Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - Alternative Brake MC's

Has anyone here fitted a different Brake MC to thier car? Seeing as how many of us swap the rear axles, I though there would prbably be someone who has done it. I am especially interested to hear from guys here in the US. I am NOT looking to go Wilwood, fancy expensive stuff. More like maybe a MC off a Mustang, Crown Vic or other common and thus cheap MC system.

My MC is just shot and I cannot see spending $250 for 26 year old parts whe I could get a 1993 Mustang MC for under $100
Larry Embrey

Larry, do you have power brabres?
If you don't you can use a Wilwood MC, yes, Wilwood is cheaper and you can buy one with the choice of piston size.

If you have power brakes the Wilwood can be adapted.
If you want something different then a GM For disc/drum brakes Early Vette MC

To eliminate the power booster use also a MC from a GM use a MC with a deep piston hole.

All of the above require adaptation, there is no direct replacement that is exactly the same as the MGB MC, but you can get close, please note that close is not good enough for safety.
Most american cars have a bolt pattern of 3 3/8, Wilwood bolts directly to the MGB.
Power brkaes require a shallow piston hole and manual requires a deep piston hole, also tghe size of the piston, manual usually are 1 inch and power brakes are 1 1//8 piston dia. Replacement would require the change of the combination valve to work with the MC.
Also knwon as the proportional valve.

Hope this helps you.
Bill Guzmna

I always thought the wilwood would be very expensive. I will have to look into that.

I have a '78 with stock braking at this point, everything except the MC is new and the brakes are just really bad, it seems like the chamber for the front brakes is shot..

I am just hoping to find some sort of stock MC that will work (adaptation is fine), so if it goes out I can easily get a replacement and be on the road.
Larry Embrey

K, the MC is DEFINITELY DEAD. I have NO pedal pressure at all now.

SO I want to make sure I am reading this right Bill...

I DO have power brakes (can change to non power if it is a big problem, though the boost assist is nice) So I can use a Wilwood with modifications or an adapter. OR I can use some GM units with adaptation?? Do I have that correct?

I have a MC out of a '91 mustang in the garage from a parts car. I might tear into it and see what I can figure out. If it is something as simple as making an adapter plate (I know the bolt pattern is different) and longer pushrod, I can easily get that done at work. I pretty much KNOw I will need a proportioning valve no pmatter what I do as I will have Mustang rear drums and MGB front disks.
Larry Embrey

Larry, the mustang MC will work, you will need to know the size of the MC piston, make plate to adapt MC to MG pedal box without the booster, use the mustang valve if it was disc/drum car.
Remember that piston and type is important, shallow or dip piston on the MC.

If you are going to remove your booster, which is not a good unit, single piston 7 inch no big deal for a booster. Yoou could use MC # 390360 $90.00 and valve #VL 3350 $99.95 and bracket and lines BL3350K $39.99
This will require a plate bolted to your existing brake pedal and drill to accept the MC with 3 3/8 bolt pattern horizantal two hole mounting. A MC rod would have to be fabricated to adapt to the the pedal.

The simple way is to rebuild your unit, kit is about $25 from Moss Motors, about 30 minutes work plus installallation time.
Bill Guzman


I am going to have four wheel disc brakes and I am very interested in using a Wilwood master cylinder. Does Wilwood make a dual circuit unit? I can't tell from looking at the catalog sources like Jegs and Summit. From a safety standpoint, as well as adjustability, I assume a dual circuit system is a must. Is there a specific MC you would recommend for use with four wheel discs? From what I've read, rear discs should use a MC that does not have the higher rated residual valve that you need for drums.

Ryan Reis
I have built for my V8 conversion a pedal box with Tilton balance bars and two AP racing MC (CP2623), I have also hydraulic handbrake and AP rear brake proportioning valve (screw type). For the rear braking I have built billet aluminium hat fitted with Brembo discs (front disc for MGB machined). I have built a new wheel bearing retainer with bracket for fasten the two pot callipers. To front I have AP 295mm vented rotor, AP four pot calliper and Mintex M1144 pads. I have built two brackets to hold the calliper to the MGB stub axle. Aeroquip hose and hose fitting. The set up is not easy, but now I have good braking.

The mustang was front disk rear drum, just like the MG. So to use the Mustang unit you think it best to remove the booster?? Not a problem like I said and one less source of vacuum leaks I have the MC with it's resevior and the fixed proportioning block is still on it. As for Bore,t he Mustangs use a 21mm (yeah metric) bore and the MG is spec'd at .82150 per my manual which is 20.6375 so they are pretty close.

What are you refering to in terms of piston type? you mean for what length rod I would need? I already tried rebuilding the MC last year, it actually made it worse. I noticed a good size pit/groove in the chamber on the open end which is the front chanber I believe...

I THINK I found a source for a rebuilt stock unit for $95, I am going to research it a bit as lastime it was bogus. $95 I can swing for a stocker, if that fails then I will push forward with the mustang unit.
Larry Embrey

Larry, before you change the MC you might check with your local auto parts store. I found that O'Reilly auto parts here in the midwest carries rebuilt MC's for both the B and the midget for under $50 exchange. They usually have to order from their warehouse, but that only takes a day on average. They also list rebuilt calipers for the brakes.
Bill Young

check out:

I used a 7 inch dual MC from them works great. I have 4 wheel disk brakes.
Michael S. Domanowski


I meant a 7 inch power booster and dual MC from Masterpower.
Michael S. Domanowski

I just called Schucks HQ, they kist none anywhere in thier system, I then called Cardone who rebuilds them and they have none. Do you have number to O'Reilly's?? I wonder if they will do "mail-order" on it... The shipping would be cheaper than doing the send mine out and wait routine...

Do you rememebr by chance how much that cost you?? Do they maybe make a MC that will bolt up to stock booster??
Larry Embrey

Larry, the simplest way is to order a kit from Moss Motors.
Blalance bars are great for the track and they require once a while to re-check of the balance. It's a way to balance the bias between the rear and the front brakes. I have a similar set up on my race car with a cable adjuster to blanace the brakes fron the inside.
Deep piston(internal piston of the MC) means that the piston has a deep hole for the rod etc.

Wilwood has several MC's and they all come in different piston size, they are located in Camarillo Ca. about 4 miles from my house. They are very busy but always have time to help their phone # is 805-388-4938 be patience. Also their clucth MC is a direct bolt on but have to fabricate rod.

mpbrakes have great stuff I use their kits allot, problem is they are hard to deal with sometimes.
They have a booster 7 " that can be use as replacement for the B with minor cutting of the rod to fit. Power booster is a waste of space in the B unless it was a double 7" booster. The MG already has 7 to 1 pedal ratio that ratio with the right MC will act as power brakes.
Dis/disc require a different MC than a dis/drum combination.
Get the same piston dia from an early B without a booster with disc/drum brake.

Disc/disc should use a power booster. mpbrakes have the right MC to use wiht disc/disc and without power booster, they work great, I have not use one in a B.

The secret to good brakes is the maching of parts, right size MC, pedal ratio, corecct poportioning valve, plumming, eg; rear axle should have 1/4" lines and 3/16 at front this helps with the bias, and and...
Bill Guzmna

Bill, Thanks, as always you are a wealth of info!! I do know brake balance is critical.

My MC is just not rebuildable, I already tried it once and there is a large pit/groove in the bore. Converting to non power brakes might be a good option, or are you saying maybe get a early car piston and modify the stock MC to fit with it a a rebuild kit?? Are the early cars larger bore?

I will look into MC for those car as well as look into adapting the mustang MC to fit in a non power set-up. I DO plan to use a wilwood proportioning valve no matter what option I choose.

Larry Embrey

Replacement MGB MC. Napa has them part #TSM111672 @ $46.99 - Core $13.00.
Hope that this helps someone.
Mike Cook
mike cook

That does not show up on the website as a valid number?? That pricing also matches up with the pricing of thier rebuild kits?? Is that a early or late model MC??
Larry Embrey

Amazing I only got it 6 weeks ago. They do have one at $95.49 core $55.56. Part # TSM 112437
I was obviously very lucky.
Mike Cook
mike cook

You may want to consider having the MC resleeved by Whitepost (located in Whitepost, Pa). I think they use stainless sleeves - should be good as new when done.
Tom Sotomayor

Larry for the power booster and dual master cylinder plus a universal brake pedal mount linkage (which I didn't have to use) it was $500.00 plus shipping. I can look up the part numbers and actual $$$ per item for you if you are interested.
Michael S. Domanowski


I would be very interested in having the parts numbers and prices if it's not too much trouble. Two questions: What are using for calipers and rotors front and rear, and what year 'b do you have? I don't care if I have the power booster, but my wife would be more comfortable driving the car if it had one.

Ryan Reis

Just for your information. MGB came with power brakes to keep up with the market. power brakes uses a larger bore MC to compensate for the booster thus given the feel of a good pedal with the booster. non-power brakes use a small bore MC to give you the needed pressure and good pedal feel. What is important in a brake system is the pedal ratio. Must common cars use a 6:1 pedal ratio for manual brakes and a 4 or 5:1 ratio for power brakes with dual piston booster. The MGB has a 7:1 pedal ratio and it's the same ratio with the booster.

Where it gets tricky is with dis/disc then you need a MC that can deal wuth the extra volume and right pressure needed to apply the right pressure for disc to work correctly.

Bill Guzman

That second part number is a Cardone part number and I know they (cardone)don't have any cores.

I will have to call Napa and see if they have that number listed.

Larry Embrey

Man I wish we could edit posts!!

ANYWAY, called Napa, that part number pulled up, but did NOT cross reference to a MGB. AND they had none shown in stock anywhere in the country or the Mfg :-(

TOM - Do you have contact info for Whitepost?? or at least a full company name?
Larry Embrey
I looked up the master cylinder for a non-power brake '76 MGB and they show one in stock at my local store but the price is higher than I remember at $85 plus $45 for the core. Cardone is the rebuilder for these units, so the listing may be in error if you have already checked with them.
Bill Young

Oops, my bad - they are in Virginia, not Pennsylvania.

White Post Restorations
One Old Car Drive
Post Office Drawer D
White Post, VA 22663
(540) 837-1140 Fax 837-2368
Ask for Billy or "W.R."

Good luck,
Tom Sotomayor

Larry, I'll look up the P/N for you tonight. Our B is a 1978. Front disks are the drilled and slotted stock replacement, I think I got them from Moss Motors, with standard calipers. The rear came from a Ford Explorer, they came from Currie Enterprises on my 9.0" rear that I ordered from them, you could check on their website to see what they use or call them but I think they were from a 96 or Ford Explorer, I had to trim a corner off the rear caliper so it would not rub in my 15 inch minilites, no big deal.
Michael S. Domanowski

Hey thanks for all the info folks!!

I have a new local transplant BBS member with one in his MGC. Stopped by his place Wed night and pulled it out. Took both units to work and upon tearing my old one apart found a seal installed backwards. Everything else looked good, so I put the seal in properly and installed it Thurs night. Sure enough the brake work great now!! YIPEE!! I just walked in from letting the cooling system fill up. car idled @1000rpm for over 15min and was not above 180*! Looks like I need to get those fan hooked up to a temp relay so the car gets hot enough for the EFI.
Larry Embrey

Larry, You might want to check out if you need something in the future. I had a new one from Lockheed fail after about 2 years on my 73. I found Cardone didn't have any cores, but would redo mine and return it. I found one on that web site that was rebuilt by Bendix. When the Lockheeh MC failed I found some fairly large pcs of metal inside that were never cleaned out after machining. I had thought I did a good thing in going with a new MC. So much for Lockheed quality!
J Davis

Yeah they do have the Bendix, but they are $350!! I love parts america, it is where I find all my part and part numbers. They are actually Schucks online company.

Car ran great yesterday, only issue is that she needs the alignment done and the speedo is acting up.
Larry Embrey

This thread was discussed between 25/09/2004 and 03/10/2004

MG MGB GT V8 Factory Originals Technical index

This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.