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Home » Public Forums » GMCnet » Genuine GM /ACDelco Brake combination valves ( 1257177 or 172-1350 )
Genuine GM /ACDelco Brake combination valves [message #348117] Thu, 19 September 2019 08:27
JohnL455 is currently offline  JohnL455   United States
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
Senior Member
Bob Stone pointed out how small the ports are on the common replacement PV2 Chinese brake valves sold everywhere on line compared to what came on our coaches from Pontiac assembly. The correct part number GM 1257177 or ACD 172-1350 is getting scarce and also fits several other GM applications (1974 SD-455 Trans Am and other HD disc/drum listings). I had my friend who is an ACDelco dealer put in an order for the remaining inventory. These are available at Highwaystars.net. Be sure to select the genuine GM part as he also stocks the cheaper PV2 in 3 different finishes. According to Bob the smaller PV2 ports trying to satisfy 4 rear cylinders volume MAY lengthen full apply time. My theory is since at 70 MPH, 1 second is almost 4 coach lengths, I prefer the correct OE part on my coach. GM does not allow licensing of any brake system parts as "GM Restoration" so there is no incentive to do a perfect correct reproduction part. When they are gone, they are gone.

John Lebetski
Woodstock, IL
77 Eleganza II

[Updated on: Thu, 19 September 2019 08:34]

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