Brake booster on my 86 K30

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.

WutupYo

WutupYo

Junior Member
Joined
Sep 26, 2017
Posts
22
Reaction score
6
Location
Virginia
First Name
Jason
Truck Year
1987
Truck Model
K30/V30
Engine Size
454
90% sure my vacuum booster is bad. Wooshing noise inside the cab, very hard to push the brake pedal. Truck originally had a 350, has a 454 in it no (bought it this way). I'm trying to find the correct brake booster. A lot of the ones I've found say on rock auto, do not have the bracket on the back of the vacuum like mine has.

First question: Am I on the right track thinking its the booster?
Second: when I pull up k30 brake boosters it doesn't have the one with a bracket on it for a vacuum booster, and also, its offering a hydroboost option as well. How can I tell if this was originally hydroboost and maybe converted to vacuum? I do notice my power steering pump has a third line on it that is plugged...

You must be registered for see images attach
You must be registered for see images attach
 
Rickf

Rickf

Full Access Member
Joined
Jul 29, 2017
Posts
468
Reaction score
561
Location
Grafton NH
First Name
Rick
Truck Year
1974, 1954 & a 1937
Truck Model
K20
Engine Size
350
My vote is it originally came with hydra-boost. I have never seen a CK30 with a vacuum booster, I could be wrong, I've made misteaks before.
 
Mr Clean

Mr Clean

Super Moderator
Staff member
Super Moderator
Joined
Aug 18, 2010
Posts
9,876
Reaction score
8,582
Location
North East Texas
First Name
Shawn
Truck Year
1982 & 1985
Truck Model
K10 Extra Cab w/ Proper SWB, & 85 K5 Blazer
Engine Size
454 BBC, & 383 Stroker
With your pump having a third line...yes it was a hydro-boost. IMO that is the way to go...I have converted all my trucks to hydro-boost. It is so much better than a air booster. If you source one out of a salvage yard make sure you get the brake pedel also.
 
86454k30

86454k30

Full Access Member
Joined
Oct 16, 2017
Posts
93
Reaction score
140
Location
PNW
First Name
Larry
Truck Year
1981
Truck Model
CHEVROLET
Engine Size
350
By the looks of the master cylinder I'd bet that truck was body swapped. Does the VIN on the cab match the title?
 
Mr Clean

Mr Clean

Super Moderator
Staff member
Super Moderator
Joined
Aug 18, 2010
Posts
9,876
Reaction score
8,582
Location
North East Texas
First Name
Shawn
Truck Year
1982 & 1985
Truck Model
K10 Extra Cab w/ Proper SWB, & 85 K5 Blazer
Engine Size
454 BBC, & 383 Stroker
86454k30 said:
By the looks of the master cylinder I'd bet that truck was body swapped. Does the VIN on the cab match the title?
Click to expand...
What's wrong with the master cylinder? It's a 87, my 85 had that same master cylinder. The plastic reservoir would have been used in small block 1/2 ton trucks. I would almost guarantee that what the brake booster came from.

By the way like the wheels on your truck...
 
PrairieDrifter

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,461
Reaction score
4,572
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
My 84 and 85 has that style as well,
 
WutupYo

WutupYo

Junior Member
Joined
Sep 26, 2017
Posts
22
Reaction score
6
Location
Virginia
First Name
Jason
Truck Year
1987
Truck Model
K30/V30
Engine Size
454
The plot thickens...

I bought this truck through a guys Dad who was handling it. His son was deployed. He called it a K30. I just checked the sticker in the glove box. Picture below. After some googling, I think I have a K20, and not a K30. C6P code though...

I looked up the K20 brake booster, and it looks like the one I have. I wouldn't mind converting to hydro boost, but I'm guessing I'd have to swap out my steering box to do it. I can only see 2 lines on my steering box. Could be wrong, I haven't researched it enough to know what all is involved with the swap.
 

Attachments

  • PXL_20220724_161328806.jpg
    PXL_20220724_161328806.jpg
    142.9 KB · Views: 81
  • PXL_20220724_161345576.jpg
    PXL_20220724_161345576.jpg
    119.9 KB · Views: 64
85K304SPD

85K304SPD

Full Access Member
Joined
Mar 29, 2022
Posts
395
Reaction score
590
Location
Las Cruces, NM
First Name
Richard
Truck Year
1985
Truck Model
K30
Engine Size
383
The steering gear (box) should be the same. There is only 2 lines , supply and return. The third line from the pump goes to the master cylinder.
 
Frankenchevy

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
5,963
Reaction score
7,418
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
85K304SPD said:
The steering gear (box) should be the same. There is only 2 lines , supply and return. The third line from the pump goes to the master cylinder.
Click to expand...
The master cylinder doesn’t get additional hydraulic plumbing, but the hydroboost unit does.
 
85K304SPD

85K304SPD

Full Access Member
Joined
Mar 29, 2022
Posts
395
Reaction score
590
Location
Las Cruces, NM
First Name
Richard
Truck Year
1985
Truck Model
K30
Engine Size
383
Oops, I meant the Hydro booster, not the master cylinder. Thanks for clarifying that.
 
86454k30

86454k30

Full Access Member
Joined
Oct 16, 2017
Posts
93
Reaction score
140
Location
PNW
First Name
Larry
Truck Year
1981
Truck Model
CHEVROLET
Engine Size
350
Mr Clean said:
What's wrong with the master cylinder? It's a 87, my 85 had that same master cylinder. The plastic reservoir would have been used in small block 1/2 ton trucks. I would almost guarantee that what the brake booster came from.

By the way like the wheels on your truck...
Click to expand...
k30'S have the clamp style cover not the snap on.
 
Keith Seymore

Keith Seymore

Full Access Member
Joined
Jul 13, 2015
Posts
2,636
Reaction score
8,110
Location
Motor City
First Name
Keith Seymore
Truck Year
1987
Truck Model
R10
Engine Size
4.3L
WutupYo said:
The plot thickens...

I bought this truck through a guys Dad who was handling it. His son was deployed. He called it a K30. I just checked the sticker in the glove box. Picture below. After some googling, I think I have a K20, and not a K30. C6P code though...

I looked up the K20 brake booster, and it looks like the one I have. I wouldn't mind converting to hydro boost, but I'm guessing I'd have to swap out my steering box to do it. I can only see 2 lines on my steering box. Could be wrong, I haven't researched it enough to know what all is involved with the swap.
Click to expand...
You are correct; model code CK20903 =

C = Chevrolet nameplate
K = 4x4
209 = long wheel base 3/4 ton
03 = pickup

K
 
SquareRoot

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,698
Reaction score
6,692
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
I have the same truck. I converted from vacuum to hydroboost. Not a big deal. I have often wondered what the C6P "heavy duty chassis" actually means? Keith?
 
You must log in or register to reply here.

Similar threads

Elliot W
Brake booster bolts
Replies
6
Views
380
squaredeal91
squaredeal91
C
Brake pedal sinks to floor engine on
2
Replies
25
Views
1K
Ricko1966
R
Doppleganger
Brake Booster Vac Hose Size
Replies
10
Views
492
dngrby
D
Scarlett77camaro
Vacuum hose routing for brake booster
Replies
5
Views
574
Turbo4whl
Turbo4whl
B
Vacuum Brake Booster
Replies
7
Views
1K
SquareRoot
SquareRoot

Latest posts

Forum statistics

Threads
42,120
Posts
909,540
Members
33,613
Latest member
Sahara
Top