NO BRAKE PRESSURE AFTER ALMOST FULL SYSTEM REPLACEMENT!!

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.

BabyD

Junior Member
Joined
Apr 19, 2026
Posts
1
Reaction score
0
Location
Sacramento
First Name
Squared.Society
Truck Year
1984
Truck Model
C30 Scottsdale
Engine Size
7.4L 454
Hello everyone, I recently came into my single cab after 17 years of being parked.. I've replaced hydroboost, ps pump, master, calipers, pro valve. STILL NO PRESSURE! pedal depresses maybe 2 inches and then I have to put my whole rear into it just for one of the fronts to start to engage. I disconnect lines at master to bench bleed and everything feels as it should but as soon as the lines are back hooked up same brick pedal, almost feels like pressure is blocked somewhere but where? Someone anyone please send some Intel my way I've been at this since Jan with no prevails, thank you all in advance for any info that may help.
 

KWMECH

Junior Member
Joined
Dec 28, 2025
Posts
6
Reaction score
8
Location
northern calif
First Name
kevin
Truck Year
1991
Truck Model
V2500 Suburban
Engine Size
350
So does the booster seem to be working? Do you feel this is a booster problem or an actual hydraulic brake problem. Air bubble still in booster, Power steering working? . I had an issue years ago where I had inadvertently switched the return hoses to the ps pump. Proportioning valve off center? collapsed hose/s? Push rod between master and booster out of adjustment? Just throwing things out there
 

Finkaire

Finkaire
Joined
Dec 28, 2021
Posts
629
Reaction score
1,230
Location
California
First Name
Loren
Truck Year
1984
Truck Model
Silverado c10
Engine Size
305
Brake line hoses, maybe? Not exactly the same problem but it fixed mine.
 

CountKrunk

Full Access Member
Joined
Aug 3, 2023
Posts
981
Reaction score
2,275
Location
SW VA
First Name
Count
Truck Year
1984
Truck Model
C20 Custom Deluxe 3+3
Engine Size
v8 350
Did you do all new lines? How are the brakes at the tires?
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
9,429
Reaction score
17,285
Location
The Right side of Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
Parked 17 years can do a lot of damage.
You don’t mention replacing brake hoses or checking the lines.
If it feel like the fluid is dead ending before the calipers, it probably is.
And you mention nothing about rear brakes. Those are likely fubar too.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,947
Reaction score
19,078
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Hard pedal would be an indication of no power brakes not low pedal or soft pedal. Did the brakes bleed correctly? Was the truck originally equipped with power brakes.Did you check clearance between master cylinder and booster pushrod(.020). If yes to all three,my first assumption would be rear brakes way out of adjustment.
 

Ken B

Supporting Member
Supporting Member
Joined
Sep 18, 2019
Posts
1,378
Reaction score
2,120
Location
indiana
First Name
ken
Truck Year
81
Truck Model
c10
Engine Size
350
I have the same brake issue.
Rear drums all new. Front pads replaced . Master cylinder replaced with the addition of a booster....didn't have a booster b4...doesn't feel any different. Still standing on the pedal to stop....
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,947
Reaction score
19,078
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I have the same brake issue.
Rear drums all new. Front pads replaced . Master cylinder replaced with the addition of a booster....didn't have a booster b4...doesn't feel any different. Still standing on the pedal to stop....
What do you mean didn't have booster before.non power brake converted to power brake,you have to relocate the pushrod on the brake pedal. Different pedal ratio,non power vs. Power brakes.
 

Ken B

Supporting Member
Supporting Member
Joined
Sep 18, 2019
Posts
1,378
Reaction score
2,120
Location
indiana
First Name
ken
Truck Year
81
Truck Model
c10
Engine Size
350
I am questioning whether this was done or not..
 

Ken B

Supporting Member
Supporting Member
Joined
Sep 18, 2019
Posts
1,378
Reaction score
2,120
Location
indiana
First Name
ken
Truck Year
81
Truck Model
c10
Engine Size
350
Ricko your knowledge and willingness to assist is greatly appreciated
 

xm20k

Runs on 93 octane, caffeine, and spite
Supporting Member
Joined
May 26, 2025
Posts
1,110
Reaction score
2,853
Location
Girard, Ohio
First Name
David
Truck Year
78
Truck Model
c10
Engine Size
388
Says hydro boost was it bled correctly they take a whole procedure that needs ran thru multiple times sometimes. My swap to hydro took running thru the bleed process like half a dozen times with an hour in between each cycle for the air bubbles to dissipate.
 

Ken B

Supporting Member
Supporting Member
Joined
Sep 18, 2019
Posts
1,378
Reaction score
2,120
Location
indiana
First Name
ken
Truck Year
81
Truck Model
c10
Engine Size
350
Pedal is hard and I gotta stand on it like there is no booster. ..I drove it forever without a booster....I recall how hard the non booster leg had to work .
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,947
Reaction score
19,078
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Pedal is hard and I gotta stand on it like there is no booster. ..I drove it forever without a booster....I recall how hard the non booster leg had to work .
Okay you have a legitimate booster problem start a new thread so we don't hijack this one.
 

Forum statistics

Threads
48,413
Posts
1,066,819
Members
42,794
Latest member
Huffer8
Top