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Case 580SK Master Cylinder replacement

EppNation

New Member
Joined
Dec 29, 2025
Messages
3
Location
Tampa, FL
Per every parts manual I found, part number: D143162 When I search for it, it's replaced with 182445A1
Pictures looked right as far as the ports facing the correct directions and the bore/ear locations. However, what arrived does not fit into my firewall (if it's still called a firewall on heavy equipment). The new ones are smaller in bore and in bolt distance. The old ones fit snug into opening, new ones do not, and the bolt holes aren't even close.

I've spent all day trying to find an alternate part number for a larger version of the same part, no listing I find will specifiy the bore diameter or the measurement between bolt holes in ears, and nearly every listing I find has 580sk in the list of compatibility. The stamping on the old one I have off yielded zero results.

I can't be the only one who has run into this issue. Someone please advise!
I'm just going to have to put it back together with the bad cylinder for now.

Thank you in advance!
 

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EppNation

New Member
Joined
Dec 29, 2025
Messages
3
Location
Tampa, FL
Booo 4 image limit... maybe it's just cause I'm brand new here
 

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EppNation

New Member
Joined
Dec 29, 2025
Messages
3
Location
Tampa, FL
Old master cylinder specs:
1 & 5/8" outside diameter
2 & 1/2" bolt pattern

What showed up when I ordered p/n 182445A1
1 & 3/8" outside diameter
2 & 1/4" bolt pattern
 

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alrman

Senior Member
Joined
Jun 20, 2009
Messages
3,490
Location
SE QLD Australia
Occupation
Diesel Fitter;Small Business Owner;Cleaner
Welcome to HEF @EppNation
What did the company you purchased from have to say? Probably closed for the holiday period.....
My guess is that they have got something wrong.

The early master cyls had 7/8" bore ID & were replaced by a 1" bore ID - i don't recall there was never an issue with fitting them to the machine.

Yet, the website below states there is a difference??

Reliable Aftermarket Parts list the cylinder & state that it has 2.5" between the mounting bolts - https://www.reliableaftermarketpart...k6fuveT56SjE0ltI7mOfsOORwxRoP7lLO9xnAtkxbBQ3N
 
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