New Disc Pads Instaled And Brakes Hardly Holding

[awesomeandre]

So me and me ole man installed front disc pads and when test driving the pedal was going straight down and hardly getting any brakes at all



So we bleed the front and pedal standing up good, but while testing again it was dropping again

When we was installing the left side front the rubber around the piston was leaking not heavily but it was dripping now and then

i would like to know if by this rubber leaking if it is causing the brakes not to hold

[Dragsta]

Yes, once fluid is leaking, it will affect ur braking...

[cinco]

brakes are a hydraulic system once you getting air into it you will have a problem

[X2]

The rubber on the piston is leaking ? If so, you need to change it asap... BUT it should not negatively affect braking immediately.

When you change the brake pads, it requires you screw-in/depress the piston to fit the pad... You would have HAD to do this... and when you did... did you make sure the master cylinder cap was screwed off ?

If not, you could have blown out the seals on the master cylinder (sounds stupid, but entirely possible).

Now, if that is not the issue, you are also bound to have air in the braking system... it is common that you should do a full brake bleed after changing pads.

When I say FULL bleed, I mean you need to bleed ALL FOUR corners. you start with the farthest corner from the master cylinder, meaning the back left brake for RHD cars. You then bleed the front right, back right, front left. As long as your master cylinder is in good order, you should get a tight, constant brake pedal feel with very little pedal travel.

[awesomeandre]

The rubber on the piston is leaking ? If so, you need to change it asap... BUT it should not negatively affect braking immediately.

When you change the brake pads, it requires you screw-in/depress the piston to fit the pad... You would have HAD to do this... and when you did... did you make sure the master cylinder cap was screwed off ?

If not, you could have blown out the seals on the master cylinder (sounds stupid, but entirely possible).

Now, if that is not the issue, you are also bound to have air in the braking system... it is common that you should do a full brake bleed after changing pads.

When I say FULL bleed, I mean you need to bleed ALL FOUR corners. you start with the farthest corner from the master cylinder, meaning the back left brake for RHD cars. You then bleed the front right, back right, front left. As long as your master cylinder is in good order, you should get a tight, constant brake pedal feel with very little pedal travel.

well id did take off the cap

and i did not know that the bleeding should take place from the farthest corner

[W2J]

If not, you could have blown out the seals on the master cylinder (sounds stupid, but entirely possible).

Now, if that is not the issue, you are also bound to have air in the braking system... it is common that you should do a full brake bleed after changing pads.

unless he broke the line and air entered the system I doubt he would have any issues like what you describing here but then again he said that his piston seal was leaking. Also when Changing your pads you should only do one at a time and after the change is complete you should pump up the pedal before starting the car.

[TriniGT]

I would suggest you bleed the entire system to help the situation. Rule of thumb, bleed from the furthest point up, so if you have all discs and the car is RHD then back left, back right, front left and then front right. If it still persists then the MBC may need bleeding. This is quite difficult while having it on the car already. You will need to get threaded lines like those on the hard lines going to the master cylinder, the lines can be from an old brake cylinder that have been cut , just needing the threaded area going into the brake cylinder. From there you can attach two rubber hoses and route them back to the top of the MBC where it refills and try bleeding the MBC, bubbles should come out if there is any air in the MBC. You will be surprised how many people upgrade their MBC and never bench-bleed the MBC before putting it on and then find that the pedal is spongy. Do this and everything should be in order.

[Anil_Sooknanan]

ah boy like yuh try to change d pads yuhself anf yuh use ah bar to pri back the piston well yuh just F**** yuhself and yuh eh even know when yu do that the piston never goes back level always slant think of it a while .... what you have to buy is a G clamp that presses the piston evenly using a bar will send the piston bend and the seal inside does move and doesn't be straight again some times it does bla bla bla just change d seal and buy ah G clamp

[W2J]

^ don't need a g-clamp an a large adjustable pliers could work.

[TriniGT]

Also for many nissan cars the pistons actually need to be spun and pressed at the same time to be moved back. If you turn the piston counter-clockwise they come out, an easy way to do this is to slacken the nipple for bleeding and spin it clockwise and press it in at the same time. Collect the brakefluid via an aquarium hose attached to the nipple and routed to an empty bottle. Once the piston has been moved back enough insert the pads with the shims and reinstall and then bleed accordingly. X2 sorry only read after I type your post. From everything here you can get the jist of things.

[Anil_Sooknanan]

W2J, wha kinda pliers yuh have day TriniGT, yea that too good info slipped me to say

[W2J]

^ its called a slip joint pliers

[awesomeandre]

Anil_Sooknanan, yeah boy that is what exactly what happened

so i have to get me one of those

and the car is mazda and drum brakes in the back

the rear also has to be adjusted, hand brake holding slightly also

[Anil_Sooknanan]

W2J, i won't use that it will do the same thing meh boy G clamp is what should be used

[W2J]

^ nah the one I have has a flate circle on both sides you could use so it wont send it in uneven.

[cinco]

best thing to do is place back the old pad across the piston and then press with the pliers thats what i do

[X_Factor]

best thing to do is

pay 40$ and let ah mechanic do it yes..

[xxSTAY TUNEDxx]

pay 40$ and let ah mechanic do it yes..
Ah laughing but i agree

[Anil_Sooknanan]

stupid idea ^^^^^ when d g clamp is only about $60 for a life time come nahh be real

[Doom]

^^yuh know how much $40 i saved
plus basic things that supposed to be done aren't done by a mechanic
thanks eh but that job too easy

[Anil_Sooknanan]

yea boy whats d you comming here for if at d end yuh still going by a mechanic d idea is to DO IT YOURSELF anyway ah feel them fellas is d rich boys type unlike me

[awesomeandre]

well i went by d mechanic sorry to say, but he bleed the front, and the back also

what i notice what i did wrong when the pads was installed was that when we (Me and ole man) was bleeding and i pump up the pedal, he break the nut to let the air / fluid out of the lines, what i did wrong was before he closed the line i released the pedal so air was still in the line, a good lesson learn, is the keep th pedal straight down until the line is closed.

also the rear brake shoes have to be adjusted or be changed cause is little brakes i getting in the back.

[Doom]

yeah but u say u loosing fluid too
u need to replace the piston ring

[awesomeandre]

^^^^ yeah dat too

all this may contribute to the pedal dropping yes

[cinco]

if the rubber is busted most probably air will get back into it
so u better off fixin dat
u gonna have to bleed again when u change that