M1009 Master Cylinder

[Dispatcher7]

According to the TM's the original part number is 2232073. Is their a source to buy one? Cross reference to a parts store part? From what I am reading it should be DOT 5 brake fluid, is that right?

Thanks

 

[cucvrus]

I have bought the master cylinder from an auto parts store and used DOT 5 in it. I never had any issues. I did it many times. I keep the DOT 5 in the system because it is there now and worked all these years. No other reason. I use power steering fluid in the power steering regardless that the lube order says ATF is good. Do as you wish. I a simple man. Good Luck.

 

[Jeepadict]

I sourced a CUCV master cylinder and booster last year to upgrade my K25. Zero difference in parts from over the counter in a similar era Squarebody (78-86). GM always calls for DOT-3 in the Civvy trucks, so that's what I stick with. In contrast with the power steering, I've had better behavior with ATF...even tho it's arguably the same fluid minus the red coloration...hydraulic fluid is hydraulic fluid for a large percentage of systems.

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[Keith_J]

Glycol is cheaper but it attracts water. Never had rust in any DOT 5 systems.

 

[royalflush55]

Both atf and power steering fluid are similar as hydraulic fluid. However atf has detergents and friction modifiers added that the automatic transmission requires.