Rebuild Original Brake Master Cylinder vs. Aftermarket Unit (Pro & Con Discussion) (Page 1/1)
Vintage-Nut MAR 27, 02:47 PM
Yes, the ‘nut’ is back……

This thread can be all years; however more recent conversations were centered on the ‘88

Firstly, “Thanks” for the help cam-a-lot , Brian D and Rick Vanderpool for getting me on the right path with the genuine repair kit!

Now I have both options:

*Rebuild the original Moraine/Delco brake master cylinder with the authentic kit
*Aftermarket/alternative unit which is the aluminum Centric 130.62030

I don't have any experience with either and my Moraine/Delco bore seems ‘good’ without any scoring or corrosion.

Of course, my top concerns are safety and reliability, not the cost. My ‘gut’ is to use the “Made in USA” GM rebuilt unit, put the “Made in China” unit as a spare.

By reading other threads, I see that some members don’t like the idea of rebuilding the Moraine/Delco cylinder…..

So, what you say as the jury………

Install the rebuilt GM unit or the aftermarket/alternative unit?
theogre MAR 27, 04:30 PM
Rebuilding Al MC or Calipers often fail after if works now.

May look good but Most times the surface has enough "rust" pitting so new seals fail fast.
Many have enough crap where seals and pistons never touch during normal braking causing failure too like Dead MC after "Pedal Bleeding" because 1 or both pistons hit the crap section(s) in the bore. see https://web.archive.org/web...ierocave/brakes3.htm

You can't hone them like cast iron parts in many "books."
1. Many Al parts are anodize and honing removes that then the bore "rots" faster.
2. Most brake honing "kits" have wrong stones and eat the Al fast and uneven making problem too.
3. Even some "Scott bright" materials can wreck the bore trying to remove other crap in there. Actual 3M or clone make a lot of different ones w/ or w/o adding extra abrasives to the mix. I mention this because Dremell (and maybe some others) make several "Scott bright" tips under "EZ Lock Abrasive Buff." Dremel "Finishing" buffs (511E) can "grind" hard enough to marks on steel.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Vintage-Nut MAR 27, 09:38 PM
Thanks theogre, and yes - the manual says "No abrasives should be used in the bore"

The original aluminum bore seems ‘good’.....

"Bleed the MC on the bench" - clearly, the new MC needs bleeding, but it's my first of a 'dry' master on car.

Dry motorcycle masters had been no problem as no secondary and I use a hand vacuum pump at the caliper.....