replacement hydroboost unit?

the one on my kids 87 K5 is leaking. Id rather not put a remanufactured cardone unit in it.

Does anyone know a more modern boost unit that would work? swapping brackets is easy enough, as is swapping the pushrod. Dont even care if the fittings are different, but would still need it pretty close and a two post master mount.

so I ordered a stock reman unit and one from an 05 master.


Im guessing a chevy HB unit crosses over from rig to rig, with just the brackets being different and possibly pushrods (confirmed by the gal at Vanco. BTW Van is no longer there). However, the 06 silverado unit I got my hands on is totally different where the master attaches, with a star washer thing and pushrod already installed, and a smaller body over all. Its been years since I installed the HB unit on my car (purchased from vanco like 15 years ago.) fitting threads seem are the same.

Am I missing something? Are the washer and pushrod pulled from the stock booster when I replace it, and just happens to be in the newer version? both seem to have standard 2 bolt master cyl mounting. Id run a stock master cylinder till I swap discs in the back with the one ton swap and then likely run that late 70s corvette MC which I seem to remember as the right master.

I Don't know allot about hydro boost. I like it lol. But I know they made some difference here and there 1995 was a special year for GMT400, but being GM with enough pieces around almost anything is adaptable. I'm thinking you can probably get away with hydro boost stuff from the 90s chevys aka GMT400 to fit on the square.

We used a Wilwood hydroboost unit in the '63 Nova. It's just a Bosch. Anything off an Astro or Express should work for people too. Sorry I'm late to the party.

Tonimus said:

We used a Wilwood hydroboost unit in the '63 Nova. It's just a Bosch. Anything off an Astro or Express should work for people too. Sorry I'm late to the party.

Click to expand...

Hydroboost on a 63 chevy 2/ nova? Why? I bet it stops good lol

squaredeal91 said:

Hydroboost on a 63 chevy 2/ nova? Why? I bet it stops good lol

Click to expand...

Because we didn't want vacuum issues with the 427 Shafiroff in it, and hydroboost units are a lot smaller than vacuum boosters.

And yes, it stops. Biggest brakes we could put inside 15" wheels. When you stomp the brake pedal, you go back in time.

squaredeal91 said:

Hydroboost on a 63 chevy 2/ nova? Why? I bet it stops good lol

Click to expand...

A big choppity choppity cam?

SquareRoot said:

A big choppity choppity cam?

Click to expand...

Yess!!

Tonimus said:

Because we didn't want vacuum issues with the 427 Shafiroff in it, and hydroboost units are a lot smaller than vacuum boosters.

And yes, it stops. Biggest brakes we could put inside 15" wheels. When you stomp the brake pedal, you go back in time.

You must be registered for see images attach

You must be registered for see images attach

Click to expand...

Yessssssss! GM power baby!!

Lol i never question increasing safety!

I'll keep this info tucked away, not sure what I'll uncover as i move through the brakes on my truck.

It stops fine so i expect a new master isnt in the cards, yet! Haha

Tonimus said:

We used a Wilwood hydroboost unit in the '63 Nova. It's just a Bosch. Anything off an Astro or Express should work for people too. Sorry I'm late to the party.

Click to expand...

right, thats what I was thinking. Im running a "chevy" booster on my scout (which was on a full size bronco). I know the astrovans are a popular swap for lots of people, I think thats what I started with years ago. THat is why I am looking for something newer to swap to. Id really like to not go down the reman rabbit hole and just "hope" for a decent unit, as my son is doing to the work while I observe as I just had hip surgery and cant help. Well that, and doing this twice or more will suck. Id rather spend a few extra bucks and get a "new" one, but even for the astros, that seems hard to do.

plugugly said:

right, thats what I was thinking. Im running a "chevy" booster on my scout (which was on a full size bronco). I know the astrovans are a popular swap for lots of people, I think thats what I started with years ago. THat is why I am looking for something newer to swap to. Id really like to not go down the reman rabbit hole and just "hope" for a decent unit, as my son is doing to the work while I observe as I just had hip surgery and cant help. Well that, and doing this twice or more will suck. Id rather spend a few extra bucks and get a "new" one, but even for the astros, that seems hard to do.

Click to expand...

https://a.co/d/0jsj4s5 Check that one out.

thats interesting. rockauto says its for the 2011 year only. What do you know about it?


in doing a google search, this one showed as an alternative on some chevy truck site and its slightly cheaper, its for 07-11

Well, that HB was used on many things, GM and Ford. Many HB's from Astro vans have ended up on Broncos,Jeeps and IH's, especially the rock crawler guys, because it has a more used friendly mount and pushrod setup.
Now a bit of info, what usually leaks is right between the 2 halves. The seal there can be replaced without even removing the unit, it can be "split" and seal replaced. I have done it in an hour an Astro vans. And, the seal kit is like 20 bucks.

Tonimus said:

https://a.co/d/0jsj4s5 Check that one out.

Click to expand...

thanks for the link. I cannot find one locally to get my hands on, but was able to find a 178-1037, which durmax folks say is the "new' version of that, and about 30 bucks cheaper. I have a few pics compared to the stock K5 unit. It seems to be pretty much spot on except for two points. The pedal pushroad hole is .2" smaller (6.34 for k5 and 6.21 for this 2011 unit), and more imortantly, the booster to MC pushrod is about 1/4" too long. Not sure if the 1036 you linked would be any different, but I didnt want to buy one from amazon as you cant return it. I imagine I can just swap the pushrod from the K5 to this new booster, but I can not verify that as I dont have mine pulled from the K5 yet.