Brakes locking up after Master Cylinder Swap - new pads

Hi Guys

Last week i finally finished the brake upgrade on my eg civic (ITR disks and brakes, Prop valve and now a 1" Master). I modded the line and flared the new fitting on and bled the system fine.

took it for a drive to bed the pads in. then after abit the car got harder to drive....stopped tried to roll the car and the brakes were locked up. Gave the peddle a few hard pumps and it released...

I ended up doing the hnationals on the weekend with intermitent problem... every now and then it would happen not all the time.

What could it be? the Master Cylinder? i replaced the O ring inside it before putting it in, and the fitting i did notice has started to weep. so it needs reflaring

any ideas on a fix? rebuild master again? will fixing this line that weeping fix the problem?

thanks

Neil

Brake master/booster is a ABS 1" item if that helps?

Maybe ur front calipers need a rebuild kit???

all 4 wheels locking up? just sounds abit coincidental that it happened straight after putting the brake master/booster on. ive bled the brakes with the old brake master and it never locked up. soon as i put this on and started to bed the pads in it just got harder and harder and locked up. now it does it randomly.

Adjust the brake booster shaft from under the pedals, maybe someone has messed with it before and its already putting pressure on the MC without you pressing the pedal.

I would also check the condition of the front and rear caliper sliders.

Quote:

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Originally Posted by Egxris

all 4 wheels locking up? just sounds abit coincidental that it happened straight after putting the brake master/booster on. ive bled the brakes with the old brake master and it never locked up. soon as i put this on and started to bed the pads in it just got harder and harder and locked up. now it does it randomly.

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how do you know its all 4 wheels locking up?
did u jack up car and try to rotate each or just assumed

Yeah just the fronts have been locking up not the rears, can tell by looking at the pads, i removed the line lastnight that was leaking so i'll fix that, when i took the brake master off a gush of pressure released so im guessing its that shaft that pushes it in like grifty said. going to try adjusting that and see if i can get some slack in the master before its under pressure.

EG's would have diagonal opposed brakes - Left Front linked to Right Rear, and Right Front linked to Left rear.
It could look like the front because the brakes are biased to the front, and that could mean an issue with your Master Pump.

i would take it out and make sure its not seized (or missing a return spring)

Thanks ive pulled it out will inspect it tonight, it seems to pump fine alot of spring compression on it. but by the looks its on slightly all the time (by the push rod of the booster).

so whats the progress here?

I had the line reflared so that it will now seal. ive pulled the brake master off checked it springs back as it should, pulled the booster out and have adjusted the rod 5mm out at the booster and 5mm in from the peddle so it should be 5mm less pushing on the booster (hopefully), so tonight it goes back in and i guess i'll bleed the system and hopefully alls good. otherwise im burning the POS.

so howd it go buddy, hey befor you burn it lemme know ill buy shit lol its an intersting one, if it dosnt sort it i would be rebuilding the front calipers because it sounds to me that the square cut seal isnt pulling the piston back but thats cheap as to fix up

will see tonight how it goes, just need to rebleed the brakes. LOL im not going to burn it, will work out what the problem is soon hopefully. isnt the calipers as it would have done it previously, has something to do with the booster/master cylinder. worst case i rip it out and replace it with another one from the wreckers.

So i ended up getting the line reflared by a brake shop, adjusted the pushrod/U bolt on the peddle out 5mm~ and rebled the entire system and its now working fine :D

Awsome work...

Time to go back to Winton again! :D