68' brake proportioning valve question
Thread Starter
Drifting
Joined: Oct 2008
Posts: 1,369
Likes: 12
From: wichita kansas
68' brake proportioning valve question
i still have the old master cylinder (i'm replacing) and the old proportioning valve and bracket are still on it. my question is this, is it likely that the valve still works? and if so, how would i know? this car has been apart for many years, and was in pretty bad shape when i got it. i'm sure i could clean up the old valve, but don't want to spend any time on it if i don't know whether it works.......anyone? Rick
Melting Slicks
Joined: May 2012
Posts: 2,192
Likes: 343
From: Allenton Wisconsin
Hi Rick, other than putting the valve on a flow bench for testing I don't know of any other way to test other than mounting and test driving on a car. if you clean and can use air pressure through the ports, I think they are fixed orfices and as long as they can flow you'll be alright. Terry
Thread Starter
Drifting
Joined: Oct 2008
Posts: 1,369
Likes: 12
From: wichita kansas
thanks Terry, i guess i'll clean it up and see how air flows through it...so your understanding is that it is a pretty constant distribution block, based on the orifices size, not something that "adjusts" or changes? what finish is correct for the proportioning valve, my old one has been painted black. Rick
Melting Slicks
Joined: May 2012
Posts: 2,192
Likes: 343
From: Allenton Wisconsin
Hi Rick,the valve is just brass, the bracket well I don't know, mines just metal, stained, aged and in a box with the old master. Just a tidbit of info; my 69 has P/brakes the 68 has manuel master wildwood, the 68 stops better with less pedal effort. the only problem is the 68's used the spindles from 67, in 69 they upgraded to what is known as large spindles. Not that it makes any difference when driving on the road, but lets say you do an autoX or get a chance on a road track to go blistering into a corner with the brakes on then hit the go pedal existing corner the smallspindles flex causing brake pad knockback. Next corner hit the brakes pedal way down and need to pump. needless to say I'm looking into getting larger spindles, hubs and knuckles. Is that enough rambling? Terry
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
My 68 with manual brakes the valve is a pressure differential switch only. If hydraulic pressure is lost in the front or rear brakes the plunger moves in the valve to turn on the brake warning lamp.
I can't say for certain this applies to the power brake equipped cars.
I can't say for certain this applies to the power brake equipped cars.
Thread Starter
Drifting
Joined: Oct 2008
Posts: 1,369
Likes: 12
From: wichita kansas
sorry , i was using the wrong terminology, i was actually talking about the distribution block. i cleaned it up, and installed it tonight along with bracket and new master cylinder (after the bench bleed)......now we get to see if i can bleed a complete new brake system without some sort of power assist! thanks everyone for the education, Rick
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Team Owner
Joined: Sep 2002
Posts: 38,360
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From: California
No I wasn't beating you up!
sorry , i was using the wrong terminology, i was actually talking about the distribution block. i cleaned it up, and installed it tonight along with bracket and new master cylinder (after the bench bleed)......now we get to see if i can bleed a complete new brake system without some sort of power assist! thanks everyone for the education, Rick
I have one of those handpump units from Harbor Freight that has given me good results.
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
The name mix up has become generic. Kinda like saying T-top coupe.
Thread Starter
Drifting
Joined: Oct 2008
Posts: 1,369
Likes: 12
From: wichita kansas
exactly, and that's how i took it, i appreciate your help along with everyone else on this forum, Rick