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Re: Problem with brass body proportioning valve [message #365358 is a reply to message #365293]

Sun, 11 July 2021 13:33

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma:

Senior Member

The GM unit sold by Highway Stars is the best current solution today. Mr.Stone has been using this part number for over a decade ‘as is’ with proportioning and zero failures. The MBM PV2 have had what I would very kindly call a high fail rate. At times the 2nd replacement still either leaking or not passing pressure. Bob can elaborate on this. The end user can modify the GM brass valve per the CPP link and defeat the proportioning so valve retains hold off, safety shuttle and light switch. Again, this is to be done by end user in a simple pre install procedure. Stock, the GM brass unit when above threshold, reduces rear pressure as a PROPORTION of front pressure as drum brakes are self energizing and in most cases untethered this leads to rear drum lockup before front disc lockup. Remember that Cinnabar installs MBM PV2s with proportioning as common practice. The MBM PV2 has visually smaller fluid ports which may add milliseconds to wheel cyl fill time by acting as a fluid orifice. Scientific testing needs to be done to time this. Bob has done pressure gauge testing on GM valve stock and with CPP mod completed and confirmed the modification does eliminate proportioning.
The MBM PV2 is so prevalent because there is really no competition in the aftermarket. GM does not license reproduction brake parts due to liability. So having a company build the OE TZE valve but in brass would have no endorsement possible by GM. The best bet I see is to do the CPP mod on the GM old stock brass valve.
I would not trust an OE steel valve shuttle to function in a one sided fluid loss scenario. GM vehicles had steel combination valves from factory into the 80s. However by 1990 GMSPO had replaced the steel with brass. I believe there were TSBs or recalls due to steel corrosion when DOT 3 became wet saturated.

John Lebetski
Woodstock, IL
77 Eleganza II

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[Message index]

		Problem with brass body proportioning valve By: Matt Colie on Fri, 09 July 2021 07:59
		Re: Problem with brass body proportioning valve By: JohnL455 on Fri, 09 July 2021 09:22
		Re: Problem with brass body proportioning valve By: Matt Colie on Fri, 09 July 2021 11:07
		Re: Problem with brass body proportioning valve By: JohnL455 on Fri, 09 July 2021 14:07
		Re: Problem with brass body proportioning valve By: blur911 on Fri, 09 July 2021 15:00
		Re: Problem with brass body proportioning valve By: JohnL455 on Fri, 09 July 2021 17:40
		Re: Problem with brass body proportioning valve By: Green machine on Fri, 09 July 2021 23:35
		Re: Problem with brass body proportioning valve By: ebyker on Sat, 10 July 2021 07:43
		Re: Problem with brass body proportioning valve By: MikeB on Sat, 10 July 2021 10:01
		[GMCnet] Re: Problem with brass body proportioning valve By: Thomas Pryor on Sat, 10 July 2021 11:08
		Re: Problem with brass body proportioning valve By: Greg C. on Sat, 10 July 2021 19:05
		Re: Problem with brass body proportioning valve By: Larry on Sat, 10 July 2021 20:24
		Re: Problem with brass body proportioning valve By: Tom Katzenberger on Sat, 10 July 2021 19:38
		Re: Problem with brass body proportioning valve By: Tom Katzenberger on Sat, 10 July 2021 19:40
		Re: Problem with brass body proportioning valve By: Matt Colie on Sun, 11 July 2021 08:15
		Re: Problem with brass body proportioning valve By: Tom Katzenberger on Sun, 11 July 2021 11:16
		Re: Problem with brass body proportioning valve By: JohnL455 on Sun, 11 July 2021 13:33
		Re: Problem with brass body proportioning valve By: Greg C. on Sun, 11 July 2021 19:29
		Re: Problem with brass body proportioning valve By: Bill Van Vlack on Sun, 11 July 2021 23:24
		[GMCnet] Re: Problem with brass body proportioning valve By: James Hupy on Sun, 11 July 2021 23:33
		Re: [GMCnet] Re: Problem with brass body proportioning valve By: Bill Van Vlack on Mon, 12 July 2021 10:34
		[GMCnet] Re: Problem with brass body proportioning valve By: James Hupy on Mon, 12 July 2021 10:50
		Re: Problem with brass body proportioning valve By: wally on Mon, 12 July 2021 11:55
		Re: Problem with brass body proportioning valve By: Matt Colie on Mon, 12 July 2021 19:18
		Re: Problem with brass body proportioning valve By: TR 1 on Mon, 12 July 2021 12:44
		Re: Problem with brass body proportioning valve By: Bill Van Vlack on Mon, 12 July 2021 13:31
		Re: Problem with brass body proportioning valve By: TR 1 on Mon, 12 July 2021 14:34
		Re: Problem with brass body proportioning valve By: Bill Van Vlack on Tue, 13 July 2021 10:14
		Re: Problem with brass body proportioning valve By: Greg C. on Mon, 12 July 2021 17:02
		Re: Problem with brass body proportioning valve By: JohnL455 on Mon, 12 July 2021 17:12
		Re: Problem with brass body proportioning valve By: Greg C. on Mon, 12 July 2021 17:40
		[GMCnet] Re: Problem with brass body proportioning valve By: Thomas Pryor on Thu, 29 July 2021 14:40
		[GMCnet] Re: Problem with brass body proportioning valve By: Billy Massey on Thu, 29 July 2021 15:30
		Re: [GMCnet] Re: Problem with brass body proportioning valve By: Matt Colie on Thu, 29 July 2021 16:39
		Re: Problem with brass body proportioning valve By: JohnL455 on Thu, 29 July 2021 18:57
		Re: Problem with brass body proportioning valve By: Tom Katzenberger on Thu, 29 July 2021 20:53
		Re: Problem with brass body proportioning valve By: Matt Colie on Thu, 29 July 2021 21:55
		Re: Problem with brass body proportioning valve By: Jp Benson on Sat, 31 July 2021 21:19
		Re: Problem with brass body proportioning valve By: Bill Van Vlack on Sun, 01 August 2021 13:10
		Re: Problem with brass body proportioning valve By: Jp Benson on Sun, 01 August 2021 17:24
		Re: Problem with brass body proportioning valve By: Larry on Sun, 01 August 2021 13:03
		Re: Problem with brass body proportioning valve By: Matt Colie on Sun, 01 August 2021 14:37
		Re: Problem with brass body proportioning valve By: Larry on Sun, 01 August 2021 15:06
		Re: Problem with brass body proportioning valve By: blur911 on Sun, 01 August 2021 16:00
		Re: Problem with brass body proportioning valve By: Thomas Pryor on Fri, 17 September 2021 12:38
		Re: Problem with brass body proportioning valve By: Larry on Fri, 17 September 2021 17:49
		Re: Problem with brass body proportioning valve By: blur911 on Sun, 10 October 2021 13:23
		Re: Problem with brass body proportioning valve By: Russell K. on Mon, 11 October 2021 13:14
		[GMCnet] Re: Problem with brass body proportioning valve By: stu@97381.com, Emery on Mon, 11 October 2021 14:43
		[GMCnet] Re: Problem with brass body proportioning valve By: stu@97381.com, Emery on Mon, 11 October 2021 15:55
		[GMCnet] Re: Problem with brass body proportioning valve By: jimk on Mon, 11 October 2021 20:17
		Re: [GMCnet] Re: Problem with brass body proportioning valve By: blur911 on Wed, 03 November 2021 14:39
		[GMCnet] Re: Problem with brass body proportioning valve By: jimk on Wed, 03 November 2021 15:26
		[GMCnet] Re: Problem with brass body proportioning valve By: Thomas Pryor on Tue, 12 October 2021 12:20
		Re: Problem with brass body proportioning valve By: ebyker on Tue, 12 October 2021 14:59

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