Rear brake issue after hydroboost

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
4-5 years ago I swapped in the hydroboost unit from a newer Chevy commercial van. I also swapped the brake proportioner out to an aftermarket disc/disc model. I have a 14bolt rear with disc brake conversation that has the 1/2 ton front discs.

Since doing all this I have had constant issues with my rear brakes; Fast wearing pads, easy rear lock up on rainy days, warped rotors, hot hubs, rear hop, and squeaking. Seems like I'm getting way too much pressure to the rear.

Did I miss something? Wrong proportioned valve? I plan to swap the rear out again for a newer 2000+ 14bolt axle this summer. IDK if the newer double calibers will do better.

Sent from my SM-G975U using Tapatalk
 

climb-101

Full Access Member
Joined
Mar 12, 2018
Posts
262
Reaction score
278
Location
montana
First Name
seth
Truck Year
974
Truck Model
c2 crew cab
Engine Size
6.0 LS
i just set my crew cab up with hydro brakes and i just ran new lines to the front 2 and one to the rear. In the back before the drop to the rear alxe i just added an after marker portioning valve so i can set the rears
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
I may need to add that. Thx

Sent from my SM-G975U using Tapatalk
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,036
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
I could be wrong but a van may have a different proportioning valve than a truck
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
I only put in the hydroboost/master cylinder. The proportioner was an aftermarket for GM trucks

Sent from my SM-G975U using Tapatalk
 

77 K20

Full Access Member
Joined
Nov 9, 2012
Posts
3,101
Reaction score
3,119
Location
Montana
First Name
Mike
Truck Year
1977
Truck Model
K20 5" lift
Engine Size
HT383 fuel injected
I did the rear brake conversion, used a disc/disc master cylinder, used a disc/disc aftemarket combo(proportional) valve and had the same problems as you. Mine would even lock up on dry pavement. I too added an adjustable valve inline with the rear brakes. It isn't perfect, but a lot better than it was before.

You must be registered for see images attach
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Thanks! I figured I was just getting way too much pressure to the rear

Sent from my SM-G975U using Tapatalk
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,084
Reaction score
7,759
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
Weird, mine never locks up, but I do feel like one of my rear rotors has a slight warp. It’s been there since before swapping to a disc-disc prop valve.

I’m going to get new rotors and rebuild my 14bff hubs with new bearings, races, etc. and hope it cures it.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Adding the manual proportion valve was gold! Fixed a lot of issues as I dialed it in. Thank you!!!


Swapping the front brake calipers to the 3/4 tons, is it as simple as just the caliper and the hose? Since I believe the banjo is different

Sent from my SM-G975U using Tapatalk
 

TPISly-C10

Full Access Member
Joined
Apr 1, 2019
Posts
615
Reaction score
883
Location
Boucherville QC Canada
First Name
Sly
Truck Year
1986
Truck Model
C-10 shortbox
Engine Size
LQ4 6.0L
usar17 i want to upgrade my oem 86 HB to a newer (2005) too can you tell me how you do it? since my old HB got a input master hole smaller i can't just swap the 2005 master and reservoir ( master too big wont fit small input hole from the old one) i see that newer HB got diffente mounting plate....can i swap my old mounting plate to the newer HB unit? thx for the help! :)

You must be registered for see images attach


You must be registered for see images attach
 

climb-101

Full Access Member
Joined
Mar 12, 2018
Posts
262
Reaction score
278
Location
montana
First Name
seth
Truck Year
974
Truck Model
c2 crew cab
Engine Size
6.0 LS
i pulled the plate off the newer master and made a new plate that mounts to the factory studs. I also cut the loop off the rod and threaded it since it needed to be longer to reach the stock pedal. I measured the distance from the pivot point to the mounting point for the rod on the truck i got the hydrobost from and made it the same also.
 

Latest posts

Forum statistics

Threads
44,168
Posts
950,774
Members
36,283
Latest member
Cantrell299
Top