Posted by D. Sherman on Sunday, May 18, 2008 at 22:19:29 :
In Reply to: More on the M/C posted by MoparMogSteve on Sunday, May 18, 2008 at 19:42:26 :
I've had that problem several times. It's always been a clogged relief port. Going from memory, I think it's a #72 drill size (very, very fine). I had one clog up from rust just from sitting for a year in the truck, with the brakes working fine before it sat. There's a reason it's that small, so I would not drill it out any bigger. Unless it's very lightly clogged, a wire won't push through it. If it's lightly clogged a #72 torch tip cleaner may work. The first one I worked on, not knowing how big the hole was, I put concentrated muriatic acid in it and let the acid dissolve the rust overnight. The acid eats rust much faster than it eats clean cast iron, so I wasn't concerned about damage to the casting. That worked fine. Now that I know how small a hole it is, I have some little x-acto drills I can use.
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