indigo

http://www.tech-session.com/kb/index...x_v2&id=43&c=4

indigo

okay..new post.

i guess it comes down to how do you know if you really need to rebuild your calipers? My symtoms are uneven pad wear on the outer pad and now im finding it kind of difficult to clamp the piston.

1. how much play is the piston suppost to have?

2. I have a small dinky c-clamp that im using for the job, would this attribute to my problems of not being able to clamp the piston well. I used an old pad that seemed to give me more leverage?

Sob...what shall I do!!!! :-D

-matt

83na944

1. Not much. In fact its usually hard to even rotate the piston. It goes in and out, that's about all.

2. Do you mean that the piston is extending and you can't keep it in the cylinder with the clamp?

indigo

how far is it suppost to retract and extend "in and out" and when i stomp on the brakes should it be retracking or moving at all?

edit: again, im trying to address the reason(s) why my outer pads wore much much quicker before reinstallation.

edit#2: when bleeding the brakes...other than removing the rubber cover on the bleed nipple...how to do get fluid to start comming out? I see no bleed screw and those nipples look fragile to turn :-D

PS: Yes I am RTFM (reading the manual) but id rather ask questions twice than be sorry or waste tons of time. Insight and persepective suggestion is a very powerfull thing.

Kevin Baker

Uneven pad wear suggests caliper is not functioning properly. Rebuild or replace. If you want to try it without rebuilding, make sure the frame (as mentioned earlier) is well lubricated with high temp lube. Check pad wear, as the pads come out rather easily. You can always address the calipers later if you find you need to.

Bleeding the brake is only needed IF you opened the hydraulics - disconnected a brake hose. Best way is a Motive power bleeder (from what Ive read). You can do it the old fashioned way or with a vacuum bleeder (mighty vac).

BruceWard

I second that, call Paragon and order some parts to rebuild.

I think I remember reading earlier that you only have one piston per caliper. If thats the case then it should be real cheap.

There is a good howto at http://vista.pca.org/sch/tech_articl...er_rebuild.htm .

indigo

I did the dirty....

I pressed the brakes while the pads were not in causeing my one rear caliper to fully extend while the other just sat there....a true sign of a rebuild right there.

83na944

When you push on the brake pedal, the pistons extend from the cailper body. If you stomp on the pedal you might blow the pistons from the cylinder, so you might not want to do that. They should extend at least twice the thickness of the pad lining (~1/2 inch). I think they about 2 1/3 inches long. They'll probably exten at least 1 inch.

The floating frame moves so that the pressure from the piston is applied to both the inboard and outboard pads. The wear should be even.

After you remove the dust cover from the bleed screw, you put a wrench on the hex at the base of the screw and turn it counter-clockwise a turn or two. You'll want to put a tube over the end of the bleed screw and route it to a container to catch the brake fluid.

I think Kevin is right. You should clean the calipers as good as you can, put grease on the sliding surfaces, drop in new pads, and bleed the system. Run them for a while and see how they wear. You can rebuild them if you find the pads are still wearing unevenly.

83na944

You should open the bleed screw on the caliper that didn't move, and press gently on the brake pedal. If you get a stream of fluid from the bleed screw, the piston is stuck. If no fluid comes out, you have a brake line problem.

Were the pads on both sides wearing unevening?

indigo

thanks !!!!

no the outer pad (not touching the single piston) was worn down to the metal backing, thus my jump into "Porsche Brake Job for Idiots" post :-D

Im worried that i actually need to replace the piston setup that did not come retract, I will try the afformentioned test to verify. Can these rebuild kits be obtained localy anywhere (ie: Napa Parts store?) Im actually excited this problem occured. Working on this system should restore its potential greatly.....who doesnt love to stop fast?

Final Question: If the piston does not come out easily should I just assume its bunk and replace it? Also, what freaking size wrench do I need to get the brake line off, I tried 12 but it seems to be slipping although gripping...wierd.

BruceWard

Are you using a line wrench on the lines? On my 968 many of the brake components were 11mm. Line wrenches wrap around the nut and prevent it from stripping.

My standard when rebuilding mine was that I cleaned until I could push all 16 pistons in by hand.

I bet that the cost will be real low if you call Pagaron for a price quote. If you call Sunset their kits will include new pistons as well. Dont risk your safety on trying to avoid rebuilding the calipers.

Zero10

Okay, the front axle nut, is it at 350 lb/ft as well?
If so, what size is it?
If not, I could probably get it with an open-ended adjustable wrench.
I want to have all the tools to do the job, but I can't find my shop manuals right now.

Damn good thing the back one doesn't have to come off as well.

Those crossdrilled rotors are going to look mighty nice.

BruceWard

Do you want to take the front wheel hubs off to change the wheel bearing? You should not need to remove the hubs to change the rotors.

On the 968 you pop the cap on the hub which is not as easy as it sounds, then the axle nut has a 6mm allen bolt locking it in place. Loosen the 6mm allen and then you can turn the nut by hand.

But you only need to do that if you are going to change the wheel bearings, which I would suggest if not done recently on that 240K km car.

The rotors are held on with Philips screws and by the lugs. Take out the philips and you can pull them off.

http://www.clarks-garage.com/ has all the info you need to do jobs like this. No need for shop manuals.

83na944

The front axle bolt is a spindle nut. Its like nut that's split on one side and threaded on the spindle. An allen head bolt pulls the nut together and locks the nut in place. The only trick is getting the allen wrench on the retaining bolt. There's a slot cut in the hub that the wrench fits in, so you have to turn the hub so that the slot is in the right position to access the bolt head.

Zero10

Ah, some good advice.
I read clark's garage, but I was always under the impression that I needed to remove the axle nuts.

I am about 95-99% sure that all wheel bearings are original, and I plan on inspecting the front ones and repacking them with some fresh grease, but the rear's are such a pain, I don't want to do them yet.
I have a bit of a howl as I drive, which I am 100% sure is wheel bearings, but it's still pretty quiet at this point, so I'm going to let it go until the bearings have to be changed.

Good to know I don't need to start going to the gym to get that axle nut off to change my rotors =)