydraulic pressure if your pedal is going long, which could mean a few things:
that you're losing brake fluid through a leak, or
that your brake system is full of air.

Have you checked the fluid levels? When was the last time your fluid was bled and/or changed? Brake fluid should be changed at least every 12 months.

Have you visually checked the system for signs of fluid leakage - check the calipers and all the brake lines for dampness.

What ever you do, get it sorted before you go on a long road trip through France, you don't want to be in an S2 with no brakes.

[Greenm3]

Not sure when the last fluid change was i havent done it in the last 12 months ive owned the car? Could it just be that the fluid is past it's use by date, there dont appear to be any leaks, the funny thing is i leave it for a while and then come back and it's fine untill after driving for about 5-10min then it goes really long again!
How would the system get air in it if i havent touched it?
Could it be i need new disks and pads?
Thanks Mike

[dan_b]

Air gets in to the system through all manner of ways, it happens with all sorts of hydraulic systems. Also, you'll probably have water in the lines too which may start boiling, again causing a long pedal - this also happens naturally and there's nothing you can do about it. For these reasons it's important to change brake fluid regularly (as well as other reasons).

It's easy to inspect your discs and pads for wear - look at the discs, are they nice and flat at the top edge and near the hub, or is there a clearly visable lip? If you look in to the caliper you will see the pad (that gnarly black thing), is there any visable pad material on it, or is it just the metal backing plate left?

My gut feeling is that you urgently need do to a fluid change. It's quite easy to do it yourself if you've got the right kit.

Get yourself down to Halfords and buy a "Gunsons Ezibleed", and get yourself 2 - 2.5 Litres of brake fluid. I have in the past used Halfords DOT 5.1, and I think Halfords also sell Castrol Response SR fluid DOT 4.1, which is probably better. (You could also consider getting ATE Super Blue brake fluid - it's a very high performance fluid, and handily it's coloured Blue so you can tell when clean fluid is being drawn through. ATE also make an identical-spec Red fluid for the same purpose. Only trouble is getting hold of ATE stuff quickly if you can find it. I get my ATE from ebay)

Do a complete bleed of your braking system, starting with the right rear caliper, then left rear, then front left, and lastly front right. Draw a LOT of fluid through, especially the rears as they're the longest runs for the fluid. You'll use at least 2 litres to do this, even though the capacity of the system is about 700ml. You want to make sure you have clean, clear, bubble-free fluid coming out of each caliper.


By the way, DON'T get DOT 5.0 brake fluid. This is silicone-based, and is completely wrong for the S2 and it'll wreck your brake system. Make sure and check before you buy.


Give that a try!

Dan

[jg_bgt]

On my bros comp,
Thanks will give that ago, i fear i may need new discs and pads as well! Oh well might as well do it all at the same time.
My Fluid probably has all the properties of water at the moment cause i doubt it's been changed int he past couple of years and a couple of trackdays and the way i drive probably doesnt help ( ie, go pedal, stop pedal and u keep pressing the go pedal untill u need to press the stop one)
Thanks Mike

[Doug_RS2]

BTDT on a customers s2 and a tdi recently.

Your rear caliper is seizing partially on - and this is boiling the fluid - when this happens your foot will go tt the floor - pump it quickly to brake if you have to. Get the caliper replaced and replace the fluid - that will fix it.

I would check if you have a l;eak as well - just in case - do it on a dry road and pump a few times really hard - then see if you can see any leaks under the car or around the master cylinder

HTH