I installed front disc brakes but cannot use currently available dual master cylinder adapters. The Fatman adapter would satisfy my need to use a dual mc but they've discontinued making what I need. (anyone?) So I attempt an analysis of the possibility of staying with the original single chamber mc with residual valves. The replaced front drum wheel cylinder bore is 1" diameter while the new discs have a 1.3" dia bore.. Thus, the brake fluid volume per unit of travel of each disc wheel cylinder is 70% greater than the volume of drum wheel cylinder. But the travel of a disc cylinder is less than drum cylinder travel In order to assess reliability, the question is whether the drum maximum outward wheel cylinder movement is 70% more or less than discs. Granted cylinder movement is greater when discs are worn then when new just as movement of mal-adjusted or worn drum cylinders is greater then when new or well adjusted. I have installed rear self adjusters as mal-adjusted rear brakes use up greater volume of valuable brake fluid. I cannot find data re drum wheel cylinder travel under braking. Disc cylinder travel I estimate at 1/2" to 3/4" until brakes are replaced... I invite a learned discussion. EDIT _ Just learned front drum wheel cylinders are actually 1 1/8" dia bore bringing the difference between disc and drum useage to under 10% making this more and more feasible. I'm also going to research truck mc which have the same mount but a larger bore than the car. Feeling better now.
What are the front calipers off of from the Factory? In stock application did that vehicle have rear drum brakes? If so what size rear wheel cyl did that vehicle use? Last, did said vehicle have a non Power master. Just thinking on my key board. Beyond that I don't know much. P.S. I've owned the same 50 Merc since 1963 The Wizzard
The disk conversion kit is POL which uses 4330 / 4331 calipers which are standard with Citroen/Peugeot/Vauxall/Opel. I don't know model info. The POL kit is great as it installed easily. Problem is getting a hard pedal which residual values should cure. I'd like the reliability which dual mc gives but until I find an obsolete Fatman mc adapter I'll settle with a stock Ford/Merc mc assuming the numbers work.. Rear wheel cylinders bore is 15/16" while removed fronts are 1 1/8".
Hmmm, a 50 Merc weighs in a the Curb at 3,600 lbs. The Citroen comes in at 2,100 lbs. I wonder if those Brakes are a good choice for an up grade. Something I learned way back and still seems to hold true. Kit's regardless what they are for or who they are built by seem to just take your $$$$ and leave the customer trying to come up with the rest of the answers. Even there instructions seem to be incomplete. I wonder if a Citrone or Peugeot master would be a fair choice. The Wizzard
Those who have made the disc conversion say stopping is way better. And yes Mercury weighs more than Opel. Getting off base for what I need to know --- reliable hydraulic transfer of energy from master cylinder to wheel cylinder. My math ... focusing on the wheel cylinders ... the replaced drums have 1 1/8" bore while new disc with 33mm bore are about the same when considering volume of fluid hence brake pressure to the friction surface is also equal. Unless I'm overlooking something. And yes kits leave the user to complete the engineering ... which is the fun part for me. Otherwise I would just buy new cars ... but there is no fun in that.
Possibly Fatman can supply you a drawing of their adapter, and you can duplicate it? Especially since they don't want to make it anymore. I have a Fatman front in my car, and I have to say, they were some of the most helpful and accommodating people I have ever worked with. Worth a shot.
The first upgrade in any vintage brake system should be a dual master cylinder. If a "special" master bracket isn't available for your particular chassis, then fab one, but trying to justify using the stock single system master with a front disc conversion is a complete waste of time. You need a disc/drum or disc/disc master cylinder, period. Do it right, or put the stock drums back on the car. (Hard for me to suggest that, but they'll be safer than the poor choice of calipers you have now) The calipers in your kit are WAY too small for your Mercury, in spite of what some claim. The kit may look and assemble great, but the calipers should be well over 2" to match the weight of your Merc for good safe stopping. Reducing the rotor diameter from 12" to around 11" would allow a larger caliper, and is what some other kits may provide. I know you don't want this kind of response, but a good and safe brake system upgrade requires some common sense along with some basic brake system knowledge, and that really includes some suppliers as well. My comments were interned to help you, not irritate, and hope you take them as such.
MCSFAB- Actually it would seem the socalled 'Fatman' adaptor was designed/made by ECI. After a marathon research session I find Scarebird Brakes have a suitable bracket which supports Wilwood M/Cs. I am headed in that direction but still invite discussion of hydraulic brake engineering. V8Bob - I totally agree and appreciate your stressing a tandem M/C. But where does the 2" caliper calculation come from? I do have basic brake knowledge but seek hard engineering data. Lacking that, I have to rely on the suppliers calculations for caliper selection.
Disc brakes require high pressure to "clamp" the rotor, and the larger the caliper piston, the higher the force. Along with a larger piston are larger pad (brake) surface area. Simply looking at what vehicles in your Mercs weight range use for a front caliper size would help select a sensible caliper size, but they will be well over 2" to 3".
I hear you Bob but unfortunately, no one makes a front disc kit which accommodates the Mercs 5x5.5 wheels and has a larger piston than this kit. While it isn't to your satisfaction, it is better than the drum brakes the car started life with. It would be nice to have max everything for my town driving, even to have more power than the 100 hp which my flathead has, but life is filled with compromises. And since I don't have seat belts, if I ;had super stopping power with super disc brakes I would have to upgrade my windshield.
I've replied to you last post regarding the same Q's........ AND, I showed pics of the calipers that came with the kit. Something is not right, and I know damn well I do not have foreign parts on my car as far as the kit. AND- like I had mentioned before- I SPOKE with the company owner, who designed this around/for his car= see it in the add's? I've even bought performance friction brake pads to replace the supplied ones, and it was from an AMERICAN MADE, GM product. There is too much math /engineering going on here. Required is bore sizes, and a lil smarts..... I think your overthinking, but, who am I to say........ My kit/braking system works just fine. I'm out of this discussion. Good luck.
Well I know I'm not your average builder here and what I would and have done is not in your wheel house but if you in fact want Disc brakes with 5 on 5-1/2" bolt pattern I would adapt 66 Ford truck rotors/calipers to my stock spindles. Then use said truck Master and up grade to same brakes on the rear end. Actually this is pretty standard Fab work in most real Hot Rod shops. Somebody should make a Kit. The Wizzard
I'm running the fatman bracket and a 1977 mustang manual master cylinder. The masters are getting hard to find and usually need to be ordered. I also have the jamco front disc conversion on the front. I have driven 60k miles with one new set of pads and one new master cylinder in that time. Works real good and gives me just enough space for my chevy motor and home made clutch z bar.
Just got a bracket from ECI - top photo. Bottom 3 photos are all I'd ever seen as a 'Fatman' bracket. The MC will mount quite low compared with others and the outlets will be tight against the bracket. Comments please
Ok you are slim, but that master cylinder adapter mount bracket configuration has come be known as the Fatman since Fatman sold them until recently. I was led to believe ECI built them for Fatman and ECI was the only outfit who agreed to make one for me. When it arrived it turned out to be different, but I see know now it will work I plan to use the Wilwood master cylinders with remote reservoirs instead of cast iron mc.
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