Breaks Fail - Help Needed

[Guest]

Well it's me again with yet another problem. My baby seems to spend more time in the repair shop than on the road. After getting the starter motor and one side heat exchanger replaced (oh and checked out the aircon to find I need a new condensor - any cheap ones out there?) I took her for a short drive only to have the breaks fail!!!!!

Car = 911 SC 1982
The symtoms are:
The car started to pull severly to the left
Breaks felt funny and when applied te pulling stopped
Break peddle went close to the floor before any resistance felt
So I limped to the side of the road, checked the break fuid level (same as it was yesterday) and checked each courner for any pools of fluid - none found.
Tested the breaks and wow they came back.
Drove home.

Now the break light is on all the time.

Any thoughts?

Help please and hopefully I will limp to the Ace Cafe tomorrow night (If I have some kind of breaks)

 

[bones]

Scarey, where did you get that car from? If the car is pulling to one side that suggests a sticking caliper or a warped disk. You can rebuild the caliper with a kit but if you take it to a workshop they will fit a new one most likely, they are not cheap. Other possibilities for brake failure are the master cylinder is faulty, it is 22 years old after all. Personally I would bleed the brakes through and replace the current fluid with ATE blue. It may be that one or all of the rubber hoses that attach the main brake ines to the calipers has outlived it's usefull life. On a car of that age replace them from stock or upgrade to braided stainless steel ones. Brake hoses are £40-£50 per four, fluid is about £15.00 a litre (buy two litres). Are you DIYer?

 

[danofesher]

I think an on-side caliper stuck on and consequently boiled the fluid which caused the pedal to go to the floor. Once it cooled it then worked OK. Had the car been unused for any length of time to make it more likely that a caliper would stick?.

I replaced the seals on a 3.2. I would not recommend doing that - better to send the calipers to be reconditioned at Classicar (they advertise in the Porsche Club magazine), which is what I ended up doing because the pistons were pitted.

 

[Guest]

Thanks for that Bones. I'd like to be a DIYer but need a workshop.

Thought it may be a sticky caliper or similar. Am a bit concerned as to why the break light is on all the time now.

Will probably hunt you out tomorrow night at the Ace Cafe.

Cheers

C[8|]

 

[danofesher]

Me again, rerread your posting and Bones's reply.

You say a brake light is on. I presume you mean a dash light. Is it the one that's due to a pad wear sensor or is it due to fluid level?. I wouldn't drive the car until you're sure.

I broke a pad wear sensor cable on my vauxhall Astra recently and that caused the light to go on because I'd broken the circuit. It may be a broken wire. You should be able to easily test whether it's the fluid level sensor that's in the cap (maybe you've disconnected a spade terminal?).

Untill I think of something else, Dan.

 

[Guest]

Dan

Thank you for that - sounds likley that your right about the caliper boiling the fluid. So it looks like time for new calipers [&o]

There is only one break light on the dash (the one that indicates the hand break, although I'd guess it covers any break failure).

About to do some research in the manual

I'll also check out regarding the spade terminals to the fluid pot as I was fishing arround it yesterday working out how the heating goes (which works now).

Thanks again

Cheers

C[:-]

 

[danofesher]

It's very easy not to release the handbrake properly and hence the light stays on. Your book should tell you that there is a light that warns of brake failure (fluid level) and the need to replace pads (my 1988 3.2 had both, I think, possibly in the same light as the handbrake, I can't remember).

Edited Below:

I checked the Haynes manual that I'd kept. There isn't a brake fluid level warning light (I was getting mixed up with other cars). Regarding possibility of master cylinder sticking, that's not impossible - it's a dual circuit, front and back, so if one stuck on it'd heat the brake fluid - however, it wouldn't necessarily pull to one side (some cars with dual circuits split the circuits diagonally but the 3.2 is front and back).

 

[Guest]

I hope this does not cause any confusion, but the peddle going to the floor and then being ok later sounds more like a master cylinder problem to me, a sticking caliper may be hiding the real fault. My brother in law had the same fault as you and needed a new master cylinder. If your brake warning light is still on try disconnecting your battery and then reconnecting it, this worked for me.
Good luck
Ian

 

[SJW BASIRE]

If the brake pedal goes to the floor it will trip the warning light on the dash.You will now need to reset it by groping around in the pedal area so that the contact pin clicks back into it's proper place.It is hard to describe in words but when you can see it you will be able to work out what you need to do.

 

[Guest]

Thank you for your help. I noticed in my 1000 odd page manual (light bedtime reading) that when the break light is tripped it need to be reset by disconnecting the battery.

This Sunday I will hopefully get the opertunity to have a poke arround and see if there are any visable issues with the master cylinder. Then I guess the thing to do is get her on a hoist and investigate each caliper etc.

Will let you know the result.

Cheers

C[]

 

[Guest]

I'm not sure that you will be able to see anything wrong with the master cylinder because the fault is likely to be a (partial) failure of the internal diaphragm. The fault that you described of losing your brakes and then getting them back, but noticing no leaks or fluid loss is exactly what happened to my brother-in-law. He had the master cylinder replaced and the problem went away. I do not think that a sticking caliper is the main fault, merely a secondary one.
Good luck, let us know how you get on.
Ian

 

[geoff Ives]

I've had this one. Change the brake fluid it has become contaminated with water. It frightened the crap out of me. I was travelling along the M40 when for some reason I tried the brakes. Pedal to the floor. I pulled in and called the AA but whilst I was waiting I tried the brakes again. PERFECT. The next day I completely evacuated the fluid and changed it.
I have sinse had the same trouble with another (non Porsche) car.