What has happened to my brakes?

macman · 15-08-2010, 09:43 PM

Hoping someone here can help me out and shed some light on this for me.

The brakes went downhill on the TS50 (AU1) after I'd let it "stand" for a week. The brakes work, but have no bite to them. Apply the brakes and it's more like you've pulled the handbrake on if that makes sense. They don't clamp on, they don't wipe off the speed at the last few moments of braking as you would expect. Just a gradual slow down, though jump on the brakes with two feet and you CAN stop.

I've checked the booster which seems to be functioning correctly. I then made the assumption the brake pads were probably shot. On closer inspection the pads were practically brand new Bendix with plenty of meat on them.

I've roughed up the brake pads with a piece of very coarse sand paper, to give them a rough finish again and roughed up the discs as both seemed to be very smooth and glazed.

Brakes are slightly better, however still not acceptable IMO.

Brake fluid is at correct level, and although it appears darker/muckier than you would want (possibly not been changed for a long time) but doesn't stand out as a problem.

Anyone got any ideas as to what might be going on?

macman · 15-08-2010, 09:47 PM

Oh and also the ABS and traction control light is on constantly. I don't know if that's an issue though, as it has always been on, even before the brake issue appeared.

My TE50 has this same issue (ABS and traction control lights on) however the brakes function beautifully (but with no ABS) so I'm thinking not. What could be causing this?

JC · 16-08-2010, 08:27 AM

Sounds like air in the brake lines, or a leak somewhere.

KR1STO · 16-08-2010, 08:55 AM

I'm with JC..
I'd have a shot at bleeding the brakes first, also, get all the wheels off and see if any of the lines have a pin hole leak...
Start with the easy stuff first...

If you're not confident in doing so, get the car to a brake specialist..

And don't worry about the TC and ABS lights being on.. From what I've seen nearly half the AU's I know of have these lights on, or have had. It always turns out to be a sensor... And that can be easily rectified..!

Cheers
Kris

Hords · 16-08-2010, 09:08 AM

Yeah Dave,

If it's this sudden I'd be guessing at a leak too somewhere allowing air into the system. How's the reservoir level?

As for the ABS light I've only had it come on once out of 3 AUs. That was in the TS after the second run at Heathcote recently. Bagged 'em up heavily (well, for me) before hand. Shut her down for 5 minutes and didn't reappear.

Handbook says to take to dealership if light comes on. F@ck that, ring a couple of brake joints for an explanation. You definately don't want to gamble on brakes.

Keep us posted.

GK · 16-08-2010, 09:32 AM

Quote:

Originally Posted by Hords

How's the reservoir level?

The OP said it's normal but murky.

I'd be doing a full brake line flush first. The fluid might simply be shot and have absorbed a lot of moisture.

The full flush is cheap and easy to do, only costs you a hour or so with a mate and a few bottles of fluid. I always have 3 for such flushing, even though I end up with one spare. Better safe than sorry.

Also as you're going through the flushing process, you should be pretty easily able to spot any leaks etc.

All the best with it.

GK

Hords · 16-08-2010, 09:48 AM

Sorry George, skipped over the OP detail.

However, I'd be looking for a leak first before bleeding. Fix that then flush.

Edit: as for a few bottles of fluid, I'd need 24 if a mate get's involved

svo supporter · 16-08-2010, 06:47 PM

I'm with GK here. If it had a small leak, the resoviour level would drop fairly rapidly. So go with the fluid flush first. Having it all merky indicates the fluid is old and has probably absorbed a heap of moisture, which would be causing your problem.

macman · 16-08-2010, 08:42 PM

Thanks for the suggestions, and yes the fluid is mucky but level is fine.

Fluid change is obviously the next step, however if it was due to degraded fluid, surely this would happen "overnight?" I mean it was a Sunday it was fine, car was parked for a week and the following Sunday the brakes were stuffed?

Some else suggested to me to replace the one way valve on the booster as it might be leaking back the wrong way?

FTe342 · 16-08-2010, 08:51 PM

I don't agree with any of the above posts except your own. Bad fluid would give you a spongy pedal at worst and a leak would have a sinking pedal.
My money is on low power assistance due to a vacuum problem. Either the booster is not holding vacuum OR its not getting the vacuum from the inlet manifold. Possibly a cracked or disconnected hose

macman · 17-08-2010, 12:20 AM

I'm tempted to look past the fluid, however it's probably due to be changed/bled anyway.

How can I test the booster for any failure, further than I already have? I've checked for visible damage, checked the vacuum hose is ok and connected.

Also with the engine OFF, I pumped the brake pedal a few times (till it didn't hiss and went hard) then held my foot on the brake and started the engine, and the pedal sank and vacuum returned). As far as I know, this means the booster is working as it should?

Is there anything else I can try myself before I book it in?

I don't feel it's "unsafe" to drive, like I said I can slam the brakes and STOP, just not how I should be able to (with Tickford Premium brakes and new pads). I mean, my TE (with identical setup) can stop on a pinhead.

svo supporter · 17-08-2010, 07:05 PM

Sounds like the booster is doing it's job. Go for the fluid flush first then post back with the results

macman · 17-08-2010, 08:33 PM

It's going to be next weekend (at the earliest) before I'll have time, but that is the next step.

**FLOORED** · 18-08-2010, 09:56 AM

Quote:

Originally Posted by FTe342

I don't agree with any of the above posts except your own. Bad fluid would give you a spongy pedal at worst and a leak would have a sinking pedal.
My money is on low power assistance due to a vacuum problem. Either the booster is not holding vacuum OR its not getting the vacuum from the inlet manifold. Possibly a cracked or disconnected hose

If the pedal is hard with no bite I would be looking into this as a booster that is not working correct or is not getting enough vacuum will need two feet to pull it up because there will be no vacuum assistance to make the pedal have that softer feel.
A fluid flush is never a waste of time and remove the gunk out of the reservoir (after draining it with a syringe or something else) because you do not want all the gunk going through the brake system and causing any more headaches.
Sometimes these things can be caused by the least likeliest problem or a combo of others so if the problem does persist have a specialist look over the car.
1.Check booster for leaks (generally at the rear)
2.The check valve on the booster as it is a one way valve
3.The vacuum hose kinked or damaged
4.The valve blocked on the end of the vacuum line (engine side)