Hydroboost to master cylinder....

[-83MONTESS-]

Since I cant seem to get any info on this in my build thread I figured I would try here. I mounted my hydroboost pump to the firewall and went to bolt the master cylinder to it when I ran into a snag. The master cylinder will not bolt on because the bore seems too large to slide into the front of the hydroboost pump.
hydroboost fitment by bwollens1983, on Flickr
hydroboost fitment 2 by bwollens1983, on Flickr
I think the master would slide in if this green/tan seal looking thing was taken out the master would go in but there is a spring behind it so im not gonna pull it out until I know for sure what the deal is. Can anyone help me here? Do I need a smaller bore master cylinder???
hydroboost fitment 3 by bwollens1983, on Flickr

 

[RegalBegal]

Do you have the right master cylinder? From what I've read, hydroboost calls for a different unit. Standard calls for a 15/16" bore, hydro is a 1 1/16". Admittedly, I'm not sure if that would affect the mounting outer diameter of the master, but it's the best guess I've got.

 

[-83MONTESS-]

Do you have the right master cylinder? From what I've read, hydroboost calls for a different unit. Standard calls for a 15/16" bore, hydro is a 1 1/16". Admittedly, I'm not sure if that would affect the mounting outer diameter of the master, but it's the best guess I've got.

So the hydroboost uses a bigger bore than the stock vacuum assist brakes? Does anyone know any part numbers of a master cylinder that will work? I checked on Summit and Jegs but theres no hydroboost filter to search by. I will do some more looking because evidently no one knows.

 

[tc1959]

Do you have the right master cylinder? From what I've read, hydroboost calls for a different unit. Standard calls for a 15/16" bore, hydro is a 1 1/16". Admittedly, I'm not sure if that would affect the mounting outer diameter of the master, but it's the best guess I've got.

So the hydroboost uses a bigger bore than the stock vacuum assist brakes? Does anyone know any part numbers of a master cylinder that will work? I checked on Summit and Jegs but theres no hydroboost filter to search by. I will do some more looking because evidently no one knows.

Rock auto lists this for a Hydroboost.WAGNER Part # MC105798 {#F105798}
1-1/16" Bore; w/Hydroboost; Except Powermaster For A 1987 Grand national.

 

[RegalBegal]

Rock Auto lists for an 86 regal 3.8 turbo.....

WAGNER Part # MC107050 {#F107050}
15/16" Bore; w/Vacuum Boost; Except Powermaster

WAGNER Part # MC105798 {#F105798}
1-1/16" Bore; w/Hydroboost; Except Powermaster

Hope that helps. Aw sh*t, beat me to it!

 

[-83MONTESS-]

A quick update. I found a hydroboost master cylinder with 1 1/16" bore from Oreillys for $16!!! I also ordered new pressure hoses for it. They should be in tomarow afternoon. I will update you then.

 

[TexasT]

http://i444.photobucket.com/albums/qq16 ... AG1226.jpg

This is the one I used on my H-boost conversion.

my conversion thread