5 lug mgb brake

mgb260 · January 14, 2011, 11:09:24 AM

Carl, Just 40 years of street rodding,muscle cars and 4 wheelin'. Old coupes,Jeeps,Gawd don't get me started. Actually I think it's fun! The gears are always turnin'. I am ordering Cressida rotors today. They have 100 mm bolt circle.MGB is 96mm. So 4mm smaller divided by 2. 2mm in. should be easy. I like the Mazda calipers too. Lots on Ebay.Happen to have the larger 88-95 V6 4X4Toyota calipers on hand, a little larger than the S12-8 as all 4 pistons are the large size.They are real popular in Nissan Z conversions.The bracket would be the same though. Would need a 15/16"-1" master. It probably wouldn't work with all 14" wheels. Would work with any 15" though. Here is a picture:

mgb260 · January 18, 2011, 03:26:23 AM

Another option, third gen 93-95 RX7 caliper. Same mounting and pads as earlier one. Looks a little more modern. The Mazda aluminum calipers weigh about half as much as the iron large Toyota V6 caliper in picture above. The smaller Toyota above weighs about the same as stock or in between the larger iron one and the aluminum.

Remember these calipers are for 22mm (.88) thick rotors like the Cressida. Also if you grind off the Mazda name, don't grind off the square bump or rib, there is a passage underneath.

DC Townsend · January 18, 2011, 06:25:51 AM

Jim,

What rotor is that pictured with the Mazda caliper? I'm all set with the T-100, Mustang hubs, and Intrepid parts but now you have me thinking...

DT

mgb260 · January 18, 2011, 12:40:08 PM

David, The rotor is on a Volvo(stock 10 1/2" .88" thick). Those calipers are for those who want to fit more modern setups under 14" wheels with the stock hubs and Cressida rotors. 38MM pistons compared to 45mm on large Toyota calipers. The Intrepid rotor is 1" thick. Lots of different options.

BlownMGB-V8 · January 18, 2011, 01:12:49 PM

Does the Volvo use the Ford pattern, or Chevy?

Jb

mgb260 · January 18, 2011, 01:21:47 PM

Neither Jim, The Volvo rotor is just to show the Mazda caliper. Volvo is 5X4.25. I think I'm confusing people with too much info. I'm getting slammed with E-mails on upgrades for stock MGB hubs. So, with stock 4 lug hubs,14" wheels the Cressida rotors and S12-8 Toyota calipers, or Mazda calipers. Jim, the Lexus one up above is a large caliper with 12.4" rotor with Ford pattern,the Mustang hubs narrow the track 3/4" each side so with the 1" adapters you would be close to stock and allow clearance for the large caliper. .

BlownMGB-V8 · January 18, 2011, 01:54:33 PM

Appreciate that Jim but I don't plan on running adapters. Right now I've got modified wire wheel hubs (they are forged or billet steel unlike the cast steel wheel hubs and are fitted with a 5/8" thick pressed and welded flange) drilled to the Ford pattern. When the time comes to change over I'll just re-drill the flanges for the Chevy pattern and move the studs. So I'll have to match up hats and caliper mounts to get the right spacing. At the moment I don't recall if the hats mount to the front or the back of the flange, probably the back though, it was the standard Mustang setup before they went to one piece replacements. But, with the Jag/Chevy pattern at the rear the front will be due for an upgrade. I'll be running 17" wheels so space is not a limitation. I like the looks of those Mazda calipers. Getting away from the Ford units will drop a good bit of unsprung weight. Then it's just a matter of finding the right hat. Something light would be nice, maybe in a large diameter. I think using the Chevy pattern is going to be the way to go. Wonder what they used on the late model Vettes?

JB

DC Townsend · January 18, 2011, 02:07:47 PM

For those interested, I'm working on a simple "how to" based on Jim's combination of Mustang hubs, Intrepid rotors, and T-100 calipers (with his blessing). I have all of the parts on hand (also happen to have the entire front cross-member and suspension out of the car on rack - great for pictures) and just need to squeeze in some time to take a few pictures, make the parts list (a bit more than those listed above), and do a write up. It may be a week or so before I can post anything. I'd also like to add a disclaimer here: I'm aware of Bill Guzman's and Ted Lathrop's brake kits. They are both fine products with solid value. For some (myself included), part of the fun of all of this is seeing what can be done with off-the-shelf or salvage parts, part of it is to see how inexpensively a "big brake" kit can assembled by your typical DYIer. There is no doubt, there will be some trade-offs here over a Wilwood aluminum caliper and a hat/rotor set-up (or similar), weight for one but right now, this about seeing what can be done. Stay tuned...

BlownMGB-V8 · January 18, 2011, 04:25:05 PM

I think it's a great route to be pursuing. Again, no dis to our vendors, for a no fuss no muss theirs is the way to go. But with all the really good OEM brake packages out there, something has to fit without too much trouble.

JB

DC Townsend · January 18, 2011, 06:47:29 PM

Appreciate that Jim B.

Here's the basic idea. Low cost, off-the-shelf or salvage parts, machine work minimal (preferrably something you could accomplish at home), offers a significant improvement over stock, fits 5-lug (Ford in this case) hubs. I want to say right up front, that Jim Nichols is the guy who did all the work figuring this stuff out. I'm just going to organize it, put it down on paper, and make it (hopefully) easier for others who want to follow the same path. Not everyone has $600, $700, or $1200 to spend on a decent set of brakes. With today's components it should be possible to put together a real stop-fast package for $300 or less. That's the goal. We'll see how it comes out.

mgb260 · January 18, 2011, 07:37:30 PM

Well said guys, Jim, those RX7 calipers are light but a little on the small side. They were originally on 11" diameter,22mm thick(.88") rotor for 14"wheels. The Cressida rotor is 22mm thick and will mount behind the stock MGB hub just like the TR6 pictured above. You should check out the other thread in the Handeling section. You could use the newer Camaro rotors and calipers(same calipers as C5 Vette except mounting pattern and less fins) about twice as big as stock MGB and should use the 1" Corvette master cylinder like the Roadmaster. I don't plan on putting a rotor behind the Mustang hub like original,just too many nice slip on rotors out there. I think the confusion started when I suggested you might put the solid early Toyota pickup rotor behind the hub like stock MGB to use the stock calipers. I think that would be a lot of work just to get 5 lugs. You might as well go vented and better calipers.

BlownMGB-V8 · January 19, 2011, 01:29:45 PM

For my car, I'm thinking a slip-on rotor would be a better choice too. It won't work with 14" wheels because the hub is too big to leave room for the brakes once the rotor goes over top of it I'm thinking. But for a larger wheel application it should not be a problem. So, the newer Camaro and Corvette rotors might be a good choice. As I recall the Camaro used a 16" wheel and the Corvette used 17's for sure. It bears looking into. This puts the wheel flange outboard by the thickness of the rotor hub but that isn't a problem and actually will probably be helpful in making the front wheels a closer match to the rear ones on the Jag IRS. Any caliper mount I can make is going to be simpler and lighter than the existing early 70's Mustang-to-MGB adapters on the car now, they weigh several pounds each.

JB

MGB SS · January 19, 2011, 09:47:50 PM

Great info and a write up would be awesome.

One thought though It has mentioned several times above about 14" wheel fitment, Just my opinion but who is going to change over to 5 bolt or build up a nice brake set up and still run a 14" wheel, just a thought.

Again all, great job, I have been wanting to research all this for a few years now.
Joe

mgb260 · January 19, 2011, 11:24:52 PM

Joe, I think the confusion is my fault, the 14" setup is for the guys who want more modern brake with the stock 4 lug hubs.Should have started a new thread. All the 5 lug setups would be for 15" -16"-17" rims. Then there is also Ford or Chevy? I think the Mustang hubs/Intrepid rotors for Ford and Chevelle/Monte Carlo hubs/Camaro rotors for Chevy.

J Man · January 23, 2011, 08:10:57 PM

I would be interested in a complete bolt on 5 lug disc brake swap if that is possible. Small Ford pattern. I also can not go any wider than stock.

I do not have access to machining equipment.

mgb260 · January 23, 2011, 08:32:08 PM

Jason,The only reason the 65-66 V8 Mustang hub outer race hole should be bored 1/4" deeper and trimmed on the outside is to set the bearing back in the MGB location so you can use the castle nut and cotter as intended. I wonder if the Mustang II halfnut threads are the same. In my setup I originally ground the castle nut down and drilled the cotter hole a little further out. The bearing is O.K.(before the threads) and the shorter nut has full threads. The machining of the hubs is the right way though. The track width comes out 3/4" narrower(about the same difference as the wire wheel rear axle. It would allow more room for wider 0 offset wheels. I am working on caliper brackets for various brake setups.

mgb260 · January 25, 2011, 07:40:21 PM

O.K., I am getting questions on why you need a bigger master cylinder for some of these setups. Some of you know why,especially the racers or some who have put on bigger calipers and didn't like the longer pedal travel with the stock too small(3/4") master cylinder. On the other hand those that put the 1" Corvette or Lincoln master cylinder with stock too small calipers and need both feet to move the hard pedal any. Simply matching your caliper piston size with master cylinder size. The stock MGB 3/4" master with twin 54MM caliper pistons(108MM total). The small Toyota S12-8 caliper has two 42MM and two 36MM=156MM and Mazda RX7 caliper has four 38MM pistons=152MM so both would be better with a 7/8" master cylinder. The large Toyota S12W caliper(a favorite with Nissan Z guys) has four 43MM=172MM so size up again to 15/16" master. The Toyota T100 S13W caliper I'm using has four 45mm=180MM and needs a 1" master. It is all in matching the size. My aftermarket clutch slave cylinder(7/8") works best with a 7/8" master cylinder for the same reason. Hope that answers some of the questions.

DC Townsend · January 28, 2011, 12:03:46 PM

A quick update on the promised "How To".

I finished the write up and have most of the pictures but am waiting on a couple of small parts (caliper adapter, dust caps, AN line adapters) to arrive so I can wrap this up. Just to tease you a little further, I'll be including a couple of versions of the parts inventory - the down and dirty cheap version and a slightly 'upgraded' version featuring a lighter caliper. So far I'm into this for a little over $300 (sourcing everything with new parts). I know Jim has much less in his set-up but trying source parts out of a bone yard in the middle of winter in Vermont doesn't meet with the most success. The machine work needed to do this is minimal so far and the results are really nice - everything fits together like it was made to. Pretty cool. For those into the fancy schmansy rotors (dimpled, dimpled and slotted, slotted and cross-drilled, cross-drilled, anodized black or silver, etc.) I found a source that's very reasonable.

Stay tuned...hope to be posting this up next week.

mgb260 · January 28, 2011, 11:40:11 PM

Excellent, David!

mgb260 · January 29, 2011, 02:46:04 PM

More on brake balance. The smaller Toyota and Mazda calipers aren't that much bigger than stock to affect the rear balance too much,probably don't need a proportioning valve with stock rear drum(GT wheel cylinder recomended) or Scarebird rear disk kit. The Large Toyota and T100 really need a larger rear setup. The Nissan Z guys noticed and usually go with the street rod favorite Cadillac Eldorado rear caliper(GM Metric with parking brake) with slip on S-10 4X4 1" thick front rotor(drilled for Ford also)on 8" and 9" rears. I'm using 92-95 RX7 Rear 20mm thick vented rotors and 89-94 Subaru Loyale Front calipers. They have a large(54mm/2.34") piston and larger pads than the Cadillac as they were designed for a front brake. The neat thing is they have a cable operated parking brake. I'm also working on a Acura/RX7 setup for the stock 4 lug rear.

mgb260 · January 29, 2011, 02:46:04 PM

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BlownMGB-V8 · January 30, 2011, 11:43:13 AM

Jim, I wonder how that balances out with Jag brakes on the rear? That's something I need to sort out. I don't have the area of the pistons but I can try to get it.

Jim

mgb260 · January 30, 2011, 12:04:24 PM

The Jag being a large car probably will be fine. Where we hotrodders run into problems most of the time is putting oversize front brakes on our smaller lighter cars and leaving the stock rear small drums or disks. That is what the Nissan Z guys found when they went to the large Toyota calipers in front with the stock rear brake drums in autocrossing. They first switched to small disks and still had problems. After they went to the large GM (pretty standard streetrod stuff) they had a matched killer setup. I think you will be happy with the Jag rear brakes as they are probably way bigger than the stock MGB drums. I still think the newer Camaro set up in the other thread on the front would work really well,those calipers are the same design as Baer and PBR racing calipers and the same as C5 Corvette except less fins and different mount spacing. 12" diameter,1 1/4" thick rotors. When you change your bolt pattern slip the rotor on, mount the calipers with slider bolts like GM Metrics to your custom bracket. Easy!

BlownMGB-V8 · January 30, 2011, 02:47:22 PM

Sounds really good, I'll look into that.

socorob · January 30, 2011, 02:55:03 PM

I have the gm metric with parking brakes on the rear of my sunbeam with an 8 inch ford rear. Those things are heavy. If I had to do it over again, I would try to use the mazda rear calipers from the rx7, as those are smaller, and are cable parking brake actuated also. I may change them down the road, since i have a clearance issue with the big gm calipers. If I hit a huge bump, the frame rail will hit the caliper. I cant make it happen trying to push the rear of the car down, but it has happened twice over the last year when I couldnt avoid giant potholes. I think the mazda brake cables pull towards the center of the car, which would be easier in my situation for a parking brake cable. The gm pulls forward, so with wide wheels with a lot of offset, you would have to angle it out around them.