Brake booster on my 86 K30

[WutupYo]

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...

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[Rickf]

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]

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]

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]

By the looks of the master cylinder I'd bet that truck was body swapped. Does the VIN on the cab match the title?

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]

My 84 and 85 has that style as well,

 

[WutupYo]

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.

 

[85K304SPD]

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]

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.

The master cylinder doesn’t get additional hydraulic plumbing, but the hydroboost unit does.

 

[85K304SPD]

Oops, I meant the Hydro booster, not the master cylinder. Thanks for clarifying that.

 

[86454k30]

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...

k30'S have the clamp style cover not the snap on.

 

[Keith Seymore]

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.

You are correct; model code CK20903 =

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

K

 

[SquareRoot]

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?