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Brakes Failed


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Anyone got any ideas on this one?

Driving home the other night I noticed the brake pedal required a little bit more then the normal travel to start slowing the car down, it was only just noticeable and I had only travelled about 15 kilometres by this time. But a further few kilometres on, going down a good hill I applied the brakes and the pedal went straight to the floor! I managed to pull over pumped them a few times and the pedal got a bit firmer.

I got to my local garage that was only a couple of kilometres away. I stopped in his yard and got the mechanic to look at it, by this time the car had been standing for about 15 minutes and the pedal was back to normal and everything working ok! I was going away for a week so I left the car with him to check over but he has found nothing wrong. The fluid was clear and full (has now been changed). No obvious signs of leaks or seals passing. He took the car out several times and the brakes are working fine. At this point we have not started stripping anything down. The only suggestion so far is that the hand brake may have been on slightly and boiled the fluid. I am pretty sure the brake light was off when driving home and thought if this was the case I would have at least smelt hot brakes when stopping in his yard. The car is a 1988 Stevens Carb Turbo.

Anyone had this happen to them? Was wondering what people thought before starting to take things apart :)

Cheers.

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Hey Greg

If you press and hold the pedal firmly while the engine is running, does it creep to the floor?

also listen out for a hissing noise from the booster?

often also, if the master cylinder is leaking it may not leak from behind the master cylinder in the frot bonnet compartment, it may leak through the firewall and into the carpet behind the brake pedal

HTH

Justin

"Laugh" and the world laughs with you - "Cry" and you just wet your face...

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So the pedal has gone to the floor, but there is no loss of fluid and the pedal came back. Whilst plausible I question your mechanics theory it seems unlikely it could effect the front as well, but I do lean to brake fade, how hard were you driving the car, when did you last flush the hydraulic fluid? Come to that are you using a recommended fluid. I have it happen total loss of brakes due to fade, but it was a 72 Elan and I was pushing hard!

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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If there is no loss of fluid I would lean to what Roger suggested as to brake fade. How old was the brake fluid? Over time it absorbs water which significantly lowers the boiling point. So what you thought of not being very hot might be too much for old fluid. What you described of allowing it to sit and cool and then brake pedal functions normally is also a indication of brake boil. If the system has been flushed, you have a firm pedal and no fluid drop you could go out and find a safe stretch of road to do some hard brake stops to test it out.

good luck,

jeff

www.espritturbo.com

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  • Gold FFM

Not forgetting master cylinder internal pressure seals. A worn internal could allow fluid to bypass it, behaving differently at various temperatures, and demonstrate no leaks. First thing I'd do is replace the seals or the entire cylinder.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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A friend's 89 Turbo had that happen several times. Replaced the master cylinder and it happened again...

Turns out it was a mis-adjusted parking brake. It was rubbing and boiled the fluid at the rear calipers every time the car was driven.

Travis

Vulcan Grey 89SE

 

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A mystery...

As the car has a dual circuit master cylinder a failure in either circuit should not allow the pedal to go to the floor. I would also not expect a boiled rear brake to significantly affect front brake performance (as probably 75% of braking is from front brakes).

Having said that it must be one or the other. I tend to agree with an internal leak in master cylinder, If a caliper was binding, I think you or the mechanic would have noticed it.

cheers Steve

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Thanks everyone for your replies / advice. I pick the car up on Monday so will check out those suggestions Justin before I drive it away.

The original fluid could well have been in there a long time. The day it happened was while driving in traffic with no hard braking at all, just lots of stops and starts and then a bit of open road. I think I will go down the Master cylinder track first and see what we find from there. Will let you all know the outcome.

Cheers.

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  • 2 weeks later...

Got the car back yesterday after having the master cylinder overhauled. They re-sleeved it after finding pitting in the bore. Hopefully this was the cause of the problem! Pedal feels good and the car pulls up nice and straight, still might take it easy for a while it was a horrible feeling having no brakes! Thanks all for your advice. :D

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