Hey guys,

Just ordered a brand new MC from PartsAmerica, spec'd to a 1985 NewYorker. The PN was MC39451 but when it arrived, it was cast iron, not aluminum. Does Raybestos make a similar aluminum one? Thanks in advance!

MJ

Most of the aftermarket 2-bolt masters are iron, that I've found.

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Too many people who were born on third base actually believe they've hit a triple.

Yeah that seems to be the case. Would that handy raybestos catalog happen to have a list of one that isn't?

MJ

Almost certainly not. I do not believe Raybestos offers any that are aluminum, and pretty sure it's the same with the rest of the aftermarket. Those castings are probably all coming from one or two places, bored and drilled to suit various different applications. It's considerably less costly to put together an iron casting, because the raw material is less expensive and no costly anodizing process is required for the bore.

Um...most of our cars stop just fine with iron cylinders...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

of course they stop fine, I was just trying to get a cheap MP one instead of paying the price for it. Its still less iron than the other which I'll use for a dumbbell, or name it after me, since its all the same

I don't think I've ever seen new parts store aftermarkets in aluminum.

On the other hand, if you get rebuilt, theres a chance you'll get an aluminum one. If its a rebuilt original chrysler, it will be aluminum. Otherwise if ts a rebuilt aftermarket original it will be iron. Parts store had 2 in stock when I was looking for mine, one iron and one aluminum for same part #.

Careful with the MP aluminum ones - I believe I read somewhere that they aren't machined for the safety rubber grommet.

I know iron ones stop as well initially, but don't the aluminum ones out last them due to the iron ones rusting inside out from brake fluid absorbing moisture?

Any master cylinder will rot from the inside out, together with the rest of the brake system, if the vehicle owner neglects to flush and change the brake fluid every couple of years. Iron master cylinders last for many years even in cars belonging to neglectful owners, as long as the car is used regularly. Aluminum cylinders don't last longer.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

http://www.magnumhp.com/showdetails.php?ITEM=MAG-1

New aluminum master cylinder, 1 1/16" bore with rear piston machined for rubber retainer, reservoir included, $90.

So, would this MC work on my disk brake setup? Setup from a '73-'76 a body going on a '72 Valiant with 9''ers all around? Not to hijack your thread or anything, i'll contribute as well.
Here is a link to an auction on ebay for an aluminum MC: Alum. MC w/ adapter
Thanks,
Cory

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-'72 Valiant Sedan, Stock (For Now)

My worry about aluminum master cylinders is that they would wear out like I've seen the aluminum pistons do........

At least with the iron master cylinder you have a chance to use a rebuild kit if that's your only option at the time

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Hmm, good question about wear. Don't modern cars use aluminum mc's? I would think a piston in an engine sees lots more stress - its working whenever the engine is running, where as mc piston is moving only when you press the pedal. I'm not positive but I believe the piston and liner is still iron in the aluminum mc's. Either way, as Dan points out, as long as you maintain them you should be ok

Cory - I don't see why not, auction states its made for disc/drum cars so you should be ok. That master, being 1 1/32" vs your stock 15/16" with drums so it will be a firmer feel. If you have power brakes it won't be an issue. If you have manual brakes and don't mind a bit extra effort (and less pedal travel) to stop the car then you will be fine. One thing to watch out for - he says it includes the rubber retainer, but he doesn't specifcally mention the rear piston is machined for it. You can fit the rubber retainer in any piston, but if its not machined for it, the retainer has no groove to sit in and render it ineffectie. May want to ask the seller that question specifically so your not disappointed in the end.

The piston in master (and slave) cylinders are aluminum. Don't know about an iron liner.

The pistons I've seen wear are the type that float against the cup, not the ones with the cup attached. Some of the movement in the lever arm gets transmitted to the piston, wearing the piston out. Figure if the piston wears away, so would a aluminum bore. (way past what honing could fix). With iron/aluminum, the aluminum is sacrificial

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

The piston and the cylinder bore are anodised aluminum (same kind of piston as used in iron master cylinders).

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Cory that would work fine, it appears to be using the ARE adapter as well. The price is the same as magnumhp.

Pierre I was just trying to avoid paying $90 for a MC. The one I got was only $40.

Snag on it though--it appears that it is one reman'd for a chevy or something because the bore isn't the right size. I'm not sure if power brakes have a smaller pushrod, but my pushrod wouldn't slide in. Talk about a high pedal

I'm going back tomorrow and we'll see what I can find.

MJ

I bought a new Bendix (Aluminum) MC for my 73 and it was about $70.

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70 Dart, 360, 727