Hydroboost issue MC wont work

[awdvette]

I have a hydroboost system from a Astro van I am installing on my 87 SS. I have a 1-1/8 Mid 80 B-body MC. The bore is too big. It will not fit this unit. What MC should I get? I currently have 13" C5 Fronts and 12" LS1 Rears.

Thanks

[Mike Holleman]

I have a hydroboost system from a Astro van I am installing on my 87 SS. I have a 1-1/8 Mid 80 B-body MC. The bore is too big. It will not fit this unit. What MC should I get? I currently have 13" C5 Fronts and 12" LS1 Rears.

Thanks

I recently built a very similar system. Same brakes with hydroboost. Used a master for a late sixties to early seventies Corvette with four wheel disc. I believe it is 1 1/8 as well but works flawlessly. Cost approx. $90.00 at Carquest. This is a new not rebuilt MC.
Mike

[awdvette]

Will this Wilwood MC work pn:260-4894

[Olav]

S10 master and machine it to fit the hydroboost. Take a look at my Cardomain site.....

[maldo]

dumb question why can you use the master cylinder from the s-10

[Apogee]

dumb question why can you use the master cylinder from the s-10

You machine the pilot register on the mating surface of the 80's S10 master cylinder to match the standard 37.5mm [1.476"] diameter found on most mid-size GM car brake boosters. This gives you a quick take-up master cylinder with a secondary bore size of ~24mm [15/16"] and a much larger primary bore (31.75mm or 36mm depending on whether you use one from a manual or power brake application) resulting in a high, firm pedal that still generates adequate pressures without the pedal travel length associated with most straight 7/8" or 15/16" bore installations.

I think the modified S10/C10 units tend to be more popular than say the 3rd gen F-body units because they have SAE ports on the driver's side and a relatively flat reservoir, whereas the F-body has metric ISO ports on the passenger side and a very angled reservoir designed for a steep installation to clear the inner fender well.

Tobin
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