Separating a stuck brake piston and rebuilding the cylinders

[Linda]

You don't remove it. The pin is not fixed it is meant to move a bit. The rebuilder who resleeved my cylinders can straighten a slightly bent pin. Otherwise I was told by the other resleever that a slightly bent pin is OK..
Seems to be true, brakes working

Linda

[Roman]

The seal kit is still available from Nissan.
The best way to remove the pistons is to use air. Wrap the piston assembly in an old shop rag or t-shirt so that the spray (and the piston) doesn't go flying everywhere...and it will. Plug one hole, a standard 3/8"(?) bolt will thread right in and use a rubber tipped shop air gun in the other hole to launch the sucker. Be careful.
When you are doing this, you hold the piston assembly wrapped in a rag while blowing air into the chamber but be careful...if you are pushing down on the piston too tightly, the piston will still pop out but you will push it back down cockeyed onto the pin and bend it.

If you are uncomfortable with compressed air, take them to a shop to do it.

I just did this and it works like a charm. At 100psi it popped out the piston and then I simply pulled it apart the rest of the way..........................Easy. It took like 30 seconds. Finding a bolt to plug up the other hole took more time than the operation.

[Linda]

Oh yes, that project Happy to report brakes working fine.

Linda

[Roman]

Maybe that saga was hell for you Linda, but that thread had a ton of useful info. Seeing how I'm working on brakes right now, it didn't hurt to bump the thread..........may help others as well.

Glad your brakes are fine!

[Linda]

Glad the thread helped. A picture is worth a 1000 words,eh?

Linda

[Roman]

thanks for starting the thread, it did help. And yes a pic is priceless.

[Linda]

Update:
Well 10 years later, thought some would be interested to see how the stainless cylinders hold up.
Here is a pic as opened before any cleanup. No rust in the cylinder, just some around the outside, which is easy to clean. Once cleaned, interior was shiny. The cylinders came apart easily with 50 psi air. Rubber seals are good as expected, so I just cleaned everything with brake cleaner, then used brake grease like is done for the initial assembly. Then installed pistons without any problem.
Very happy with Karps work
Only issue now is a stripped and stuck bleeder valve so I have to find a machine shop...I tried everything except ATF.
Linda

87C1B35D-61A9-469C-B528-E07B0706F740.jpeg

[theunz]

Linda, you might look at the EDM bolt removal process. It uses electricity to disintegrate the broken part without touching the threads. It’s pricey, but so are your calipers!

[C.Costine]

Or you could do it the old fashioned way. When you have your new bleeder get a tap to match the threads and a drill to fit inside of the threads, then cut the fitting off flush, and drill it out. You then pick the pieces out of the threads with your dental pic, then clean the threads up with the tap, and back flush any possible small chips out with brake fluid.

[Linda]

I am hoping the bleeder comes out without tapping. That could be a tricky job to tap, the bleeder comes to a point, right, so can't mess that up. A machinist could do it, if it is a good machinist....We shall see what happens.
Linda

[fj20spl311]

I am not sure there is room, but a bleeder valve repair kit is my first idea for a repair.
I would try heat first if the bleeder is stuck. I would wrap the cylinder is a wet rag covered in aluminum foil and heat the bleeder.

Napa link

bleeder valve repair kit.jpg

[Curtis]

Lots of good advice here. I recently had success removing two broken screws in the body. I repeatedly heated them with the Mapp torch and cooled them with penetrating oil. Then took the vise grips and turned them out. Yup, smoke and a little fire, mostly smoke. Took me a couple days of soaking it and coming back to it.

With a caliper the only thing I might be concerned with is the the center pin but I doubt it will be affected. Nice heavy cast iron. I would also cool it in between in water.

The good thing about a bleeder is it has already been drilled in the center so you don't have to worry about drilling it off center. I would drill it with progressively bigger bits and use heat and oil on it if the it doesn't come out with the vise grip, heat and oil method.

I put in all new stainless steel speed bleeders. I really hate dealing with tubing and flare nut stuff.

[fj20spl311]

My main reason for the protection from heat is the Stainless Steel Sleeve. I don't know if its pressed into place or some other method of locking it into place that the heat might damage.

[Linda]

Got it out via Orme Bros, www.ormebrothers.com ,machine shop, hydraulic specialists, Reseda, CA.
“Discretion is the better part of valor” , letting the pros do it.
Seems like stainless sleeve looks glued in place if that is possible, it does not move.
Thx all for help.
Linda

[fj20spl311]

good news