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**WorkinLonghorn** · 02-19-2019, 09:36 PM

Power brakes or manual? If Vacuum assist, check the vac line to the reservoir/assist unit. Check the reservoir for ability to hold a vacuum.
If manual brakes, they are the dual system (starting in '69 i believe) so if both front and rear were KNOWN to be working and then suddenly not working with a firm peddle then you have something wrong between the peddle and the distribution block. Did you bleed the MC? Do you have the warning light operational that shows pressure differential between front and rear systems? You need to look into this area.

02-19-2019, 09:36 PM	#7
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,861	Re: Brake help!!! Danger!! Power brakes or manual? If Vacuum assist, check the vac line to the reservoir/assist unit. Check the reservoir for ability to hold a vacuum. If manual brakes, they are the dual system (starting in '69 i believe) so if both front and rear were KNOWN to be working and then suddenly not working with a firm peddle then you have something wrong between the peddle and the distribution block. Did you bleed the MC? Do you have the warning light operational that shows pressure differential between front and rear systems? You need to look into this area. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, 2nd owner, Work-Truck supreme. Best $300 I ever spent.