Brake Job gone wrong

So I successfully replaced the pads, rotors and sensors in three wheels of my '99 cab. When I got to the fourth wheel (right rear) I somehow lost my mind and pressed the brake when the caliper was off. As a result, one of the caliper pistons came out (along with brake fluid). As I attempted to get the piston back in, I ripped the piston's dust boot. Then I decided that I had done enough damage and called it a day. I have the replacement caliper piston dust boot and my question is, do I put the piston back in the caliper and then put the boot on or does the dust boot go on first, followed by the piston? Also, should I open the brake bleeding valve on that side of the caliper to reduce the back pressure when I try to put the Piston back in. TIA

This may help...not a total disaster by any means. http://www.pelicanparts.com/techarti...e_Calipers.htm

Thank you. That is exactly what I needed.

Put the "Das Boot" in first then crack the bleeder screw open and push the piston in.

What possessed you to step on the brake pedal without pads in?

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Does it matter at this point? The OP is looking for help. Van has a great YouTube vid that shows how do a caliper rebuild. Search pprsche caliper rebuild. It is for a 944 but the principal is the same.

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No, the damage has been done. Just curious as to why Fortunately it's easily fixed

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We have all had brain farts......I have too many to count on one hand. It's all good.

Hope that doesn't put you off working on the car yourself... Now you're ready to rebuild a caliper if you ever have to!

So the reason I stepped on the pedal was that I wanted to seat the pads I had just put in on the left rear side into the adhesive on the brake dampers. I had forgotten that I had already taken the caliper off on the right rear side, and thus the mess. When I did the front wheels, I did them one at a time, so I was able to press the brake after each new set of pads was put in. ...and that is the answer to "why". Live and learn. I have now successfully replaced the caliper piston and its das boot and all four wheels have new rotors/pads and a well-adjusted parking brake. But, it turns out that too much fluid drained out of the caliper. The brake fluid reservoir is currently reading "Min". When I press the brake, it goes to the floor with almost no resistance (and I am not losing fluid anywhere). I believe there is a LOT of air in the system. Does this make sense? I think this is going to force me to bleed all of the brakes. I guess I could top off the reservoir and bleed the one caliper but I don't think I can buy a small amount of brake fluid and I understand that the fluid goes bad fairly quickly. So should I just bleed the whole system? I hate to ask, but what brand/type of fluid should I get for street use?

Bleed the whole system, only way to make sure there is no air in the system. If you don't have a Motive power bleeder, you should consider getting one, it will be the best $60-$70 you ever spent

Hey Steve, 1L of ATE TY200 will be good. I suggest you bleed the whole brake system (optionally the clutch). Drain about 125mL per bleeder screw (outside bleeder first for each caliper) and that should change out all the fluid in the system barring the amount retained by the ABS.

Be carefull. Do not lett the reservoir run dry. If you pump out too much fluid and the reservoir goes dry, the abs may get air and to bleed the abs you a need a durametric, or a trip to the dealer. Brake fluid is cheap, motul 200 is about $20-25 for litre which is more than enough to do the whole car. I would get power brake bleeder, bleed the caliper that you goobered first and if that gives you a hard pedal you dodged the bullet and then just flush the rest of the system.

Good points. Also a good idea to use a rubber mallet to knock lightly on the caliper you just installed the new seals to dislodge any air bubbles stuck on the inside walls of the caliper.

You should absolutely bleed all brake lines after pad replacement, even if you didn't put a bunch of air in the system when you accidentally popped your piston out. Seating the brake pistons back into the bores to make room for new pads pushes the crappiest fluid in the entire system back up into the brake lines and you want to get it out. That is also were air entrapment occurs first as the fluid sitting against the pistons (and rotors) gets all the heat. 1+ on not running the master dry when bleeding, just adds more work. Check/refill the master twice as often as you think you should! I have tried pretty much every 'time saver' brake bleeding system out their on my cars and motos over the years... Far and away the simplest/best is a pressure cap and bleed bottle. There are quite a few different threads discussing it, but this one came up first in a quick search. If you don't have a compressor, the old 1)light pressure on brake pedal, 2)open bleed valve, 3)press brake pedal and hold, 4)close bleed valve, 5)release brake pedal works fine but it takes two people working in coordination. For street fluid, I like Ate 200 as suggested above:

What works best for me is fill up the reservoir to max, fill the motive bleeder the whole 1L of new fluid, connect it to the reservoir then pump it up to 15PSIG. Make sure the bleeder is level at all times so it won't pick up air. Then open each bleeder valve one by one and drain ~125mL per bleeder valve. This way you don't have to worry about running the reservoir dry. It may waste some fluid but the 1L is less than $20.

OK so the brake fluid and bleeder bottle should be here tomorrow (Amazon is amazing). I'm going old school and employing the two-man method. I understand to bleed the outer and then the inner on each caliper. Does the order of caliper to bleed matter?

Normally start with the one farthest from the reservoir, then the second farthest and so on. However, in your case I would recommend you start with the caliper you installed the new seal first to prevent air spreading to other calipers.

Great. Thanks. By coincidence the rebuilt piston is the farthest from the reservoir.

...and don't go torquing on those bleed nipples when you tighten them or you'll have another unexpected repair on your hands. Very low torque to seal them.

Thanks for the heads up, I'll be careful (I have a 9/11mm flare wrench). They should really have you use a socket and specify a torque. I'm a big fan tightening to a torque spec.

The spec for the bleeder screws is 6-9 ftlb. A deep socket should work. Best is to use a small torque wrench in inlb.

I recommend NOT using a torque wrench... unless it's a *really* small one like a bicycle torque wrench. 6-9 ft-lbs is snug with a short wrench, nothing more, and well below the accurate range of most torque wrenches. Torque wrenches on tiny bolts like that are how bad things happen... For the initial loosen and final tighten I use a tiny 1/4" ratchet and deep socket and tighten *very* gently. For open/close when bleeding, a short box wrench slipped on the nipple before attaching the hose.

Agree on being easy with the bleeder screws. They are soft and can strip very easily. Just snug tight.

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Have you ever done anything like this on any car?

Nope, never used a torque wrench on a brake fitting. But this is a Porsche. Those Germans are nothing if not precise. I do have a small torque wrench that I use on my carbon fiber road bike, but I'll just snug them by feel.

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Hillary??????? Hillary Clintoon?

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She said that not me..........and i did not inhale........and I did not have sex with that woman. Hilliary said all of it.

Not getting the Hillary reference... Anyway, the brakes are done. Everything seems to be working great. I put in a liter of new brake fluid and bled all four calipers. Thanks for the help everyone.