arenared911cab

Just completed the worlds longest rotor/pad change and caliper paintng. (we have alot of down time up here in Canadian Winters...except at the Olympics)

Anyway, a couple of issues:

1) The outer bleed screw on the rear rotors barely squirts out anything, or is very slow and low volume, is this bad? or normal for a '96


2)What is the break in process for new pads and rotors, I saw a great post a while ago with a step by step process but I can't find where I bookmarked it!

Here's some pics...

chris walrod

Are you using a pressure bleeder of some sort? If so, how much pressure are you applying to the BF reservoir?

If yes to the above, and if over 10psi, you may have a plugged bleeder port, or at least restricted. With no pressure on the system, remove the bleeder screws completely and with a pick or the like, poke around in the bleed port on the caliper. This should dislodge the mucus membrane thats restricting the flow.

This is typical of a system that hasnt been bled in a long time.

I had a 964 I was working on some years ago that was doing this, only absolutely no flow was present! Removed the bleeder nipples completely (with pressure on the system) and still nothing, not a drop. Picked around in the ports and bingo, flowed like it should.

2ndof2

Don't forget to keep some water in a spray bottle handy as you do this to clean off any fluid that goes astray in the process to get things flowing.....wouldn't want to mess up the nice paint job on those calipers!

g_murray

I concur - -take the nipples off completely and, if you have to, "poke around a bit".

Having done the brakes on my car (which hadn't been done in a long time by the PO) there was this white cottage-cheese-like stuff just behind each of the nipples. I was told that this happens to the fluid, over time, as it absorbs moisture.

Gerry

bart1

Good bedding procedure and general brake info at http://www.stoptech.com/tech_info/wp...contents.shtml

arenared911cab

Hey thanks for the directions. I'm using a Motive power bleeder @17-18 lbs (is that enough/too much) and have taken about 2/3 of a quart (litre for us canucks). I'm now going to do a flush with ATE blue. I'll take the bleeders out completely and try cleaning them out. Is the hole pin sized?, pen sized? And should a guy add some pressure to the system with them off to "blow" it out? Understanding that I don't want brake fluid everywhere! or is that to risky/messy for the potential benefit.

Also, thanks for the link to stoptech, I'll put to work this afternoon.

ppressle

Be careful with too much pressure. Not sure with the 993, but some cars have the reservoir slip fit onto the mc with an o ring. Too much pressure and that might pop off and make a big mess.

I use 10 psi or so.

arenared911cab

So I've flushed twice with motive and still a crappy pedal...Master cylinder? Air in ABS, both? Any suggestions?

ppressle

Did you do anything to introduce air in the system? Are you getting air out when you bleed?

Probably not your issue, but in the past, I installed new calipers and hard a hard time getting a firm pedal. It was recommended to tap on the calipers when bleeding to free the air bubbles. That worked for me, but that was for new dry calipers.

arenared911cab

Yes, T think the reservoir did go dry when the calipers cam off. Surely that is not fatal, and if so how do I recover? I tapped the calipers, cycled the abs pump by turning the ignition on and of then bleed. I'm still having an issue with the outer bleed screws on 3/4 calipers. I get very restricted flow, the inner is great. I took the previous mentioned advice and completely removed the bleed screw and fished around to clear the hole but to no avail. The flow would start strong for about an ounce and then slow off.

I'm wondering if I should add pressure with these bleed screws out, I know it will be messy, but clean up is easier than new calipers or master cylinder. Ironically I had a perfect pedal until I took it into a local porsche dude for a flush, ever since then I have vere been able to get the stiffness back! (and I allready tried viagra!)

CaptainGSR

Power bleeders are very slow. More pressure won't change much. Just be patient or get a buddy to help you speed up the process.

ppressle

I would keep working to free those clogged calipers. You probably have air in there. You also want your brakes to be right.

One more idea... You should be able to get more pressure by having a buddy pump the pedal if you need help freeing the gunk with the nipple out.

aj986s

X2 on getting the air out. Remember that air compresses, so any air in the system will make the "pushing" process less effective. It can take a while, especially if some air was introduced at the MC reservoir. Chances are, you will know when it finally escapes. Clear vinyl tubing at the bleed nipple also helps to better see what's happening.

There's also some bleeder systems (like MityVac) that use compressed air supply to create a vacuum and suck the fluid out. Not sure if this might make evacuating an air bubble any easier. Someone local to you might have one.

arenared911cab

It looks like I've cleared 3/4 calipers in that they are all flowing fine, and I have bled them all. The drivers rear is still giving me greif. When my daughter pumps the brake the out side pistons don't move, and the inside pistons torque the rotor. This of course is the same bleeder screw that does not allow any flow. When I pushed the pistons back to do the brakes is there a chance I did something. I had no direct pressure on the actual piston as I kept the old pads in to retract the piston.

Can I unstick these? Is my caliper hooped? can they get THAT clogged? that no fluid is flowing to the piston?

This was fun until now...

ppressle

What if you pump it instead? You need to get that last one flowing.

Worst case, you can rebuild the caliper.