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MG MGB Technical - Rotors on REAR of 80 MGB. Is this a conversion? HELP

My l980 MGB has rear rotors instead of hubs. Uses brake pads instead of shoes. Can't find pads to fit. Do not know who makes calipers. Moss, Victoria Brit. or any of several parts suppliers contacted can furnish any info. Is this a conversion? I have not seen this type of set-up before. Previous owner no help. Anyone out there familiar with this set-up?. Your help will be greatly appreciated.
Jim Hughes

That is not stock. Someone has converted the car to a 4-wheel disk brake setup. Sorry, don't have any help for you on replacement parts. Do the calipers have any name brand info or numbers cast into them to help with ID?
Paul Konkle

I remember hearing of a conversion that put Spitfire or midget front brakes on the rear of an MGB. Don't know anything else about it. Maybe some of the racers know?
Regards,
Gary
Gary Wiggins

I'm sure a break place would beable to get some pads to fit just take your ccar in and say you want new back pads only. Make them earn there money!!
Ross

Being a little more sensible about this, look for casting info on the calipers, this will tell who the manufacturer is, and pull both pads from one side. armed with the pads and the information, the poor dumb parts guy will stand a lot better chance! Explaining your dilemma is a must. (We usually earn our money every day, anyway!) Letting the parts guy know who the mfr. is will speed up his process and help your cause a bunch! They might even enjoy the challenge!
Rod Nichols

Jim:

Are you sure the rear end is MG? Just a thought.

Pete
Pete

Jim, sounds like the PO stuffed another type/brand of rear end in the car. Best thing that you can do is take a picture of it. Go to a Napa or some other parts house and try to ID it. Take a pad with you for them to try to match up. Take a rotor to a brake house to try to match up. Take a mirror and look on top for some casting ID. things of that sort. Good luck
Victor Gardino

Take a pad to a parts store or better a parts store that specializes in brake parts and show it to them. They should have books that have illustrations of pads and can get you a set of pads and maybe even narrow down the origin of the calipers. Surprised if there is no marking on the calipers at all.
Mike
Mike Hayworth

Possibly someone swapped in a Volvo rear axle. Or maybe just the disc brakes. Look for ATE cast on the calipers.
Andrew Blackley

Steve S, this is right up your future alley, if i remember correctly!
Ken R
Ken Rich

Ken-
I'm still researching the matter of using MGA Twincam parts to do the conversion. I've figured out sources for everything except for one measly part (I think). However, that's been delayed by having to figure out how to install a proper heater valve with a Derrington Crossflow head conversion and where to get the right parts to run a remote oil filter. That's all done now, so I'm back into the disc rear brake project again. Never fear.

Jim-
I have an idea that might help (maybe, it depends). I know that you should have a Salisbury tube-type rear axle. My question is: Do you have a Salisbury tube-style rear axle or a Hardy-Spicer banjo-style rear axle on your B?
Steve S.

Jim:


Box it up, send it to me. I have a spare 71 rear that will solve the problem ;-)

Pete
Pete

Over the years, there have been many different methods for installing disk brakes onto the MGB
- ranging from a complete rear axle swap; to using disks and calipers from a variety of other production
cars (including VW Golf) via special adaptor plates; to installing specialty disk brakes from ATE, Hurst,
Bear Claw, etc..

You can usually tell if it's a brake conversion (instead of an axle swap) as the gear and axle housing will
still be MGB and it would be a simple matter of looking underneath another late model "B" to compare
it with.

As mentioned previously - your best bet is to take a pad (or a tracing or photo of one on paper), along
with any casting identification on the caliper, to your nearby friendly brake parts specialist...preferably
on a slow day. They should be able to identify it's silohette through one of their illustrated parts
catalogs.

Knowing the I.D. of the pad will really be helpful when it comes time to rebuild the caliper, too.
Daniel Wong

If you have a banjo type axle it could be that someone has gotten ahold of the MGA rear disc axle maybe? Im not sure what the measurements of the A axle are compared to the B. Maybe.
Jarrod Hills

Jarrod-
That's exactly what I had in mind. Apart from the crownwheel and pinion gears, the Hardy-Spicer tube-type wire wheel rear axle used on the early MGB was the same as that used for the late production MGA. The halfshafts for both are the same part number. The only external difference is that the Twincam rear axle has a different parking brake bracket, however, but that's not a particularly hard thing to change. The only real question relates to the wheel hubs, since the hubs used on the Twincam are unique to the Twincam. What I'm not sure about is the issue of the mounting studs on the rotor lining up with the holes on the wire wheel hub! It is possible to fit disc wheels, but this would require custom machinework and fabrication. Now if Jim Hughes will just respond we just might be able to narrow his search down.
Steve S.

Many thanks to all of you for your prompt and enlightening replys. Since putting this problem on the thread I have taken my 80 B to Knoxville, TN. to a MG shop for clutch, rear-end and BRAKE repairs. The shop owner was able to find pads that would fit. He said they came from a GM car, but didn't say which model. However, since the hand brake actuating lever is at the rear of the calipers, the stock hand brake cable is too short. I believe this problem can be solved without too much trouble.

As far as can be determined the rear axle is stock. No sign of any modifications such as drilling new holes, etc. Why the rear disc brakes? Maybe eventually the answer will pop up.

I also have a 78 B that I have been restoring since 99. It will be finished, except for body work and painting, this summer. It has taken a lot of hard work, but all of us who own these cars are well aware of that. Just about every day I ask myself why I'm wallowing in grease and dirt and the answer is ---I love it. While driving my 80B to Knoxville last week I was being passed by cars, trucks, motorcycles, and maybe a bycycle or two. I was enjoyably tooling along at 60 MPH asking who was having the most fun. I was.

This is a rather long blurp, but since I had so many responses I wantead to update you as much as possible. Again, many thanks and God bless to all.

Jim H.
Jim Hughes

This thread was discussed between 22/03/2002 and 29/03/2002

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