'67 230 rear wheel cylinder

[zenuff]

Hello, Does anyone know of a place to get a wheel cylinder rebuild kit? I took apart the cylinders on the rear, the rubber piston cups are 3/4 inch. I assume I could use any piston cups that are that size.
Any suggestions?

Thanks

[Mike D]

NAPA can usually still get the old stuff. Have you tried to locate an entire cylinder? You'd probably be better off. Oh, by the way, ALWAYS replace the cylinders in pairs! Do not replace just one side. You are asking for disaster making one half of a hydraulic system operate at a different pressure than its mate.

[mbbuff]

And, unless they've been changed in the last 20 years, I would change the brake hoses while I was at it.
Very true, kits and cylinders are readily available for the old stuff.

[KCM]

Just rebuilt the cylinder on my '67 diesel. The kits I did find were $50, and cylinders were $70 to $80 (over $200 from Mercedes). It appears kits are being discontinued and you must buy the complete cylinder. They were both discontinued from Mercedes and Beck-Arnley. Found this universal kit on the web at Car Parts Wholesale:

http://cpwstore.carpartswholesale.com/catalog/details/Univ/Omix/Wheel_Cyl-dot-_Repair_Kit/O321672401.html

Bought it and it worked great. The place had fast shipping too. My cylinder was not that bad, so just honed it out. Make sure you hone and clean up yours for proper cup seating. If it is pitted where the cup seals, best to replace the entire cylinder. If pitted where the piston rides or further out, you should be okay.

I must disagree with Mike D about replacing both cylinders. Unless the other is leaking, or you are doing preventative maintenance, you do not need to replace both. Don't know why the other side would operate at a different pressure, and as long as they are the same bore, they will operate at the same force.

[Mike D]

A new/rebuilt cylinder actually requires a higher pressure to operate. Tighter seals and more friction. If you were operating at say, 70 PSI on the old cylinders and now it requires 72 PSI to completely engage the new cylinder, that pressure is distributed equally between the old and new cylinders. If the old cylinder was marginal at 70 psi what's it like at 72 psi?

Even though the new cylinder requires more pressure to actuate it is a lot more efficient due to the tighter seals. It only needs to expand at a 1" throw to create X amount of force as opposed to the old cylinder expanding to 1 and 1/8" for the same force.

I know this explanation seems vague but I didn't really want to have to dig into exact pressures, condensation of hydraulic fluid under pressure and spring tension rates.

Just remember, when it comes to brakes, it's not YOUR life and car I worry about! It's the child riding his bike or the mom with a car load of kids in front of you! NEVER, EVER, EVER try to scrimp on a brake job!