928S4 Brakes Replacement question
Thread Starter
Racer
Joined: Nov 2011
Posts: 309
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From: St. Augustine, Florida
928S4 Brakes Replacement question
I am in the process of a brake job on my 928S4.
Can anyone tell me how much pressure is normally applied to compress the pistons on the front. I pulled the wheel, released the pad retainer clips, and cannot, get the pistons compressed, although I am being delicate with it, and maybe a bit paranoid.
Anyone done these recently?
Can anyone tell me how much pressure is normally applied to compress the pistons on the front. I pulled the wheel, released the pad retainer clips, and cannot, get the pistons compressed, although I am being delicate with it, and maybe a bit paranoid.
Anyone done these recently?
Three Wheelin'
Joined: Feb 2009
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From: Washington "Dc"
Crack the bleed on the caliper slightly when you are relieving the pressure. I would also open the master cylinder brake fluid reservoir cap .
If you have a spreader tool its pretty easy. [I have one that looks like this]
If you have a spreader tool its pretty easy. [I have one that looks like this]
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From: Boulder Creek, CA
Well...thats the funny part.
You should never be adding brake fluid to the reservoir.
It goes DOWN because the pads are wearing. If it goes down so far you are below the min line..you have a leak..and needs fixed.
Putting in new pads, will raise it, but only back to "full".
Its one of those "Its just how it works" things..that needs thought out, and then you go "Ah".
Fluid IMHO should only ever move down in the system..open bleeder, push in piston, install pads, fill top, bleed a little more down..done.
When it looks low..consider a brake inspection..betcha you need pads.
Just dont -add- fluid.
You should never be adding brake fluid to the reservoir.
It goes DOWN because the pads are wearing. If it goes down so far you are below the min line..you have a leak..and needs fixed.
Putting in new pads, will raise it, but only back to "full".
Its one of those "Its just how it works" things..that needs thought out, and then you go "Ah".
Fluid IMHO should only ever move down in the system..open bleeder, push in piston, install pads, fill top, bleed a little more down..done.
When it looks low..consider a brake inspection..betcha you need pads.
Just dont -add- fluid.
Three Wheelin'
Joined: Feb 2009
Posts: 1,808
Likes: 0
From: Washington "Dc"
Well...thats the funny part.
You should never be adding brake fluid to the reservoir.
It goes DOWN because the pads are wearing. If it goes down so far you are below the min line..you have a leak..and needs fixed.
Putting in new pads, will raise it, but only back to "full".
Its one of those "Its just how it works" things..that needs thought out, and then you go "Ah".
Fluid IMHO should only ever move down in the system..open bleeder, push in piston, install pads, fill top, bleed a little more down..done.
When it looks low..consider a brake inspection..betcha you need pads. Just dont -add- fluid.
You should never be adding brake fluid to the reservoir.
It goes DOWN because the pads are wearing. If it goes down so far you are below the min line..you have a leak..and needs fixed.
Putting in new pads, will raise it, but only back to "full".
Its one of those "Its just how it works" things..that needs thought out, and then you go "Ah".
Fluid IMHO should only ever move down in the system..open bleeder, push in piston, install pads, fill top, bleed a little more down..done.
When it looks low..consider a brake inspection..betcha you need pads.
Just dont -add- fluid.You should only have to do the smallest of bleeds. If you do crack the bleeder (slight 1/8 - 1/4 turn) the smallest amount of fluid will come out (if you attach the brake bleed hose to the line before you crack it you will not introduce air into your system).
IMHO you always need to do a mini-burp of the system just to be through. I always do it this way and I have never had a problem.
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From: Boulder Creek, CA
::This
You should only have to do the smallest of bleeds. If you do crack the bleeder (slight 1/8 - 1/4 turn) the smallest amount of fluid will come out (if you attach the brake bleed hose to the line before you crack it you will not introduce air into your system).
IMHO you always need to do a mini-burp of the system just to be through. I always do it this way and I have never had a problem.
You should only have to do the smallest of bleeds. If you do crack the bleeder (slight 1/8 - 1/4 turn) the smallest amount of fluid will come out (if you attach the brake bleed hose to the line before you crack it you will not introduce air into your system).
IMHO you always need to do a mini-burp of the system just to be through. I always do it this way and I have never had a problem.
It may, but it will gravity bleed out of the caliper almost instantly as well...unless you have a directional caliper installed on the wrong side and the bleeder is at the bottom..then God is not on your side, and you'll never get the air out. (Bleeders are always at the top of the caliper chamber for this reason..air CANT stay in with the bleeder open)
There isnt much head pressure in the system, but theres enough that the 'introductin of air' will be -a- bubble at the fitting in the caliper, will will come out once gravity ans physics get to work immediately there after.
Using the brake pedal or a pumping system for a bleed is indeedn quicker, and for a TOTALLY dry system, a requirement, but a maintenance bleed..gravity works while im doing other things on the car between races...or at home...typically by myself.
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Three Wheelin'
Joined: Feb 2009
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From: Washington "Dc"
The pads have a little notch on them you can usually get them expanded far enough from that point to slip them out.. then using the tool i gently push the pistons back. I have put the tool directly on the piston however you have to be careful and be sure the piston is going in slowly. If you crack the bleeder and you have strong fingers you can actually push them back in by hand.
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From: Boulder Creek, CA
I leave the pads in..to make sure im pushing on the caliper pistons EVENLY.
And I use this:
http://www.alltradetools.com/catalog...-spreader.html
Thread Starter
Racer
Joined: Nov 2011
Posts: 309
Likes: 33
From: St. Augustine, Florida
Thank you all for the help. Got it done last night. Cracking the bleeder was the ticket. Calipers look great, and all 8 pistons compressed fully and smoothly. She is all back together with fresh hardware. Re-used the pad backers(dampers). They were in good shape. Bled it out. Great pedal, but really doesnt stop any better. It was pretty good to begin with. I had one pad, on one side, that was making noise for some unknown reason, and it was hellaciously embarassing when rolling up next to hot babes at the stop light. Under inspection of both the rotors and pads, nothing too much out of the ordinary. Not sure where the noise was originating, but the noise is now gone, and I feel better with having those old, dirty pads off of it.
Thank you all, and thanks to Roger for some phone support.
Thank you all, and thanks to Roger for some phone support.
