Hydroboost master cylinder

[-83MONTESS-]

Im trying to find a master cylinder for my hydroboost setup. Came off an 81 El Camino I was told. Every site I check doesn't tell me whether or not the master cylinder is for vacuum or hydro brakes. I don't want the old cast iron style master cylinder. I can find photos of them online but no part numbers. I even look up Grand National or cars I know had diesels but I still get vacuum setups. Any help is appreciated.

 

[dr78442]

http://www.powerbrakeservice.net/95c2andk2sus.html. This might help

 

[Texas82GP]

My 82 Grand Prix is a factory hydroboost car (formerly a diesel) but it has the cast iron master cylinder. I bought one from Rock Auto for the diesel application. It's an old NAPA United piece that was made in the USA and they practically gave it away because it was on closeout. I don't understand the attraction to the plastic reservoir master cylinders. I thought they were pretty squirrely when they came out. Especially when I went to take the top off and the reservoir is flexing around in those grommets. I also don't like how the plastic reservoir inevitably gets dirty on the inside and the plastic gets yellow and cloudy. Are you sure the part numbers you are coming up with are wrong? I would think if you look it up for a car with the diesel you should get the right one. What is the difference between a hydroboost master cylinder and a vacuum brake master cylinder? Bore size?

 

[Longroof79]

I honestly didn't think there was a difference between hydroboost and standard vacuum master cylinders.

 

[MC96]

For all the research I have done you want 1-1/8 bore minimum. Thats what size the master was on the van I pulled my hydroboost from.

http://www.wilwood.com/MasterCylinders/MasterCylinderProd.aspx?itemno=261-13270-BK

Im not sure if the master would fit down in the bore of the hydroboost or not. Anybody know what that measurement is?

 

[-83MONTESS-]

Everytime I look up diesel cars or boosted cars like the GN I get the same part numbers and sometimes even vacuum boosters thrown in there.

I tried using my old vacuum master cylinder with my hydroboost when I got it and it wouldn't fit together. I feel dumb for not even thinking about rock auto. I'll give it a shot here in a minute.

 

[-83MONTESS-]

Newb question time.....when measuring master cylinder bore is it measured on the inside or the outside that slides into the booster?

 

[Texas82GP]

I did some looking on Rock Auto and it looks to me like the hydroboost cars came only with the cast iron master cylinder. It shows the bore size to be 1-1/16". I looked at several cars like my 82 Grand Prix, an 84 Cutlass and an 85 Regal with a turbo 3.8. On the GP and the Cutlass I looked at both gas and diesel engines. According to the quick research I did online,85 was the last year of the Grand National with hydroboost. When you look up the master cylinder for it, it shows the cast iron one, just the same as the diesel cutlass or Grand Prix. An 84 Cutlass with a 307 shows the aluminum/plastic master cylinder and notes the bore size as "24mm and 36mm".

 

[Texas82GP]

The bore size is the diameter of the bore (inside diameter), just like measuring the cylinder bore on an engine.

 

[jlcustomz]

Got the cast iron mc on my 83 also. I believe stainless steel brakes corp {ssbc) also has some billet choices.