Brake issues - pedal feels soft
Hi guys,
I replaced my brake pads yesterday (front and rear), and ever since it feels like my brakes are kinda soft (the feeling on the pedal).
I followed the directions on this post:
Replacing front brake pads
Anywho here's the gist of it:
took out the old pads, opened the bleed nipple and compressed the pistons (or piston on the rear) so the caliper will fit over the new pads. Closed the bleed nipple, installed the new pads, put the caliper back on etc etc.
Did this for both front left and right then performed half pushes on the brake pedal till I could feel the compression of the pistons from the foot pedal.
Then followed the same for the rear.
Drove around to bed the brakes in and as I said the pedal feels kinda soft, I have to push the pedal in a lot further to actually feel the brakes engage. As in it feels like the pistons aren't compressed.
Something I did notice as well, if I do a little pump of the pedal (pressing my foot down to before the point where I can feel the brakes engage) then press down on the pedal again straight away it feels as though the pistons have compressed more then what they were.
Could there be air in my lines? If so what is the proper procedure to bleed my brakes (I ask this as my brother did this a couple of years ago and had to get his master boot cylinder replaced as he apparently didn't do it correctly).
Cheers guys,
Daz
I have a VY Exec series I
Gas Sleeper
so you reckon there's air in my lines?
6 speed
yes, there is a way to change them without haveing to bleed the brakes but it doesn't involve the brake nipples
Chev badges are an instant fail
Now w/Phreddied Dash
I don't know why you would need to open the bleed nipple. Once you touch that you need to redo your brake lines. You could have done it without touching the bleed valve.
Just undo the caliper at the bolts, remove old pads, use proper tool or two spanners to put caliper back in place, insert new pads, put caliper back on and your done. Just pump the pedal to make sure it engages.
A Commodore is a passion. Anything else is just a car
"use proper tool or two spanners to put caliper back in place"
Sorry what do you mean by this? Are you just talking about putting the calipers back on over the disc? Also as the new pads will almost always be thicker can you just push the calipers apart to fit the new pads without having to open the bleed nipple?
Cheers,
Nil Bastardo Carborundum
The front calipers have two pistons, and you need to compress both of them simultaneously to force them back into the caliper to provide space for the new, thicker pad. My method is to use two G clamps.
1. Undo the lower caliper bolt and lift the caliper upto release the old pads.
2. Place the two G clamps over the caliper, one clamp to each piston.
3. Screw both clamps in to compress both pistons.
4. Remove both clamps, fit new pads to caliper mountng brackets, and lower caliper over pads onto bracket.
5 Reinstall lower bolt and tighten.
You do not need to touch the bleed valves, but you should check the level of the fluid in the reserviour to ensure it isn't over-full.
From your description, it sounds like you have air in the system. Only a full bleed will ensure that all air is purged. Follow the thread already indicated above.
When bleeding brakes, it is usual practice to start with the longer brake line first. As front and rear are separate circuits, do the passenger side caliper first on each circuit.
The Wagon on Wheels..
Agreed, definatly air in your lines. As you pushed the pistons back, did you keep the pressure on the pistons while you did the nipple back up. If you didnt then i would say you have sucked a small amount of air in each caliper. I would maybe try just cracking each nipple 1 by 1 as a helper keeps pressure on the brake pedal and just try to expel any air pockets in the top of the calipers and do the nipple back up quickly before the helper stops applying pressure to the pedal. You might get lucky and it will be a easy fix.
Originally Posted by Blown V6 Hatch
It's cheap and half arsed - perfect fit for a Commodore
Reaper
No, I believe after we pushed the pistons back we did not close the bleed valve before releasing the pressure on the pistons.
Thanks guys, will bleed the lines over the weekend and let you know how it goes.
Thanks for your help
Daz
The Only 6sp VZ Wagon
i crack the nipples when doing brakes at work, but i use a hose on the nipple to direct the fluid into our bleeding container to eliminate the chance of air getting in,
cracking the nipple is less fiddly, quicker, and makes doing 2 and 4 pot calipers much easier, it also eliminates the chance of the master cylinder over-filling and having brake fluid run down the engine bay paint
EASTERN CREEK JCNSW 2009
The Only 6sp VZ Wagon
Grandpa
sorry but if you dont understand how the braking system works you shouldnt be touching them.
next time at least get someone who knows what they are doing to watch you.
how would you feel if your brakes failed & you injured someone... or worse?
That is why I came on here and found a thread for replacing the brake pads... (which told me to open the bleed nipple and compress the pistons). It didn't tell me that if I left the bleed nipple open whilst taking off my G-Clamps air would get in my lines.
I took the advice of people who know about such things. So next time think before you say something. As I did mention above that I had followed a thread on here regarding replacing the brake pads, not to mention me and my brother were also going off a Gregories service manual.
And for your information, as soon as I noticed there was something wrong with my brakes I took my car home and haven't driven it since!!!
I could go on, but I feel that if I do I might say something that the administrators of this forum might not like, and I use this forum regularly so I will finish there...
The best way to learn something you dont is to research it and then in this case do it for yourself (learning about these sorts of things as you do). And in my case my research had left out some details.
crappy ol' VN driver
you want to post a link to that thread. normally i push the pistons back in and don't touch the bleed nipple. i double check the mastercylinder reserviour after every piston is compressed to ensure no leakage. a old medical syringe is ace for removing excess fluid.
to open the bleed nipple would require you to follow the proper brake bleeding procedure at the same time as replacing the pads. not a bad idea if you know what your doing and the fluid is old and needs changing etc.
best way to learn is hands on. it's a shame that you have fallen foul of instructions without the relevant warnings.
post the link and we'll check the thread and have it updated with the correct info
Body by Holden, Soul by Brock
the Legend will live forever
VN exec T5: 15.1sec @92.2mph 1/4 mile, 9.7sec @ 74.6mph 1/8mile, 2.3sec 60ft, 0-60mph 6.827sec 22/11/07 Gtech competition
Oh god... 'Yes daddy'
the main reason u crack the nipples is so that the brake fluid in the caliper is replaced.
The Only 6sp VZ Wagon
correct, crap can build up in the pistons in the calipers, if you compress the piston the particles can be transfered through the lines back up into the master cylinder and abs system, which could cause blockages in the valves of the abs or cause damage to the cup seals in the master cyl.
of course this is a 'could happen' type of thing, but i crack the nipples at work all the time without and dramas thats of course if you know what your doing
EASTERN CREEK JCNSW 2009
The Only 6sp VZ Wagon
did you place a tight fitting hose onto the nipple once you cracked it, the reason for this is to eliminate the problem you have, if the connection between the hose and nipple is sealed when you push the piston back the fluid will fill the hose, when you release the clamp, if the piston moves back out you will draw the fluid from the hose and not let air in,
when it comes down to it, everyone has different methods to doing procedures, this is how i do it, so thats how i wrote it,
EASTERN CREEK JCNSW 2009
Grandpa
say whatever you like, i stand by what i said, after all its common sense isnt it?
yes making mistakes is an excellent way to learn BUT not when it compromises the safety of yourself & others on the road.
i dont know any mechanics that open the bleeder nipple to push the pistons back as a matter of course.
putting a hose on it will certainly eliminate the problem.
& a special message to the fool with the "yes daddy" comment ...unless you have something constructive to say please dont bother
man this is funny, reminds me of a little kid having a tanty.
Common sense and ALSO a gregories does mention to close the nipple!
all good now, was just air in the lines.....
Donating Member
i don't touch the brake lines, unless i am changing the fluid, far safer to unclip the master cyl container and let the pressure out there, just put some rags around the container "incase" fluid spills over, but its doubtful unless you slam the pistons hard enuf.
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