Infiniti G20 – rear disc brake service and a 2 Q’s

[david]

Hi.

Thought i’d share a little.
This is my G20 2000 year model.
Serviced rear brakes.

Car was purchased about 2 months now and have done various service to it.
Brakes were spongy and a little bit whiny.

fix now – i think (you’ll see why “i think” later).

Anyhow, first time around, with the brake line pinched and the bleeder open (no bottle), i could not get the piston to turn at all. Wanted to reseat the piston to try to remove the whining. I did notice the dust boot was really really contorted. sprayed a little silicone spray on it to see what may come of it and in the mean time, shop for brake caliper.
The very next day, i noticed, i was breaking toward the side i did this little repair to.
So, i was thinking, well, maybe it’s just that dust boot seizing the caliper from turning.
Well, also, i did not have any break tool at the time and the long nose pliers i had really could not get me enough purchase (or so i had felt).
Anyhow, i got around to making my bleeder bottle – can’t stand people trying to sell a bleeder bottle for 14 bux online .. sorry, selling bottle with short hose and a magnet for 14 bux online.
unlike Eric, i used Dasani water bottle, it’s not so colored and so can see the brake fluid color better and the cap is thinner than typical soda bottles so easier to drill (i guess this is an upgrade of sorts vs. Mountain Dew – not hating on the Dew).

I set up to do a bleed and try to turn in the calipers. My brake line had some air in it.
And after a relatively short bleed, no more bubbles. I go back to trying to move the brake piston back in, to see if it is really seized or not. Well, i have bought that cube break tool and i read somewhere to actually fasten back the caliper and piston with the rotor removed to get it solid to work on.
However, that dust cover was still all twisted.

And note, this was after some time spraying more of the silicone.
I kept peeling around the dust boot because i noticed the folds were gradually unfolding and eventually,
it evened out all the way around.

After this, then i used the break tool on an extension and ratchet and the piston actually turned – very little. However, here is a weird thing … saw many sites and this one too, where everyone says you must turn the caliper clockwise. Well, for this infiniti/nissan, in the FSM, to remove the brake piston, you are supposed to turn the piston counter clockwise. So, what i did was – cheat. turned a little counter clockwise, like maybe 1/8th and then go back clockwise. And then it was able to turn and push in at same time – though, still requiring quite some force. After like 3 full rotations or so, the piston was seated pretty much all the way in and though i turned, the dust boot stayed nicely set and did not contort like it was before this whole thing started.

Did the lube on the slide pins and did the dab of anti-seize on the brake pad corners and all good.

And of course, did this to both rear brakes.

[the fix part ends here]

My Q’s:
Could a contorted dust boot cause my brakes to not work (barely work)?
What causes brake piston to seize? inner O-ring? thought that if it was O-ring, then might lose brake fluid all over the place?

Any input greatly appreciated.
Thank you for the read / time / any replies.

EDIT: uh oh. i think i should be posting this in another forum. moderator please move if necessary.

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Topic

[Peter]

Could a contorted dust boot cause my brakes to not work (barely work)?
If it was sealing properly – i don’t think so. The job of a dust boot is to prevent water and other stuff to contact with the piston. Nothing more.

What causes brake piston to seize?
Most of the time it is rust. Brake fluid absorbs moisture. Many people don’t change their brake fluids often enough and after some time brakes start to seize.

[david]

Hi DarkViggen,

i could not turn the piston at all with the dust boot all contorted.
however, i did not try this with the caliper/bracket assembled onto the wheel so maybe it was just because i did not have enough muscle.

but the contorted dust boot looks like it was maybe wedging in the piston into the seat/bore.
the first pic i showed, was actually like already 10 minutes or so of spraying some silicone and attempts to ease to boot back to normal. I had to do it some more, just slowly prying at the dust boot and twisting it back other way and sprayed more silicone until it finally got all nice and seated as shown in the second picture.

anyhow, going to do a full brake fluid flush this weekend. since the brake pads are really thick, and does not look distorted, i will keep them for a while. Just hope they work normally. the grinding rubbing brakes sound has gone away completely.

Thanks for response.

[quote=”DarkViggen” post=98567]Could a contorted dust boot cause my brakes to not work (barely work)?
If it was sealing properly – i don’t think so. The job of a dust boot is to prevent water and other stuff to contact with the piston. Nothing more.

What causes brake piston to seize?
Most of the time it is rust. Brake fluid absorbs moisture. Many people don’t change their brake fluids often enough and after some time brakes start to seize.[/quote]

[Author]

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