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**HO455** · 01-22-2021, 02:29 PM

I would look at the proportioning valve after all other components have been verified as good. Proportioning valves are pretty bulletproof especially compared to other components in the system.
After 5 years of no use any part with rubber pieces is suspect. And hopefuly I'm not to being too negative, but there may be more than one problem with the system.
You could have a master cylinder problem affecting the front brakes and a bad hose to the rear axle causing the rears to lock. (Been there last summer)
If the hard pedal problem isn't easily remedied you ma need to get a brake pressure guage to find the problem.
Good luck and keep us posted.

01-22-2021, 02:29 PM	#7
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,611	Re: Brake troubleshooting I would look at the proportioning valve after all other components have been verified as good. Proportioning valves are pretty bulletproof especially compared to other components in the system. After 5 years of no use any part with rubber pieces is suspect. And hopefuly I'm not to being too negative, but there may be more than one problem with the system. You could have a master cylinder problem affecting the front brakes and a bad hose to the rear axle causing the rears to lock. (Been there last summer) If the hard pedal problem isn't easily remedied you ma need to get a brake pressure guage to find the problem. Good luck and keep us posted. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377