Any car brake savvy folk out there ?

[A11an]

I have a '95 vw passat estate and the brakes were going soft soft so i bled the system thinking it would solve the problem. After that the brake fluid level was full and the pedal pressure fine. But alas, as soon as I turn on the ignition, the pedal goes straight to the floor ....? What could be the problem and the cure ?

[Kai]

Without the engine running after a couple of pumps of the brake pedal it should be rock solid then should go down a little when you start the engine and the brake servo comes in. If your not losing any fluid from the system then you probably have a leaking seal inside your master cylinder. You can either strip down the master cylinder and repair it but it would be probably easier and safer to just replace it.

[A11an]

Thanks, you could be right the pedal pressure is hard with the engine off. There is a small leak in the rear right side and I normally just top up with brake fluid and it is fine for a few weeks, but recently it was happening more frequently. I think the opening and closing of the fluid reservoir could have affected a pipe or something near the master cylinder. Also there is something attached to the master cylinder/servo, am not sure if it is part of ABS but it looks like a solenoid or motor with wires leading to it. It struck that maybe there was an electrical fault ?

The battery is now also flat so it will take me a while to check again.

[DMC]

How to put this politely?

- You don't seem to know much about the way your car works.
- You have worked on your brakes and made a known problem worse.
- You seem to think that topping up the brake fluid regularly is a safe alternative to fixing a known leak.

In all honesty, do you feel competent to work on your vehicle's braking system? If you want to learn to do your own repairs I suggest you start on something that is not safety-critical. In this instance I think you would be well advised to pay a professional or enlist the help of a knowledgable friend.

Having said that, Kai's suggestion re the master cylinder is probably right, but an accurate diagnosis is difficult until you have fixed all visible leaks. Do that work first.

[A11an]

The manual says that bleeding the brake requires a level three proficiency which is well within the reach of the weekend diy. I have done it before and it worked fine, But I agree with you about the rest, the small leak is still there and I'm not about to tamper unescessarily with the servo and mc. My resources are rather limited so I was hoping that I can avoid some of the costs ( for example, to tow the car not even 3km costs e139 and the hourly labour rate is e60 ) by doing it myself or with the assistance of someone that has experience in these things.

[Rob A.]

The manual says that bleeding the brake requires a level three proficiency which is well within the reach of the weekend diy. I have done it before and it worked fine, But I agree with you about the rest, the small leak is still there and I'm not about to tamper unescessarily with the servo and mc. My resources are rather limited so I was hoping that I can avoid some of the costs ( for example, to tow the car not even 3km costs e139 and the hourly labour rate is e60 ) by doing it myself or with the assistance of someone that has experience in these things.

Well...it "ain't rocket science"...well...maybe it once was, but it isn't now...

Anyway it's "probably" a leaking master cylinder seal...and you "probably" can get a rebuilt one for a reasonable price....and that will "probably" solve the problem....There's likely no problem at all with the booster or anything electrical...

So just go through it systematically and gradually.....and you should be OK....

I probably would take more chances driving a car with faulty brakes...and I have ...than I would be prepared to recommend to someone else....

However, as long as you're not a total "airhead"...and kind of understand the laws of physics, ...you'll probably figure out the safe way to fix it...

[Mattlill2000]

you'll probably figure out the safe way to fix it

I don't know about that. I'll agree with DMC with the simple matter that brake failure in the worst circumstances could cause injury resulting in death. Simple as that. "probably" shouldn't be a consideration.

[Rob A.]

you'll probably figure out the safe way to fix it

I don't know about that. I'll agree with DMC with the simple matter that brake failure in the worst circumstances could cause injury resulting in death. Simple as that. "probably" shouldn't be a consideration.

Well...I guess I could have worded it a little better...In a good quality car, the chances of total brake failure are remote...

Usually you will get a warning that there's a problem...sometimes along with a nice shot of adrenalin... and then you can take action and get the problem fixed. I remember as a teenager...driving those old English cars with the single chamber master cylinders...with those cars brake failure was BRAKE FAILURE....but it felt good to be alive after one of those episodes where the pedal sank straight to the floor without a hint of any attentuation in the car's speed...

...And one of my university buddies...an exchange student, or whatever they called them back then, from Germany, drove an old Hillman Minx for about six months using only the hand brake for stopping ... needless to say I did all I could to avoid driving with him...

It looked like this, I think...but a pale green version...




I think a smart, systematic person can easily do it themselves...but I agree not everyone should try it... The OP seems reasonably bright and reasonably careful...

[FraserinFinland]

Well I am with DMC on this.
I always try to help out where I can. I used to work for Audi, I could run you through the proceedures and I know what tools you will need.
But in your case I will make an exception after reading this..."I think the opening and closing of the fluid reservoir could have affected a pipe or something near the master cylinder. Also there is something attached to the master cylinder/servo, am not sure if it is part of ABS but it looks like a solenoid or motor with wires leading to it. It struck that maybe there was an electrical fault"

I'm going to be blunt, you shouldn't be working on your car. Do what ever it is you do to earn money and pay a VW garage to do it.

[sinikala]

my resources are rather limited so I was hoping that I can avoid some of the costs ( for example, to tow the car not even 3km costs e139 and the hourly labour rate is e60 ) by doing it myself or with the assistance of someone that has experience in these things.

I'm another who would warn against playing with brakes, it's the one part of a car you should make sure works. Leave it to the pros.

As general comments, if the brake pedal goes to the floor, it's probably the master that's goosed (or the ABS control unit), if it's a minor leak near the wheel I'd suggest looking at the slaves at the same time (I went through a bunch of slaves on my old Polo).

I would be truly astounded if even a VW main dealer would charge €139 to send a truck out to pick up your car and take it to their workshop .. as an aside when did they start using €€€ in Jo'burg?

If your budget's tight, I hope it's not the ABS; VW/Audi ABS parts are ridiculously expensive, the ABS unit went on my Dad's Audi... the bill was well over £500 ... closer to £800 IIRC.

[Cod]

the small leak is still there

..so do you mean -brake fluid leaking out which means you're probably getting air into the hydraulics?

You can't top up brake fluid at the resevoir when you have a leak, you have to rebleed the brakes in the correct order or the air in the line makes the hydraulics go soft. My understanding is that the resevoir is only for topping up as part of the bleeding process - at least that's what's worked for me.

[A11an]

my resources are rather limited so I was hoping that I can avoid some of the costs ( for example, to tow the car not even 3km costs e139 and the hourly labour rate is e60 ) by doing it myself or with the assistance of someone that has experience in these things.

I'm another who would warn against playing with brakes, it's the one part of a car you should make sure works. Leave it to the pros.

As general comments, if the brake pedal goes to the floor, it's probably the master that's goosed (or the ABS control unit), if it's a minor leak near the wheel I'd suggest looking at the slaves at the same time (I went through a bunch of slaves on my old Polo).

I would be truly astounded if even a VW main dealer would charge €139 to send a truck out to pick up your car and take it to their workshop .. as an aside when did they start using €€€ in Jo'burg?

If your budget's tight, I hope it's not the ABS; VW/Audi ABS parts are ridiculously expensive, the ABS unit went on my Dad's Audi... the bill was well over £500 ... closer to £800 IIRC.

I live in Haaga ( Helsinki ) and the towing co. said that they charge a flat fee of e139.

I would't be asking for help if I had the resources to pay a garage, I don't have a fixed profession and have no work.

[Tiwaz]

If you are that strapped for cash....


Then perhaps, just perhaps, you should accept that driving car is not necessity and get one of those nice chargeable cards for local public transportation.

It does not matter if "usually" catastrophic brake failure does not take place. It only requires one case to happen to kill you, or someone else.

[A11an]

Here is a pic of the MC etc, there is no signs of leaking brake fluid and no way for me to tell if the MC or Servo is faulty. The leak in the rear where handbrake cable meets caliper and is so slow it takes maybe 2 weeks before warning light comes on.

[A11an]

If you are that strapped for cash....


Then perhaps, just perhaps, you should accept that driving car is not necessity and get one of those nice chargeable cards for local public transportation.

It does not matter if "usually" catastrophic brake failure does not take place. It only requires one case to happen to kill you, or someone else.

I have no fixed work so I travel to wherever I can get work, for example I had work for 2 days in Porvoo recently and the bus cost e20 return, for this amount I can go to Porvoo twice by car. Plus if I have to stay there I would have to pay accomodation otherwise I would pay e40 for the bus.