Brakes losing pressure

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wizzball

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Hope someone can give me an idea of where the fault could be. I've got a Mazda Rustler bakkie and the brakes have suddenly started loosing pressure.

If I put my foot gently on the brake to slow down for a corner, or come to a slow stop for a red light the pedal will gently sink in all the way to the floor with almost no braking power until the very last centimetre before the carpet. However, if I brake hard, or pump the brake it's got great pressure and comes to an immediate stop.

I had a brand new brake master cylinder fitted in November last year so I don't think it's that, or at least I hope it's not that.
 
I presume you changed your brake fluid when you did the master cylinder, because that is also a sign of old fluid. Otherwise check to see that you don;'t have a leak that is causing the pressure to drop. The rubbers in the system could also be shot, age has nothing to do with it if one is the wrong size or nipped in some way or another.

NB - LOOSE - something that is not tight

LOSE -to lose something...like pressure...;)
 
Yeah, sorry about that. I only saw the grammar mistake after I posted the thread and you can't edit the title afterwards.

Surely a leak would mean constant low pressure on the brakes and not the low pressure when gently braking and full pressure when forcefully braking?

Thanks for the advice.
 
wizzball said:
Yeah, sorry about that. I only saw the grammar mistake after I posted the thread and you can't edit the title afterwards.

Surely a leak would mean constant low pressure on the brakes and not the low pressure when gently braking and full pressure when forcefully braking?

Thanks for the advice.
Click to expand...

Leaks can be deceptive, a slightly loose (correct term ;) ) connection might just need enough fluid pumped past it in order to build up the pressure.
 
wizzball said:
Yeah, sorry about that. I only saw the grammar mistake after I posted the thread and you can't edit the title afterwards.

Surely a leak would mean constant low pressure on the brakes and not the low pressure when gently braking and full pressure when forcefully braking?

Thanks for the advice.
Click to expand...

Not necessarly. Is your break light coming on now and then?
 
If there isn't a leak or a ton of air in the system then there is a problem with your master cylinder.

Sent from my HTC Desire using MyBroadband Android App
 
wizzball said:
Checked the brake fluid level last night and it's still sitting snug just below Max.
Click to expand...

You could try bleeding the brakes. You get little bleeding kits from Midas. It's pretty easy. Bleed then top up, if you're still having problems it's fairly major.

Just a tip: if you feel your brakes go soft, pump the pedal once or twice.
 
I second Nick, air in the lines is the most likely cause for this - do a propper bleed of the lines flushing the system completely and test again.
Also top-up the fluid to the max, I had an issue with VDC/Slip once where my brake-fluid was just below max and it took just a few ml to get it sorted.
 
1. When last did you check brakefluid
2. Could be leaking out by one of your wheels (there are ''cylinders'' there)
3. After the last time your car was worked on: has the breaks always been like that? If so then the brakes might need ''bleeding''
4. If you can't find the cause take it to a QUALIFIED mechanic.
 
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