rebuilding front brake calibers?

crashmy911 · 02-12-2007, 10:25 AM

How do you get the pistons to come out? they are disassembled down to halves and need to push pistons out? Do I have to reassemble them and use air or something to push them out. Any one done this before? Tell me what I have to do. I have the parts and they don't look to complicated.

cbeers · 10:45 AM

First thing is to search on this topic, it has been posted many times with pictures, detailed explanations etc. I am not blowing off your question, just saying that someone else has already provided the info on this site.

The short answer though is you can pop them out with air or fluid, many variations on the same theme, pressure gets them out. PLEASE read up first as when these puppies finally let go they can be projectiles!

Once you get the first one done, they are all a snap after that, it's just doing it for the first time.

Here is a good start, from the Pelican Parts Technical How To Articles, but there are TONS more in the archives. I'll try a search later on if you don't get links directly.....

http://www.pelicanparts.com/techarticles/911_caliper_rebuild/911_caliper_rebuild.htm

-Chris

Quicksilver · 02-12-2007, 10:37 AM

If you use air be careful because they will come out with great force. You want to pad them with something so they don't get dinged when they come out.

I prefer to use a set of extra heavy duty snap-ring pliers. They just grab the inside of the piston and you rotate them out.

Walt Fricke · 02-12-2007, 10:53 AM

Yes - read up on this. I fear you have already made a mistake, since you say you disassembled them into halves. Unnecessary, complicates things as you have found out, and requires something the rebuild kits don't have - new little seals to go between the halves.

I suppose you can blow air into the passage between the halves for one side, and block off the threaded line in hole for the other side. All you need for air is a rubber tipped nozzle, if even that. But with them apart you can't just plop a piece of wood in between the halves to limit the excursion and so on. You have created a small air mortar.

Or use Wayne's version of internal pliers - that would be a good thing to have. Always something one can learn.

Walt Fricke

juanbenae · juanbenae's Garage

walt points out your BIG mistake. you know, the breaking them in half. ouch!

Emission · Emission's Garage

It's a fun project, but you want to read up on it first. Breaking them apart may cause some misery.

aigel · aigel's Garage

Maybe searching for "calibers" instead of "calipers" did not help.

It's not a spelling bee here, but when searching, it is a good idea.

The seal for the halfs is available, no problem. It's not like you killed your calipers. Just put them back together.

When using air to push them out, restrict travel with a piece of wood, if it can not go further than 10 mm, it won't hit you in the head either.

Rebuilding calipers is pretty easy, overall.

George

CharlesJones · 02-12-2007, 01:42 PM

If you regret disassembling them into half you could always try to use them as exchange units for reconditioned items. Very often when you buy reconditioned calipers they ask for your old ones in exchange, and if they took your two halfs it might save you the hassel of sticking them back together again. I think reconditioned calipers aren't expensive.

I'm going to do my front calipers next week. I can't wait to fix an annoying dragging caliper I have.

crashmy911 · 02-12-2007, 02:06 PM

reassembled them and made sure the rubber seals didn't fall out so I'm good.

Erakad · Erakad's Garage

Anyway...when I did mine I blew them out with the little air compressor I use to put air in my tires, you know, the type that plugs into the cigarette lighter. They come out with a vengence, so I c-clamped some pieces of wood to stop them (per recommendations). Piece of cake them to use your fingers to pull them out. I don't know, using pliers and such around pistons makes me nervous.

MattAlpha · MattAlpha's Garage

Erakad,
Great suggestion! I'll try your method to remove my pistons in the calipers in the next month or so.
-Matt

Emission · Emission's Garage

To clean the old calipers, I soaked them in a bucket of hot water and laundry detergent (yes, like TIDE). Soak for a couple hours, and then use an old toothbrush. Decades of grime floats away... and it doesn't hurt the gaskets.

CharlesJones · 02-13-2007, 03:08 AM

Good idea - I'll give that ago when I do mine next week. Saves on buying brake cleaner stuff.

It's amazing how common household detergent work so well for cleaning and degreasing dirty bits. I used laundry powder for my heads, although I used Surf rather than Tide - I liked the pine fresh fragrance.

crashmy911 · 02-13-2007, 03:55 AM

How do you tell if you have dragging calipers?

Emission · Emission's Garage

Quote:

Originally posted by crashmy911
How do you tell if you have dragging calipers?

Mine would pull to one side under braking.

In addition, I used a hand-held infrared thermometer to check the temps of each caliper after driving for about ten minutes on an open stretch of road. The hanging caliper was noticably warmer than the others because it was dragging.

Navaros911 · 02-13-2007, 07:37 AM

Here's one you can try:

Brake Caliper Rebuild Service?

I didn't use a compressor, but prefer a regular pump as I would use on bike tires. The feel of the applied pressure is much better. The only problem is attaching the line to the brake fluid feed line opening. I just cut off the rubber hose from the pump and pushed that in the hole really hard.

It's not that much work getting the pistons out and the whole rebuilding process was the first work I carried out on my 911.

Good luck.

- Michiel

Monza_dh · Monza_dh's Garage

I just did this job and it is easier than you would think. I used all the "Pelican approved" hints: bike pump, c-clamp, baby food lid, etc. I used the bike pump method since I do not have a compressor and it worked perfect. I placed a hockey puck between the pistons and pumped air through the line and on one caliper both came out a hitch. Once they hit the puck I used a smaller piece of wood for till they popped. Drivers side was a little more sticky so c-locks were needed.

I used a plastic pencil to removet the inner seal and cleaned with alcohol, brake cleaner and wet sanded away grime and a few pock marks with 2000 grit. Once cleaned all went back in perfect.

Oh, forgot to mention the home made 20 degree guide form the $1.00 Walmart protractor!

Good luck!

RichMink76 · 02-13-2007, 08:23 AM

Mine came out using an air nozzle (very low pressure, it does't take much).

Rich

CharlesJones · 02-13-2007, 08:28 AM

Quote:

Originally posted by crashmy911
How do you tell if you have dragging calipers?

As well as pulling slightly, my caliper makes an aweful howling noise from time to time, which stops immediately if I dab the brakes. It's really annoying, and I'm sure it must sound pretty loud outside the car as well as in. I always have the affected wheel permanently covered in brake dust too - I clean it off, but after half an hours drive it black again. Man, I just can't wait to get this sorted!

kentenmann · 05-24-2009, 11:23 AM

Thank you all for the info. I have a sticky caliper on the passenger front and was going to replace them with rebuilt. I think I'll try to rebuild them myself first. Haven't done that in probably 25 years but I'm looking forward to the fun. It's been suggested to replace the lines with stainless steel. Any comments?
Thanks
Karl in Gig Harbor, WA
88 Carrera Cabrio