Brake master upgrade??

[1956322]

So my special has already has been upgraded with the scare bird front disc kit.. At the same time the previous owner upgraded it to the factory power brake set up..I believe he literally just put one on from a parts car and it worked well enough.. Anyhow I have a little money to spend soon and was thinking about going this route.. Figure it'll address the inconsistent pedal feel and also be a better match for disc brakes up front.. Does anyone have any experience with this kit??

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F131841914934

[Beemon]

I personally felt that the drum setup was better than the disc setup, having done both with the same master and realizing the system has a residual valve designed for drums (creates dragging condition for discs). The pistons were also not valved correctly for the stock hydraulic system and by nature of function, discs require more pedal pressure due to their clamping mechanic versus the self energizing drum (also discs use the principal of radial acceleration, which is inferior to the principal of tangential acceleration that drums utilize).

 

In order to accomplish better braking with discs, there are three things to consider. 

1. The size of tubing does matter. Without knowing what master cylinder and "proportioning valve" is in that kit, it will be hard to gauge what is actually going on. You would be best to look at the first run of disc brake cars with equal or similar volume calipers, wheel cylinders and master cylinder bore as well as front and rear line size differences, as well as the potential of residual valves. Most people buy the whole lot of "dual master cylinder with xxx proportioning valve" and don't think twice, with their "improved" braking capabilities being no more than a placebo effect. In the hydraulic system, usually the volume of the caliper and wheel cylinder dictates braking proportion, but also master cylinder valving and line diameter. Pressure is force over area, and a larger diameter tube is going to carry more pressure than a smaller diameter tube, so everything must be considered. 

2. Pedal ratio is key, which this kit seems to address. The only issue is the washer jar, which in my opinion is a staple for the vintage under the hood look. I guess you could take a look at a 57 and copy how it's mounted by the radiator. 

3. The original master cylinder is a really good design and pretty straight forward to rebuild. Do not buy this kit or go down this road thinking that it will be any safer than the stock system. Having experienced brake failure in a modern car, you have zero brakes to stop and must rely on the parking brake just like these proclaimed unsafe single stage master cylinders. 

 

That being said, this is the best and only kit for our 54-56 Buicks. It's pretty straight forward. Same with his AC kit. I personally like using my vents and having the washer jar on the firewall, so I can't really justify it myself. Would have also been nice if the pedal was the same size as the original so you could buy a repro pedal to complete a stock look... not sure what happened there. 

 

Edit: just read the description. Looks like your brake light switch goes above the 10 lbs residual valve in the original distribution block. That doesn't make any sense to me but those switches hardly worked to begin with so why not? 

Edited August 5, 2018 by Beemon (see edit history)

[cords]

4 hours ago, 1956322 said:

So my special has already has been upgraded with the scare bird front disc kit.. At the same time the previous owner upgraded it to the factory power brake set up..I believe he literally just put one on from a parts car and it worked well enough.. Anyhow I have a little money to spend soon and was thinking about going this route.. Figure it'll address the inconsistent pedal feel and also be a better match for disc brakes up front.. Does anyone have any experience with this kit??

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F131841914934

have delt with this guy he is great and I would recommend the conversion 

 

[Bhigdog]

4 hours ago, Beemon said:

Pressure is force over area, and a larger diameter tube is going to carry more pressure

 

Not trying to split hairs but would not a larger tube carry more pressure over a given time. In other words larger tubing would reduce the speed of application but not final force (PSI) delivered. .................Bob

[1956322]

Well I'm not going to argue the benefits or lack of benefits of converting to discs... It's already done probably not something I would have done on my own but I do feel it does brake better with the discs plus it now has modern tapered wheel bearings and that's a huge plus to me... All that being said I do understand that the original master was not at all designed for discs hence my thinking about going this route.. Not doing it for any extra perceived safety features besides the fact that it's new not who knows how old and just slapped on lol. I haven't had any issues with my discs dragging due to that valve.. My guess is that after 60 odd years it's not doing what it was designed to... Brake light switch wise I already did the mod that beemon came up with and I'm intending on sticking with that set up vs any kind of pressure switch.

[1956322]

15 hours ago, cords said:

have delt with this guy he is great and I would recommend the conversion 

 

If you don't mind me asking did you buy a kit from him?

[Beemon]

17 hours ago, Bhigdog said:

 

Not trying to split hairs but would not a larger tube carry more pressure over a given time. In other words larger tubing would reduce the speed of application but not final force (PSI) delivered. .................Bob

 

Force delivered is from your foot depressing the brake pedal. 

[cords]

On ‎8‎/‎6‎/‎2018 at 11:49 AM, 1956322 said:

If you don't mind me asking did you buy a kit from him?

yes buddy I did minus the booster and master because I'm in Australia and the extra weight made it cost prohibitive