Hydro boost brake boster question

[toms57]

Are the hydro-boost brake boosters that are becoming increasingly popular available as a salvage yard item, or should I just plan to spring for a new one?
What are they originally out of?

Thanks, Tom

[Rick_L]

You can do it both ways.

The most popular unit for our cars is one from a 90s Astro van, but others will work.

I got a brand new unit of Ebay for $60.

[toms57]

Rick,
Is this the same unit that retailers are selling in the $450.00 range without master cylinder?

[Rick_L]

I don't know what every one of them sell, but it's what some sell. For $450, you should be getting a bit more hardware, for instance it should have a mounting plate for a 55-57, a modified pushrod with a clevis that will mount to your brake pedal, etc. But if you're handy you can do all that yourself and save a lot of cash. Plus there's no assurance that the pieces they sell you will fit without mods.

[markm]

Plus there's no assurance that the pieces they sell you will fit without mods.

Rick, that the understatement of the day.

[chevynut]

I think I paid $100 for a brand new on on eBay. I noticed an article in PHR this month (April issue) that CCP is selling kits now.....they say they're for those "on a budget". They're $750-899. The Hydroboost alone is $389.

I sell laser cut steel Hydroboost adapters if anyone needs one to bolt the hydroboost to their 55-57 or other cars with the same bolt pattern. That includes 58-64 Impalas, and the late 50's Olds, Pontiacs, etc.

[toms57]

I think that those are the kits that I have been looking at. Price seems pretty high if the booster itself is a $100. item.
My problem is that I don't have a feel for what other hardware is needed to make it all "right"...
I currently have a chrome Master Cylinder and Vacuum booster from CCI (I think). Will the MC be usable with the new stuff? I currently have front disc/ rear drum. Will this cylinder still work if I get to put disc's on the rear? I currently have a proportioning valve mounted directly off of the MC. Will it have to be different?
Lots of questions. Any input is appreciated.

Tom

[Rick_L]

The $60-100 units on Ebay are definitely going at a discount compared to other sources including the auto supply. Part of it is no warranty. The one I bought was definitely new/unused.

You should be able to use the same master cylinder if it was sized correctly. The only concern is whether the pushrod is the correct length, and you may need to modify so that it is.

The only deal with rear drums vs. rear discs relative to a master cylinder is the reservoir size. Disc brake master cylinders have a bigger reservoir. A drum/drum m/c will have 2 small reservoirs; a disc/drum m/c will have a big one and a little one; a disc/disc m/c will have two big ones. This is not the end of the world though. If you have a small reservoir, you just need to be picky about the fluid level. The other issue is that you can't use a GM combination valve made for disc/drum with disc/disc, as it has a residual valve in the outlet port for the rear brakes. You don't want a residual valve with disc brakes. The only exception to that is if the master cylinder is below the calipers, which is the case if the m/c is mounted on the frame, like in street rods and old pickups.

[toms57]

Rick, Thanks for your explanation. Are you saying that I can simply eliminate the proportioning valve completely? I can live with the size of reservoir's if they are not technically correct.

[Rick_L]

I personally like the combination valve in some cases but it's not a requirement. Some kind of proportioning valve is a requirement though.