> From: Alan Bowes <firstname.lastname@example.org>
> To: 'email@example.com'
> Subject: [MV] Brake Cylinders - Rebuild vs. Replace?
> Date: Thursday, October 30, 1997 10:07 AM
> Hi List,
> Several recent postings have discussed brake issues, often related to
> the effects of corrosion. Here are a few opinions from various sources
> regarding rebuilding vs. replacing brake cylinders. As always, please
> feel free to comment or critique.
> A light honing can remove minor surface corrosion problems, but you
> can't remove more serious pitting without honing the cylinder too far,
> which can cause leakage, seal failure, binding, etc.
> Fred Puhn, in his Brake Handbook (HPBooks), talks about a phenomenon
> called "heel drag" that occurs when there is too much piston-to-bore
> clearance. This is where the seal gets forced into the gap between the
> piston and the bore, and this pinching causes the piston to retract
> slowly or stick. He recommends replacing a master cylinder if there is
> .005 inch or more clearance between the piston and the bore.
> To check the clearance, if a very narrow .006-inch feeler gauge can be
> inserted between the piston and the cylinder bore, there is too much
> clearance and you should replace the cylinder (or have it sleeved). Or,
> if you happen to have a small inside micrometer (or telescoping gage)
> and an outside micrometer, you can compare the diameter of the piston
> and the bore. If there is .005 inch or more difference, replace (or
> sleeve) the cylinder.
> I've also seen warnings about over-zealous honing in various
> manufacturers' documentation.
> There are numerous companies that will bore and sleeve master cylinders
> or wheel cylinders. This is not a cheap process, often costing more
> than a new cylinder, but if you can't find a new or good used cylinder,
> it may be the best alternative. In some ways, it may be superior to a
> new cylinder, since they typically use brass, bronze, or stainless
> steel sleeves that are more corrosion resistant than the original cast
> iron or aluminum cylinder bodies.
> Here are some prices that I was quoted by White Post Restorations. You
> can visit their web site at http://www.whitepost.com/brake.html
> Master cylinder (less than 1.5-inch bore diameter): 150 dollars
> Master cylinder (greater than 1.5-inch bore diameter): 200 dollars
> Wheel cylinder (single bore size): 80 dollars
> Wheel cylinder (stepped/dual bore): 120 dollars
> Prices include bead blasting, boring, sleeving (with brass), sizing,
> applying a baked-on epoxy finish to the exterior, replacing all
> internal parts, and a lifetime warranty. Not real cheap, but I think
> they'd be better than new.
> Does anyone on the list have any recent experience having cylinders
> Can you recommend a good shop?
> Any price estimates?
> (Salt Lake City, Utah)
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