Well, here we go again. Questions whose answers should be hiding somewhere in "Searchdom" but continue to evade me. The key word here is "simplify". I have removed the CPP power booster, M/C, and combination valve on my '56 Chevy, and replaced it with a Manual Corvette-style disc/drum master cylinder (1" bore) and a simple SSBC adjustable prop valve. The new master (p/n M-C100-L) came from CPP via Danchuk. I'm removing the current hodge-podge of old and new lines and totally re-plumbing front to back. 1. Do these master cylinders have a built-in residual valve as 31vickywithahemi mentioned on another thread? It is sold as a disc/drum M/C. 2. If not, since the master is mounted in the stock location on the firewall, do I need to add a residual valve (or two), or are they mostly required on under the floor mounted M/Cs? What difference would I feel at the pedal with them vs without them? I've done this manual disc/drum system under the floor with residual valves on my old Fords with good results but this is the first time with a firewall mounted M/C. I don't want to install residual valves if they are not needed. Thanks in advance......
With the master cylinder mounted on the firewall, I don't think you need residual pressure valves, since it's higher than the wheel cylinders. Proportionong valve, yes. I'm replumbing now too. Fun!
Always check the master for the prop valve(s) first, never assume they're in there. Use a paper clip, insert it into the center of the tube seat on the master, gently push in, if you feel it spring back then it has a res valve in it. If you have a firewall mounted master you still need a res valve for the drum part only.
That's what I've always 'heard' but I wondered if having them in the system would "tighten up" the pedal feel.
I'll check it tomorrow. This car had an issue with the front brakes dragging when I first got it so I'm glad to hear a recommendation of no residual valve in the front system.
Did you bother to look in the ports of the master cylinder for the brass check valves? Some are supplied and honestly I've no idea if they maintain residual pressure for the discs. I went through the exact same transition on the 33....removed power booster, all lines and added new remote 1" from CE. Used a 2 lb check for front disc, needle valve for rear drums...my brakes were way too sensitive and were pulling ( on the front)... so after just about no adjustment on the needle valve, I've got great brakes.... Sent from my iPad using The H.A.M.B. mobile app
The only time discs may need a (2 lb.) residual is when the master cylinder is lower than the calipers, to prevent fluid drain-back. Older drum brakes used and needed residuals up to the mid '70s, but later drums will benefit from residuals with better pedal feel, as you've already heard. The M-C100-L master you bought is labeled for disc/disc and disc/drum, so internal residuals are not likely. An external 10 # residual to the rear drums is recommended. Internal residuals are normally rubber and are located behind the brass tube seats. Curious, but what is a needle valve???
I checked this morning and like V8 Bob surmised, it has no residual check valves in any of the ports. I just happen to have a Wilwood 10# residual in stock so I guess it's time to break out the ol' tube bender and get to work. Thanks. Here's the before, and the (mock-up) after. Between the power brake assembly, the huge power steering box and the alternator, it was not fun servicing the spark plugs or the valves on this side. Removing the alternator was somewhat helpful but sheesh..... I'm just not a fan of this kind of self-inflicted agony.
Ah yes...much cleaner without the booster. And yea, looks like a plumbers nightmare with the lines on the cross-member too. For some reason, I thought this car was "all" cleaned up and ready for... Mike
It looks much cleaner now indeed. I know I may get some flack for this but its speaks volumes when you say a phrase to yourself when trying to clean up congested areas on a hot rod...... That phrase is.... "I need to hide or get rid of as many parts that are in plain sight as possible so it looks like it wont even run."
For years the trend has been to add on everything that it takes to make an old car feel like you are driving a new Lexus. Consequently the cars got more complicated and engine compartments started to get filled up with accessories. They even turned to full engine covers to hide it all. That's not for me. I like my cars simple, easy to work on with decent power and a single style - most often the '58-64 period. I try to only do modern improvements that do not significantly detract from the style. Hot rods should be hot rods, not disguised luxo-barges. IMHO, of course.
Power and manual brakes usually use a different pedal ratio, if it was originally set up with power, you may need to reinforce your seat so you can really stand on the pedal to build pressure with the manual system.
Man, I hope the pedal effort ain't that bad! The pedal has two different locations for the master cylinder rod. With the power brakes, it was in the one farthest from the pivot, I will use the one closer to the pivot and see how it works.
Curious, but what is a needle valve???[/QUOTE] A valve that has the plug( not the seat) shaped like a very thin needle which provides very precise orifice size adjustment....sorry probably using an industrial term and not the correct SAE name....just a type of flow valve... Sent from my iPad using The H.A.M.B. mobile app
A valve that has the plug( not the seat) shaped like a very thin needle which provides very precise orifice size adjustment....sorry probably using an industrial term and not the correct SAE name....just a type of flow valve... Sent from my iPad using The H.A.M.B. mobile app[/QUOTE] OK, I was being facetious. I've never heard of an actual needle valve being used to control pressure on a rear brake system, but figured you were describing an adjustable proportioning valve, correct? If so, prop valve function is much more involved than a simple needle valve. If you really are using a needle valve , remove it and install an adjustable prop valve for a safer and proper brake system.
Did two tri five cars for a friend. Both have Wilwood 4 wheel disc brakes. We used the vette style master. Brake pedal pressure is just fine no issues. They stop straight and with ease.
I just had to change my master cylinder like that one. It was not returning all the way. The more l drove it the more the front brakes would drag. It was a real drag trying to sort it out.
A little mid-project update; I finished running the new front brake lines today after two days of sitting in the engine compartment welding up and finishing holes in the firewall and inner fender panels. As soon as I can, I'll push it out and put it on the hoist to do the rear brake lines and a new fuel line. I'm gonna spend the next day or so sanding the rest of the engine compartment (ugh). The pictures show it as it was and as it is now (with a placeholder m/c) - I'm happy with the way it cleaned up that side of the engine compartment. I also cut out the bellhousing mounts and the shift pivot bracket - much cleaner. Okiewelder; When I bought this car the front brakes were dragging. After a lengthy troubleshoot fest it turned out to be the pedal return spring not pulling the pedal all the way back - by only about 3/8". I "moused it" with an extra spring. It will get new bushings and a new return spring during this freshen-up.
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