Most Annoying Search...Hydrobooster - The 1947 - Present Chevrolet & GMC Truck Message Board Network

C10forDad · Today, 12:39 AM

I am about to go to manual brakes because I can't find a clear answer to this question...

What hydraulic booster pairs up exactly with a master cylinder with a 1.125 " bore?

Currently there isn't a parts store around me where I can walk in with my Wilwood master cylinder (PN 261-13270-BK) for a test fit. I also cannot fathom paying $600 for Hydrastop.

Things that I do know...

81 and newer have metric lines and before that was standard
These boosters were in everything from 3/4 ton pickups, vans, and more
They were installed in both gas and diesel vehicles
There are a dizzying varieties of mounting plates -> equal number of part numbers

There are too many posts that say grabbed one out of or for an Astro, old square body diesel, or something else without mentioning a part number

There has to be someone on here that has a part number.

C10forDad · Today, 12:53 AM

Here's that nice firewall and some countersunk washers and screws that playing around with

**Rust_never_sleeps** · Today, 01:50 AM

You might call Summit and ask about their reman Cardone units. Spec doesn't indicate MC size on this one, but there are numerous options:
https://www.summitracing.com/parts/aaz-52-7409#overview

Joyridin · Today, 07:02 AM

It is going to be a bit hard as the print for your master cylinder does not have the pilot dimension. It looks like the holes are slotted, but not sure how much. My hydroboost bolt pattern is 3.34" roughly from center to center of master cylinder mounting holes.

This is what I used.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Here is the master I used. You can look up the dimensions on the Cardone site.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Keith Seymore · Today, 07:34 AM

Random brake chart, since I had it scanned and it is a clear copy:

Keith Seymore · Today, 07:40 AM

It looks like "none", at least originally.

These are all paired with 30mm or 31.8mm bores.

My guess would be the 1.125 (28.6mm) master cylinder is the same on the outside as the other masters.

K

**Jason Banks** · Today, 08:18 AM

I have a hydroboost setup from a 2002 silverado 2500 and the exact same Wilwood master cylinder you mention sitting on the shelf(because I swapped it for smaller bore). When I get to the shop, I'll see if I can dig out the hydroboost and see if they will work together. I am 99% sure they will, because I'm pretty sure the mating surface on the master cylinder's are the same regardless of bore.

edit: looks like the Hydroboost joyridin links above is the same as the one I have.

Today, 12:39 AM	#1
C10forDad Registered User Join Date: Oct 2014 Location: Two Rivers, WI Posts: 90	Most Annoying Search...Hydrobooster I am about to go to manual brakes because I can't find a clear answer to this question... What hydraulic booster pairs up exactly with a master cylinder with a 1.125 " bore? Currently there isn't a parts store around me where I can walk in with my Wilwood master cylinder (PN 261-13270-BK) for a test fit. I also cannot fathom paying $600 for Hydrastop. Things that I do know... 81 and newer have metric lines and before that was standard These boosters were in everything from 3/4 ton pickups, vans, and more They were installed in both gas and diesel vehicles There are a dizzying varieties of mounting plates -> equal number of part numbers There are too many posts that say grabbed one out of or for an Astro, old square body diesel, or something else without mentioning a part number There has to be someone on here that has a part number. __________________ Ben 1969 C10 LWB Fleetside Project C10 for Dad

Today, 12:53 AM	#2
C10forDad Registered User Join Date: Oct 2014 Location: Two Rivers, WI Posts: 90	Re: Most Annoying Search...Hydrobooster Here's that nice firewall and some countersunk washers and screws that playing around with Attached Images __________________ Ben 1969 C10 LWB Fleetside Project C10 for Dad

Today, 01:50 AM	#3
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 481	Re: Most Annoying Search...Hydrobooster You might call Summit and ask about their reman Cardone units. Spec doesn't indicate MC size on this one, but there are numerous options: https://www.summitracing.com/parts/aaz-52-7409#overview __________________ 1970 C10 Custom longbed 350/350

Today, 07:02 AM	#4
Joyridin Registered User Join Date: Sep 2020 Location: Cleveland, Ohio Posts: 522	Re: Most Annoying Search...Hydrobooster It is going to be a bit hard as the print for your master cylinder does not have the pilot dimension. It looks like the holes are slotted, but not sure how much. My hydroboost bolt pattern is 3.34" roughly from center to center of master cylinder mounting holes. This is what I used. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Here is the master I used. You can look up the dimensions on the Cardone site. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Today, 07:34 AM	#5
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,191	Re: Most Annoying Search...Hydrobooster Random brake chart, since I had it scanned and it is a clear copy: Attached Images __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

Today, 07:40 AM	#6
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,191	Re: Most Annoying Search...Hydrobooster It looks like "none", at least originally. These are all paired with 30mm or 31.8mm bores. My guess would be the 1.125 (28.6mm) master cylinder is the same on the outside as the other masters. K Attached Images __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

Today, 08:18 AM	#7
Jason Banks Senior Member Join Date: Dec 1999 Location: TX Posts: 1,560	Re: Most Annoying Search...Hydrobooster I have a hydroboost setup from a 2002 silverado 2500 and the exact same Wilwood master cylinder you mention sitting on the shelf(because I swapped it for smaller bore). When I get to the shop, I'll see if I can dig out the hydroboost and see if they will work together. I am 99% sure they will, because I'm pretty sure the mating surface on the master cylinder's are the same regardless of bore. edit: looks like the Hydroboost joyridin links above is the same as the one I have.



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