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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: Sawilli95 on July 20, 2017, 03:06:09 pm

Title: 1975 chevy k10 with 350 small block rear brake issues
Post by: Sawilli95 on July 20, 2017, 03:06:09 pm
So I'm replacing my trucks brakes and I got the fronts done and bled, but I'm not getting any brake fluid to my rear brakes at all, I unhooked the rear hose from the metal line and nothing is coming out, any ideas what the issue could be?
Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: Irish_Alley on July 20, 2017, 04:00:46 pm
did you check your brake fluid? your proportioning valve could of also been tripped as a fail safe.  if you make sure the front and rear are full you could press on the brakes hard you can untrip it
Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: Sawilli95 on July 20, 2017, 04:22:09 pm
Any ideas where the proportioning valve is located?
Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: Captkaos on July 20, 2017, 04:25:48 pm
Front crossmember by the steering box.

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Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: fiddler on July 20, 2017, 04:27:29 pm
I had the same issue on my 74.  Turns out the "Y" block at the rear of the truck was plugged with crud and wouldn't let any fluid pass.  I replaced that connection and re bled the brakes until fluid ran clear.  Also had plugged bleeders at the front of the truck.  When we bleed the fluid and replace we actually end up freeing up gunk off of the lines and such and it gets into all of the places it can plug.  The proportioning valve is at the front of the truck.  Follow the lines from the master cylinder and you should be able to find it.  If you are getting fluid out the front though my bet is on the splitter, ("Y") connection at the back.  One line runs to the back and gets split between the two rear wheels. 

good luck.  Hope this helps.  Oh I also bought a reasonably priced bleeder setup that has the equivalent of a bug sprayer and plate to put on the master cylinder.  Makes bleeding so much easier....If you are interested I will see if I can find a link....

ricky
Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: Sawilli95 on July 20, 2017, 04:33:48 pm
I had the same issue on my 74.  Turns out the "Y" block at the rear of the truck was plugged with crud and wouldn't let any fluid pass.  I replaced that connection and re bled the brakes until fluid ran clear.  Also had plugged bleeders at the front of the truck.  When we bleed the fluid and replace we actually end up freeing up gunk off of the lines and such and it gets into all of the places it can plug.  The proportioning valve is at the front of the truck.  Follow the lines from the master cylinder and you should be able to find it.  If you are getting fluid out the front though my bet is on the splitter, ("Y") connection at the back.  One line runs to the back and gets split between the two rear wheels. 

good luck.  Hope this helps.  Oh I also bought a reasonably priced bleeder setup that has the equivalent of a bug sprayer and plate to put on the master cylinder.  Makes bleeding so much easier....If you are interested I will see if I can find a link....

ricky
I already have the Y block unhooked and nothing still comes out

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Title: Re: 1975 chevy k10 with 350 small block rear brake issues
Post by: blazer74 on July 20, 2017, 06:41:40 pm
Crack open the line at the Master Cyl is there fluid and work down.

Combo valve is the next stop.