Save those old brake wheel cylinder parts

[femtnmax]

The 'china' wheel cylinders sold these days still have the spring between the rubber cup seals, but some of them lack the 'cone' shaped washer that each end of the OEM springs had.  Instead the end of the spring pushes against a small contact area of the rubber seal, leaving a deep indentation which could eventually start a brake fluid leak.  The oem cone washer helped keep the seals pressed against the walls of the wheel cylinder to prevent leaks when the brakes are retracted when no pedal pressure is applied.
I saved the oem style springs from my old wheel cylinders.  These springs have the cup shaped washer on each end that helps expand and seal the rubber cup seals.  Plus the cone shape helps spread out the contact area so the spring doesn't press into the rubber.
In the photo, NAPA was the closest to OEM though the springs end-cones were a smaller diameter than OEM so not sure if they would spread the contact area out correctly.  The Oreilly spring is mislabled, its actually a Carquest spring, the end of the spring has NO cone shape, and was leaving a deep indent in the cup seal.
I cleaned and installed the oem springs/cones into the napa wheel cylinders, and the In-Line Tubing brake lines are going in next.

[Katfish]

Whats the process / technique for removing and replacing these without creating more problems (leaks)?

Thx

[brads70]

Funny I saved my original wheel cylinders and I have no clue why I did?
Just the pack rat in me I guess?

[femtnmax]

Whats the process / technique for removing and replacing these without creating more problems (leaks)?

I only changed the springs just being kinda a purist.  Not like its got to be done, but seemed like there could be a problem over time.  There has to be a reason all wheel cylinder springs had the cone shaped washers all these years when parts were made in USA.
You could just watch for leaks, may take more time than even I recognize for a problem to arise.  The way to check is pull off brake drum, may have to back off brake adjusters to do this.  With drum removed, use your finger nail or gently with small screwdriver pry back rubber end covers on each end of wheel cylinder.  If any liquid (brake fluid) runs out then the wheel cylinder seals are starting to leak, and time to repair/replace them.
If your wheel cyliinders have many miles on them, probably need to install new cup seals, but these are now made in china just like the complete wheel cylinders, so for the $10 each might as well buy the whole units.  Then can take apart and change the springs prior to install on the car. 

[Topcat]

If your wheel cyliinders have many miles on them, probably need to install new cup seals,

Should hone the inner cylinder areas first before rebuilding too.

[Katfish]

I only changed the springs just being kinda a purist.  Not like its got to be done, but seemed like there could be a problem over time.  There has to be a reason all wheel cylinder springs had the cone shaped washers all these years when parts were made in USA.
You could just watch for leaks, may take more time than even I recognize for a problem to arise.  The way to check is pull off brake drum, may have to back off brake adjusters to do this.  With drum removed, use your finger nail or gently with small screwdriver pry back rubber end covers on each end of wheel cylinder.  If any liquid (brake fluid) runs out then the wheel cylinder seals are starting to leak, and time to repair/replace them.
If your wheel cyliinders have many miles on them, probably need to install new cup seals, but these are now made in china just like the complete wheel cylinders, so for the $10 each might as well buy the whole units.  Then can take apart and change the springs prior to install on the car.

I was actually asking about changing the inner spring, not the entire WC.

[Aussie Challenger]

You don't need to back off the brakes to check for leaks, as mentioned just peel back the dust boot and if liquid is there then the seal is leaking. The brake master cylinder has a residual check valve in the outlet to hold a small line pressure to among other things hold the outer edges against the wheel cylinder body, the "cup" at the end of the spring helps in this process. Some later styles of cylinder cups have a reverse chamfer on the outer edge. Always check inside the bore before replacing the cups, at the very least use a fine piece of emery tape to clean out any rust, don't rub along the length of the cylinder, rub around the bore in a circle, a hone is best. Use lubricant, anything thin can be used so long as it is washed out properly afterwards. If there is any pitting the cylinder will need to be replaced or re-sleeved, I get stainless steel sleeves fitted and they never rust again. Use rubber grease or brake fluid on the bore and cup when re-assembling, make sure that the bleeder is free to move and clean because they block up over time.   

[femtnmax]

I was actually asking about changing the inner spring, not the entire WC.

Yes, but to change the spring requires removal and inspection of the wheel cylinder seals,etc...can't just take apart and reuse old seals.   Rehoning or replacing seals may be required....Aussie Challenger is 100% correct.