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60 Bugeye Disc Brake Conversion

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erstearns

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I am converting to front disc brakes and I would like to modify the brake and master cylinder to a more appropriate "newer" design. I assume that whatever upgrade I make it will require modification to the pedal, mounts etc. What would be the most desirable upgrade, what year(s) and what mods need to be made? /ubbthreads/images/graemlins/confused.gif
 
The 63 master will bolt right in, looks the same as stock but with a 3/4 bore. works well for street driven cars. Or you can go with a later duel master and peddle box. Requires a little more fitting but basically pretty simple.
 
Like Taz said, the easiest is to use a 3/4" bore brake master from a 63-66 Spridget or have the original 7/8 master resleeved to 3/4.
Or find a later pedal box and master set up which will require cutting, moving the wiper motor, and some basic fabrication work.
 
Thanks. I think the KISS principle may be applicable here. If the smaller diamter cyliner will do the trick that seems like a logical choice. I will take a look at the additional work required for a later unit though. It is hard to resist making a project more complicated when it involves another opportunity to use saws, hammers and welders. Thanks again.
 
Could you use a brake proportioning valve to compensate? I haven't thought it through yet.
 
OK, I described the issue to Pop. He said that: while a proportioning valve would help in heavy breaking sistuation it would not solve the issue. He thinks that a metering valve is needed on the front circuit . He then tried to explain how this would hold off pressure to the front until the rear drums had enough fluid to start engaging. I'm not sure we were on the same page. Anyone else have a thought.
 
Curious why the 7/8 bore wont work with the disk conversion? A slightly harder pedal with less travel is all it should cause.
 
Please feel free to jump in if I'm saying anything wrong here. The tricky thing with a single master serving a drum / disc setup is that the two systems require different pressures to operate. The drums start working at around 600 psi while the discs require more like 1000psi or more. Also a disc setup requires more fluid. That's why the disc reservoirs are typically larger than drums. The larger the diameter of the master cylinder the less pressure you get. In this case, if you want to stay with a single master, I'd use a stock factory unit for a disc / drum setup. They had it figured out pretty well for the street. For more spirited driving a dual system is the way to go, and again I'd stay pretty much with the factory setup. Downsides here are the cost of a stock master cylinder. If you are adventurous you could try to engineer a setup with a 70's datsun dual master. They had sizes from 11/16" through 7/8", all with the same hook-ups, and cheaper than the stock unit.
 
I love the forum for just these type of questions. The really good ones like this one everyone has an opinion and they all are right, but each person has to weigh their priorities. Origional, functional, what is easiest and still good. I am involved in a redo on a car I've had for 25 yrs. and have made the decision to go with the dual master setup regardless of the problems. Heres why. The brake masters before 1968 are a single stage, what this means is with failure, no brakes. If you look in the catalogs you will see the first dual master on the 1967, the brake is still a single stage. I believe 1968 the law mandated a dual stage simply for the safety issue. I've comitted to several performance upgrades and have made the decision that if a brake failure were to cause me to lose the ole bugeye, I would be sick. The cheapest way through this problem is to find a later spridget and pull the disc brakes, pedal box and masters, and then rebuild. It was my experience that the disc brake change was pretty easy, a really good and much needed improvement. Good luck.
 
Though I haven't switched to a dual system yet myself, I agree with kcbugeye. If you have ever experienced total hydraulic failure, and you have to totally rely on the old handbrake, it is a heart-thumping, emergency situation to be avoided!
 
I agree that this forum is a great arena to discuss these types of issues. After considering the additional comments I think I will seriously consider a dual system. I am planning to other power upgrades and as long as I am converting to front discs I should opt for stopping power over ease of installation. Sleepless nights are good for searching for parts anyhow. Thanks all for the input. /ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]
Also a disc setup requires more fluid. That's why the disc reservoirs are typically larger than drums....In this case, if you want to stay with a single master, I'd use a stock factory unit for a disc / drum setup.

[/ QUOTE ]

The disc setup doesnt really need more fluid. It runs at zero clearance and requires little volume to engage. But does use a larger amount as pads wear. Drum brake adjustment make minimul change in fluid level. Late model master cylinders have gone back to a common resevoir feeding both circuts. I am using the old 7/8 m/c core and sleeve it down to 3/4 like for the later disc/drum models. I am also converting to rear disc, so a proportioning valve isnt going to be as necessary for my application.
 
Interesting, rear disc, you have caught my attention. I've been told that with rear disc, you lose the ebrake. I didn't want to do that trade off. Somewhere in the future I can see mods on the rear axle towards better handling and would consider anything in reason. I'm curious about what has led you to rear disc, and how you are doing it. Thanks.....
 
I asked about the feasability of rear discs some time ago on this forum, and the general consensus was too much work/overkill for the difference in upgrade, especially since the disc/drum setup works fine, even in G & H prod.
 
Researched this some time back.

Victory Circle makes a rear disc brake conversion, and you can add a Wilwood (or similar) spot caliper (https://www.wilwood.com/Products/001-Calipers/023-SFM/index.asp) to be used as an emergency brake. You would need to fabricate a bit to get the additional spot caliper mounted.

Or, of course, you can be totally creative and "Mite"-like (https://the-mite.com) for just your time essentially.

As for my application--Lets see how the drums work out for me...and then I will decide if I need it.

Mustafa
 
Ahh the plot thickens. Given the variety of responses I am left with a few questions but lets start simple. If I convert to disc on the front, keep the drum in the back, can I use a later model dual line brake cylinder without any other mods than the pedal box. With the conversation regarding different pressure, response etc with drum and disc combination, is some type of metering device required? If the later model sprites had disc front and drum rear I assume that would not be necessary. The floor pans in my girl are impeccable so the Fred Flintstone braking method is unacceptable. Any comments.
 
Using the set-up from a car that had disc/drums should work just fine! I am using the old dual unit w/larger bore and it works well.
 
I think you mean Winners Circle for a rear disc set up. I've bolted up 4 or 5 of those kits on the race cars, they are well engineered, but as you mentioned you on your own to fiquire out a working parking brake as this set up was designed for racing where a parking brake is not used.
 
I have another thread to add to this discussion.

Years ago it was more or less standard practice to upgrade the braking on Minis by adding a brake servo (I belive the US word is "booster") to handle the extra power that a tuned engine might put out. This became so common that BMC started fitting them in the factory, at least to the Cooper and Cooper S models, and to the later 1275GT etc.

I already have the front discs from a 1275cc Midget in my Bugeye (as well as the engine) and I feel it still needs some more stopping power, even in the base state of tuning that it is.

Does anyone have any experience of adding a remote type servo to a Spridget? I was quoted 165 pounds sterling (plus shipping) for a servo to fit my car by JLSpares of Rochdale, Lancashire, UK (https://www.jlspares.com). I think Automotive Products (UK) used to offer a generic one for sale.

As an aside, in my college days (late 1960s) I had a 1964 Woody Mini Traveller 850 with a Stage 2 head and a 1 1/2 inch SU, and adding the servo made a big difference. Ideally it should have been converted to discs at the front as well, but I was just an impecunious college student... Ahhhh those were the days...
 
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