hi all i can get good presure when i pump them up but 30 seconds later there is no pedal there are no visable leaks i think it is the master cylinder has anyone else had this problame?

Have you undone any of the junctions in the brake pipes lately ? check the junction block where the pipe goes from the master cylinder before it splits for the front to rear . Also check for leaks in the rear wheel cylinders and front caliper seals/wheel cylinders . What master cylinder are you using by the way single or dual ciruit ?

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look for this...if you find it its a wheel cylinder but you would be loseing brake fluid in your resivour


Additionaly check your brake pedal if its wet

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Stop Licking the Dog...I Don't Care Who Started It

single system new caliper seals and new rear slave cylinders, yes i have undone is a few places but i have checked and double checked, my booster blew and i have just rebuilt that now my oil filter housing has decided to leak screw on type leaking above the filter, something tells me my mini dosn't want to go to the muster despite all my best efforts and all the late nights things keep going wrong.time is running out very fast.