was wondering if anyone has done a disc conversion with powerbooster and dual master cylinder. im currently in the process of doing this but have not purchased the master cylinder/booster combo just yet, seems like speedway and jegs offer so many to choose from. anyone got pictures of their setup? also, did you remove that black plenum box off the firewall? or leave it. ive seen them with both. pros and cons of both? thanks
Go to this thread at the AACA site for the BCA... http://forums.aaca.org/f162/newbie-1957-buick-super-371169-3.html <script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/3ae13c55/background/helpers/prefilterHelper.js"></script>
thanks, Ive been following that thread, but it doesn't discuss the booster/master cylinder just yet, and what he did with the firewall if he left the plenum box or removed it.
I've got everything in place but not getting enough psi to the calipers. I have a 1" bore size on the mc and dual 8" booster. I think the problem is the pedal ratio. Does anyone know what the ratio is on a stock 57 with factory pb? I kno how to measure the ratio but these buicks have lots of moving parts for the brake pedals, there are multiple pivot points .
I have a friend who had this issue. He changed the pedal assembly to a manual assembly. Different ratio.
You kno I was thinking that too but one of the brackets bumps a pivot. I will modify and see if that works . Thanks for the info !
I'm a friend of Adam Martin's. I'm the one he was referring to in regards to the pedal swap. I just recently converted my system to a Dual Power Booster/Dual Master with Discs in front using an adjustable proportioning valve. The original power pedal assembly has a 1.5:1 ratio which is not enough to engage the proper pressure in the newer systems which prefer a 4:1 ratio MINIMUM. I won't bore you with the other issues I had, but if you have everything else hooked up properly, you NEED to get your hands on a manual brake assembly from a 57 or 58 Buick and swap it out. The assemblies for the 57 and 58 Buicks should be identical. The manual pedal used a 6:1 ratio. You will have instant brakes once you switch. The pedal rests a bit higher off the floor than the manual, but once you get it in and know it's working, you can measure the gap you have when the pedal is at full braking position and then adjust it's height at the clevice so it's more comfortable, but still has a slight gap at the floored-position. If you have any other questions, I can be reached at 518-928-1550. I'll be writing a tutorial on the complete conversion for an upcoming newsletter for the Buick Club. Joe G
Thats exactly what I needed to know Joe! Curious what year and model ur Buick is? What size booster and bore size mc are u running ? Are u using Gm calipers or something else ? Really appreciate the info. I regret taking the original factory power brakes out of the car. Hopefully this will make me feel better about the conversion
Don't regret it. I only did when I was having problems. My new set-up is better than factory and safer. I have a '58 Buick Special series. Same as Century. The 57 and 58 are identical in brake systems. I used the Scarebird conversion kit and used the calipers from a 2002 AWD Astrovan purchased at NAPA. Booster is a Dual 8" Power Booster from THE RIGHT STUFF and Master is a 1" Bore Dual Master from Speedway Motors. What company did you buy the conversion kit from? Once you get everything adjusted and put the right pedal in you'll be on your way.
I went with disc brake mikes kit. We opted to use wilwoods 2 piston calipers which I had to grind on to clear stock wheels. just picked up a manual brake pedal with brackets off ebay. Looks like I'm good to go!
Joe, I was just looking at the manual pedal. made me wonder about something. is the hole in the firewall and pushrod in the same location on power and manual cars? what im asking is, is this pretty much a bolt on, or do I have to modify anything where the push rod clevis connects to the bracket?
The following are my thoughts and opinions: I rebuilt my completely original 57 Buick system and it works great but changed to metal sleeved DOT front and real axle brake hose, stainless lines and brass sleeved wheel cylinders so chances of any failures now have been made extremely minimal since the original 57/58 Buick master brake cylinder is a negative exchange pusher type metal plunger which does not wear out as it does not ride in a bore cylinder but rather displaces fluid by the same amount equal to it's mass. Failures on theses older Bendix or Moaraine setups were almost always at the flexible front rubber brake lines due to age or rubbing wear when not installed properly rather than the master cylinder failing to deliver the fluid due to the fact you had a metal displacement piston going into a cavernous reservoir type cylinder. The newer split systems with their bore riding rubber suction/friction type setups are not without their weaknesses either. These units installed in most newer master cylinders that are pushing both the earlier drum brakes setups as well as disk brakes use the rubber piston plungers in a bore, the rubber cups wear in the bore due to wall friction and or rubber piston plunger swelling and shrinkages and eventually fail to seal or leak from prolong sitting. The split system can then be viewed more as a design deviation necessity rather than a completely improved upon and independent improvement over the older dependable metal plunger displacement setup as found on all those Bendix or Moraine setups of the late fifties. Having a separate front and separate rear brake line with split fluid delivery reservoirs necessitated the use of separate rubber suction/push pistons in the master cylinder itself which by this design was prone to rubber piston failures. The proportioning valve was a necessity as well more than a safely feature since when splitting the lines the psi balancing was required due to the separate delivery of fluid to the front or the rears. Spend the money, time and work to convert to a split system with disks brakes if you so desire but doing so under the overall impression and viewing of the older metal displacement Bendix or Moraine units with their giant front drum brakes as generally inferior to that of a split system with front disk brakes is in my opinion not a completely honest nor accurate dismissal of these older but durable, dependable units. The original system if kept up, yet slightly improved upon by using metal sheathed front flex lines/axle line and overall regular fluid changes along with general periodic system maintenance performed, these stock units will stop that 4,500 lb car very well thank you and can even put your head up front as a hood ornament any time if so desired.
I have put front and rear discs on my 58 Buick Estate Wagon. I'd like to keep it as stock as possible under the hood. Is there any dual master cylinder and booster system that would allow, for example, the washer bottle to stay in place as well as the plenum? Pictures and brands would be appreciated. Up in Alberta. Cheers. Michael.
