Help: Rotora 4-piston front BBK installed, but...
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Help: Rotora 4-piston front BBK installed, but...
I installed my 4-piston front BBK and installed the braided lines that came w/it. I bled the system multiple times. Intitially, I bled the inner valve and then the outer valve of each caliper. I got to the point where there was no air left and turned the car on and tried the brake but it's not firm at all. So I bled again and then I bled each valve at the same time. I tapped on the calipers w/a rubber malet as well to try and force any air pockets out...But the brakes still are not right, when I push the pedal it sinks all the way into the floor. I opened the valves just a little bit (and also opened the valves a lot more) and bled and made sure that the master cylinder did not get too low. I think I have done everything possible. I really don't think that there can be any air in there. Anyone have any ideas as to what it could be or any recommendations as to what I should try next. Thanks
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Originally Posted by cnile51
did you close the lid on the brake fluid reservoir? sounds like your doing everythng right but if that remains open your just sucking in more air....
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If youve bled multiple times and still havent been able to get the pedal back, it usually meands there is some air that has gotten into the master cylinder.
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Originally Posted by StopTech
If youve bled multiple times and still havent been able to get the pedal back, it usually meands there is some air that has gotten into the master cylinder.
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#8
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If youve bled and bled and are sure that there is no air in the lines, the car will usually have to be taken to the dealership to have the master/ABS unit bled. Just for the sake of trying, you might want to just crack the bleed screws with the engine running. No reason to pump the pedal, just to see if you get any more air out of the system. That may halp to get any small bubbles that may be trapped.
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Originally Posted by abstrakt
I got to the point where there was no air left and turned the car on and tried the brake but it's not firm at all.
How many times did you pump the brake pedal? It's normal for it to be super spungy the first 4-5 times.
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Originally Posted by Kolia
Just asking to make sure we're not missing anything...
How many times did you pump the brake pedal? It's normal for it to be super spungy the first 4-5 times.
How many times did you pump the brake pedal? It's normal for it to be super spungy the first 4-5 times.
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Originally Posted by abstrakt
I'm pretty much a 100% sure I pumped enough during the bleeding...and also on start-up afterwards...it still remains loose/spongey. I'm going to bleed again today just to make sure.
Pumping with the engine OFF, you'll be lucky to get 300 psi in the lines.
Pumping with the engine ON, the pressure will be over 1500 psi.
It's normal to have to pump again once you start the engine the first time. The pedal will feel mushy until the pads are properly bedded-in. They don't lay flat against the rotor yet and they bend a bit.
You might have been wasting your time when all you had to do is pump the pedal a few times and drive off to bed your pads in...
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Originally Posted by Kolia
No. I meant AFTER you start the engine. How many pumping did you do?
Pumping with the engine OFF, you'll be lucky to get 300 psi in the lines.
Pumping with the engine ON, the pressure will be over 1500 psi.
It's normal to have to pump again once you start the engine the first time. The pedal will feel mushy until the pads are properly bedded-in. They don't lay flat against the rotor yet and they bend a bit.
You might have been wasting your time when all you had to do is pump the pedal a few times and drive off to bed your pads in...
Pumping with the engine OFF, you'll be lucky to get 300 psi in the lines.
Pumping with the engine ON, the pressure will be over 1500 psi.
It's normal to have to pump again once you start the engine the first time. The pedal will feel mushy until the pads are properly bedded-in. They don't lay flat against the rotor yet and they bend a bit.
You might have been wasting your time when all you had to do is pump the pedal a few times and drive off to bed your pads in...
#13
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If the pedal is mushy but the brakes are working properly with the pedal not falling all the way to the floor, it may be that the caliper pistons may just be oversized causing a soft pedal. If the pedal has a progressive feel where it starts off soft and then grabs suddenly then it is a classic case of oversized piston bores for your application. I do not know what piston sizes are used in your kit so I cant say for sure whether or not that is the case, but if all of the air is out of the lines and there is no air in your master cylinder, the pedal feel will not be improved without a larger master cylinder or calipers with smaller pistons.
#15
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Originally Posted by Bubble
let professional bleds for you instead of DYI.
#16
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I had the same problem with a clutch master cylinder I was bleeding once. Make sure the car is on. You will need two people. Pump the brakes several times, but this time have someone in the car that will keep the brake pedal down while you bleed the valve. This will force the air pockets out of the valve, instead of staying trapped in your lines. You'll probably have to do this a few times b4 you get a firm brake.
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